I'll see if I can draw one up for you Mike. And put pictures up for all to
look at. But it want be tomorrow. It take me some time to do things these
days.
John, WA5BXO
-Original Message-
Geoff said: So, John has Otis' 833 final in his possession and is going to
replace the bias
Correction to spelling:
But it won't be tomorrow. It takes me some time to do things these days.
Sorry
John, WA5BXO
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of John E. Coleman (ARS
WA5BXO)
Sent: Monday, June 04, 2007 10:52 AM
To: 'Discussion of AM
Tom
Does this rig use a plug in coil assembly on a large ceramic jack
bar? And is the coil connected to the plate of the tube or is it connected
through a coupling capacitor to the plate.
There or only a few ways to wire an output link coupled rig with a single
tube (not Push pull).
Are
Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of John E. Coleman
(ARS WA5BXO)
Sent: Sunday, June 03, 2007 10:09 AM
To: 'Discussion of AM Radio in the Amateur Service'
Subject: RE: [AMRadio] HB Transmitter Schematic
Tom
Does this rig use a plug in coil assembly
There was no trouble with the receiver. I regret to say that I forgot about
wiring the RF gain control backwards to avoid a bad spot on the control.
Shoot - I can't remember what I've done to my on rig let alone what I did
for Otis. So you have to turn the RF all the way counter clockwise for
Opps, sorry I meant to send that to Geoff, W5OMR
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of John E. Coleman (ARS
WA5BXO)
Sent: Sunday, June 03, 2007 2:46 PM
To: 'Discussion of AM Radio in the Amateur Service'
Cc: 'Perry Mason'
Subject: [AMRadio
Hey guys,
If you get a chance go by the Alinco booth. I think it is 76 and
77, to visit with an AM friend of mine, Larry, WD5CFJ. Larry was the one
that supplied Otis, K5SWK, with the rig to get back on the air. Otis has
only been on once with it but as soon as we get the coax run into
Bow:
You need to start over if you want to get 600 watts carrier output.
A pair of 813s is just not capable of doing this in linear AM service. 150
to 200 watts is about it. And you don't have enough power supply either for
large AM service. Keep in mind that to get a carrier of 600
in a hurry, or and are words are interchangeable.
Sorry,
John, WA5BXO
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of John E. Coleman (ARS
WA5BXO)
Sent: Monday, April 23, 2007 10:04 AM
To: 'Discussion of AM Radio in the Amateur Service'
Subject: RE: [AMRadio
George
If you asking to me, WA5BXO/John, then no. I will not be going to Belton.
Sorry, I have Boy Scout stuff to deal with but thanks for asking.
John Coleman
WA5BXO
__
AMRadio mailing list
List Rules (must read!):
No Problem George, hope you all have a great time.
John, WA5BXO
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of George
Sent: Wednesday, April 11, 2007 10:17 AM
To: 'Discussion of AM Radio in the Amateur Service'
Subject: RE: ***SPAM*** RE: [AMRadio]
Jim:
We might want to clear up something here about plate efficiency. Many new
people get confused about all this.
Starting with a triode because it is easier to explain:
Suppose we have a triode tube operated in class C service for plate
modulation. Let's use 3000 volts and at 86 ma of
I have known Don, K4KYV a long time and Have never know any transmissions
from the K4KYV memorial station to be 15KC wide, 7KCs maybe. Don has a very
linear modulation system with very low intermodulation or harmonic
distortion. He has an audio filter that cuts off pretty sharp in the 3KC
range.
The big rig move is not planned for yet. We are still getting the temp
station set up. You have to move very slowly with Otis! He doesn't like
changes.
John WA5BXO
__
AMRadio mailing list
List Rules (must read!):
possibility would be the filaments are not lit up good.
Rule for the day:
You can't have a 100 volt drop across a good 5ft #12 wire with out a fire.
John
Previous message:
John E. Coleman (ARS WA5BXO) wrote:
What you're saying is that at no time, can you get more that 20 ma of
plate current? Try
I have a 450 Mhz repeater that was given to me buy Steve K5LTK. He wants me
to try to find a home for it. Spread the word please.
