Re: [AMRadio] Breaker Info

[Mike Dorworth, K4XM]

There are so many " What if's" that only guessing works well. There are also
" Shunt Trip" breakers that break with say 50 mills to cut a 20 amp circuit.
Usually we think of a  breaker with a bi-metal strip heating and curling out
of the way at a certain temp caused by over current. Some even reset by
themselves!. The shut trip can be configured to trip if a overvoltage
condition occurs instead of over current. Even if a interlock door is
opened. I have a Heinemann that has extra coils that sense the current while
the contacts only open or close the circuit without regard to actual current
through contacts.Think it is called hydraulic, but I would bet there is no
oil.. Just another $0.01 worthless.. 73 Mike


Bi-metal is very interesting stuff. Since all metals have a different
thermal coefficient of expansion, two metals of different types bonded
together will curl when it gets hot or cold.Makes dandy breakers, and
thermostats!


- Original Message - 
From: "John Lawson" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio in the Amateur Service"

Sent: Monday, December 04, 2006 12:40 PM
Subject: Re: [AMRadio] Breaker Info


>
>
> On Mon, 4 Dec 2006, Jack Schmidling wrote:
>
> > I need some help understanding the main power switch on my powersupply.
> >
>
>
>Here is some info on current (no pun intended) Hienemann/Eaton
brakers -
>
>
> http://www.circuitbreakersinc.com/cirguide.pdf
>
>
> it's possible you have one of the "dual-rating" devices - with two
> different ranges that will trip the breaker.
>
>
>The diagrams show 38 different configs - a bit more tracing and/or
> voltmeter work might narrow this down some.
>
>
>Cheers
>
> John
> KB6SCO
> DM90fg
>
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Re: [AMRadio] Meter

[Mike Dorworth, K4XM]

the meter you describe is from a Johnson 6 and 2. It would need no repair.
it looked neat in the 6N2 mounted up side down.
- Original Message - 
From: "Rick Brashear" <[EMAIL PROTECTED]>
To: 
Sent: Friday, November 24, 2006 11:31 PM
Subject: [AMRadio] Meter


> I am in search of info on a meter.  The one I have is out of a Ranger
> and it works backwards!  I don't know if somewhere down the line it was
> zapped or what, but it works fine and is accurate as far as I can tell,
> however, it works from right to left instead of left to right.  The
> scale is correct for a normal reading meter so I know it wasn't made
> that way.  The needle rests on the right side of the meter.  It is an
> original Johnson Ranger meter.  Has anyone ever encountered such a
> thing?  Does anyone do meter repair?
>
> Thanks,
> Rick/K5IZ
>
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[AMRadio] Changes to band plan EST

[Mike Dorworth, K4XM]

 The changes in the R&O will take effect Friday,
December 15, at 12:01 AM EST, 30 days after its publication.
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Re: [AMRadio] Ranger Audio... the numbers

[Mike Dorworth, K4XM]

Audio transformers are rated for impedance step up or down. It is ,of
course, the square of the turns ratio. A simple check is a known voltage at
1 khz, say 1 volt, and read the voltages of the windings. The z can be
determined by applying a ac voltage at a frequency of interest and placing a
resistor in series with the winding and adjusting the resistance until the
same voltage is on both. The resistive value is equal to the z of the
winding. The peak voltage, RMS times 1.414 must equal the B plus, in this
case 550 volts or so in order to modulate 100 percent. Also, even thougth a
1614 is a healthy 6l6 a 6l6 is not a 1614. One (the 6L6) is rated by any
manufacturer at 360 volts MAX and the 1614 is 550 volts, hey, the same as
the Ranger Power supply, Imagine that! Also lest we forget the modulating
load is the B plus divided by the current. The RF tube load impedance is the
Voltage divided by TWICE the current. The tank values and operating Q
depends on operating at the designed value. Ditto the load the modulator
sees.
On z's of windings the transformer need not operate at the stated z, as long
as the ratios are correct. Too low of frequencies would not have enough iron
and too high would make it jump through the capacity instead of the iron.
But a 2 to 1 at say 6000 to 3000 ohms would work fine a 12000 and 6000
ohms..or 3000 to 1500 ohms. Transformers for light commercial service and
amateur service are rated for a certain amount of DC in the windings, these
can not be exceeded or the thing will become a magnet and not work.
Saturation, I think they call it!

Hope this hepls a little. 73 Mike




- Original Message - 
From: "Jack Schmidling" <[EMAIL PROTECTED]>
To: "Mike Dorworth, K4XM" <[EMAIL PROTECTED]>; "Discussion of AM Radio in the
Amateur Service" 
Sent: Saturday, November 18, 2006 10:14 AM
Subject: Re: [AMRadio] Ranger Audio... the numbers


> Mike Dorworth, K4XM wrote:
>
> > Ranger modulation Transformer
> >
> > 33 watts voice
> >
> > Primary 7083.8 ohms plate to plate. Red is ct.
> > Secondary 3571 ohms. Black is ct. 892 ohms each side to tridode grids.
>
> You lost me here.  The manual says 100 ohms and 28 ohms respectively
>
> > 1.9837 Z stepdown ( nominal 2:1)
> >
> > 1.4085 step down turns ratio..
>
> I guess we are talking z vs resistance.
>
> So, how does one measure the Z of a transformer?
>
> If I put a 1khz sig in one end should the amplitude drop by the z
> stepdown ratio?
>
> js
>

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Re: [AMRadio] Ranger Audio... the numbers

[Mike Dorworth, K4XM]

- Original Message - 
From: "crawfish" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio in the Amateur Service"

Sent: Friday, November 17, 2006 7:54 PM
Subject: Re: [AMRadio] Ranger Audio... the numbers


> Impedance at the plates is more than 50 ohms.

Some measurements:


Ranger modulation Transformer

33 watts voice

Primary 7083.8 ohms plate to plate. Red is ct.
Secondary 3571 ohms. Black is ct. 892 ohms each side to tridode grids.

1.9837 Z stepdown ( nominal 2:1)

1.4085 step down turns ratio.. hope this helps someone.. mike

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Re: [AMRadio] 220 volt AC Power Question

[Mike Dorworth, K4XM]

Jim I do not know the laws but all new dryers have four wire cords. Only the
old ones are three. The ground wire would need to be twice as big as either
hot wire. By the codes I don't think you can use a neutral for fault
current. At the box, the neutral and ground are tied together. Most stoves
and dryers are 220 and the third wire is for the fuse blowing function only
but there must be exceptions. Hope the electricians let you know exactly. 73
Mike

- Original Message - 
From: "Jim candela" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio in the Amateur Service"

Sent: Monday, October 30, 2006 8:09 PM
Subject: [AMRadio] 220 volt AC Power Question


>
>
> Hi all,
>
>I am building an amplifier that has a combination of 220 volt and 120
> volt transformers. The HV plate supply is 220V, and the rest is 120V. I
will
> be keying the plate supply. My 220V outlet has phase, phase, and ground.
> There is NO neutral. The outlet is not a GFCI outlet so ground current
will
> work, BUT.
>
>   The BUT here is whether this is legal with the National Electric Code?
> Before you say NO, consider the electric clothes dryer. These all run off
> 220V, and have 3 prong power cords. I have heard that in some dryers there
> are 120 volt loads (lights, and timer) as well as 220V (heater and motor).
> If this is true, then my approach must be OK so long as my power switch
uses
> a DPST switch and (double fuses)to insure everything is off when it is in
> the OFF position.
>
> Comments please...
>
> BTW, I do have a 240/120 autotransformer of suitable size (VA rating), but
> space does not permit it's use.
>
> Jim
> JKO
> --
> No virus found in this outgoing message.
> Checked by AVG Free Edition.
>
>
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Re: [AMRadio] 6L6 or 1614

[Mike Dorworth, K4XM]

Let me add that a 6L6GC is rated at higher voltage and I suppose the 5881
military 6L6 is rated for more volts and would make a dandy substitue for
the 1614.. 73 Mike


- Original Message - 
From: "uvcm inc." <[EMAIL PROTECTED]>
To: "'Discussion of AM Radio in the Amateur Service'"

Sent: Friday, October 27, 2006 3:37 PM
Subject: RE: [AMRadio] 6L6 or 1614


>
>
> Both will work in a Johnson Ranger and no doubt the 1614 is the better
> choice, but does anyone have facts as to the feasibility of using the
> 6L6?  I personally think the 6L6 works fine, but doesn't last long in
> comparison.
>
> Any thoughts?
>
> Thanks,
> Rick/K5IZ
>
> Try 6550 or KT88 used them for over 20 years never damaged or harmed any
> component on a ranger 1
> Brad Kb7fqr
>
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Re: [AMRadio] 6L6 or 1614

[Mike Dorworth, K4XM]

A 6L6 in any book is listed at 360 volts Maximum. The 1614 is listed at 550
volts ICAS and, of course, the unmodified Ranger uses 550 Volts DC on the
final and modulator. We once had a post that the 1614 is really only a
selected for high voltage service 6L6 and it sounds reasonable to me. In
fact, the 1614 is listed as a RF Transmitting tube in the RCA Transmitting
tube manuals but, alas, the 6l6 is not. Use what you got. 73 Mike
- Original Message - 
From: "Rick Brashear" <[EMAIL PROTECTED]>
To: 
Sent: Friday, October 27, 2006 3:32 PM
Subject: [AMRadio] 6L6 or 1614


> Both will work in a Johnson Ranger and no doubt the 1614 is the better
> choice, but does anyone have facts as to the feasibility of using the
> 6L6?  I personally think the 6L6 works fine, but doesn't last long in
> comparison.
>
> Any thoughts?
>
> Thanks,
> Rick/K5IZ
>
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Re: [AMRadio] Dow Key

[K4XM, Mike Dorworth]

> Okay... maybe I missed something the day they taught magnetism.  I have
> a Dow Key that sometimes stays energized with the source completely
> removed.  Not every time but sometimes.  It has a 115 vac coil and
> nothing else.  No capacitor across it, no nothing.  It's as if the coil
> is acting as a capacitor and retaining enough of the 115 vac to keep the
> armature of the relay engaged.


It's name is " residual magnetism" High quality relays have a tiny brass
screw in the center of the armature with an adjusting nut so that the
armature can never quite touch or get too close to the pole piece. You might
try a piece of scotch tape over the pole piece to keep it from getting too
close.. Mike

- Original Message - 
From: "Rick Brashear" <[EMAIL PROTECTED]>
To: 
Sent: Saturday, September 16, 2006 5:57 PM
Subject: [AMRadio] Dow Key


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Re: [AMRadio] Microphone assistance

[Mike Dorworth, K4XM]

. I was thinking of a transformer in the microphone case and the 9 foot cord
which goes against my grain. I know we can make any of them work. When I
hear AM radio guys talk about HighZ I think of a D-104 and it's ilk at about
5 megohms, this is high Z! When I hear 30K ohms I am thinking of a Hi-Z SSB
like Kenwood TS520s,Drakes and Collins. That is what they call high Z. Most
broadcast mics, I think are about 50 ohms ( dynamic types). I notice that a
Shure 515SB is rated at 150 ohms, actual is 170 ohms and is for use on 19 to
300 ohm inputs..I too like the mixer plan.. 73.. Mike
- Original Message - 
From: "John E. Coleman (ARS WA5BXO)" <[EMAIL PROTECTED]>
To: "'Mike Dorworth, K4XM'" <[EMAIL PROTECTED]>; "'Discussion of AM Radio in
the Amateur Service'" 
Sent: Thursday, August 31, 2006 5:40 PM
Subject: RE: [AMRadio] Microphone assistance


> You are correct Mike,
> One way to help with the cable capacitance trouble, if a XFMR is to
> be used to step up the voltage, is to put the XRMR close the input circuit
> or preferably in the speech amp chassis and incorporate a 3 pin XLR
> connector.  Run balanced low Z from the microphone to the XLR input and
> using the shield of the cable for just a shield and not common the audio
of
> the microphone.  The mixer is a good plan if available and may have other
> uses.

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Re: [AMRadio] Microphone assistance

[Mike Dorworth, K4XM]

The trouble with low z microphones is that some times


Once a Hi-Z mike sends it's signal out it needs a short low capacity cable
to keep from effectively shorting the highs. Putting a transformer in the
mike is ok as long as the cord is low capacity and short. The 9 foot cord
sounds like a disaster waiting to happen. The reason, I thought, for the
LowZ mics was so a long cable, 20, 30 40 50 feet would not suffer such
troubles. The idea of a mixer and then the Z conversion sounds good.. Just
another $0.02.. Mike

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Re: [AMRadio] Antenna Idea and lightning precautions

[Mike Dorworth, K4XM]

Motorola says the simple measure of placing a piece of pipe over the coax
where it enters the house and bending the coax sharply where it stops it's
downward run and enters the house is good. I KNOW that lightning goes in
straight lines and the few thousand amps on the coax would see the pipe as a
transformer with a single shorted turn that can handler thousands of amps
for long enough delay time for the juice to jump to ground . To help it
along. commercial installations strip the jacket off and wrap a copper strap
around the coax at the bend ( JUST BEFORE) AND CONTINUE ON DOWN WITH A
NUMBER 6 OR NUMBER 2 GROUND WIRE. The scrap of pipe, perhaps a foot long
need not be grounded it is merely a transformer turn that can " take it" a
very cheap insurance policy regardless of all the other really good advice
and opinion to be found on the sublect!  73 Mike

Re: [AMRadio] Antenna Idea and lightning precautions

[Mike Dorworth, K4XM]

I can see this is the beginning of a long thread since everyone has their
own ideas. In commercial work a sharpened spike above the thing to be
protected is to DRAW the lightning to a well insulated and very well
grounded ground system. This is to protect the equipment below it. To
dissipate,  the ball should be rounded like a car radio antenna to gently
discharge the corona.  We put up a series of 150 foot towers at work with a
21 foot stainless sharpened lightning spike above the tower top to draw the
lightning. All of our ( 92 each) microwave towers had a 3 or four inch
diameter sharpened brass rod 2 feet above the tip top of  the tower. It's
ground cable was insulated from the tower all the way down. Of course the
tower and all the guys were also grounded to the common ground. A dipole can
easily discharge static build up with a 100 k ohm resistor of at least 1
fourth watt. This keeps the system equalized. Lightning usually hit the
HIGHEST ( though noy always) spot, so if there are taller trees they would
get it first. I like insulated wire instead of bare since the damp wind will
not build up thousands of volts when it blows over..just before a storm. For
fun take the antenna connector and put in a mason jar and place near ground
and watch the 4 inch long blue firs just before a storm on a hilltop. A
Johnson Matchbox sounds like a fourth of July celebration if left connected.
I guess, in the end a direct strike is bad news in every case. Most of us
are really talking about big static discharges I think. A real strike will
blow every receptacle in the house out and the wire on on side of every
power cord will vaporize and the fuse box will be blown off the wall. Let
the tall trees take that!.. 73 Mike
- Original Message - 
From: "Jim candela" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Saturday, August 05, 2006 2:36 PM
Subject: [AMRadio] Antenna Idea and lightning precautions


>
>
> Hi All,
>
>I am contemplating putting up an inverted Vee antenna where the center
> point is above my house suspended with a 30' Lowes push up mast attached
to
> my roof with a tripod mast base made for roof mounting. This would make
the
> apex at almost 50', and with the trees around my home, the ends at about
> 30'. Other locations that I might have the antenna apex at will be densely
> surrounded by trees, and I am trying to avoid that.
>
>My question is about lighting concerns with this approach. I would have
> multiple 12 awg ground straps from the mast base to earth ground via
copper
> ground stakes at least 5' long. This would act as a counterpoise for the
> antenna, and provide a DC ground reference for the 30' mast. My fear is
that
> the antenna would attract a lightning hit (direct) and that would cause my
> home to burn up in a flaming fireball.
>
>Then I was thinking about how lightning rods work, and when done
> properly, don't lightning rods work by having a sharp point at the tip,
> where they bleed the static (a corona discharge) to prevent a lightning
> strike? If so, why can't I take a 1/8" stainless 8' whip with a point on
> top, mounted above the inverted Vee apex, and use that as a lightning rod?
I
> guess I'd need to beef up my ground wiring scheme just in case of a direct
> hit. Any suggestions?
>
>I am hoping for having more lightning protection with my antenna in
place
> over that of no antenna at all? Is this possible?
>
> Regards,
> Jim Candela
> WD5JKO
> --
> No virus found in this outgoing message.
> Checked by AVG Free Edition.
> Version: 7.1.394 / Virus Database: 268.10.7/409 - Release Date: 8/4/2006
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>

Re: [AMRadio] DC Load

[Mike Dorworth, K4XM]

In January 1950 CQ magazine page 20 the article " Licking the Regulation
Problem" by Joseph Saugier, Jr. W9KSQ describes a electronic bleeder
resistor , the 2500 volt 400 ma version used a pair of 211 tubes.At that
time 211 were the cheapest tubes in surplus.

- Original Message - 
From: "Don Merz" <[EMAIL PROTECTED]>
To: 
Sent: Wednesday, August 02, 2006 5:30 PM
Subject: [AMRadio] DC Load


> A local ham SK built himself a variable DC load which I recently found in
> the N3BM estate stuff. The ham was W3QNI. QNI worked for Western Electric
> and was a master builder. He must have died 10 or 15 years ago. I have one
> of his transmitters and it is almost a work of art. This "Variable DC
Load"
> is no different.
>
>

Re: [AMRadio] Re: WRL Globe King 500C rebuild

[Mike Dorworth, K4XM]

811A's take -4.5 volts bias @ 1500 volts and give about 340 watts audio
level. They will take 2000 volts OK since the am rating is 1250 volts ( 2500
volts peak). 9 volts is the standard for 2000 volts I think.The Viking 500
uses 811A at 2000 volt and OK by the tube manufacturer at that time. Since
the 572B is a 2750 volt tube and will give way over 500 watts audio I would
just use them since the transformer is adjustable and going to changed
anyway. That way the voltages can all be the same.Mod and final.  73, Mike

[AMRadio] Radio Handbook

[Mike Dorworth, K4XM]

> The latest and LAST is the 23rd edition. (1987) Bill Orr is SK. Try
E-Pay..
>
>
> - Original Message - 
> From: <[EMAIL PROTECTED]>
> To: 
> Sent: Friday, June 09, 2006 7:07 AM
> Subject: [AMRadio] Radio Handbook
>
>
> > I am looking for a recient copy of the Radio Handbook anyone know where
I
> > can find one? I think the latest edition is the 21st. ed. 73, Steve
> ve2swc
> >
>

Re: [AMRadio] PA set up using ant analyzer

[Mike Dorworth, K4XM]

- Original Message - 
From: "Edward B Richards" <[EMAIL PROTECTED]>
To: 
Sent: Thursday, June 08, 2006 5:48 PM
Subject: Re: [AMRadio] PA set up using ant analyzer


> Hi Dennis;
>
> I am having trouble resonating the plate tank on the linear amplifier I
> just built. When checking for resonance with a grid dip meter using a
> 5,000 ohm resistor from plate to ground, should the tubes (4-400 X 2) be
> in the circuit?




