The Johnson Matchbox has its own area of usefulness. There was a set of
calculations and measurements made on several "feedline impedance
transformation devices" a while ago. The article pointed out that is
was possible to dissipate much of the energy in the transformation
device which would
Original Message
Subject:Re: [AMRadio] Hazernut was MFJ
Date: Thu, 07 Dec 2006 19:06:14 -0600
From: Larry Taft <[EMAIL PROTECTED]>
To: Discussion of AM Radio in the Amateur Service
References: <[EMAIL PROTECTED]>
*THIS IS THE FIRST GOOD
How about hanging an inverted V dipole from the Hazer for now. Mine is
35 feet in the air and has 3 sets of wire, 80, 40, and 20 which I
adjusted for a reasonable SWR on each band by adjusting 80 first, 40 and
then 20. The RG-8 coax feed has a 8 turn coil on a gallon plastic jug
at the center
To repeat an earlier comment, try a load resistor on the output leads,
say 5K or something in that range at least 20 watts and 50 watts would
be ideal for full power tests. Pull the 6146 and the osc tubes to get
rid of the RF. You have to have a load on the mod iron to keep things
under contr
Try again, only this time wait to push "send".
Unfortunately an ohmmeter test on the leads of a xfmr will not show a
turn to turn short in the same winding. The real way to test is send
AC, ie audio, into the iron at a modest power level and look at the
waveform coming out. Distorted wavefor
Jack Schmidling wrote:
Gary Schafer wrote:
It's beginning to sound like a partially shorted mod transformer.
I checked the resistances of the transformer earlier in the game and
they are nominal.
>With 20 volts signal on the grids of the mod tubes I would think
that >you should see at lea
Gary has, I think, hit the tube on the plate cap.
I went looking for a set of curves for the 6L6 in my pile of old books
and data but no find yet.
Just from "rule of thumb" for audio tube amps you should get a couple
hundred volts audio swing (not related to BIRD WATTS) at each plate to
gro
K2LT
Gary Schafer wrote:
-Original Message-
From: [EMAIL PROTECTED] [mailto:amradio-
[EMAIL PROTECTED] On Behalf Of Larry Taft
Sent: Thursday, November 16, 2006 11:06 AM
To: Discussion of AM Radio in the Amateur Service
Subject: Re: [AMRadio] Ranger Modulation
Well, I tried...I wasn&
in the Amateur Service
Subject: Re: [AMRadio] Ranger Modulation
Larry Taft wrote:
Try reversing the phase of the audio by swapping the output leads of the
modulation xfmr.
First I swapped the tubes to no avail. I then swapped the wires and now
have a strange buzzing that I can not locate
15/06, Larry Taft <[EMAIL PROTECTED]> wrote:
Try reversing the phase of the audio by swapping the output leads of the
modulation xfmr.
Asymmetrical modulation? And too much in the negative direction is the
flat line.
Weak tube in the audio chain causing lack of gain needed for the
posit
Try reversing the phase of the audio by swapping the output leads of the
modulation xfmr.
Asymmetrical modulation? And too much in the negative direction is the
flat line.
Weak tube in the audio chain causing lack of gain needed for the
positive peak.
I understand what I'm trying to say. I re
That sounds terribly eastern! Hooie-yah followed by QTF and dropped
carrier while tracing the arc sound is good 5 land AM.
Larry K2LT (in 5 land)
[EMAIL PROTECTED] wrote:
Remember, always be extra careful using..Oh. La for
testing
Great discussion fellows.
73,
Bob,W4WS
I have three D104 mics wired up for different rigs. On the SDR-1000
into a Delta 44 sound card I use the built in preamp in the mic base to
get enough audio to drive the line-in input. This minimizes the RF
pickup through the audio wiring.
For the Drake 4 series I run straight into the mic i
Gates BC250GY that will run better than 500 W out with full modulation.
810s in parallel driven by 813 with 807 osc stage. Mod is PP810s driven
by PP6L6s.
RF section is edgewound fixed coils with large variable air caps.