See the pictures and explanation at the link below. First picture has text
embedded.
http://wa5bxo.shacknet.nu/ForSale/450%20repeater/
There is also a lot of hand
At the link below is a box of interesting old radio parts
From the chassis of a United States Radio and Television Corp model 46
Screen grid TRF radio. Sorry no tubes were in the chassis.
http://wa5bxo.shacknet.nu/ForSale/old%20radio%20parts/
If someone is interested in restoration of one of
Maybe it could be used on 10 meters if someone was familiar with it?
Base station is in a small 19 rack cabinet and the mobiles mount under
dash.
This includes a couple of Johnson handy talkies and some regency equipment.
http://wa5bxo.shacknet.nu/ForSale/EFJohnson31MHZ_Equipment/
Make an
The repeater and associated equipment have been pickup up.
Good Luck to WB5UGT and Salt Grass group. 8 PM SAT 1-6-07
John, WA5BXO
___
Amradio mailing list
List Home: http://w5ami.net/mailman/listinfo/amradio_w5ami.net
Partner Website:
I agree with John Lawson, that learning code has nothing to do with
intelligence any more than learning Spanish or playing the guitar which I
can do neither. Yes I did pass my 20WPM but I am thankful I don't have it
to do again. So let us all hope that the loss of the testing for CW will
bring a
The tubes have not arrived yet Brett. I am certainly in no hurry but was
wondering if you have the address. Thanks for your consideration on this
gift please let me send you something in return.
The Computer Fixer
1622 Sawdust Rd. Ste A1
The Woodlands, Texas 77380
281-367-6765
I will be on the
Otis, K5SWK may be on the air tonight from the BXO/PKD shack.
If the noise is too bad I may have to call someone on the phone to act as a
remote receiver site.
John, WA5BXO
__
AMRadio mailing list
List Home:
for him, and plan to record the entire session with Otis as well.
73
Brian
On 12/14/06, John E. Coleman (ARS WA5BXO) [EMAIL PROTECTED] wrote:
Otis, K5SWK may be on the air tonight from the BXO/PKD shack.
If the noise is too bad I may have to call someone on the phone to act as
a
remote receiver
No, look again, it is internal series multiplier, so that the meter will
read volts with a direct hookup. If this is a 0-500 Volt meter as the
picture seems to indicate, and multiplier was 500,000 ohms then the meter
movement would have been a 1ma movement. I see no reason for a capacitor to
Jack I would dispense with the startup circuit. With the choke input filter
system and only 4mf of output capacitance you want need a start up circuit.
When I hit the push to talk switch is when my PS plate XFMR comes on. The
heaters to the 866 are on all the time.
John
-Original
BJ WB5PKD and I are fighting noise again
Noise in the shack Saturday night - Sunday morning - on the HQ145 was S9+
and Don (KYV) was 40 over with noise when he hit 60 over at the top of the
meter was when the noise when quite
BJ sent this to me after the rain, thought it might get a laugh.
will
read 500.
Good Luck
John, WA5BXO
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Jack Schmidling
Sent: Monday, December 11, 2006 5:32 PM
To: Discussion of AM Radio in the Amateur Service
Subject: Re: [AMRadio] Component ID please
John E. Coleman (ARS
Jim: (JKO)
That is an interesting statement which I had never thought of
before. Using two XFMRs like Jack said, seems at first to be a good theory
but as you pointed out each transformer will be looking into a half
rectifier circuit so that the duty cycle on each core and primary would
. After all , over 50 now, so CRS is a fact of being
an OM! ;-)
I had to make a 0-200amp DC linear series regulator for that supply. A
large water cooled heatsink and 32 TO-3 2N6258's in parallel. What a
monster that was!
Regards,
Jim
JKO
- Original Message
From: John E. Coleman (ARS
Or maybe it the center connector is just a terminal post with no function in
the switch.
John, WA5BXO
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Rick Brashear
Sent: Monday, December 04, 2006 10:51 AM
To: Discussion of AM Radio in the Amateur
Hold on to that Jeff I think I may build a little 812s X 811s rig again in
the future.
John, WA5BXO
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of ARS W5OMR
Sent: Monday, December 04, 2006 5:00 PM
To: Discussion of AM Radio in the Amateur Service
Rick
The most common type of failure is dried up electrolytic capacitors.