This is not Dennis but the answer is the tubes must be there or a capacitor
equal to the total output capacity of the tubes in their place. i.e.28 pf
( 14 each) for a pair of 813's check tube table for output cap. The analyzer
should show a 1 to 1 swr from the antenna looking in when it is resonated.
The grid dipper technique is differnet. You take the resonate plate load z ,
plate volts divided by 2 time plate current and divide by disired operating
Q, 10 or so for the input capacitor, with the tank cold disconnected. use a
capacity meter to set the C1 and then leave it alone, the output cap C2 is
the load z ( 50) divided by q, about 2. These give the x sub c value which
must be converted to capacity.  Then you tap ( short coil till the analyzer
shows one to one from the output jack). Hope this helps..For pi-network.
check ARRL handbook for pi-l. Mike

Re: [AMRadio] PA set up using ant analyzer

[Mike Dorworth, K4XM]

The resonate plate load is the same for any class C amplifier, plate voltage
divide by 2 times plate current. It is one half of the modulating inpedance.
It is the same for a 6V6, 6AQ5 or a pair of 4-1000's.. Mike

- Original Message - 
From: "uvcm inc." <[EMAIL PROTECTED]>
To: "'Mike Dorworth, K4XM'" <[EMAIL PROTECTED]>; "'Discussion of AM Radio'"

Sent: Sunday, June 04, 2006 11:12 PM
Subject: RE: [AMRadio] PA set up using ant analyzer


Does it matter the type of tube, 833 or 592 r
Thanks
Brad

-

Re: [AMRadio] PA set up using ant analyzer

[Mike Dorworth, K4XM]

- Original Message - 
From: "uvcm inc." <[EMAIL PROTECTED]>
To: 
Sent: Sunday, June 04, 2006 8:13 PM
Subject: [AMRadio] PA set up using ant analyzer


> Does anyone know what value resistor between the plate of and ground for a
> 833 and a 892r, so I can set up the tank using an antenna analyzer like a
> mfj 369?

The resistor value is determined (exactly) from the platevoltage divided by
2 times the plate current.. About 5000 ohms or so.

Re: [AMRadio] Shorting stick

[Mike Dorworth, K4XM]

I am certainly learning here. I always thought of a shorting stick as used
in 1 to 5000 watt transmitters (AM TRANSMITTERS) as a guide to put a well
grounded piece of thick braid on the hv points after every thing normally
done has been done to discharge any remaining stuff lurking about. The
grounded braid at the end of the "broomhandle, is millions of times more
conductive actually BILLIONS of more time conductive the wood. The wood
stored inside a power supply case is not creosoted or soaked in water. I
have no qualms about holding a ground strap  against a normally and supposed
NO VOLTAGE point as a last defense of my life with a three foot or so piece
of dry wood. Use a glass ten foot pole if you wish, I would like to be able
to see how a normal wooden broom handle will not function to guide the
ground point to the test points. It is better than most folks use. I have
seen plastic screw driver handles depended on for this. The broom handle is
a great improvement and way better than nothing. I think that if we as AM
ers take away from all this that it is just cheap insurance to make sure by
grounding supposed NO voltage points it will be worth while. 73 Mike


- Original Message - 
From: "John Wright" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Saturday, June 03, 2006 9:10 PM
Subject: Re: [AMRadio] Shorting stick


>
> I wouldn't use wood for an insulator.  Its insulation
> properties change drastically depending on the
> relative humidity.  I have seen telephone poles light
> up quite nicely with 10K volts on them.
>
> PVC pipe (the white stuff) is a good insulator.

Re: [AMRadio] Stock or modify? BC rig "value" -- Shorting Sticks

[Mike Dorworth, K4XM]

Yes. I would not want my life in the hands of an alligator, crocodile or
battery clip. Since you will always use it every time it is best to make it
permanent. That one time you don't could be you last time to EVER need it!
- Original Message - 
From: "Rick Brashear" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Friday, June 02, 2006 9:12 AM
Subject: Re: [AMRadio] Stock or modify? BC rig "value" -- Shorting Sticks


> That ought to work.  So, these "shorting sticks" were more or less
> permanently attached to the cabinet?

Re: [AMRadio] Shorting stick

[Mike Dorworth, K4XM]

On a BC-610 using a external VFO, just kill exicitation, ALL METERS fall to
ZERO, the B plus will go to 4000 VOLTS and if you have bypassed the
interlock and touch the link you will be GONE, Forget the meters! Trust the
stick!  I know!


- Original Message - 
From: "John E. Coleman (ARS WA5BXO)" <[EMAIL PROTECTED]>
To: "'Discussion of AM Radio'" 
Sent: Friday, June 02, 2006 10:11 AM
Subject: RE: [AMRadio] Shorting stick


> If you do things right,
> Power Down,
> Watch the HV meters fall down,
> Then - Apply the shorting stick,
> There won't be an arc.
>
> WA5BXO, John
>
>
>
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
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> AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
>

Re: [AMRadio] Shorting stick

[Mike Dorworth, K4XM]

Discharging is not the idea. If all is well it will NEVER discharge
anything. A nail with a good hooked ground strap in a broom handle is
perfect. This is to keep you from making a sudden trip to the hereafter
only. If it should ever actually be called on to work you will normally
holler out the name of the Christian Savior in a loud voice! This is why
folks in the business call them "Jesus Sticks!"
- Original Message - 
From: <[EMAIL PROTECTED]>
To: 
Sent: Friday, June 02, 2006 9:57 AM
Subject: [AMRadio] Shorting stick


> I always thought you had to discharge though a high value resistance to
avoid
> damaging arcs that would hurt the surface you were discharging through a
plasma
> arc.
>
> I do remember using a shorting stick in a job I had 20 years ago.
>
> Alan
>
>
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio@mailman.qth.net
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> AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
>

[AMRadio] -- Shorting Sticks

[Mike Dorworth, K4XM]

.  You are not allowed any mistakes with
> 3kv @ almost half an amp.

Half an amp? a well charged capacitor delivers way more than half an
amp. A 12 guage shell goes poof compared to a full cap. being discharged
with the Jesus Stick!

Switch to Safety!ABC..always be careful.

Re: [AMRadio] Ferroresonant transformer revisited

[Mike Dorworth, K4XM]

> > How hot is the darn thing -supposed- to get?


For your unit I don't know. I have used hundreds of SOLA Constant Voltage
Transformers, of the 250, 500, 1000, and 3000 watt versions. They were of
the CVH (harmonic neutralized..SQUARE WAVE) and the CVS (SINE wave type).
The 250 watt is impossible to touch in service even with no load. They will
remove skin but will work for over twenty years without fail. The 500
watters and the bigger ones being larger (having more mass) can be touched
but still run warm. What these things were for was to take a voltage of 90
to 140 volts ac and maintain it at exactly 120 volts. We used them for
lightning protection and they worked fine protecting what ever was plugged
in; radio equipment and test equipment in the racks. They all draw current
when not in use and therefor are a waste of electricity unless they are
actually supplying something. Protecting a EIMAC high dollar tube filament
would be a great use. We nailed them to concrete block walls vertically for
convection cooling. I worked with these things 38 years and don't remember
but one capacitor failing in one which was easily replaced and returned to
service. Hope this non-answer helps. 73 Mike

Re: [AMRadio] shunt

[Mike Dorworth, K4XM]

  If I'm not mistaken the BC-939 antenna coupler used with
> the BC-610 transmitter uses a 15 amp meter in the antenna output
> circuitry and the BC-610 is capable of only 400 watts carrier.

Again it is still I squared R so at a TWO OHM load and 15 amps you would
indeed have 450 watts. The way the BC-610 ran mobile is into a 15  foot whip
so the resistance could be perhaps as low as 2 ohms, negelecting ground loss
which is in series BUT the BC 610 is looking into a fifty ohm load into the
tuner and the meter should be looking at the  output.  mike

Re: [AMRadio] shunt

[Mike Dorworth, K4XM]

I squared R is 31,250 watts.  (25 amp). You are going to get the house
breaker before the ammeter pegs.  A nice 8 amp would handle 3200 watts and a
ten is handy for 5000 watts.

> 73,
> Rick/K5IZ
>
> Rev. Don Sanders wrote:
>
> >What are you planning to run on AM
> > if you need to go from 1250 watts to
> >21,250 watts? Or did you just get a job
> >with VOA.

Re: [AMRadio] antenna tuners transmision lines and more

[Mike Dorworth, K4XM]

- Original Message -
From: "Donald Chester" <[EMAIL PROTECTED]>
> I recall there was a Central Electronics rig that had a no-tune broadband
> output network with a tube type final.  They sealed the whole thing in
> something like epoxy, and gave no technical data on how it worked.

Yes but it was a patented device and the patent number was shown. I sent for
the patent disclosure and built the coil as presented. It worked perfectly
and I made measurements that showed it's own impedance to be 25 ohms and it
would easily match 25 to 100 ohms 2:1 SWR. Mine was for a single 813 final.
As I recall the network was in some ceramic that was nearly impossible to
open short of an A-Bomb and many wondered what was inside since no-tune was
a mystery at that time.. Mike

Re: [AMRadio] antenna tuners transmision lines and more

[Mike Dorworth, K4XM]

> Actually there are a number of commercially manufactured tube
> RF finals that DO indded use toroidal transformers.
> Dentron, for one example - they made a number of linear amps
> like that, and they were/are not alone.
>
The Alpha 374 had nothing but toroids. It might be remembered as the legal
limit amp that ran for months with a brick on the key.. I bet most all
Alphas are the same..Had 3 each 8874's..

Re: [AMRadio] antenna tuners

[Mike Dorworth, K4XM]

I was beaten to the door on this. Actually there is a spot up about one
third wavelength that is 100 ohms,for a perfectly resonate radiator. So it
would be 2 to one and a dandy perfect resonate  vertical with over a hundred
radials is about 35 ohms so the magical 1 to 1 is nothing magical. I would
beg everybody to read at least two chapters of Walt Maxwell's book "
Reflections". The right SWR for the wrong reason, and the Wrong SWR for the
right reason. The first I would call dummy load syndrome and the second as
above. This stuff is not opinion or politics it is pure science and can be
tested at YOUR house.. 73 Mike


- Original Message -
From: "Gary Schafer" <[EMAIL PROTECTED]>
To: "'Discussion of AM Radio'" 
Sent: Thursday, April 20, 2006 10:12 PM
Subject: RE: [AMRadio] antenna tuners


> This is another tidbit to keep in mind for those that still may think that
> an antenna has to be resonant to give 1:1 swr.
>
> A dipole antenna rarely is 50 ohms at resonance. It is very dependent on
> height above ground as to what impedance it presents at the feed point. It
> can range anywhere from below 30 ohms to above 70 ohms.
>
> So if you cut your antenna so that you have 1:1 swr at the transmitter end
> of the coax, the antenna is probably not tuned to resonance! You have
> detuned the antenna to change its impedance that the coax sees.
>
> Only rarely does a resonant antenna turn out to be 50 ohms.
>
> 73
> Gary  K4FMX
>
>

Re: [AMRadio] Correct tuning procedure

[Mike Dorworth, K4XM]

- Original Message -
From: "gwt" <[EMAIL PROTECTED]>
To: "AM Radio List" 
Sent: Thursday, April 20, 2006 6:07 PM
Subject: [AMRadio] Correct tuning procedure


> Hi,
> I'm wondering if some "guru" out in AM land can set me straight on how
> to properly tune a long wire using an "L" network or a "T" network tuner
> configuration. I have two
> long wires, each 285 feet long. They feed directly into my shack, where
> the tuner is located.
> I have a tuner that I built using a BC610 external tuner roller inductor
> and two BC610 variable capacitors, allowing me to use either method to
> tune my long wires.
> Question #1:
> Which is the best method to tune with? An "L" network or a "T" network?
> Question #2:
> To reduce the losses coming from the tuner, which is best to use? The
> least amount of
> inductance you can use to get a match, or the highest inductance to get
> a match?
> Question #3:
> Which method will most likely give the widest bandwidth without re
> adjustment?
>
> Thanks,
> George KE4HJ


  http://fermi.la.asu.edu/w9cf/articles/tuner/tuner.html
First go read this article. To answer the questions the "L" is  best by a
factor of 7. The L must be turned around to match either high or low but is
always the most efficient. The "T" is just two "L's" back to back. This
gives many chances to mistune. The correct tuning of the "T" is to set the
capacitors at maximum capacity and use the inductance that lets the match be
with maximum capacity, especially on the output side. i.e. the first dip
from the minimum side of the coil. The loss is only in the coil and  lots of
loss will widen the match by placing resistance in parallel. In the split
stator parallel coil tuner it is the opposite. Use the minimum capacity and
max coil for lowest Q which will allow the match. Hope this helps. After you
study the link story from QEX you will be able to do your own math and
measurements and take NO One's word..There is so much misinformation around.
. If you don't have Walt Maxwell's "Reflections" get it!.. 73 Mike

Re: [AMRadio] Re: Triode connecting 803's for a Modulator

[Mike Dorworth, K4XM]

The question was: how to do it with 803's The source listed is the Bill Orr
Handbook. He calls all of the circuits Zero Bias Tetrode Modulators. Even
the 807 and 813 in TRIODE connection is shown with the beam forming plates
grounded. The circuit is about zero bias, and no screen supply. The 803's
are shown since they were one very plentiful and cheap. My understanding of
the suppressor bias is that it allows the plate voltage to swing down to it
and increases both headroom ( work space) and increases efficiency. 510
watts output with clean audio is not bad for zero bias and no screen supply,
The suppressor voltage is actually the voltage used on the speech amp plates
which is says can be 6B4's or most any 8 watt speech amp. He does say these
tube require more drive than 813's but since the then price for a new one
was four dollars a tad more drive make little difference. In W6SAI's 14th
edition Radio Handbook page 595, chapter 27-3. Seybold's patent no.
2,494,3176 explains the use of  beam tetrodes in TRIODE connection to use no
bias and no screen supply. The drive is applied to the screens and a
resistor to the control grid. The 15th Edition  says the grid resistors are
not needed for the 803 or 813 tubes.. Hope this helps..

Mike

Re: [AMRadio] Re: AM filter for an SB-300

[Mike Dorworth, K4XM]

- Original Message -
From: "Jose HF Silva" <[EMAIL PROTECTED]>
To: 
Sent: Sunday, April 09, 2006 7:21 PM
Subject: [AMRadio] Re: AM filter for an SB-300


> What about DSP or SDR?
 The front end IF Filter establishes the overall bandwidth, the DSP would
Narrow that down after the first filter..  Mike

Re: [AMRadio] Triode connecting 803's for a Modulator

[Mike Dorworth, K4XM]

No, he had the screen and control grid strapped and fed. The supressor was
biased in the center tap of the driver transformer with the voltage
indicated. Mike
- Original Message -
From: "Donald Chester" <[EMAIL PROTECTED]>
To: 
Sent: Sunday, April 09, 2006 3:47 PM
Subject: Re: [AMRadio] Triode connecting 803's for a Modulator


>
>
> >From: "Mike Dorworth, K4XM" <[EMAIL PROTECTED]>
>
> >On page 662 of the 15th Edition of  RADIO HANDBOOK by Editor and
Engineers.
> >Paragraph 30-8 the use of 803 in triode connection is fully discussed. A
> >schematic (figure 20)  shows 2500 volts at 18000 ohm plate to plate being
> >driven by a 8 watt speech amplifier through a Stancor A-4761 Class B
driver
> >transformer set for 2:1 Ratio. Eg-g =170 volts
> >Driving power 7-8 watts
> >Resting current = 50 mA.
> >Power output = 510 watts
> >Supressor volts = 280-340 volts
> >
> >A Chicago CMS-3 was used for the output transformer..
>
>
> I assume all three grids simply strapped together.  Is that correct?
>
> In some circuits with triode-connected tetrodes, particularly the 807, the
> screen grids are driven directly with the audio, and a resistor is placed
> between the screen and control grids.
>
> Don k4kyv
>
>
>
> ___
>
> This message was typed using the DVORAK keyboard layout.  Try it - you'll
> like it.
> http://www.mwbrooks.com/dvorak/
> http://gigliwood.com/abcd/
>
>
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio@mailman.qth.net
> AMfone Website: http://www.amfone.net
> AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
>

Re: [AMRadio] Triode connecting 803's for a Modulator

[Mike Dorworth, K4XM]

- Original Message -
From: "Bob Deuel" <[EMAIL PROTECTED]>
To: 
Sent: Sunday, April 09, 2006 11:52 AM
Subject: [AMRadio] Triode connecting 803's for a Modulator


> I have a bunch of 803's. In the past, I have seen modulator articles
> featuring triode connected 813's. Physically, the 803 also looks like it
> would be a good candidate for the same application. Has anybody tried
triode
> connecting 803's for a modulator? If so, what were the design parameters
did
> you used? Tnx, Bob K2GLO

On page 662 of the 15th Edition of  RADIO HANDBOOK by Editor and Engineers.
Paragraph 30-8 the use of 803 in triode connection is fully discussed. A
schematic (figure 20)  shows 2500 volts at 18000 ohm plate to plate being
driven by a 8 watt speech amplifier through a Stancor A-4761 Class B driver
transformer set for 2:1 Ratio. Eg-g =170 volts
Driving power 7-8 watts
Resting current = 50 mA.
Power output = 510 watts
Supressor volts = 280-340 volts

A Chicago CMS-3 was used for the output transformer..

Re: [AMRadio] 10 Meter AM Frequencies

[Mike Dorworth, K4XM]

From: "Theo Bellamy"

>
> I seem to remember that about 20 years ago some folks were converting 23
> channel CB rigs to use on 10 meters (by legal hams, of course). I think
they
> were just changing four of the xtals in the xtal synth circuit and ending
up
> with 23 channels in the 10 meter band. At the time I think there was some
> sort of agreed upon scheme so everyone was ending up on the same 23
> frequencies. Does anyone know what these are?