Modulator is a long one piece chassis vertical mount. Big iron goes in
Brian,
Both wires are hot with the ground as a safety connection. Check with
your voltmeter.
By your description do you have a 3 prong 220vac outlet as used for an
older dryer outlet? Or an air conditioner? Any idea as to the wire
size? Is the ground wire the same size as the hot wires?
Run any tests on the iron to check for shorts or opens? Maybe hook some
B+ through a resistor to be sure no arcing
Larry K2LT drakerepair.com.
Jack Schmidling wrote:
[EMAIL PROTECTED] wrote:
Hey Jack et al: I think the original owner was a CW operator and
intentionally removed the modul
For good AM (I mean REALLY GOOD AM) try a SDR-1000 by Flex-Radio. This
is a computer driven little black box that can create any form of
modulation and make it sound beautiful. The receiver uses a quadrature
mixer into a sound card with some free software to make the AM sound
really great. H
Don,
You that old that you wear diapers again? Seniors?
73, Larry K2LT
Don Merz wrote:
Well, I once shipped a Heathkit Mohawk to a guy. When
it arrived, he found a used plastic diaper among the
packing!
That's as close as I've gotten to accidentally
shipping a kid in with a radio...
73
John,
Suggest you check the bilge, maybe your yacht sank.
Larry K2LT
[EMAIL PROTECTED] wrote:
Hi Dave,
I have beeh having a lot of trouble hearing CHU here also. Used to get them
on my TR-7 with NO antenna connected! Now I cannot hear them on my Sony Yacht
Boy!
73,
John, W4AWM
_
|
///
Larry Taft wrote:
Typical values for a Gates BC-1G 1 KW broadcast transmitter 2500 VDC
supply are 5-15 hy at 1 amp swinging choke with 8 uf filter cap. The
load is 500 ma
Typical values for a Gates BC-1G 1 KW broadcast transmitter 2500 VDC
supply are 5-15 hy at 1 amp swinging choke with 8 uf filter cap. The
load is 500 ma continuous for the class C final ( 2 833s in parallel)
plus another 500 ma variable for the class B modulator ( 2 833s in
push-pull). The a
The D104 mic element is a high impedance crystal so resistance doesn't
mean anything.
Unplug the D104 head from the stand since there is no assurance the
stand is wired correctly. There are 3 pins in the head connector. The
2 close together are the mic element. Use a high impedance digital
m
You have checked out the D104 also? The elements can go bad. Make sure
you aren't using the amplifier in the base which would way overdrive the
audio input of the DX-40
73, Larry K2LT.
Rick Brashear wrote:
Thanks Brian. I've noticed that the loading of the DX-40 can be a
little cantankero
I would give him a bunch of literature on the use of ferrites and maybe
a sample and a list of suppliers and let him solve the problem.
73, Larry K2LT
I feel it is interference waiting to happen.
Does anyone have any experience with this? Am I to expect to QRM him?
Alan,
Maybe, maybe
Don, I'll take the 211 VT-4C pair. I have a Western Electric 451A that
I will get on the air this year. Uses 6 of the 211 tubes.
73, Larry K2LT
Merz Donald S wrote:
For Sale. All prices plus shipping.
211 VT-4C tubes, one pair, used but tested by me and
found to have excellent emission. $
Any plastic parts will be suspect. Put it up if the effort isn't too great
and see how it works.
Larry K2LT
At 10:43 AM 12/6/2004 -0500, you wrote:
I have this new, old-stock antenna here. It's a two-trap dipole made by
Western Radio Electronics dating from 1977. It's brand new in the box, a
The measurements were done several years ago with an old HP 851/8551
analyzer and I didn't write down the data. I'll do the tests again with my
Tek 2712 and plot the results. The only question is "When?"
What I see in my rounds of making the NRSC spectrum plots on AM broadcast
stations is an o
I made a set of interesting measurements with my spectrum analyzer on a
Drake TR-7 driving a L-4 amp. Set the output at 1kw through a W-4
wattmeter into a dummy load. Harmonics looked good, down quite a
ways. Crank the TR-7 up a bit to the L-4 and the power went up to 1100
watts. The fundam
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