John, WA5BXO
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Rick Brashear
Sent: Friday, December 01, 2006 4:15 PM
To: AMRadio@mailman.qth.net
Subject: [AMRadio] Schematic
Jack
You first need to decide
1. If you want push pull finals with Link coupled tank circuits and plug in
coils or
2. If you want go with the pi net on single or parallel tubes.
Push Pull can be tetrodes or triodes
Push pull is very stable and easy to neutralize with either
I thought I read where Jack said the scope pattern at the grids of the
modulator tubes looked altogether different than the pattern at the plate of
the driver tube. If this is true then the driver XFMR might be shorted. I
am not real familiar with the driver XFMR on the ranger but if it is one
I will be gone this weekend and will not be able to check email till Monday.
Can't wait to see who done it.
John Coleman, WA5BXO
__
AMRadio mailing list
List Home: http://mailman.qth.net/mailman/listinfo/amradio
Partner Website:
Radio in the Amateur Service
Subject: Re: [AMRadio] Ranger Audio
John E. Coleman (ARS WA5BXO) wrote:
Hi Jack
This may be another dumb question but when you have a 60 watt bulb
for a dummy load and you tune the ranger into, of course it won't light to
full brilliance of 60 watts
: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Jack Schmidling
Sent: Thursday, November 16, 2006 5:54 PM
To: Discussion of AM Radio in the Amateur Service
Subject: Re: [AMRadio] Ranger Audio
John E. Coleman (ARS WA5BXO) wrote:
A 150 watt bulb is going to be pretty dim with just 40 watts RF
Hi Jack
This may be another dumb question but when you have a 60 watt bulb
for a dummy load and you tune the ranger into, of course it won't light to
full brilliance of 60 watts with only 40 watts going into it but it should
brighten up a lot, even to full 60 watt brilliance, when you
I will have to disagree with that.
A 40 watt carrier with 100% modulation (sine wave audio) will produce a
120Watt PEP output, but PEP is not average. The average power that the
dummy load will see is a 50% increase.
40 watt carrier + 20 watts of sideband = 60 watts average RF power.
A
But I never could stop at thre
John, WA5BXO
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Jim Candela
Sent: Wednesday, November 15, 2006 10:13 AM
To: Discussion of AM Radio in the Amateur Service
Subject: Re: [AMRadio] Ranger Audio
John,
Push pull
John
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Rick Brashear
Sent: Sunday, November 12, 2006 10:28 PM
To: Discussion of AM Radio in the Amateur Service
Subject: Re: [AMRadio] Class C final tube swaping
John,
When you had these
Jack:
There should not be that much difference. Perhaps the Ranger is not
putting out enough power because of a problem or its output is not making it
to the antenna. There could be a problem on the pass through circuitry of
the SB200. Try hooking the Ranger directly to the antenna not
Mark:
There must be a magazine some where that will pay for this story.
But you need to color it up some and drag out the details of how numb your
fingers were in the cold, while working, etc. 30 seconds is just to short
of a time frame for a magazine story. HIHI
Ham Radio, Homebrew, and
Jack, pardon me if I make statements that you are already familiar
with but I am not familiar with your background and also there may be new
people to this AM tech stuff that are wondering what you talking about. So
here goes.
The purpose of the Trapezoid pattern is to verify
Hi Charlie -
I guess it might be called an airplane dial. It is circular with AM
at the top and two SW bands at the bottom. In addition to the large double
pointer it also has a single pointer which spins around the center as a band
spread (mechanical reduction vernier).
Thanks to
What was in these things? The inside of the can is lined with a perforated
brittle screen perhaps some carbon stuff. The center post is connected to a
foil which is wound in a spiral. I don't think it is laminated foil? The
other capacitor was the same except the foil same material as before
I have been given a Stewart Warner - Ferrodyne Model R-1361-A. It
is a three band radio.
Tube line up is as follows.
6F6 Audio output,
6K7 RF,
6A8 mixer/osc,
6K7 IF,
6H6 2nd det,
6J7 1st Audio,
5Y3 Rectifier.