I sure don't know, but it was written up in the QST magazine with conversion
articles. Should have been in the late seventies. I might find it
accidently, but have no clue where to look right now. Mike
- Original Message -

Re: [AMRadio] Modulator design needed

[Mike Dorworth, K4XM]

6146 AB-1, 500 volts, 75 watts, 600 Volts, 95 watts, 750 Volts, 120
watts..

I thought the original question was to modulate a Johnson 6N2 which uses a
5894. Usually one uses the same Plate supply for the final as the modulator.
The 6146 gives way too much power for the voltage rating the 6N2 would use,
450-600 Volts. The AB-1 807 or some of the hotter 6L6 versions such as 6L6GC
seem more in the same voltage line to give the power needed.

The Viking II could do the whole job with a Ceramic 4 pole, 2 position
switch as shown in Bill Orr's 14 Edition Handbook (his First) It was mounted
on the rear apron along with a 3 lug terminal strip.

In the older 12th Edition (Editors and Engineers) there is shown a phase
inverter driving 6V6's and also one driving pair 813. A 6C4 in the former
and a pair of 6SJ7's in the later case. On the AM Forum Archives there is a
pair of 4-400's driven in AB-1 by a pair of 2E26. Google N9FOY and click on
modulator. Circuits from 6AQ5, 6V6, 807, 6146, 813, 4-400 all published and
none using driver transformers shows this is an OK way to go for most any
power level.

Mike

Re: [AMRadio] Modulator design needed

[Mike Dorworth, K4XM]

807 in class AB1 at 400 volts 36 watts, 500 volts 46 watts, 600 volts 56
watts and 750 volts 72 watts.
Usually subtract 10 to 15 percent for transformer losses etc.
 Almost a perfect match for the 6N2 at any voltage used.. Mike


> Just remember if you are going to use a tube phase inverter rather than a
> driver transformer the modulator tubes need to be run in AB1 and not AB2.
> You can't run any grid current without a driver transformer.
> This leaves out 807's as modulators as you can't get very much power out
of
> them in AB1 but they are fine in AB2 as they are used in most rigs. Dx100
> etc.
>
> 73
> Gary  K4FMX

Re: [AMRadio] DX60 modulator chassis ready to go

[Mike Dorworth, K4XM]

The circuit is a patented design and appears in the Bill Orr Handbooks, The
CQ Mobile handbooks and others. The circuit is class B and is suitable to
the KW level with 813's and other large tubes. The driving power is low but
the voltage is higher. Also the Jones VHF handbook has several examples of
this circuit , perhaps the exact one you have. Mike
- Original Message -
From: "John Lyles" <[EMAIL PROTECTED]>
To: 
Sent: Saturday, March 18, 2006 5:55 PM
Subject: [AMRadio] DX60 modulator chassis ready to go


> This modulator is not exactly like the 1952 nor the 1959 ARRL HB 807
modulators. It appears to be a class B modulator, > Has anyone seen this
particular design commercially made years ago, or in any articles? It
appears quite compact, and with the cathode followers to the 807s, reminds
me of the audio lineup of a Gates BC1G, with 807s driving 833s that way.
>
>

Re: [AMRadio] Amplifier to use with my DX-60

[Mike Dorworth, K4XM]

 YES,in fact he could. 100 watts carrier or 80 watts carrier. The power
supply is the limiting factor here. The SB200 with a big fan and an external
power supply could actually run 160 watts carrier. The word Max is actually
maximum. The wimpy supply holds it to about 80 watts. You might like the
smell of hot tar and burned kraft paper! I would stick to 80 watts or there
abouts and check the transformer with the " can I hold a finger full on it
for 3 full seconds" test.. Mike

> If I understand these responses this all boils down to answer Alan's
> original question and that is that a SB-200 would be ok with the DX-60 at
> the DX-60's max output . Correct?
>
> Tom K3TVC

>An SB-200-230 seems to be a Class B amp. There for it only conducts on
the
> >positive going cycle. I don't mean to sound silly, but someone told me I
> >could run this in SSB Mode using AM input from my DX-60, I run 100 Watts
> >carrier for 400 Watts peak, now that makes sense.
> >

Re: [AMRadio] Amplifier to use with my DX-60

[Mike Dorworth, K4XM]

YUP. The two things are the tubes and the power supply.. One half
dissipation is MAX.. you are using 800 watt tubes so 400Watt carrier is max.
The Thunderbolt has a real power supply, so, sure 300 watts is fine.Since
SSB is 25 to 30 percent average of peaks the manufactures can squeeze in
small supplies for voice or CW service. Ever make you wonder that they might
allow 2500 watts input SSB but only 400 for RTTY. AM and RTTY separates the
Men from the boys.. Mike
- Original Message -
From: "Dale Smith" <[EMAIL PROTECTED]>
To: "Mike Dorworth, K4XM" <[EMAIL PROTECTED]>; "Discussion of AM Radio"

Sent: Thursday, March 16, 2006 5:43 PM
Subject: Re: [AMRadio] Amplifier to use with my DX-60


> How about a Johnson thunder bolt is 300 watt carrier ok ? I hope so
> cause that is what I have been doing
>  The transformer in there is twice as big as my swan mark 1.
>  thanks ..de/dale/ka5who
>

Re: [AMRadio] Amplifier to use with my DX-60

[Mike Dorworth, K4XM]

Short answer. The SB200 uses a pair of 572B/T160L rated at 160 watts each.
AM Linear  output can not be more than one half of total dissipation. The
power supplies are usually rated for continous service (AM) at 25 percent of
the peak. For SB220 a 400 watt transformer is used for 2000 watts pep input.
The SB200 is rated at 1200 watts pep input and would have about a 300 watt
transformer. If the supply were strong enough the SB200 could run 160 watts
carrier. Best to stick with one half of that..80 watts. For the SB220, L4B,
TL922A best to stick with 250 watts carrier, or less. The answer below is
exactly correct except for the tubes in the SB200.. The SB230 uses a
conduction cooled 8873 with about 300 watts dissipation, 80 watts carrier
would probably cook it in short order because of the non-cooling system heat
load. 73 Mike
- Original Message -
From: "Donald Chester" <[EMAIL PROTECTED]>
To: 
Sent: Thursday, March 16, 2006 4:48 PM
Subject: RE: [AMRadio] Amplifier to use with my DX-60


>
>
>
> >From: Alan Beck <[EMAIL PROTECTED]>
>
> >I would like to use a cheap am with my DX-60.
> >
> >An SB-200-230 seems to be a Class B amp. There for it only conducts on
the
> >positive going cycle. I don't mean to sound silly, but someone told me I
> >could run this in SSB Mode using AM input from my DX-60, I run 100 Watts
> >carrier for 400 Watts peak, now that makes sense.
> >
> >What does not make sense is how do I get the other side of the wave
> >form The Tank??? I guess the tank.
> >
>
> The linear will work on AM as long as you don't exceed the peak power
output
> rating.  Exceeding the peak output rating will cause the signal to
flat-top,
> distort and splatter.
>
> Another thing to watch for is the plate dissipation of the tubes.  If I
> recall correctly, the SB-200 series uses a pair of 3-500Z tubes in the
> final.  That means you have 1000 watts of plate dissipation available.
> Running AM linear @ 100% modulation will give carrier output efficiency of
> about 30%.  So you could run maximum 1500 watts DC input to those tubes,
> with 500 watts carrier output, and 1000 watts dissipated by the tubes.
With
> modulation, the tubes will actually cool down slightly, since the DC input
> will not vary, but the amplifier will deliver sideband power in addition
to
> carrier power output.  So some of the input power will be converted to rf
in
> the sidebands instead of heat in the tube plates.
>
> But you also have to be careful with the power supply.  AM runs at 100%
duty
> cycle, so the power supply in the amplifier may not be rated to run 1500
> watts continuous duty.  After a few minutes, the power transformer may
> overheat.  In that case you will have to run it at reduced power.  But be
> careful that the plate efficiency does not exceed about 33%.  If you run
it
> at too high plate efficiency, it will not leave you enough headroom to
> accomodate the positive peaks, and flat-topping/distortion/splatter will
> result.
>
> Don't worry about the missing half of the rf cycle.  It works with AM
> exactly the same way as it does with SSB.  Since the amplifier is single
> ended and not pushpull, the missing half of the rf cycle is filled in by
the
> "flywheel effect" of the rf tank circuit.
>
> In summary, with class-B linear AM operation, the final will run about 33%
> carrier efficiency.  The peak efficiency on modulation peaks will be about
> double that, 67%.  Two-thirds of the DC input to the final will be
> dissipated as heat in the plates of the tubes under carrier-only, no
> modulation conditions.  That means the carrier output will be one half the
> plate dissipation of the tubes.  The peak power output should be about 4
> times the resting carrier output at 100% modulation, if flat-topping is to
> be avoided.
>
> Linear amplifier AM operation dates back to the very earliest days of
radio.
>   The earliest high power broadcast stations used it.  It was used for
years
> before anyone figured out how to run audio amplifiers in class-B.  Before
> then, the only kind of high level plate modulation that was used employed
> class A audio amplifiers, usually the "Heising" circuit but sometimes
series
> modulation was used.  Both those systems ran at lower ovarall efficiency
> than linear rf amplification.  Therefore, AM linears were used long before
> high level plate modulation for high powered AM transmitters.
> _
>
> This message was typed using the DVORAK keyboard layout.  Try it - you'll
> like it.
> http://www.mwbrooks.com/dvorak/
> http://gigliwood.com/abcd/
>
>
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio@mailman.qth.net
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> AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
>
>

Re: [AMRadio] Morrow Equipment

[Mike Dorworth, K4XM]

Oh yes indeed. You will find some interesting circuitry that is all in
parallel. Such as a bad capacitor for , say ten meters is killing you on
forty. What a thrill it was to take the rack loose and get in there and pull
the bad mica capacator out and re assemble. Thankfully I had to just do it
once. You will also find interesting the double knot and figure eight loops
that Collins used to hold each part in place. Must have been in case it was
used in aircraft or combat tank service.A solder sucker, solder wick and
couple dental picks and a good magnifing glass and some double jointed
physical exercises will show you the neat way they attach each part.Lotsa
LUCK.. 73 Mike
- Original Message -
From: "DAVID O'NEILL" <[EMAIL PROTECTED]>
To: "'Mike Dorworth, K4XM'" <[EMAIL PROTECTED]>; "'Discussion of AM Radio'"

Sent: Wednesday, March 15, 2006 5:53 PM
Subject: RE: [AMRadio] Morrow Equipment


> I HAVE A 32V3,IT ONLY WORKS ON 80 MTRS.DID YOU EVER WORK ON THE DOUBLER
> STAGE?ALL THE CAPS AND RESISTORS ARE UNDER THE BAND SWITCH.
>
> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Mike Dorworth,
> K4XM
> Sent: Wednesday, March 15, 2006 3:28 PM
> To: Discussion of AM Radio
> Subject: Re: [AMRadio] Morrow Equipment
>
> MY 32V3 includes the cabinet, works real good. Will let go for $4999.99
> plus
> first class postage from Georgia..
>
> As a bonus, the 32V2 Collins supplied manual will be included for only
> $74.99 extra.,with purchase. So as not to forget, order before midnite
> tonight.. Operators are standing by.73 Mike
>
>
>
> >
> > I would also offer a very clean 32V3 for $5000.00,
> > but I gave the cabinet away to someone.
> >
> > Brett
> > N2DTS
>
>
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio@mailman.qth.net
> AMfone Website: http://www.amfone.net
> AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
>
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio@mailman.qth.net
> AMfone Website: http://www.amfone.net
> AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
>

Re: [AMRadio] Morrow Equipment

[Mike Dorworth, K4XM]

MY 32V3 includes the cabinet, works real good. Will let go for $4999.99 plus
first class postage from Georgia..

As a bonus, the 32V2 Collins supplied manual will be included for only
$74.99 extra.,with purchase. So as not to forget, order before midnite
tonight.. Operators are standing by.73 Mike



>
> I would also offer a very clean 32V3 for $5000.00,
> but I gave the cabinet away to someone.
>
> Brett
> N2DTS

Re: [AMRadio] FM transmitter

[Mike Dorworth, K4XM]

Yup. He is talking about rebroadcasting hambands to hambands for HIMSELF..
Permitted under aux stations in FCC rules.. Mike
- Original Message -
From: "Warren" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Friday, March 03, 2006 5:32 PM
Subject: Re: [AMRadio] FM transmitter


> Is it not against regulations to broadcast music etc. on the HAM Bands?
>
> Warren
>
>
> - Original Message -
> From: "Rev. Don Sanders" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>; "Discussion of AM Radio"
> 
> Sent: Friday, March 03, 2006 10:14 AM
> Subject: Re: [AMRadio] FM transmitter
>
>
> > Better yet, set a 2 meter hand held to low power and feed receiver audio
> > into the mike jack and use another hand held to listen. I do this on
> > simplex
> > freq 146.55 and can go 3 to 400 feet with no problem monitoring the net
> > freq
> > or dxpedition freq.
> >
> > Healthfully yours,
> >  DON
> > - Original Message -
> > From: "Brian Carling" <[EMAIL PROTECTED]>
> > To: "Discussion of AM Radio" 
> > Sent: Friday, March 03, 2006 7:26 AM
> > Subject: RE: [AMRadio] FM transmitter
> >
> >
> >> Yipes - for $399.00 it better be DARN good, LOL!
> >>
> >> On 2 Mar 2006 at 21:53, Bob Peters wrote:
> >>
> >> > The best FM xmtr I have used is from Broadcast Vision in Ca. They are
> >> > used in health clubs all over the USA. A little costly but work well.
> >> > Are in Sterol and digital. The Crane does not work well. The Ramsey
is
> >> > very expensive..
> >> >
> >> > Bob W1PE
> >> >
> >> > -Original Message-
> >> > From: [EMAIL PROTECTED]
> >> > [mailto:[EMAIL PROTECTED] On Behalf Of Jim Miller
WB5OXQ
> >> > Sent: Thursday, March 02, 2006 9:28 PM
> >> > To: Discussion of AM Radio
> >> > Subject: Re: [AMRadio] FM transmitter
> >> >
> >> > Get some wireless speakers.  They come with a small 900mhz
transmitter
> >> > and
> >> > usually work up to 150' though they claim 300.  Around $60 a pair at
> >> > radio
> >> > shack
> >> > - Original Message -
> >> > From: "Donald Chester" <[EMAIL PROTECTED]>
> >> > To: 
> >> > Sent: Thursday, March 02, 2006 4:40 PM
> >> > Subject: [AMRadio] FM transmitter
> >> >
> >> >
> >> > >
> >> > >
> >> > >>>Hope they don't measure the FM broadcast transmitter I have,
> >> > >>>so I can listen while doing stuff around the house and yard
> >> > >>>with a walkman, its over a watt I think...
> >> > >
> >> > > What kind of FM transmitter do you use?  I have been looking for
> >> > something
> >> > > so I can use to feed streaming audio from my desktop computer to
all
> >> > the
> >> > > FM radios on my property, so I don't have to sit in front of the
> >> > computer
> >> > > to listen.
> >> > >
> >> > > I ordered one of the little FM stereo xmtrs from C Crane.  It had
> >> > > good
> >> >
> >> > > synthesised frequency stability, but the audio was distorted and it
> >> > had a
> >> > > range of about 35 feet.  I need good solid coverage within a radius
> >> > > of
> >> > at
> >> > > least 100 feet.  I had intended to experiment with an external
> >> > > antenna
> >> >
> >> > > with the thing, but it crapped out before I could do that.  They
> >> > refunded
> >> > > my money.
> >> > >
> >> > > I think Ramsey sells kits, but I have heard they are pieces of
crap.
> >> > >
> >> > > Don
> >> > > k4kyv
> >> > >
> >> > > ___
> >> > >
> >> > > This message was typed using the DVORAK keyboard layout.  Try it -
> >> > you'll
> >> > > like it.
> >> > > http://www.mwbrooks.com/dvorak/
> >> > > http://gigliwood.com/abcd/
> >> > >
> >> > >
> >> > > __
> >> > > AMRadio mailing list
> >> > > Home: http://mailman.qth.net/mailman/listinfo/amradio
> >> > > Help: http://mailman.qth.net/mmfaq.html
> >> > > Post: mailto:AMRadio@mailman.qth.net
> >> > > AMfone Website: http://www.amfone.net
> >> > > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
> >> > >
> >> > >
> >> > >
> >> >
> >> >
> >> > __
> >> > AMRadio mailing list
> >> > Home: http://mailman.qth.net/mailman/listinfo/amradio
> >> > Help: http://mailman.qth.net/mmfaq.html
> >> > Post: mailto:AMRadio@mailman.qth.net
> >> > AMfone Website: http://www.amfone.net
> >> > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
> >> >
> >> > __
> >> > AMRadio mailing list
> >> > Home: http://mailman.qth.net/mailman/listinfo/amradio
> >> > Help: http://mailman.qth.net/mmfaq.html
> >> > Post: mailto:AMRadio@mailman.qth.net
> >> > AMfone Website: http://www.amfone.net
> >> > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
> >> >
> >>
> >>
> >> __
> >> AMRadio mailing list
> >> Home: http://mailman.qth.net/mailman/listinfo/amradio
> >> Help: http://mailman.qth.net/mmfaq.html
> >> Post: mailto:AMRadio@mailman.qt

Re: [AMRadio] 6BG6 ad

[Mike Dorworth, K4XM]

Maximum voltage for the 6L6 is 360 volts. Fot the 1614, it is 500 volts.
That is why the ranger, which uses 500 volts or a bit more uses the 1614
instead of the cheaper 6L6. The 1614 is RF rated as a transmitting tube
while the 1614 is not. A 6L6GC is a pretty close relative.. My $0.02..Mike
- Original Message -
From: "W5OMR/Geoff" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Wednesday, March 01, 2006 8:04 AM
Subject: Re: [AMRadio] 6BG6 ad


> Jim candela wrote:
>
> >Hmmm, Well it seems like the ads claim is true, verified by Mahlon, K4OQ.
In
> >that case I reiterate, this is "one heck of a deal". Try pricing the
6L6GC
> >from any source NOS or new, and compare. How many AM rigs use the 6L6 as
> >modulators?
> >
> >Johnson Ranger (is this correct?)
> >1614
> >7027
> >
> >How many others?
> >
> Yogie/KC5MIP had a Temco that used (4) 6L6's in the Modulator stage.  I
want to say it had a pair of 807's in the final, but I don't remember,
exactly.
>
>
> Ronnie/K5WLT built a modulator for his Knight Kit T-50, just after he
> graduated up from being a Johnny Novice, to General.  That's an
> interesting modulator, in that it uses a pair of 6L6's and was built
> from a Popular Elextronics magazine article, from back in the
> mid-to-late 50's.  One of those 6L6's is apparently slightly
> microphonic.  He can take the plastic handle of a screwdriver, hit the
> metal 6L6 and the tube 'rings' like a bell.  Ronnie has had so much fun
> with that rig, running a single 807, modulated by a pair of 6L6's... and
> has worked all over the country with it.
>
> I, myself, have plugged in 6L6's into the Ranger, and Rager II I had,
> back before I got the titanic.
>
> I've got an old audio amp here, that I got from John/W5MEU that runs
> either a pair, or 4, in p-p paralell.
>
> 6L6's are populare everywhere.  And, while the engineers mght have
> decided to use either 1614's in the Rangers, or 7027's in the Ranger
> II's, I couldn't tell a nickles worth of difference in the rigs that I
> had, between those tubes, and the 6L6.
>
> Just my .02c.
>
> Do I get change? ;-)
>
> --
> 73 = Best Regards,
> -Geoff/W5OMR
>
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio@mailman.qth.net
> AMfone Website: http://www.amfone.net
> AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
>

Re: [AMRadio] 1930's Old Buzzard Open Rack TransmitterFinallySeestheAirwaves! (Long)

[Mike Dorworth, K4XM]

811/812 CCS phone dis is 27 watts with 82 watts output.

811/812 ICAS phone dis is 40 watts, with 120 watts output

811A/812A CCS Phone dis is 30 watts, with 85 watts output

811A/812A ICAS Phone dis is 45 watts, with 130 watts output.

Per RCA Transmitting tube manuals..Sadly, page 21 is missing from my Taylor
Catalog.
 Taylor did not use ICAS Ratings to my knowledge.
 RCA introduced those with the 1941 Tube Guides..

 The 1939 ARRL handbook, page 80 shows the phone ratings  for the T-55 as
1500 volts and 150 plate mills.Peak power output of 652 watts and a carrier
power of 168 watts..With the input of 225 watts and a output of 168 watts,
then the CCS Phone dissapation would have been 57 watts.  Mike


From: "Brett gazdzinski" <[EMAIL PROTECTED]>
To: "'Discussion of AM Radio'" 
Sent: Tuesday, February 21, 2006 10:44 PM
Subject: RE: [AMRadio] 1930's Old Buzzard Open Rack
TransmitterFinallySeestheAirwaves! (Long)


> The T55 has 55 watts of plate dis, and gives 170 watts out?
> The 812A has 65 watts of plate dis and gives 130 to 150 watts out?
>
>

Re: [AMRadio] 1930's Old Buzzard Open Rack TransmitterFinallySeestheAirwaves! (Long)

[Mike Dorworth, K4XM]

811/812 CCS phone dis is 27 watts with 82 watts output.

811/812 ICAS phone dis is 40 watts, with 120 watts output

811A/812A CCS Phone dis is 30 watts, with 85 watts output

811A/812A ICAS Phone dis is 45 watts, with 130 watts output.

Per RCA Transmitting tube manuals..Sadly, page 21 is missing from my Taylor
Catalog.
 Taylor did not use ICAS Ratings to my knowledge.
 RCA introduced those with the 1941 Tube Guides..

 The 1939 ARRL handbook, page 80 shows the phone ratings  for the T-55 as
1500 volts and 150 plate mills.Peak power output of 652 watts and a carrier
power of 168 watts..With the input of 225 watts and a output of 168 watts,
then the CCS Phone dissapation would have been 57 watts.  Mike


From: "Brett gazdzinski" <[EMAIL PROTECTED]>
To: "'Discussion of AM Radio'" 
Sent: Tuesday, February 21, 2006 10:44 PM
Subject: RE: [AMRadio] 1930's Old Buzzard Open Rack
TransmitterFinallySeestheAirwaves! (Long)


> The T55 has 55 watts of plate dis, and gives 170 watts out?
> The 812A has 65 watts of plate dis and gives 130 to 150 watts out?
>
>

Re: [AMRadio] 1930's Old Buzzard Open Rack Transmitter Finally SeestheAirwaves! (Long)

[Mike Dorworth, K4XM]

811/812 are 6.3 volt filament, the T-55 is 7.5 volts..otherwise similar to
the 811 NOT A.. Mike
- Original Message -
From: "Brett gazdzinski" <[EMAIL PROTECTED]>
To: "'Discussion of AM Radio'" 
Sent: Tuesday, February 21, 2006 4:08 PM
Subject: RE: [AMRadio] 1930's Old Buzzard Open Rack Transmitter Finally
SeestheAirwaves! (Long)


> What is the difference between a T55 and an 812/812A?
> I know a V70D is good for more power, but has different filament
voltages...
>
> I think I have some T55 tubes, never knew they would do as 812
substitutes.
> I thought they looked lower power (smaller plates).
>
> The amount of turns on the link coil impacts what you can load up to a
LOT.
> I made my own link for the 812a rig, and had to try various link turns
> before
> it loaded up right.  I have the series cap also, and that does change how
> the
> rig loads up, but does not seem to change the efficiency or anything else.
>
> At 1500 or more volts, I run the 811a's at zero bias, the 812A's run 340ma
> cathode current, 70 ma grid drive, 275 watts out with no color on the
> plates.
> The 812A's get fixed and LOADS of grid leak bias...
>
> I have tried 811A's in the RF deck, they seemed to work just the same as
> the 812A,s.
>
> Good deal on getting the old rig running!
>
> Brett
> N2DTS
>
>
>
> > -Original Message-
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED] On Behalf Of ne1s
> > Sent: Tuesday, February 21, 2006 3:27 PM
> > To: AM Radio Reflector; [EMAIL PROTECTED];
> > [EMAIL PROTECTED]
> > Subject: [AMRadio] 1930's Old Buzzard Open Rack Transmitter
> > Finally Sees theAirwaves! (Long)
> >
> > Hello,
> >
> > Some of you may remember that a few weeks ago I posted a
> > question regarding
> > optimizing the layout for a push-pull triode HF final deck,
> > given that the
> > deck in question was already partially built (by someone
> > else). This was a
> > component of a larger project involving
> > completion/restoration of a 1930's
> > vintage homebrew open-relay rack AM transmitter I had
> > initially acquired
> > some 15-20 years ago, and has been sitting patiently in my
> > cellar shack
> > since this time waiting for me to ge a round tuit. Well, the
> > elusive and
> > highly-coveted tuit finally arrived about a year ago, when I started
> > drilling and blasting for the modulator deck. I had to take a
> > rather long
> > break from itarting last July, when I started a major effort
> > to bring a
> > majorly-hacked Johnson Valiant back from the dead for a
> > friend which led to
> > the birth of FrankenValiant. But that's another story for
> > another time. With
> > FrankenValiant finally completed, I finally got back to the
> > project at hand
> > a month ago, and to make a much longer story less so, the
> > transmitter made
> > its maiden voyage on the airwaves last Sunday evening, when I
> > used it during
> > the final 2 hours of the AWA AM QSO party, on 75M.
> >
> > The final presently uses a pair of 812s, which are modulated
> > by a pair of
> > 805s. When the debug/shakedown stage is over I'll switch over
> > to T-55s in
> > the final (harder to find, and more expensive, than 812s).
> > There are still a
> > few problems, which I hope to rectify next weekend:
> >
> > (1) My bias supply for the modulators and finals, built onto
> > the modulator
> > deck, failed. I had used a period resistor from the junkbox - it was
> > working, now it's opened up. Replacing it will involve removing the
> > modulation transformer from the deck (to make the weight more
> > manageable,
> > removing the deck from the rack, replacing the resistor, and
> > assembly in
> > reverse order of disassembly. So my on-th-air use was with
> > grid-leak bias
> > only on the finals, and zero-bias on the modulators (the 805s
> > were still
> > operating within their ratings, though).
> >
> > (2) The speech amp has an intermittent noise which modulates
> > the finals
> > quite "nicely" when it is present. No surprise: all the caps
> > in the deck are
> > original wax-paper. I did check the DC blocking caps for
> > leakage beforehand
> > (by measuring the DC grid voltages), but guess I shouldn't
> > have trusted
> > them.  A little benchwork with the 'scope should trace down
> > the faulty
> > component. It's in the first stage, 'cuz its intensity varies
> > with the mic.
> > gain control. I actually saw it on the scope when I was
> > checking out the
> > speech amp initially, and made a conscious decision to deal
> > with it later.
> >
> > (3) The link output is directly feeding coax which directly feeds the
> > antenna tuner, and I can only load the finals up to ~150 mA
> > for about 160W
> > output. Should be able to load them to nearly twice that. I
> > need to install
> > a series breadslicer to resonate the link.
> >
> > (4) I need to improve the grid drive on 10M.
> >
> > (5) I want to use a spare set of relay contacts to disable
> > the speech amp
> > (by removing the B+) on standby (receive).
> >
> > And

Re: [AMRadio] word for word

[Mike Dorworth, K4XM]

Never ever once has it 1000 watts carrier power level PERIOD. So how could
it be reduced? It was 1000 watts or 900 watts INPUT regardless of
effeciency, Class C being the best.. About 700 watts. Without meters to
measure accuractly it was 900 watts INPUT. With a Linear the 1000 watts in
would get you a coupla hundred watts at best. The PEP OUTPUT was deemed easy
to measure with standard PEP meters. Sure we lost aboout 50 percent at full
modulation but could use grid modulated, linears, or poor quality tank
circuits and only had to measure the power OUTPUT. Life ain't always fair..

I was here for 52 years watching. They stole the 11 meter band from us also
in 1958. Want it back?
Mike




 Original Message -
From: <[EMAIL PROTECTED]>
To: 
Sent: Thursday, February 02, 2006 4:33 PM
Subject: [AMRadio] word for word


> 1.  Thank you Paul/VJB for the courtesy and seeing my 'faux paux' in the
> wording...good example of Ham espirit in practice, right there from that
gent.
>
> 2.  I had to leave Ham radio back in 1965...as per political orders from
> Washington to destroy Asian countries and kill people there...got my
license back
> 3 years ago..along with my original call...so...
>
> why did FCC reduce the 1000 watt carrier power level?
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio@mailman.qth.net
> AMfone Website: http://www.amfone.net
> AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
>

Re: [AMRadio] Pro AM heat on FCC?

[Mike Dorworth, K4XM]

Hold on there! It was 1000 watts DC input on the meters. With no meters it
was 900 watts maximum INPUT! With class C, High level that could be 70
percent, i.e. 700 watts carrier, with a grid modulated (can you say Linear?)
then it was about 330 watts carrier or maybe even 250 watts.. Eggs are eggs
and oranges are well, you know.  You want only High Level 1 KW input with
multiple efficiency or a standard output read on standard meters?
Back to just reading and not talking. 73 Mike
- Original Message -


From: "Ben Dover" <[EMAIL PROTECTED]>
To: 
Sent: Thursday, February 02, 2006 2:56 PM
Subject: [AMRadio] Pro AM heat on FCC?


> Hello Steve
>
>
> >>Snip!<<
>
> Nevertheless, I wanted to put some heat and noise from a Pro-AM direction
to
> let the FCC folks know there are some opinionated AM'ers working the bands
> who
> do not want any future restrictionsthey were talking about it this go
> around.
>
> And...while I was at it...thought I'd ask for more "respect"...namely
AM-use
> only segments so as to diminsh the AM/SSB elbowing...and add some of that
> Pro-AM heat.
>
>
> >>Snip!<<
>
>
> It may be beating a dead horse, but I'd like to see an attempt to restore
the
> OLD AM power level of 1000 watts of carrier!
>
> Even if the effort fails, if we make enough noise about it the attempt
might
> might well give a LOT of folks out there pause for though before
assaulting us
> again!
>
>
> Mr. T., W9LBB
>
>
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio@mailman.qth.net
> AMfone Website: http://www.amfone.net
> AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
>

Re: [AMRadio] UG 634U

[Mike Dorworth, K4XM]

I have a Millen ad in a 1963 CQ Magazine that says the Red and Black Millen
connectors are for HV and the Brown (yellow) is a special filled bakelite
for RF use ONLY! My friend says the Reds are the best since the Black are
pigmented with carbon to give the black color. Sounds right. Mounted on a
plastic disk they do count as pretty good. Metal screws are asking for
trouble. Nylon handy for this.  73 Mike.

- Original Message -
From: "Mike Sawyer" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Sunday, January 29, 2006 6:11 PM
Subject: Re: [AMRadio] UG 634U


> Unfortunately Ed these are the 'Millen' connectors are only good to about
> 2KV. I know the spec say more but this was discussed at length on the AMPS
> reflector. I have a bunch of the brown ones where the flanges apparently
> broke down under HV stress. I couldn't prove it but the insides of the
> material looked to have been molten.
> Mod-U-Lator,
> Mike(y)
> W3SLK
> - Original Message -
> From: "Edward B Richards" <[EMAIL PROTECTED]>
> To: 
> Sent: Sunday, January 29, 2006 5:47 PM
> Subject: Re: [AMRadio] UG 634U
>
>
> I got my high voltage connectors from RF PARTS[EMAIL PROTECTED]
> part # 37001 (A,B,C,D) rated for 7000 VDC @ 2 amps. Chassis mount flang
> $6.90, cable mount shell $5.90. Good luck.
>
> 73, Ed Richards K6UUZ
>

Re: [AMRadio] Good solid state/hybrid rigs for AM use

[Mike Dorworth, K4XM]

> Keep in mind, when you run the 32V2, you should get 80/90 watts
> out in the high voltage position (and should have solid state rectifiers),
> but running an ft101, and others of its ilk, you get about 20 watts out.

My 32V3 gets 107 (exactly) watts out in HV position with 121 volts AC input
and using the original tube rectifiers. I would be afraid to use solid state
rectifiers even though I have them on hand. Maybe some day when the tubes go
bad and I use LOW voltage I will try them.With 2 used, 1 new 4D32 tube I get
the the same results.. 40 meters as reference.
I get good reports on a TS-570D with a 444D mike using a 3 tube 811A amp. It
all works if not overdriven.. 73 Mike

Re: [AMRadio] (no subject)

[Mike Dorworth, K4XM]

Not sure exactrly what you want but B&W coil stock 8 tpi number 14 makes a
wonderful tuner for 80 through 10 meter at full power. A piece 3 inch
diameter 8 tpi number 14 is fine for 160 through 10 at full legal power. A
100 pf split stator in the first case a 200 in the second is sufficent for
any know amateur use. I been using same for years.  B&W will make them with
Lexan Rods and they make wonderful 1 kw mobile coils.73 Mike
- Original Message -
From: "Greg Schultz Sr" <[EMAIL PROTECTED]>
To: "'Discussion of AM Radio'" 
Sent: Sunday, January 08, 2006 10:02 AM
Subject: RE: [AMRadio] (no subject)


> I checked B&W site and they have coil stock but not large enough for
> what I need.  I am building a balanced link coupled tuner that can cover
> at least 80 meters.
>
> Thanks, Greg W5RY
>
> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Jim Wilhite
> Sent: Saturday, January 07, 2006 8:35 PM
> To: Discussion of AM Radio
> Subject: Re: [AMRadio] (no subject)
>
> Greg the B&W ministock is still available.  Is that what you are
> seeking?
>
> http://www.bwantennas.com/
>
> 73  Jim
> W5JO
>
>
>
>
>
> > Does anyone know of a source for winding air core coils similar to the
> > old B&W types??  I need two 2-3in diameter with about 60-70 turns for
> a
> > tuner - at least 12ga.  There was a seller on ebay several months ago
> > who wound coils to your specs but I lost his email address.  Anyone
> know
> > of this person??
> >
> >
> >
> > Greg W5RY
> >
> > __
> > AMRadio mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/amradio
> > Help: http://mailman.qth.net/mmfaq.html
> > Post: mailto:AMRadio@mailman.qth.net
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> > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
> >
> >
>
> __
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>

Re: [AMRadio] WTB/WTS and a question

[Mike Dorworth, K4XM]

> > > > The tubes all have 2V filaments.  The radio has two inputs for a
> >
> > > > filament
> > > > supply, 2V or 2.5V (the 2.5V input merely inserts a series
> > > > resistor).  My
> > > > question iswhy did anyone manufacture 2V filament tubes and


>Two volt tube were used in the 19 twenties and thirties for FARM radios.
They used a 2 volt wet cell. One third of a car battery for those tubes.
Also The audio always push pull class B triodes for maximum B battery
utilization. Folks carried the cell to the service station or perhaps had a
windmill generator from a T model Ford connected for recharging. REA did not
start until about 1933 or so and almost no Farmer in America had Electric
power. The dry B batteries were 135 volt and lasted a long time but many
units had a vibrator pack that ran off a 6 volt wet cell battery from a car
or the Edison Electric Company. By the mid 1930's the 230's etc were amost
obsolete. Hope this helps HNY, 73 Mike

[AMRadio] Politically Correct Holiday Greetings

[Mike Dorworth, K4XM]

>Please accept with no obligation, implied or implicit our best wishes for
>an environmentally conscious, socially responsible, low stress,
>non-addictive, gender neutral,  celebration of the winter solstice
>holiday, practiced within the most  enjoyable traditions of the religious
>persuasion of your choice, or secular  practices of your choice, with 
>respect for the religious/secular persuasions  and/or traditions of others, 
>or their choice not to practice religious or  secular traditions at all . . 
>.
>
>and a fiscally successful,  personally fulfilling, and medically
>uncomplicated recognition of the onset of the generally accepted calendar
>year 2006, but not without due respect  for the calendars of choice of 
>other
>cultures whose contributions to  society have helped make America great,
>(not to imply that America is necessarily greater than any other country or 
>is the only "AMERICA" in the western  hemisphere), and without regard to 
>the race, creed, color, age, physical ability,  religious faith, or choice 
>of computer platform of the wishee.
>
>(By accepting this greeting, you are accepting  these terms.
>This greeting is subject to  clarification or withdrawal. It is freely
>transferable with no alteration to the original greeting. It implies no
>promise by the wisher to actually implement any of the wishes for
>her/himself or others, and is void where prohibited by law, and is
>revocable at the sole discretion of the wisher.   This wish is warranted
>to perform as expected within the usual application of good tidings
>for a period of one year, or until the issuance of a subsequent holiday 
>greeting, whichever comes first, and warranty is limited to replacement of 
>this wish or issuance of a new wish at the sole discretion of the wisher.)
From [EMAIL PROTECTED]  Mon Dec 19 16:13:14 2005
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Date: Mon, 19 Dec 2005 16:08:43 -0500
From: W3CRR <[EMAIL PROTECTED]>
Subject: Re: [AMRadio] Politically Correct Holiday Greetings
In-reply-to: <[EMAIL PROTECTED]>
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Discussion of AM Radio 
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I love it!