The output XFMR primary was open, probably due to the gassy
I am not a listener of CHU but I am curious as to what would be the
disadvantage to changing the license from FIXED service to BROADCASTING
service. Are there fees involved and special broadcasting requirements that
would cost a lot of money?
John, WA5BXO
This is a last minute reminder of the Jamboree On The Air (JOTO)
event that is to take place the weekend. Please join in and talk to some
boy scouts. I will be with Troup 1772 of the Sam Houston Area Council. Our
operations for JOTA will take place while camping at the Galveston Island
For what ever the reason is, Zero Beating has always been problem.
Certain people would complain about it back in the 60s. Or I should say the
lack of zero beating has been a problem. Sometimes guys would be so far off
frequency that they couldn't be heard.
I have had a couple
I operate AM because of the varied technologies that are involved in the
design and construction of the stuff. I enjoy discussions about these
technologies with others. After 35 years I still find many things to learn
about. Tubes are extremely complicated devices with parameters that extend
I wonder if the FCC plan is to trade us the bandwidth for BPL sharing. They
are really being stupid about this BPL thing. There must be a lot of money
and big company push involved.
John, WA5BXO
__
AMRadio mailing list
List Home:
I can always count on you Jim, for a good comment and a laugh.
Well Jim, That's why when I'm on the air with some one I don't know to well
and I'm not to sure how well they are hearing me so I tell them The name
here is John, like the commode
Sorry Brian, it's just been one of those days, By
That VHS tape can be digitized to a format viewable on everyone's
computers. I'm sure that John, KB6SCO or I could do that for you Eddy, and
then we could all enjoy it.
John, WA5BXO
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Ed Swynar
Sent:
The trouble with low z microphones is that some times the output of
the mic is too low and you don't have enough gain to get the modulation up
high enough. If you do have enough gain then they work just fine in the
hi-z input circuit. Beware that some input circuits do not have, or use,
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
BJ and I are having the devil of a time with line noise. As soon as one
thing in the neighborhood is fixed, a week later another is trouble. We
won't let up on the calling about the trouble but in between the fixes, it
would be nice to be able to operate. We would really like to experiment
with
That's ODD:
I've always found it to be a problem the other way around. Where
they don't like to match low Z such as 100 Ohms or lower. but it can be a
problem at higher Z if the feed point is reactive where the total length of
the ant and the feed line do not come out close to a
Ok so I found myself with out enough hardware.
I have a 100K dual audio taper pot from Radio Shack and I lost the nut. It
is one for mounting in a 5/16 hole so I assume it is a 5/16 treaded sleeve
with a 1/4 inch shaft but I can't find any hardware for it.
Now I could just go buy another pot
it The
Nut Case! hi
Tom K3TVC
- Original Message -
From: John E. Coleman (ARS WA5BXO) [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; 'Discussion of AM Radio'
amradio@mailman.qth.net
Sent: Friday, August 18, 2006 2:29 PM
Subject: [AMRadio] Hardware for potentiometer
Ok so I found myself with out
1 or 2 for now --- up to 10-20 for the future.
John, WA5BXO
-Original Message-
On Behalf Of [EMAIL PROTECTED]
J.
How many u want??klc
- Original Message -
From: John E. Coleman (ARS WA5BXO) [EMAIL PROTECTED]
Date: Friday, August 18, 2006 2:33 pm
Subject: [AMRadio
The thing about batteries is they give great isolation. A VTVM uses a
differential amplifier for the metering. It may be a problem getting
another supply in place with the isolation that is needed. I would need to
study it a little. It could be difficult or it might be easy. If either
side of
What a coincidence.
I just had a customer in my computer shop yesterday telling me her tell of
woe all and about her conversation with Frank in New Deli. Some of these
guys are actually pretty smart and some just read from a clip board as is
the case even here in the US as well. The biggest
I think the 32V2 or V3 will produce a clean 75-100 watt carrier and
modulates with good upward linearity producing a output of about 400 Watts
PEP (correct me if I'm wrong here because although I had one in operation, I
never measured it.) If that is true then it would be hard for me to believe
A friend of mine has acquired an old Grundig Console Radio and would like
more info about it such as manufacture date, etc.