I'm the public affairs director of a large non-profit agency in
Washington, DC. One of my responsibilities is editing our monthly
magazine.  Last year, at the direction of our Executive Director, I
included holiday greetings in the magazine accompanied by a small
graphic. It was a nice, simple and warmly artistic lit photograph of a
Christmas candle next to a Hanukah menorah.  Subsequently, I received
angry missives from followers of the Christian, Jewish and Islamic
faiths as well as a celebrant of Kwanzaa for either a) juxtaposing their
symbol next to the "opposition", or b) excluding their symbol from the
graphic.  (What's the Kwanzaa icon, by the way, a "Kwanzaa Hut"?)  :-)

No greetings this year...

73,

Craig
W3CRR

Re: [AMRadio] Want Ranger pwr xfmr

[Mike Dorworth, K4XM]

Hello John. The filament windings should be on the outside and should be
fairly easy to remove and or replace. I have done it many times. You have
nothing to lose. Drive out a coupla laminations and pull the e and i out.
Then  peel it like a onion and fix it.Use Scotch plastic tape and put er
together again. It will work as new. 73 Mike k4XM
- Original Message -
From: "John Lawson" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Cc: 
Sent: Friday, November 25, 2005 12:36 PM
Subject: [AMRadio] Want Ranger pwr xfmr


>
>
>Anyone happen to have a NOS or Good-Used Ranger power transformer for
> sale?  I need one - or a Good-Used Ranger - or, a new hobby... ;}
>
>
> After several hours on the bench last night - it is apparent why this
> old girl was shelved - it came to me with a 5R4 in the HV socket, but the
> fils didn't light, tho the tube was good. So sure enough - someone had
> tied the 5V fil lines back, and there was a 10-ohm 10W resistor in series
> with the B+ lead.
>
>I made a plug-in SS rectifier, installed it, switched the rig on - and
> blew both diodes and both line fuses to little bits.
>
>Ok.
>
>So I restored the original circuit - there is a definite 'under-load'
> short from the HV rect fils to the HV winding.
>
>Ok..
>
>   Disconnected all that - the LV side works fine, Osc runs, buffer runs -
> can 'zero-beat' to a receiver, frequency of VFO seems accurate.
>
>   Ok...
>
>   Tansformer voltage and resistance checks are within 10% of spec.
>
> Ok
>
> Put new diodes in put a Variac and ac ammeter in the mains line, turned it
> up slowly - POW.  Actually, with the diodes in cicuit, it appears to the
> Variac / AC Ammeter that the power transformer has a dead short. Having
> replaced the filter caps, and checked the plate choke - it ain't them. The
> B+ line resistance is slightly over 20K.
>
> Ok...!
>
>In this process the power transformer has begun to get slighly warm, so
> I went back to checking the LV side - as I was testing, the transformer
> started to arc internally - and resistance measurements now show the
> fil-to-HV short.  So: It's toast.

Re: [AMRadio] Tansmitter power reduction (Ranger)

[Mike Dorworth, K4XM]

The way the secondary is wound all the final and lv passes through the
winding so you would have TWICE as much  current if you use just the low
voltage taps. BTW the Ranger modulation transformer is (by my measurement)
7083.8 ohms plate to plate primary, 3568 ohms centertaped (892 ohms each
side) secondary.   or 1.9837 z stepdown, 1.4085 step down turns ratio.
Nominal 7000 to 3500 ohms. About 15 watts Audio level, used at 32.5 watts
ICAS voice.  Hope this is helpfull. 73, Mike
- Original Message -
From: "John Lawson" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Wednesday, November 16, 2005 10:11 PM
Subject: [AMRadio] Tansmitter power reduction (Ranger)


>
>
> On Wed, 16 Nov 2005, John Coleman ARS WA5BXO wrote:
>
> > I don't know if the power supply come from the same XFMR or not but what
> > does "10 on the knob" mean?
>
>
>   In the Ranger, the LV feed to it's rectifier is from two equidistant
taps
> between CT and the 'ends' of the HV secondary, the which ends feed the HV
> rectifier.  I'm a bit worried that if I run the whole radio on the LV
> winding, it will stress it. If anyone has any concrete "real-world" actual
> experience with doing this, I'd love to hear how it worked out.
>
>Guitar (and other musical) amplifiers traditionally have their volume
> knobs marked 0 - 10, thus '10' is 'loudest'.  From whence derives the joke
> in Spinal Tap - "This amp was custom made for me - see? the knobs all go
> to *11*!!!"
>
>   Cheers
> John  KB6SCO
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
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> AM List Admin: Brian Sherrod/w5ami
>

Re: [AMRadio] Re: [Johnson] Amp advice

[Mike Dorworth,K4XM]

75 percent is heat, 25 % in feed through power. 24 two watters going to get
nice a warm. (48 watts) best use a FAN!



- Original Message - 
From: "John Lawson" <[EMAIL PROTECTED]>
To: "Jim Brannigan" <[EMAIL PROTECTED]>
Cc: ; <[EMAIL PROTECTED]>
Sent: Sunday, October 30, 2005 1:57 PM
Subject: [AMRadio] Re: [Johnson] Amp advice


>
>
> On Sun, 30 Oct 2005, Jim Brannigan wrote:
>
> > If you look in the BAMA archives under Johnson Thunderbolt, there is a
> > schematic and parts for a 6db power attenuator.
> > The parts are available from Allied.
>
>
>
> Snagged it - Thanks!
>
> 24 2W non-inductive resitors - I gotta get a new tip for my soldering
> iron...   ;}
>
>
> Cheers
>
> John  KB6SCO
>
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
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> AM List Admin: Brian Sherrod/w5ami
>

Re: [AMRadio] Charcoal Briquettes and High Voltage Power Supplies

[Mike Dorworth,K4XM]

Sure don't want to fight on Sunday..but..most circuits avoid dropping more
that 500 volts across any one resistor, An example is metering circuits
where 1 meg resistors are series to make the total so that no single
resistor drops too much. There can be 5000 volts on the string, just limit
each one to about 600 volts. Mike
- Original Message - 
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; 
Sent: Sunday, October 30, 2005 1:52 PM
Subject: [AMRadio] Charcoal Briquettes and High Voltage Power Supplies


> In defense of the common carbon composition resistor...
>
> On 30 Oct 2005 at 9:35, [EMAIL PROTECTED] wrote:
>
> > Carbon comps aren't the most stable resistors in the world, and if they
age unevenly you've got a problem. Worse, they usually have a max voltage
rating of only
> > a few hundred volts, so in many designs they're being overstressed.
>
> Er, not so - they are regularly used in commercial power supplies
> in the 1000V to 2000V DC range.
>
> Most amateur radio tube rigs used final HT of around 600 to 900V
> DC
> and they used carbon resistors too, so I'm not sure where you got
> that idea from, but it is erroneous.
>
> Many audio amplifiers and modulators use 400 to 800V or more.
> Often a lot more.  As far as I know they all used carbon resistors.
>
> If it still works after 10 years then I don't think it is fair to call
> this results of such a design "overstressed."
>
> (Runs and ducks for cover...)
>
>
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
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> AM List Admin: Brian Sherrod/w5ami
>

Re: [AMRadio] Re: [Johnson] Amp advice

[Mike Dorworth,K4XM]

Normal wake up time is one tenth of a second to allow heating of the
filament and charging of the capacitor. To be really certain, let it warm up
a full minute before honking down on it real hard...MIKE
- Original Message - 
From: "John Lawson" <[EMAIL PROTECTED]>
To: "Ed Tanton" <[EMAIL PROTECTED]>
Cc: ; <[EMAIL PROTECTED]>
Sent: Saturday, October 29, 2005 7:41 PM
Subject: [AMRadio] Re: [Johnson] Amp advice


>
>
> On Sat, 29 Oct 2005, Ed Tanton wrote:
>
> > Well... just my 2 cents, mind you... but it's bad enough using a linear
for
> > AM, considering the efficiency yielding only a little more signal than
> > talking louder would accomplish... but a **SINGLE** 3-500Z combined with
all
> > that INefficiency? Complete waste of time and 3-500Z after (what will
be)
> > short-lived 3-500Z.
> >
>
> Thanx Ed!
>
>
>
>Well:  Nummer One - It's only a Hobby. As in: to have fun with.
>
>   Nummer Two - I got the AL-80 and Tuner pretty cheap. (SK estate)
>
>   Nummer Three - I have a Ranger and a Valiant. The Ranger needs a
> couple of minor 'tweaks'; the Valiant has a few things that need fixin',
> and that equals time and money, thus I'll go with what I have, and work on
> Improvements later..
>
>   Nummer Four - I'm actively looking for a Thunderbolt - none on
> the hook right now.
>
>   Nummer Five - No one's actually *answered* the questions I have
> about 'waking up' the amp. (Yet, at any rate.) There has been some very
> pertinent and helpful advice, however - much appreciated.
>
>   Nummer Six - see Nummer One. Don't curse the QRP - light a
> Filament!
>
>
>
>  Cheers
>
> John   KB6SCO
>
>
>
>
>
> __
> AMRadio mailing list
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> Post: mailto:AMRadio@mailman.qth.net
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> AM List Admin: Brian Sherrod/w5ami
>

Re: [AMRadio] Amp advice

[Mike Dorworth,K4XM]

Good point. The Ranger modulation transformer is 7500 to 3500 ohms and rated
for about 15 watts audio level. It was used at 32.5 watts for voice service
which is A-OK. As example the famous ART-13 transformer is rated at 50 watts
and we all know that they will do plenty more for VOICE service. The mod
transformer that has to pass the magnetizing final current requires very
careful spacing of the core gap. Broadcast service gets by this at the
higher powers by using a choke and capacitor to shunt feed the final. This
allows more BASS. They have to do 50 cycles ( Hertz for new guys).
.
>
> Remember, the less load drawn through the secondary of the stock Ranger
> modulation transformer, the better the audio is going to sound, stock
> out of the Ranger.
> The reason being, there's less plate current being drawn through the
> secondary of the modulation transformer, and therefore less chance of
> core-saturation, cause the hysteresis curve of the transformer not to be
> as linear as possible.
>
> ---
> 73 = Best Regards,
> -Geoff/W5OMR

Re: [AMRadio] Amp advice

[Mike Dorworth,K4XM]

It seems we're back to where we were. In theory the maximum carrier is
limited to half the tube dissipation. i.e 250 watts. The power supply is
good for about half that amount. This means the Ranger can put out at MAX
around 12  to13 watts. The carrier about 125 watts, the pep output about 500
watts. Your ability to buy power transformers and tubes may vary.. Hope this
helps.. Mike
- Original Message - 
From: "John Lawson" <[EMAIL PROTECTED]>
To: 
Cc: <[EMAIL PROTECTED]>
Sent: Saturday, October 29, 2005 4:25 PM
Subject: [AMRadio] Amp advice


>
>   I have recently acquired (from the estate of a Silent Key) an Ameritron
> AL-80 (not A, B, or C) and the Ameritorn ATR-15 tuner.
>
>   These were used together for years, then sat for an unknown length of
> time before being disconnected and moved.   I am the second owner.
>
>The tuner exhibits constructional saliency with masonry defecatoria,
and
> appears to be in nearly factory-new shape internally - the case is dusty a
> bit, but also very nice.
>
>The amp, [while modified slightly with some extra ventilation holes and
> a large power-transistor type heatsink bolted to the case adjacent to
> where the 3-500Z lives], seems to be visually in good shape - it seems to
> have had one of it's power-equalizing resistors (on the rectifier/filter
> board) replaced. It's wired for a 220 mains supply, which I will also
> operate it on.
>
>   Initially I'll be driving the AL-80 with a Ranger, thence into the
> ATR-15, 450-ohm ladderline to the 450' fence-top loop guarding my back
> yard.  I've completed the re-route of that ladder-line following previous
> suggestions and admonishments, BTW - and thanks to y'all for that!!
>
>
>I've not owned a higher-power amp before, so aside from the usual
> caveats concerning powering up 'older' gear for the first time - I was
> wondering if there are any Ameritron-specific "gotchas" to be aware of -
> and certainly if there is any wisdom, anecdotes, or cautions concerning
> this amp - especially as I'm going to use it on AM fone - I'd be
> appreciative of the experiences you've (collectively) had.
>
>
>Cheers
>
> John KB6SCO
> __
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> AM List Admin: Brian Sherrod/w5ami
>

Re: [AMRadio] Re: need help

[Mike Dorworth, K4XM]

That would do the bias supply but he is talking about the peak RF voltage to
make the tube work. Peak RF voltage is a hair less that the 130 volts for
grid current less AB-1 operation.
- Original Message -
From: <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Saturday, October 22, 2005 12:20 PM
Subject: RE: [AMRadio] Re: need help


> What about using a 130 volt 5 Watt zener diode in the cathode?
>
> On 21 Oct 2005 at 21:48, Gary Schafer wrote:
>
> > I just looked up the 4-400 and I see it requires more bias than I had
> > remembered for AB1 operation. It requires -130 volts with 2500 on the
plate
> > and 750 on the screen.
> > So a 50 ohm resistor with 100 watts would only provide around 100 volts
peak
> > drive voltage. Not quit enough.
> >
> > A 100 ohm resistor should provide around 140 volts peak with 100 watts.
That
> > should work with little drive to spare.
> > Probably the easiest would be a 200 ohm resistor (close to the 170 ohm
> > resistor). A 4:1 balun should match it close to 50 ohms.
> > A 200 ohm resistor and 100 watts should provide close to 200 volts peak
> > drive voltage.
> >
> > I did this setup (balun and resistor) with a pair of grid driven 1625,s
> > driven by my 20A. It worked well. Voltages were less of course!
> > Stray capacitance will change things a bit.
> >
> > 73
> > Gary  K4FMX
> >
> >
> > > -Original Message-
> > > From: [EMAIL PROTECTED] [mailto:amradio-
> > > [EMAIL PROTECTED] On Behalf Of ne1s
> > > Sent: Thursday, October 20, 2005 12:30 PM
> > > To: Discussion of AM Radio
> > > Subject: [AMRadio] Re: need help
> > >
> > > With a 50 ohm grid load on 4-400s, I think you'll find you'll get very
> > > little amplification from the stage - the 40400 grid(s) want(s) to see
> > > more
> > > voltage. I went throught this exercise one (on paper), so went with a
1:16
> > > balun into a 800 ohm non-inductive resistor network in the actual
design.
> > > Problem was, I couldn't make it broadband enough to cover more than 3
> > > consecutive bands at a time, and finally resorted to a T network on
the
> > > input, loaded with about 2000 ohms worth of resistors.
> > >
> > >  -Larry/NE1S
> > >
> > > Gary Schafer writes:
> > >
> > > > The input impedance should be very near what the value of the
resistor
> > > is.
> > > > In this case 170 ohms. The 4-400's will most likely be run in AB1 so
no
> > > grid
> > > > current.
> > > > I would put in a 50 ohm resistor instead. You should get enough
drive
> > > with
> > > > it. Figure what the bias voltage will be on the tubes. Then figure
what
> > > the
> > > > peak voltage will be from the exciter at 50 ohms. If the peak
voltage
> > > will
> > > > be greater than the bias voltage on the tubes then you have enough
> > > drive.
> > > >
> > > > 73
> > > > Gary  K4FMX
> > > >
> > > >> -Original Message-
> > > >> From: [EMAIL PROTECTED] [mailto:amradio-
> > > >> [EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
> > > >> Sent: Wednesday, October 19, 2005 10:46 AM
> > > >> To: amradio@mailman.qth.net
> > > >> Subject: RE: [AMRadio] need help
> > > >>
> > > >> I'd have used an MFJ 259B to actually measure the input Z.
> > > Alternatively,
> > > >> you  can always use a  small tuner to "tune" the input.  I do that
> > > anyway
> > > >> with my Drake L4B, (use a small MFJ mobile tuner with meter).
> > > >>
> > > >> 4-400's, eh?  Nice amp!  If your plate voltage is high enough, you
> > > ought
> > > >> to
> > > >> get serious power out of that baby!
> > > >>
> > > >> 73, Ed, VA3ES
> > > >>
> > > >>
> > > >> From: Edward B Richards <[EMAIL PROTECTED]>:
> > > >>
> > > >> I want to drive a linear amplifier with a rice box that requires a
50
> > > ohm
> > > >> load.
> > > >> The linear amp uses an input to a 170 ohm, 80 watt swamping
resistor to
> > > >> ground, then
> > > >> through a .001 mfd capacitor, then through a VHF parasitic
suppressor
> > > >> consisting of  4 turns of wire around a 47 ohm resistor, to the
grids
> > > of
> > > >> a pair of parallel connected 4-400A tubes.
> > > >>
> > > >> What I need to know is the impedance of the input. Is it close to
50
> > > ohms
> > > >> or do I need to use a matching network between the rice box and the
> > > >> linear amplifier.
> > > >>
> > > >>
> > > >> __
> > > >> AMRadio mailing list
> > > >> Home: http://mailman.qth.net/mailman/listinfo/amradio
> > > >> Help: http://mailman.qth.net/mmfaq.html
> > > >> Post: mailto:AMRadio@mailman.qth.net
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> > > >> AM List Admin: Brian Sherrod/w5ami
> > > >
> > > >
> > > > __
> > > > AMRadio mailing list
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> > > > Post: mailto:AMRadio@mailman.qth.net
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> > > > AM List Admin: Brian Sherrod/w5ami
> > >
> > > _

Re: [AMRadio] Minature Mobile Transmitter

[Mike Dorworth,K4XM]

For class A audio,with a pentode, you do not need a step down transformer
of 2.66 or 5 to 1 to each half of the secondary. You don't need push- pull,
and it is OK to use cathode bias which can never be used for class B. Zero
Bias Class B triode operation is to save current while idle and take a big
peak for a little while. Class A is a power waster, that is why the majority
of later car radios used a single Class A Transistor. The cars had bigger
batteries and alternators. Ditto the 6V6, 6AQ5, 6K6 output stages. Notice
that all the old communications  receiver that used the single ended Class A
stage called for 10 percent distortion, Ugh!

- Original Message - 
From: <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Tuesday, October 04, 2005 5:21 AM
Subject: Re: [AMRadio] Minature Mobile Transmitter


> On 3 Oct 2005 at 0:39, Bob Bruhns wrote:
>
> > That's amazing.  Can't argue with success.  And
> > the 7.5W-300V-16K p-p adds up.  The published
> > 12AX7 plate dissipation spec must be overly
> > conservative, and the cathode must be pretty
> > efficient.
> >
> > I always thought of the12AX7 as an audio preamp
> > tube.
>
> It is... There HAS to be a good reason why manufacturers
> used things like 6AQ5 and 6BM8 for 4 watt audio output
> stages instead of a 6C4 or 12AX7 !!
>
>
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
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> AM List Admin: Brian Sherrod/w5ami
>

Re: [AMRadio] Minature Mobile Transmitter

[Mike Dorworth,K4XM]

OK, from the top. There are several dozen examples of mobile rigs in QST, CQ
magazine and both the ARRL Mobile Book and both CQ Mobile Handbooks all of
which use a 12AX& in class B, zero bias. So they must work OK. I have run
mobile AM with the 12AX7 modulating a 5763 so there can be no doubt it
works. In the 14 th Edition of the Radio Handbook edited by Bill Orr on page
452 is a Modulator using a 12AX7 that modulates a 2E26 at 12 watts input.
Using a plate to plate load of 18000 Ohms and 300 volts the 12AX7 delivered
almost 7 watts of SINE WAVE audio. As stated earlier, the inexpensive power
supplies of those days furnished 300 volts at 100 ma. A Class B audio system
could produce 6 to 8 watts of audio to run a 12- 15 watt input mobile rig.
There was then, and it remains true today, that no known tube other than the
12AX7 had such a  a low resting current  of 6 - 10 ma. With a peak of 40 ma
the modulator will use about 50 ma total to run  mudulator including the
pre-amp, usually a 12AU7, this leaves 50 ma at the 300 volts to run a
oscillator, buffer if needed and drive a final and furnish it's screen grid.
This is another 50 ma. So then the 100 ma is used up. The ARRL Handbook for
1960 clearly shows this to be the correct tube for the job. Without looking
it up, I seem to remember about 70 ma idle for a pair of 6AQ5s which pump
out FIVE watts?  This all started with a question if the ARRL Handbook was
misprinted. Several dozen successful rigs printed in standard Mobile Manuals
, QST, CQ etc makes it a correct choice under the required circumstances..
As a extra bit of information, all of the old farm radios for the AM band of
the 20s,  30s and 40s all used TRIODES in Class B to conserve battery power
in the audio driver and output circuits. Ditto all of the original
transistor radios of the 50 and 60,s used class B audio to keep down the
current drain.

- Original Message - 
From: <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Tuesday, October 04, 2005 5:21 AM
Subject: Re: [AMRadio] Minature Mobile Transmitter


> On 3 Oct 2005 at 0:39, Bob Bruhns wrote:
>
> > That's amazing.  Can't argue with success.  And
> > the 7.5W-300V-16K p-p adds up.  The published
> > 12AX7 plate dissipation spec must be overly
> > conservative, and the cathode must be pretty
> > efficient.
> >
> > I always thought of the12AX7 as an audio preamp
> > tube.
>
> It is... There HAS to be a good reason why manufacturers
> used things like 6AQ5 and 6BM8 for 4 watt audio output
> stages instead of a 6C4 or 12AX7 !!
>
>
> __
> AMRadio mailing list
> Home: http://mailman.qth.net/mailman/listinfo/amradio
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> AM List Admin: Brian Sherrod/w5ami
>

Re: [AMRadio] Re: Minature Mobile Transmitter

[Mike Dorworth,K4XM]

The resting current is total for both sections. 10 ma would be 1.5 watts per
section at 300 volts. Peak current is 35 ma total for the two sections.
Works very well. Tube life not a problem. These were used for years in
mobile requiring a total of 100 ma for final, osc and modulator. The last
ten ma were taken from a large output capacitor when total current was about
110 ma on a 100 ma system.A single 12AU7 was used for mic preamp and driver,
consumed about 4 ma. Current was measured in mills by each ma Not a single
one was wasted. 6 volt cars were lucky to have a 15 to 30 amp Generator.
Even as late as the mid fifties on 12 volt cars a 35 amp alternator was
special factory order. No one wasted MA in mobile. Hence the zero bias
tubes, 1635 and 12AX7. A 1635 will modulate 100 percent a 50 watt rig and
automatically hi level clip and increase talk power without splatter.The
Johnson Mobile used bias for the modulator, look up the circuit on BAMA!

- Original Message - 
From: "Patrick Jankowiak" <[EMAIL PROTECTED]>
To: 
Sent: Monday, October 03, 2005 7:06 PM
Subject: [AMRadio] Re: Minature Mobile Transmitter


> What I don't get is the tube current ratings, and, was tube life a
concern?
>
> 300V zero bias gets you 8mA per section, and is also 2.4 watts
dissipation!
> I suppose these are the ICAS ratings :-P
>
> -and that's zero signal. The curve is very linear from 2mA to 8mA and even
> pretty good down to 1mA idling current.  -but those would take bias.
>
> PJ
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>

[AMRadio] Minature Mobile Transmitter

[Mike Dorworth,K4XM]

>From QST, September, 1952 Class B modulator. The 12AX7 modulator tube
delivers approximately 6 watts output.

>From QST, November, 1951  A Deluxe Mobile Transmitter for 14 and 28 Mc. Two
12AX7s- each tube having similar elements in parallel- operate at zero-bias
in Class B modulator circuit which delivers approximately 15 watts output.
(300 volts)

ARRL Mobile Manual 1st edition, page 178, The modulator employs a type 12AX7
tube and delivers approximately 7 watts output.
280 volts resting 10 ma, peak 30 ma.

QST, December 1956 . 10-12 watts input 50 mc mobile transmitter designed to
operate on the most INEXPENSIVE power supply readily available (for mobile)
. The modulator tube is a type 12AX7.the modulator plate current should
jump 20 to 25 ma above the no-signal value of 6 ma.

>From ARRL Handbook, 1960,  37th edition, page V17,  12AX7, 300 volts, 0
volts grid bias load resistance 16 k ohms output power 7.5 watts.

[AMRadio] 12AX7 Modulators

[Mike Dorworth,K4XM]

>From Radio Amateurs Mobile Handbook, 1st edition edited by Bill Orr, W6SAI.
Page 85. The 12AX7 makes an excelent class B modulator for low powered
mobile transmitters. Operting at 300 volts it requires no bias with a
resting plate current of 10 ma. This is lower than ANY tube capable of
producing the same audio power. 6N7, 35 ma, 1635, 11 ma, push pull 6AQ5
draws minimum of 70 ma when the stage is OVER biased. The 12AX7 will deliver
7 watts of VOICE audio with negligible distortion at 300 volts . The plate
current will rise from 10 ma resting to about 35 ma on voice peaks. Two
12AX7 tubes may be used in push-pull parallel to obtain 15 watts of audio
power. The CORRECT load impedance for a single 12AX7 is in the vicinity of
14000 ohms. Two tubes in push-pull parallel require a load impedance of 7000
ohms. On page 92 of the same manual is a 12 watt mobile, 3 band transmitter
running 12 watts input which delivers 8 watts of FULLY modulated carrier
which was modulated by a single 12AX7 at 300 volts.

Re: [AMRadio] GG 813 Linear in GE Ham News -12AT7 12AX7

[Mike Dorworth,K4XM]

well. there are several dozen examples of this in the mobile handbooksCQ
magazine and QST,both of the CQ books and all five of the ARRL's. It was
done to get lots of audio, very low resting current, ditto 1635, a special
6N7 with zero resting current gives 14 watts sine wave RMS, can be made to
modulate 50 watts with reasonable tube life. Remember, speech is 20-25
percent of peak when viewed as average. That is why 3 kw Alphas only have
1kw CCS supplies!.On the 12AX7, my mobile used this for years and no tube
ever failed. Lotsa good audio!.. Mike
- Original Message - 
From: "Patrick Jankowiak" <[EMAIL PROTECTED]>
To: 
Sent: Saturday, October 01, 2005 10:15 AM
Subject: Re: [AMRadio] GG 813 Linear in GE Ham News -12AT7 12AX7


> don't laugh too hard, In the ARRL handbook it claims 8 watts audio from an
> 12AX7 in zero bias class B push pull into 8000 ohms. I have never
> understood that one, if you look at the currents stated in the book, they
> seem pretty high for the tube.
>
> PJ
>
>
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> AM List Admin: Brian Sherrod/w5ami
>

Re: [AMRadio] 813 GG Amp

[Mike Dorworth,K4XM]

Not sure. Radio Handbook, 17th edition page 682, Utility 2 KW Linear pair
813's GG, also  Radio Handbook 23rd edition page 17-6 An 813 Economy
Amplifier for 160 or 80 meters pair 813 GG. Most of the other handbooks show
the tetrode connection that would be applicable to any tetrodes including
813 which would be grid driven. Hope this helps. Mike


- Original Message - 
From: "Bob Maser" <[EMAIL PROTECTED]>
To: "AMRadio" 
Sent: Friday, September 30, 2005 1:28 PM
Subject: [AMRadio] 813 GG Amp


> Why is it that my 21st edition Bill Orr Radio Handbook does not show the
813
> amp? Even the page numbers are arranged differently.
>
> Bob
>
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>

Re: [AMRadio] GG 813 Linear in GE Ham News

[Mike Dorworth,K4XM]

Actually, only one half of plate dissipation. The ICAS dissipation for a
single 813 is 125 watts, CCS is 100 watts.. This is the maximum carrier for
reasonable tube life. Efficiency is low without modulation., increases
during modulation. Limiting factor is one half total dissipation.Sorry but
the facts are so. Mike


- Original Message - 
From: "W5OMR/Geoff" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Thursday, September 29, 2005 6:03 AM
Subject: Re: [AMRadio] GG 813 Linear in GE Ham News


> Gary Schafer wrote:
>
> > A pair of 813s in GG are only good for 150 watts carrier out on AM.
> >
> > 73
> > Gary  K4FMX
> >
>
> I'm not trying to start anything here, Gary, but that statement seems to
> be in stark contrast to what you said, yesterday...
>
> > With an AM linear the efficiency at carrier must be / will be exactly
> > one half what it is at PEP. Provided it is tuned properly.
> >
> > 73
> > Gary  K4FMX
>
>
> What would the efficiency be of an AM Linear at carrier.
>
> (or maybe I'm not reading this correctly, because I've yet to have
> coffee this morning, and I -know- I probably should'n't be posting
> messages in this state... ;-))
>
> --
> 73 = Best Regards,
> -Geoff/W5OMR
>
> __
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> AM List Admin: Brian Sherrod/w5ami
>

Re: [AMRadio] GG 813 Linear

[Mike Dorworth,K4XM]

1. William I. Orr, W6SAI, Radio Handbook16th Edition, section 29-8 An 813
Grounded Grid Linear Amplifier

2. William I. Orr, W6SAI, Radio Handbook, 21st edition, chapter 22

3. Bill, Orr. W6SAI (SK) Ham Radio, May 1980 Pages 47, 48, 49,50, 51. ( Ham
Radio Techniques)


The last is the best, uses zener (adjustable) for proper bias, Transceive
relay and includes input circuit, so necessary for today's modern rigs. Also
has  operating conditions for a CLEAN signal, 2500 volts , 60 ma idle, peak
plate current 450 ma, 50 ma grid (total) , 3000 ohm plate load Z, drive
impedance 135 ohms, 1120 watts input, 680 watts out, 28 watts drivepower.

This HR article has a good system to test transmitting tubes, particuarly
old surplus, NOS and Junquebox(EBAY) specials.





- Original Message - 
From: "W5OMR/Geoff" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Wednesday, September 28, 2005 3:33 PM
Subject: Re: [AMRadio] GG 813 Linear


> Rbethman wrote:
>
> > I have the pages from the Radio Handbook for a GG 813 Amp, AND have
> > the Email from W6SAI JUST prior to his becoming an SK to distribute it
> > and place on my site.
> >
> > I'll put it back on the site if anyone wants it.
> >
> > Bob - N0DGN
>

Re: [AMRadio] Pi-Net vs Link Couple

[Mike Dorworth,K4XM]

Ronnie, Hello! The 1 kilowatt Triode Pi-Network Amplifier using the 450TH is
in the Editors and Engineers Handbook 14th Edition. The first of the
handbooks edited by Bill Orr W6SAI. It has the RED cover. It starts on Page
585 in chapter 26-12 and ends on page 589. My scanner got knocked off the
table by the dog and is broken. Been looking for replacement at CHEAP price.
Perhaps some of the other fellows have this handy, if not, in a coupla weeks
I should be able to get you a copy. 73, Mike


- Original Message - 
From: "ronnie.hull" <[EMAIL PROTECTED]>
To: "Mike Dorworth, K4XM" <[EMAIL PROTECTED]>; "Discussion of AM Radio"

Sent: Thursday, September 22, 2005 7:53 AM
Subject: Re: [AMRadio] Pi-Net vs Link Couple


>
> Mike I'm the fellow that is going to build up a Class C final using a
450TL.
> I would love to get a copy of that schematic for the 450TH rig in the
Editors
> and Engineers handbook. I have a few of those, but apparently, not that
one.
>
> I have a very nice B&W 850A or 852 that I can use in this rig. Either
should
> handle that tube fine, considering I'm not going to run much more than
2500
> volts on it anyway. Maybe 3000.
>
> I just got the worled biggest honker daddy plate transformer from W5OMR.
> 8200V center tapped ( 4100 - 0 - 4100 ) at 4.5KVA !!!  Yeah suh, takes 3
men
> and a dolly to move it!!
>
> This will be a fun project.
>
> 73's & batten down the hatches, here comes Rita..
>
> W5SUM
>
>
> -- Original Message ---
> From: "Mike Dorworth,K4XM" <[EMAIL PROTECTED]>
> To: "Discussion of AM Radio" 
> Sent: Wed, 21 Sep 2005 23:10:59 -0400
> Subject: Re: [AMRadio] Pi-Net vs Link Couple
>
> > The Pi-Net will give a total of 50 db suppresion of harmonics. about
> > 20 in one spot and 30 in the other. Link couple can pass harmonics
> > to VHF by capacity coupling, hence the Faraday Shield Links used for
> > same later on. There is a nice single 450th Pi-Net rig shown in the
> > Editor and Engineers handbook. Also a couple of single ended ones in
> > the 1950 ARRL Handbook (for triodes).  Some triodes that require
> > lots and lots or drive can unbalance the grid tank, which is
> > required for triodes using Pi-Net. Lo capacity tubes like the 450th
> > is OK. The old timers mostly used tuners (antenna) and open wire
> > feeders to keep the harmonics down. Hazletine link neutralization
> > can also be used and no split tanks are needed in or out. Remember
> > Class C , which is required for Hi level AM, is a extreme distortion
> >  and harmonic generator so that some plan need to be in place to
> > handle the soup. Also a single band dipole is very frequency
> > selective and cuts way down on harmonics by itself. Multiband
> > dipoles, beams and multi dipole on one feeder and traps etc (G5RV)
> > are an open invitation to spread gook with only link output. Also
> > the guys that use CB lin years with no half wave filters get away in
> > mobile service without too many problems  due to the narrow
> > frequency discrimination of mobile antennas. Hope this helps, 73 Mike
> >
> > - Original Message - 
> > From: "Geoff" <[EMAIL PROTECTED]>
> > To: "Discussion of AM Radio" 
> > Sent: Wednesday, September 21, 2005 10:45 PM
> > Subject: [AMRadio] Pi-Net vs Link Couple
> >
> > > SO, here we are, well past 1991 and the 'law' that went into effect
> > > saying that 1,500w PEP output is the maximum RF Power output that we
> > > hams can run, regarldless of mode.  That doesn't deter the homebrewing
> > > spirit, but it does suggest that acheiving 1,500w PEP output is much
> > > easier than producing 1kW DC input to the final.  With the mindset of
> > > still wanting to use the classic high-level plate modulation scheme,
> > > engineering a rig to use only one tube in the final (a 4-250, 250TH,
> > > 304TH/TL, 4-400, etc), modulated by a pair seems to make more common
> > > sense.  That, and it's a bit more economic in filament requirements.
> > >
> > > I've heard recently that matching the output of the Class C
> > > pate-modulated final to the antenna is better, and more efficiently
> > > achieved by link coupling, vs Pi-Net.  On the other hand, it's argued
> > > that Pi-Net coupling produces less RFI than link coupling does.
> > >
> > > So, which is better?
> > >
> > > Why?
> > >
> > > What are the effects of nuetralizing a single tube in a balanced tank
> > > circuit?  If Pi-N

Re: [AMRadio] Johnson 232-620

[Mike Dorworth,K4XM]

Correction: it is a 232-620. Paralax error reading handbook!
- Original Message - 
From: "Mike Dorworth,K4XM" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Wednesday, September 21, 2005 10:48 PM
Subject: [AMRadio] Johnson 232-620


Edgewise wound, 1/4" copper strip, cadmium plated, glass bonded mica
supporting bars. Widely used commercially. Safely handles more that 1000
watts.  232-622 winding  8 5/16" Long, 4" ID. 84 Microhenry.