Pictures at
http://wa5bxo.shacknet.nu/Kathi%20Raines%20Radio%20Pictures/
Appreciate any help any one can give on this.
Thanks, John, WA5BXO
Don
You are correct of course, about the non specific 807 to 833 relationship
but this would be true also if in push pull transformer or link coupled
driver, AF or RF. Either one of the 833s will see the energy arriving from
the secondary of the XFMR coupling and does not care which driver tube
Geoff
Thanks for your concern but I did send the message to both you and the list
and it did come back to me from the list.
Thanks anyway because as you know I am just as likely to send it to my
Grandmother, rest her sole.
John
This is almost like discussing politics on the air. HIHI
But I will make a comment here any way.
Dino and Geoff
Valid comments all, but someone mentioned earlier, that we should use
complete sentences when replying. I agree with this. I like that person's
idea about how the reply should be, as
Hi Conner and welcome aboard.
Please pardon me if I am incorrect in my assumption that you are not an
amateur radio operator and may be only familiar with the hobby. In either
case you will find this list to be a great group of guys and gals, I think
around 500 in number.
I'm not sure if you
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
This is also true Jim. This is why I use a VTVM with a 1 meg resistor in
the probe. I make up a special resistor probe divider network in addition
to this to do measurements of HV with. I occasionally check the voltmeters
on the front of the transmitter for calibration using this lash up. But
At 16 - 17 years old, I got a scar on the side of my hand near my thumb
where I brushed against the end of the BW KW plug in tank coil. The rig
ran a pair of 813s push pull and had 2500 volts from a BC610 plate XFMR and
a pair of 866s rectifiers. It was operational at the time so it had RF and
Rick
What is the DC resistance of the coil measured with your ohm meter?
John, WA5BXO
.
Thanks,
Rick
John E. Coleman (ARS WA5BXO) wrote:
Rick
What is the DC resistance of the coil measured with your ohm meter?
John, WA5BXO
__
AMRadio mailing list
Home: http://mailman.qth.net/mailman/listinfo/amradio
Help
I'm sorry Geoff, but the current capabilities of those or any small relay
would not be large enough for the RF current.
John, WA5BXO
I think the XFMR has four connectors on one end and two on the other end.
The bottom two of the four are to be strapped and make the B+ connection for
the modulator. The top two, of the four, are the modulator plate
connectors. The two on the other end are the secondary winding to go to the
Strange indeed Bill!
I don't mean to be descending but have you checked to see if you
wearing your wife's glasses instead of yours. HIHI
It is possible to drive the screens instead of the control grids as
a class B zeros bias circuit however it would require neutralizing to work
Bill does the screen have a DC path to ground through the tuning coil? I
see no way that you can have grid current with no RF on the Grid. Perhaps
there is a hidden wire connecting the grid and the screen together.
I am sending you a PDF on the 813 just to make sure that you have a correct
one.
Now that is interesting Geoff. I didn't realize that Solo made filament
XFMRs. And because directly heated cathode type transmitting tubes are very
sensitive to filament voltage then it makes since to have a transformer that
will deliver the proper voltage regardless of input.
John, WA5BXO
The filament choke is why I said to just drive the grid direct or maybe put
a 50 ohm load on the grid.
John, WA5BXO
. Coleman (ARS WA5BXO) wrote:
BTW, ,John - those Transistors I got, and told you about (for the
solid-state audio driving circuit) are
2SC3461's. They would probably be a good replacement for the ECG164's,
for directly driving the grids of a Class B modulator.
--
-Geoff/W5OMR
2SC3461NPN Triple
Rick
I will apologize ahead of time here because this math may be very
easy for you but for some it may not be. So I have explained it below and
simplified it at the end. I have done this many times. I have used the
Heath Cantenna and mounted the 6AL5 in the little box on the top. You
: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of John E. Coleman (ARS
WA5BXO)
Sent: Friday, May 05, 2006 2:49 PM
To: 'Discussion of AM Radio'
Subject: RE: [AMRadio]Shunt and RF power measurment
Rick
I will apologize ahead of time here because this math may be very
easy for you
. Coleman (ARS
WA5BXO)
Sent: Friday, May 05, 2006 3:06 PM
To: 'Discussion of AM Radio'
Subject: RE: [AMRadio]Shunt and RF power measurment
Correction:
The RMS value of peak on a sine wave is the square root or 0.5
The square root of 2 (1.414) converts it from RMS to Peak.