__
AMRadio mailing list
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AM List Admin: Brian Sherrod/w5ami

Re: [AMRadio] Pi-Net vs Link Couple

[Mike Dorworth,K4XM]

The Pi-Net will give a total of 50 db suppresion of harmonics. about 20 in
one spot and 30 in the other. Link couple can pass harmonics to VHF by
capacity coupling, hence the Faraday Shield Links used for same later on.
There is a nice single 450th Pi-Net rig shown in the Editor and Engineers
handbook. Also a couple of single ended ones in the 1950 ARRL Handbook (for
triodes).  Some triodes that require lots and lots or drive can unbalance
the grid tank, which is required for triodes using Pi-Net. Lo capacity tubes
like the 450th is OK. The old timers mostly used tuners (antenna) and open
wire feeders to keep the harmonics down. Hazletine link neutralization can
also be used and no split tanks are needed in or out. Remember Class C ,
which is required for Hi level AM, is a extreme distortion  and harmonic
generator so that some plan need to be in place to handle the soup. Also a
single band dipole is very frequency selective and cuts way down on
harmonics by itself. Multiband dipoles, beams and multi dipole on one feeder
and traps etc (G5RV) are an open invitation to spread gook with only link
output. Also the guys that use CB lin years with no half wave filters get
away in mobile service without too many problems  due to the narrow
frequency discrimination of mobile antennas. Hope this helps, 73 Mike



- Original Message - 
From: "Geoff" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Wednesday, September 21, 2005 10:45 PM
Subject: [AMRadio] Pi-Net vs Link Couple


> SO, here we are, well past 1991 and the 'law' that went into effect
> saying that 1,500w PEP output is the maximum RF Power output that we
> hams can run, regarldless of mode.  That doesn't deter the homebrewing
> spirit, but it does suggest that acheiving 1,500w PEP output is much
> easier than producing 1kW DC input to the final.  With the mindset of
> still wanting to use the classic high-level plate modulation scheme,
> engineering a rig to use only one tube in the final (a 4-250, 250TH,
> 304TH/TL, 4-400, etc), modulated by a pair seems to make more common
> sense.  That, and it's a bit more economic in filament requirements.
>
> I've heard recently that matching the output of the Class C
> pate-modulated final to the antenna is better, and more efficiently
> achieved by link coupling, vs Pi-Net.  On the other hand, it's argued
> that Pi-Net coupling produces less RFI than link coupling does.
>
> So, which is better?
>
> Why?
>
> What are the effects of nuetralizing a single tube in a balanced tank
> circuit?  If Pi-Net is to be used, does the final tube still need to be
> nuetralized?
>
> I know of a guy who wants to build a rig using a single 450TL in the
> final, modulated by a pair.  He wants to pi-net the output, but I've
> heard that's a bad idea.
>
> I want to build a rig using a medium powered tride, perhaps a 250TH,
> modulated by a pair of 811's.  Pi-Net, or Link Couple?
>
> I like seeing this kind of technical discussion on the list.  I'm
> looking forward to all inputs.
>
> --
> 73 = Best Regards,
> -Geoff/W5OMR
>
> __
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> AM List Admin: Brian Sherrod/w5ami
>

[AMRadio] Johnson 232-620

[Mike Dorworth,K4XM]

Edgewise wound, 1/4" copper strip, cadmium plated, glass bonded mica supporting 
bars. Widely used commercially. Safely handles more that 1000 watts.  232-622 
winding  8 5/16" Long, 4" ID. 84 Microhenry.


From [EMAIL PROTECTED]  Wed Sep 21 23:06:30 2005
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Subject: Re: [AMRadio] Johnson 226-1
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If it was a power supply cap, they might have PCB's, but not an air
inductor.
Joe W4AAB
- Original Message -
From: <[EMAIL PROTECTED]>
To: 
Sent: Wednesday, September 21, 2005 9:30 PM
Subject: Re: [AMRadio] Johnson 226-1


> If it was in a Viking I, it may well have PCBs in it.  Be careful.
>
> 73,
>
> John,  W4AWM
> __
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> AM List Admin: Brian Sherrod/w5ami
>

Re: [AMRadio] Johnson 226-1

[Mike Dorworth,K4XM]

Johnson 226-3 Inductance 13.5 microHenry, 19.5 turns. Heavy duty rotary
inductor for amateur and commercial use. Handle over a KW of modulated RF
energy to 30 mHz. Winding 1/4" x 1/8" edgewise copper. Spring loaded
beryllium copper contact. Variable pitch winding- wide frequency coverage.
Height 6 1/2", width 4".  Guaranteed to contain NO PCB's.


- Original Message - 
From: "Bob Maser" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Wednesday, September 21, 2005 10:13 PM
Subject: Re: [AMRadio] Johnson 226-1


> My 226-3 is 14 uH and is good for a lot more goo that that.
>
> Bob  W6TR
> - Original Message - 
> From: "Barrie Smith" <[EMAIL PROTECTED]>
> To: "Mike Dorworth, K4XM" <[EMAIL PROTECTED]>; "Discussion of AM Radio"
> 
> Sent: Wednesday, September 21, 2005 9:56 PM
> Subject: Re: [AMRadio] Johnson 226-1
>
>
> > TNX, Mike
> >
> >
> > - Original Message - 
> > From: "Mike Dorworth,K4XM" <[EMAIL PROTECTED]>
> > To: "Discussion of AM Radio" 
> > Sent: Wednesday, September 21, 2005 7:37 PM
> > Subject: Re: [AMRadio] Johnson 226-1
> >
> >
> >> 22.5 microhenry, 27 1/2 turns, 1 KW of modulated energy to 30 MHz.
> >> - Original Message - 
> >> From: "Barrie Smith" <[EMAIL PROTECTED]>
> >> To: "Discussion of AM Radio" 
> >> Sent: Wednesday, September 21, 2005 9:25 PM
> >> Subject: [AMRadio] Johnson 226-1
> >>
> >>
> >> Hello All:
> >>
> >> Anyone have the specs on the Johnson 226-1 rotary inductor?
> >>
> >> Specifically need the total inductance.
> >>
> >> 73, Barrie, W7ALW
> >> __
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> >> Home: http://mailman.qth.net/mailman/listinfo/amradio
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> >> Post: mailto:AMRadio@mailman.qth.net
> >> AMfone Website: http://www.amfone.net
> >> AM List Admin: Brian Sherrod/w5ami
> >>
> >> __
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> >> Home: http://mailman.qth.net/mailman/listinfo/amradio
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> >> Post: mailto:AMRadio@mailman.qth.net
> >> AMfone Website: http://www.amfone.net
> >> AM List Admin: Brian Sherrod/w5ami
> >>
> >
> > __
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> > Home: http://mailman.qth.net/mailman/listinfo/amradio
> > Help: http://mailman.qth.net/mmfaq.html
> > Post: mailto:AMRadio@mailman.qth.net
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> > AM List Admin: Brian Sherrod/w5ami
>
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> AM List Admin: Brian Sherrod/w5ami
>

Re: [AMRadio] Johnson 226-1

[Mike Dorworth,K4XM]

22.5 microhenry, 27 1/2 turns, 1 KW of modulated energy to 30 MHz.
- Original Message - 
From: "Barrie Smith" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Wednesday, September 21, 2005 9:25 PM
Subject: [AMRadio] Johnson 226-1


Hello All:

Anyone have the specs on the Johnson 226-1 rotary inductor?

Specifically need the total inductance.

73, Barrie, W7ALW
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Re: [AMRadio] Drying out HV transformers / Chokes

[Mike Dorworth,K4XM]

Hey Joe, that's 140 degrees F without the thermostat being necessary!. Great
Idea!
- Original Message - 
From: "Joe A. Taylor" <[EMAIL PROTECTED]>
To: 
Sent: Sunday, September 18, 2005 2:09 PM
Subject: Re: [AMRadio] Drying out HV transformers / Chokes


> I'm sure may be too simplistic to work but.
> why not put the xformer in the trunk of a
> car and leave it there, outside in the sun, for
> a week or month.   Here in KY that works for
> most everything.  I've dried apples this way ;-)
>
> Joe  N4NAS
>
> >>Joe <<   [EMAIL PROTECTED]

Re: [AMRadio] Thordarson 83d21 driver transformer

[Mike Dorworth,K4XM]

T-8321 Line to P.P. grids of 46, 210, Class B, etc. 500 ohms to 5100 ,
ratio1:3.2 . 2 lbs. also 500 to 12,5000 ohms, ratio 1:5. 3 inches high 2.5
inch wide 2.5 inches deep , mounting centers 2.7/8 inches.  from Catralog
#400
- Original Message - 
From: "Mark Foltarz" <[EMAIL PROTECTED]>
To: 
Sent: Sunday, September 04, 2005 2:46 PM
Subject: [AMRadio] Thordarson 83d21 driver transformer


> Looking for specs on a 83d21 driver transformer. I think it is 500 ohm
line to
> PP Grid. However, I am not sure. Hoping to drive a pair of 811s
>
> Tnx
>
> de KA4JVY
> Mark
>
>
>
>
> 
> Start your day with Yahoo! - make it your home page
> http://www.yahoo.com/r/hs
>
> __
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>

Re: [AMRadio] Re: Choke calculations

[Mike Dorworth, K4XM]

 This was covered in QST for February 1963. page 16-17
The methode discussed uses a center tapped transformer and a full wave
rectifier. The choke is placed in series with the resistor and the voltages
are adjusted to be the same. The calculations are always at 120 Hz. It is
not necessary for the voltages to be equal if a small amount of error is OK.
The formula is XsubL equals Voltage across Reactor times the Resistance
divided by the Resistor value.  For 240 ma he uses 1250 ohm at 72 watts
resistor and about 300 volts from a replacement xformer. Heavy overloads for
a short time will not hurt the transformer. We have been here before. 73
Mike K4XM




- Original Message -
From: "Patrick Jankowiak" <[EMAIL PROTECTED]>
To: 
Sent: Sunday, August 21, 2005 6:12 PM
Subject: [AMRadio] Re: Choke calculations


> Now THAT is the key to happiness!
>
> Since we might wish to also measure the inductance of a choke with some
> amount of DC current flowing through it, does anyone have an idea how to
do
> this?
>
> In an example of a 10H choke, which would have 3768 ohms impedance, how
> would I pass 0.5 amp through it's 80 ohms of DC resistance without messing
> up the impedance measurement method?
>
> To me the obstacle looks like the issue of the power supply feeding the
> choke having a very low impedance compare to the measurement value to be
> made. Add to this the desire for a range of 0.1 to 100H and it's a real
> issue, at least from a calibration standpoint.
>
> I am certain some one on this list has done this before. It has to have
> been done in the choke factories of olden times!
>
> Patrick
>
>

Re: [AMRadio] power ratings

[Mike Dorworth,K4XM]

> However, highly non-efficient.

>Actually not TRUE. The total power pulled from power supply determines
effeciency. A low level and linear consumes less power for same carrier
power. See some KW mobile rigs from years ago.
also I remember WCKY had 50 watts modulated carrier ( 2 megawatts pep)
and it was from a LINEAR!.. my$ 0.02. Mike

Re: [AMRadio] power ratings

[Mike Dorworth,K4XM]

You will get lots of answers. the short and correct answer is 100 watts
carrier with peaks to 400 watts. I run a similar one at 150 watts carrier
for short periods. The reason the ricebox drops to 25 watts is because it is
100 pep am under those conditions about 17 watts is what I use to drive my 3
x 811a amp here. There was a great article in QST explaining this and I have
popsted ref in the past. The amp will easily do 600 pep but YOUR supply will
not, Mine will. That is why they say 400 watts PEP.. Hope this helps.. mike
- Original Message - 
From: <[EMAIL PROTECTED]>
To: 
Sent: Monday, July 11, 2005 11:54 AM
Subject: [AMRadio] power ratings


> I thought I understood these things, But I have confused me little self.
> I need some clear thinking here. I have a rice box rated for 100 watts
> SSB or 25 Watts AM. I believe the 100 watts is PEP while the 25 watts is
> RMS (continuous carrier). I want to add a linear amplifier to bring the
> 25 watts AM up considerably. I see the Ameritron AL-811 is rated for 600
> watts SSB and 400 watts AM. Is this 400 watts PEP or RMS. If PEP that
> means the RMS rating is 100 watts, the same as my DX-100. Also it
> requires 75 watts of drive. Is this PEP or RMS. If RMS my rice box at 25
> watts won't drive it. I am thinking the 75 watts of drive is PEP and my
> rice box with 100 watts PEP in AM will drive it. Can someone clarify this
> for me? Thanks.
>
> Ed K6UUZ
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>
>

[AMRadio] cooking Baxter's goose

[Mike Dorworth,K4XM]

If any person fails to pay an assessment of a forfeiture penalty
determined under subparagraph (A) of this paragraph, after it has become a
final and unappealable order or after the appropriate court has entered
final judgment in favor of the Commission, the Commission shall refer the
matter to the Attorney General of the United States, who shall recover the
amount assessed in any appropriate district court of the United States. In
such action, the validity and appropriateness of the final order imposing
the forfeiture penalty shall not be subject to review.

Re: [AMRadio] Baxter gets it

[Mike Dorworth,K4XM]

And does the FCC have the authority and the power to actually
"take" money from him?
- 

in fact they do. You should read 47USC section 503. They are limited to
$25,000 each day for each violation. Depending upon the number of violations
this can add up quickly!

The way it works, the Attorney General of the United is REQUIRED to go to a
District Court and the judges will order it done and jail those in contempt
of the order. If you will also read carefully, once the order is made it has
been made by congress not appealable to ANY court. In other words the FCC is
the due process.

TITLE 47 > CHAPTER 5 > SUBCHAPTER V > § 503
§ 503. Forfeitures


Release date: 2005-03-17

(a) Rebates and offsets Any person who shall deliver messages for interstate
or foreign transmission to any carrier, or for whom as sender or receiver,
any such carrier shall transmit any interstate or foreign wire or radio
communication, who shall knowingly by employee, agent, officer, or
otherwise, directly or indirectly, by or through any means or device
whatsoever, receive or accept from such common carrier any sum of money or
any other valuable consideration as a rebate or offset against the regular
charges for transmission of such messages as fixed by the schedules of
charges provided for in this chapter, shall in addition to any other penalty
provided by this chapter forfeit to the United States a sum of money three
times the amount of money so received or accepted and three times the value
of any other consideration so received or accepted, to be ascertained by the
trial court; and in the trial of said action all such rebates or other
considerations so received or accepted for a period of six years prior to
the commencement of the action, may be included therein, and the amount
recovered shall be three times the total amount of money, or three times the
total value of such consideration, so received or accepted, or both, as the
case may be.
(b) Activities constituting violations authorizing imposition of forfeiture
penalty; amount of penalty; procedures applicable; persons subject to
penalty; liability exemption period
(1) Any person who is determined by the Commission, in accordance with
paragraph (3) or (4) of this subsection, to have-
(A) willfully or repeatedly failed to comply substantially with the terms
and conditions of any license, permit, certificate, or other instrument or
authorization issued by the Commission;
(B) willfully or repeatedly failed to comply with any of the provisions of
this chapter or of any rule, regulation, or order issued by the Commission
under this chapter or under any treaty, convention, or other agreement to
which the United States is a party and which is binding upon the United
States;
(C) violated any provision of section 317 (c) or 509 (a) of this title; or
(D) violated any provision of section 1304, 1343, or 1464 of title 18;
shall be liable to the United States for a forfeiture penalty. A forfeiture
penalty under this subsection shall be in addition to any other penalty
provided for by this chapter; except that this subsection shall not apply to
any conduct which is subject to forfeiture under subchapter II of this
chapter, part II or III of subchapter III of this chapter, or section 507 of
this title.
(2)
(A) If the violator is
(i) a broadcast station licensee or permittee,
(ii) a cable television operator, or
(iii) an applicant for any broadcast or cable television operator license,
permit, certificate, or other instrument or authorization issued by the
Commission, the amount of any forfeiture penalty determined under this
section shall not exceed $25,000 for each violation or each day of a
continuing violation, except that the amount assessed for any continuing
violation shall not exceed a total of $250,000 for any single act or failure
to act described in paragraph (1) of this subsection.
(B) If the violator is a common carrier subject to the provisions of this
chapter or an applicant for any common carrier license, permit, certificate,
or other instrument of authorization issued by the Commission, the amount of
any forfeiture penalty determined under this subsection shall not exceed
$100,000 for each violation or each day of a continuing violation, except
that the amount assessed for any continuing violation shall not exceed a
total of $1,000,000 for any single act or failure to act described in
paragraph (1) of this subsection.
(C) In any case not covered in subparagraph (A) or (B), the amount of any
forfeiture penalty determined under this subsection shall not exceed $10,000
for each violation or each day of a continuing violation, except that the
amount assessed for any continuing violation shall not exceed a total of
$75,000 for any single act or failure to act described in paragraph (1) of
this subsection.
(D) The amount of such forfeiture penalty shall be assessed by the
Commission, or its designee, by written notice. In determining the amount of
such a forfeiture penalty, the C

Re: [AMRadio] 117Z6GT question

[Mike Dorworth,K4XM]

This is normal. The cold resistance is always much less than normal. In a
transmitting tube it is called in-rush. For the larger tubes some sort of
protection is usually used, or at least a filament transformer no larger
than necessary. The tube you are using has a 117 volt filament. 73 Mike
- Original Message - 
From: "gwt" <[EMAIL PROTECTED]>
To: "AM Radio List" 
Sent: Thursday, May 26, 2005 1:10 PM
Subject: [AMRadio] 117Z6GT question


> I have a question for the list.
> I'm repairing an old am radio that uses at 117Z6GT as a rectifier. I
> have the radio working again, but I notice when I turn it on that the
> 117Z6 filaments glow really bright for a couple of seconds. Then settle
> down to what you would expect to see, a red glow.
> I don't have any experience with this tube, or how it should act at turn
on.
> It what I'm seeing a normal condition?
> Thanks,
> George KE4HJ
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> Help: http://mailman.qth.net/mmfaq.html
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>

[AMRadio] Thordarson-Meissner Chokes

[Mike Dorworth,K4XM]

>From the Thordarson Catalog:
Chokes, Universal Swinging and Smoothing



T-20C51 5/25 MA15/35 Hy
T-20C53 60/100 MA 8/17  Hy
T-20C64 100/150 MA   3/7Hy
T-20C55 150/300 MA   2/9Hy
T-20C49 200/250 MA   4/5Hy
T-20C56 250/375 MA   4/8   Hy

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Date: Tue, 10 May 2005 16:52:39 -0700 (PDT)
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Cc:
Subject: [AMRadio] ARRL Bandwidth Regulation   --  I'm Worried!
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I keep hearing from my section leader, and sure don't like what I'm
getting!


The FACT is that they want to re-regulate us, and provide for AM in a
"special exemption" much as the KW grandfather clause. They then can
just elimainate the exemption.

To keep discussing the technical merits is a waste of time. They don't
want the facts, they have there minds made up, and are only agreeable
to amend them slightly to get it implemented. They then figure they can
change it simply by taking out the exemptions!

There is something BIG driving this, and I can't figure out what!

I just recieved this from "my" section leader:
--

Tentative proposals by frequency band:

160M - Entire band = up to 3 kHz
75/80M - Segments of up to 200 Hz, 500 Hz, and 3 kHz. A sub-segment
of 3 kHz would be open to automatic control. AM and Independent SB
(ISB) would be authorized by special exemption.
40M - Same as for 80/75.



I read this as no exemption for 160M. Therfore NO AM.

What can we do? We need to get together and get something started
or we are going to lose big! Discussion of technical aspects, which
they seem to ignore, will not help.

We need somehow to present another face to the FCC or I'm afraid we
will lose our operating privileges and can forget Ham Radio as we know
it!

I don't know how to do this, but hope we have an attorney or someone on
this list who does.

Sounds to me like we need to start a fund to fight this. Anybody got
any ideas?

I like my hobby. Don't want to give it up for "automatically"
controlled "digital" operation!!

Gary WB8BEM/8




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Re: [AMRadio] Keying a Gates BC-1?

[Mike Dorworth,K4XM]

found in ER number 160, September 2002 page 36.. Mike
- Original Message - 
From: "DAVID AABYE" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Monday, April 18, 2005 5:49 PM
Subject: Re: [AMRadio] Keying a Gates BC-1?


> Thanks for the reminder, Bob.  I have several years of
> ER and will look for your article. 
> 
> 73 de Dave
> 
> -- Bob  Login <[EMAIL PROTECTED]> wrote:
> > Hi Dave,
> > I wrote an article on a BC1T with a diagram for the
> > control circuit. It was 
> > published in ER about 2-3 yrs ago.
> > I used the BC1T for 2yrs before being forced to sell
> > because of a move73 
> > Bob, AA8A
> > - Original Message - 
> > From: "DAVID AABYE" <[EMAIL PROTECTED]>
> > To: 
> > Sent: Monday, April 18, 2005 5:18 AM
> > Subject: [AMRadio] Keying a Gates BC-1?
> > 
> > 
> > > Greetings Heavy Metal Enthusiasts,
> > >
> > > I'm trying to determine how best to place the
> > > oscillator in standby during periods of receive.
> > >
> > > I have two main concerns.  One is protection of
> > the
> > > 833's if plate voltage is applied without drive. 
> > The
> > > second is avoiding excessive cathode-to-filament
> > > voltage in the 807 audio drivers (cathode
> > followers).
> > > Perhaps both worries are more imagined than real?
> > >
> > > Anyway, please share your experiences.  Any advice
> > > will be much appreciated.
> > >
> > > 73 de Dave, W4QCU
> > > Oak Ridge, TN
> > >
> >
> __
> > > AMRadio mailing list
> > > Home:
> > http://mailman.qth.net/mailman/listinfo/amradio
> > > Help: http://mailman.qth.net/mmfaq.html
> > > Post: mailto:AMRadio@mailman.qth.net
> > > 
> > 
> > 
> >
> __
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> > Home:
> > http://mailman.qth.net/mailman/listinfo/amradio
> > Help: http://mailman.qth.net/mmfaq.html
> > Post: mailto:AMRadio@mailman.qth.net
> > 
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> 

Re: [AMRadio] Hallicrafters SX-24 coil winding information

[Mike Dorworth,K4XM]

Without a GDO you can use a wavetrap on the Broadcast band. Put the circuit
in the antenna and tune coil for null at low end of band with full cap. The
ARRL L/C/F/ Calculator, formerly known as the Lightning Calculator calls for
about 175 microhenry, on a three quarter inch form, it would take a winding
length of 7/8 inch at about 145 turns per inch of no. 34. Hope this helps..
73, Mike, K4XM

- Original Message - 
From: "Bill Fondren" <[EMAIL PROTECTED]>
To: 
Sent: Monday, April 18, 2005 12:10 PM
Subject: [AMRadio] Hallicrafters SX-24 coil winding information


> I need help I have a old Hallicrafters SX-24 that the broadcast band
coils, both osc and antenna coils are gone. For some reason the mice only
got those 2 coils and the old set works pretty good on all the other bands
so I would like to wind new coils and get the broadcast band working. My GDO
does not have the BC band on it so its no help.  I installed a universal osc
coil that seem to work but I cant seem to get the ant coil right.  I have
used formulas on the web and get about the same number of turns for the
windings.  The coils are wound on 3/4" form, the tuning cap is 440 mmfd.
with 4 mmfd of trim across it.  I am using 34 gauge wire and the formulas I
used says to use 130 turns for the secondary of the ant coil.  I used about
50 turns for the input coil.
> Any help or suggections would be appreciated.  I also have the HT-9
transmitter and would like to get the  1939 station back on the air.
ThanksBill Fondren   K5PML
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Fw: [AMRadio] B&W 5100, 5100b differences?

[Mike Dorworth,K4XM]

 The 5100B was plug and play with the 51SB-B Sideband Generator. I had one
of each and the 6100 too! Best I remember that is the main difference. Mike
K4XM
>
> -- Original Message --
> From: George KB2Z <[EMAIL PROTECTED]>
> Reply-To: Discussion of AM Radio 
> Date:  Mon, 14 Mar 2005 09:30:35 -0500
>
> >Morning all,
> >Could anyone on the list tell me the performance differences between the
> >B&W 5100 and 5100B?
> >On the schematics the changes in the audio/modulator section jump out.
Was
> >one better than the other? Any thoughts or opinions would be appreciated.
> >Thanks in advance, George KB2Z
> >
> >__
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> >Home: http://mailman.qth.net/mailman/listinfo/amradio
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> >Post: mailto:AMRadio@mailman.qth.net
> >
>
>
>

Re: [AMRadio] need help with tranmitter design

[Mike Dorworth,K4XM]

heath called it " linear master oscillator" first used in the sb300 rx..
- Original Message - 
From: "Jim candela" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Sunday, March 13, 2005 12:22 PM
Subject: RE: [AMRadio] need help with tranmitter design


> Ed,
>
> One option would be to use a DDS VFO as your RF source, and drive the
> rig in 67 ARRL Handbook without modification. What do you intend to use as
a
> receiver? Is this a tranceiver project? Also I cannot recall what LMO
stands
> for? Maybe "Local Modulated Oscillator"?
>
> Some Google hits on LMO:
>
> Living Modified Organism
> Louisiana Radio Records
> Long Mountain Outfitters
> Little Marsh Overflow
> Life Maintenance Organization
>
> :-)
>
> Regards,
> Jim
> WD5JKO
>
>
>
> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] Behalf Of Edward B Richards
> Sent: Friday, March 11, 2005 11:05 AM
> To: amradio@mailman.qth.net
> Subject: [AMRadio] need help with tranmitter design
>
>
> I am designing an AM, tube-type transmitter for mobile use. I want to use
> a minimum of parts to keep the cost, size, weight and power consumption
> to a minimum. Also, I want to use as many existing parts as possible. I
> have a Heathkit LMO for the VFO and a parts HW-101 for the tuning caps,
> coil etc. I found a circuit I like in the 1967 ARRL handbook, page 187
> using only 4 tubes plus a VR tube. I need to modify the circuit to fit my
> wants. I am not engineer enough to redesign it. Can someone suggest a
> circuit to use a 12BE6 as a pentagrid converter using the oscillator
> section for a crystal oscillator with the LMO for the RF input. The
> output would be on final frequency. For 75/80 meters the crystal would be
> 9.00 mc. I would like to follow the mixer with a driver, then a 6146
> final. It is screen grid modulated. I have all the tubes. Thanks.
>
> 73, Ed Richards K6UUZ
> AMI member #1534
> __
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Re: [AMRadio] Info on SAIT HF amp?

[Mike Dorworth,K4XM]

well, I thought it was a Olds 442 from about 1966 or so. Four BBl carb, 4 on
the floor and dual exhausts..442..would leave about the same dust as a pair
of 4-400s would on 75M.. Mike
- Original Message - 
From: <[EMAIL PROTECTED]>
To: 
Sent: Monday, February 14, 2005 2:21 PM
Subject: Re: [AMRadio] Info on SAIT HF amp?


>
> Pete wrote:
>
> >>as the 4-440A.
> >Wasn't this an Oldsmobile muscle car??
>
> -grin-   yes, I must have been thinking of my old Plymouth Fury
> ex-state-police car with the 440 V8.
>
> Naturally the tube type should have been 4-400A
>
>
> Steve WD8DAS
>
> [EMAIL PROTECTED]
> http://www.qsl.net/wd8das
> ---
> Radio is your best entertainment value.
> ---
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Re: [AMRadio] Jim's tvi problems

[Mike Dorworth K4XM]

Far be it from me to be a power line expert. However the glowing red spot
means it is: 1. About to burn out or 2. About to BLOW UP! I would leave the
sledge hammer work to the paid professionals.. 73 Mike
>
>
>
> Jim:
> get you a sledge hammer and while listening to ur radio smack the pole a
> few times. also look for poles with a bank of caps on it. these are known
> sources of pulse noise as they have two hardware nuts and a lot of the
guys
> just tighten the first one and snug the second.
> 73 Tony
> QBE  ZUT  DE WA4JQS
>
>>



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[AMRadio] AM Linear amplifier operation

[Mike Dorworth, K4XM]

QST Magazine for February 1956, on page 39 in the Technical Topics Section
 has a very nice article explaining  Linear Amps and AM operation
The Carrier never goes away and the thing runs cooler while talking when the
efficiency goes up!.

The tubes must have twice the dissipation of the carrier output.
That sounds like a 30L1 with 260 watts total dissipation should do 130 watts
carrier.
Maybeso, remembering however that most SSB rated supplies are designed
around the 20 percent duty cycle for voice operation  level. Which means
that the constant carrier works on it . Bottom line, on most SSB rated amps,
run 1/4 total dissipation as carrier unless you have that special HEAVY iron
transformer (can we say Boatanchor?).

Read the article and it will all make sense..

Hope this helps.. 73 Mike 4XM



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Re: [AMRadio] Scopes

[Mike Dorworth K4XM]

the old Heathkit vector scope has a switch and leads that come directly from
the plates, makes an instant scope for monitoring.. Mike
- Original Message - 
From: "Peter Markavage" <[EMAIL PROTECTED]>
To: 
Sent: Thursday, January 13, 2005 2:22 AM
Subject: Re: [AMRadio] Scopes


> Almost any old scope will work that doesn't billow smoke when you turn it
> on. Heath, Eico, Paco, a no name flea market treasure, and all the way to
> the whiz Tek and HP models. Some RF sampling into the vertical plates and
> you're in business.
>
> Pete, wa2cwa
>
>



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Re: [AMRadio] Grounds (was AM Amps)

[Mike Dorworth K4XM]

Since we are talking safety and AM radio, as a more than fifty year ham let
me tell you that the below stuff is true. Also remember: Turn off the b plus
when neutralizing a pair of 813..ask me how I know...DO not jump out the
interlocks on a BC610 then turn of the external VFO, then after observing
all meter on zero adjust the antenna link.(2500 volt supply under load
becomes 4000 VDC!). Happened in 1957, still have hole in finger and wrist
bone.. good news, it only took six weeks in the sling.. Things like shorting
sticks, wires across oil filled capacitors months after last use are
timeless advice that means STAY ALIVE if possible.. 73. Mike K4XM


- Original Message - 
From: "Tom Norris" <[EMAIL PROTECTED]>
To: 
Sent: Thursday, January 13, 2005 9:26 AM
Subject: [AMRadio] Grounds (was AM Amps)


> You know the old saying -- "Been there, done that, still have the scars"
> (and with a bit of time may be able to find the paramedic's report.)
>
> *Always* make sure AC powered gear has a GOOD earth/safety ground,
> even RF gear of *any* sort. You don't really want to know what happens
> when parts of you become part of the counterpoise for a 5 KW medium
> wave antenna system. And never ever defeat interlocks. Don't ask how
> I know.
>
> (OT-I've even got a couple good scars from my land mobile days
> from 1 watt UHF HTs)
>
>
> Tom NU4G
> "lockout-tagout poster child"
>
> >
> >Jim,
> >
> >If anyone believes that they don't need a good earth ground on their
> >equipment, I'd be glad to set them straight.
> >
> >Darrell, WA5VGO
> >
> >
> >At 06:07 PM 1/12/2005 -0600, you wrote:
> >
> >>Darrell,
> >>
> >>That amp you built with the 4-1000 was a "killer" in more ways than one!
> >>Time for a confession..
> >>
> >>Regards,
> >>Jim
> >  >WD5JKO
> >  >
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Re: [AMRadio] Windom

[Mike Dorworth, K4XM]

Boy are we down to the nity grity now!. Since one reactance is positive and
the other negative that is leading and lagging or Eli the Ice Man so to
speak, when they are added and the real componets are equal but the sines
are opposite they CANCEL.. Happy New Year.. 73, Mike, K4XM
- Original Message -
From: "Geoff/W5OMR" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Friday, December 31, 2004 8:35 AM
Subject: Re: [AMRadio] Windom


>
> - Original Message -
> From: <[EMAIL PROTECTED]>
> To: 
> Sent: Friday, December 31, 2004 7:03 AM
> Subject: [AMRadio] Windom
>
>
> > Gents:
> >
> > Resonance, as I understand it, occurs when the capacitive and inductive
> > reactances cancel.
>
> not cancel ..  'are equal'.
>
> R = X(sub L)=X(sub C) or when Reactance is at, or very near 0 (Zero)
>
> Definition of Reactance:
> An ac circuit condition in which inductive and capacitive reactances
interact to
> cause a minimum or maximum circuit impedance.
> www.yung-li.com.tw/EN/info/Glossary_list.htm
>
> 73 = Best Regards,
> -Geoff/W5OMR
>
>
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Re: [AMRadio] Windom

[Mike Dorworth, K4XM]

Yup, thas rite! In or on a Windom, the idea is to find that spot where the
antenna is resonant AND the feedline is attached to a piurely resistive
point so that to SWR exists. This is the reason a properly made Windom has
no feed line length restriction. The fact that it works as a resonant
antenna with no feedline SWR is why we are still talking about it 75 years
after Mr Windom worked out the formulas and a means of testing a multiband
NO SWR antenna.. happy New Year! 73, Mike, K4XM
- Original Message -
From: <[EMAIL PROTECTED]>
To: 
Sent: Friday, December 31, 2004 8:03 AM
Subject: [AMRadio] Windom


> Gents:
>
> Resonance, as I understand it, occurs when the capacitive and inductive
> reactances cancel.
>
> Regards,
> Steve
> WA2TAK
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Re: [AMRadio] Windom Antenna

[Mike Dorworth, K4XM]

Okay, let us try again. I thought the question was.." how can it be
RESONANT" at more than one place..Mr. Windom clearly shows that it is and
how to prove it. A antenna cut for twenty works great on 10, a forty meter
job works great on twenty and ten, an 80 meter works 80-40-20-10 etc. It is
always RESONANT on all harmonics.The single wire feeder shows about 600 ohms
to ground and is worked against ground from the link or output. If the wire
were fed in the center of the antenna, then the antenna WOULD NOT RADIATE at
all, only acting as a top load capacitance. Also the length of the feeder is
of no matter and 1200 feet works fine. Sure there is a little radiation from
the feeder, but not too much. The straight away part insures that the RF
picked up from the antenna  (SORTA ) cancels out..These antennas work well
with old Boat Anchor PI-Network outputs, those that go to 600 Ohms. There
are no Standing waves on this type of antenna to feeder connection on the
FEEDER!..I can e-mail the original QST article as an attachment (jPEG) for
those wishing to read further on Mr. Windom's discovery.. Happy antenna
experimenting in '05..73 de Mike, K4XM
- Original Message -
From: "Geoff/W5OMR" <[EMAIL PROTECTED]>
To: "Discussion of AM Radio" 
Sent: Monday, December 27, 2004 12:28 PM
Subject: Re: [AMRadio] Windom Antenna


> > In QST magazine for September 1929 the original Windom Antenna article
> > starts on page 19. It clearly shows that it is exactly resonant on all
of
> > it's design bands, so long as there is an harmonic relationship.
80-40-20-10
> > etc. There are diagrams included which show how this is determined with
an
> > RF ammeter and a rolling trolley after which very precise and repeatable
> > formulas were derived. Of course this is the single wire fed version.
The
> > later 300 Ohm job is merely wishful thinking.The length in feet is
always
> > 468, divided by desired frequency in Kc. For the lowest desired band.
The
> > tap is always feet times 25 divided by 180. I might add that antennas
put up
> > as temporary during this nasty winter weather last 20 to 30 times longer
> > than summer installed permanent antennas. happy antenna experimenting.
73,
> > K4XM, Mike.
>
> So, in order for this to work, you have to decide what frequency you're
going
> to operate on, on the HIGHEST frequency the antenna will cover.
>
> ie: 29MC /2 = 14.5, 7.25, 3.625, 18.125Mc.
>
> that being the case, then
> L = 468/f(L)
> L = 468/18.125
> L = 258.20689655172413793103448275862
>
> Now, you said that the 'tap is always feet times 25 divided by 180'
> T = 258.207ft * 25 / 180
> T = 6455.17 / 180
> T = 35.862068965517241379310344827586
>
> Single wire feeding it?  Fed against Ground?  Doesn't the single feed-line
then
> become part of the radiating antenna?
>
> Even if someone were to take, say the output of a link and feed it
directly to
> the
> open wire feed-line, the open wire line would have to go all the way to
the feed
> point of the antenna, wouldn't it?
>
> I'm sorry if I'm seeming a little dense, but I can't get unwrapped from
the
> 'single wire fed version' of this antenna.
>
> Open wire output from the link has *2* wires.  I can see attaching them to
some
> open wire line, and feeding this Wyndom antenna at 1.8125, and having the
> antenna resonant on 3.6250, 7.250, 14.5 (oops - can't operate there) and
29Mc,
> but I simply fail to understand how one wire is going to feed an antenna
thas
> has two posts to connect to.
>
> Certainly has me thinking, though.  Now, if I could just come up with land
that
> had 300' (for guy supports on both sides)
>
> I'll have to work CW on 3.6250, forget about 20m and enjoy a
multi-wavelength
> antenna on 10m (when the band is open).  Pardon the sarcasm ;-)
>
>
> Seriously, here. Surely, there must be something I'm missing, to be able
to use
> this antenna on all bands, with acceptable VSWR.
>
> 'Splain it to me, please.
>
> Happy New Year
>
> 73 = Best Regards,
> -Geoff/W5OMR
>
>
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