The Converted formula
Thanks Don and Gary for a better description. Gary I really liked the
descriptions and explanations of radiation resistance especially the one of
the mobile antenna. That's the one thing that a lot of folks don't quite
understand. It's what I call antenna efficiency. I've been told that the
Boy! You have to be real specific around here, HI
I should have been more specific. I meant toroid wide band transformers not
resonated and covering the entire HF spectrum with no tuning. I have seen
toriods used in HF tube type equipment also but they still have tuning. I
was speaking of rigs
There should be no problem with running coax under ground directly
buried or inside some other conduit including metal and run as many as you
want side-by-side. Balanced line is another thing. Any transmission line
will give you trouble if the characteristics of the insulation is not
Hey Brad, KB7FQR
How did the antenna work out? Have you made any more changes?
John, WA5BXO
Have you ever needed a small piece of shielded cable for under
chassis work and didn't wont to cut a piece of that expensive RGxxx that is
real small and difficult to work with. Well here is what I do.
I'm a computer tech and occasionally have a need to do some cabling
work.
Hi Jim,
Most big rigs run from 220VAC if for no other reason, just load
balancing. Big rigs will often pull more that 20 amps of AC line current on
modulation peaks. So to prevent the line voltage from dropping anymore than
is necessary, we often put the HV power supply on a separate
Brett,
Explain more about how the rig sounds better without the reactor.
To me, if the modulation XFMR is large enough to not need a reactor, then
putting in a reactor and coupling capacitor should not make any difference
unless the reactor is not doing its job or the capacitor is too
I think he's talking of the input to the modulator tubes in 20 watts to
Class B 813s with control grid and screen grid tied together.
But I may have missed something.
John, WA5BXO
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Rick Brashear
Sent:
Brett,
It is said that a critical amount of coupling capacitance will
smooth out and enhance the low frequency audio by becoming resonate with the
other inductive components. But to me it seems to change the shape of the
low frequency components and causes a loss of the asymmetrical
I have an old record player for a collector. Please don't play records on
this thing.
This is what I know about it.
It has 2 tubes, a 35W4 and a 50C5.
It has a volume and tone control with white plastic knobs.
The brand is Symphonic.
The Model is 1716.
It has 4 speeds and a 45 stack
That's interesting about the crystal radio because I did the same thing. I
had one of those rocket radio things where the nose cone pulled up and down
to adjust the slug in a coil. We lived about 1 mile from KILTs 5000 Watt AM
XMTR site and so that was all I could get on it. But it was very
Your Right Gary on the out put of AB1 VS AB2
and
Since the plate current swing is limited to not drawing grid current one
generally ops for better linearity and gain by using a high plate Z load
in AB1 than in AB2. This also reduces output slightly. It can be
accomplished on a modulator by
:[EMAIL PROTECTED] Behalf Of John E. Coleman (ARS
WA5BXO)
Sent: Thursday, March 16, 2006 9:10 PM
To: 'Discussion of AM Radio'
Subject: RE: [AMRadio] Amplifier to use with my DX-60
I still say, forget the linear, and use less money to build a plate
modulator for the DX60. It will work
Well first of all Harry I am not familiar with the Webster Electric PA amp
but 25 watts output is a little on the light side but is usable if you don't
load the DX60 to more than 40-50 watts plate input power. You could
probably use a 25 watt audio output XFMR rated of single ended use, so it
Jim,
I suppose it is also preference. BJ and I modified the Kenwood TS820 to
full double sideband and it runs about 10-20 watts carrier output in that
mode we drive and SB200 modified with a switch to kick in extra bias when we
use in on AM. It puts out about 75-80 watts carrier with good
Get a high inductance choke (modulation reactor) to shunt the DC out of the
secondary of the modulation XFMR. It will kill about 75 % of the talk back.
What's left is all second harmonic talk back and it won't feed back. Did
you ever use an old speaker that required DC to get the magnetism (no
1 - 100 of 144 matches
Mail list logo
