3 tube am 75 meter mobile
 

I am looking for information on a 3 tube 75 meter am transmitter that was
around about 1958. Two of the tubes were 6146, one for modulator and one
for final. I cant remember what the oscillator was.

J. Andy Thompson
W7CXA
Yakima, WA

3 tube am 75 meter mobile
 

On Sun, 9 Dec 2007 07:15:04 -0800, W7CXA wrote:
I am looking for information on a 3 tube 75 meter am transmitter that was
around about 1958. Two of the tubes were 6146, one for modulator and one
for final. I cant remember what the oscillator was.

I see nothing close to your description in the 1957 ARRL Handbook -
in either the "Mobile Equipment" section, nor the "HF Transmitter"
section.

Or, are you referring to a piece of commercial gear?

There was no osc. buffer, and no mic. preamp?

(I did run across an ad for Burstein-Applebee.
Now, _that_ *really* brings back memories! )
73
Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
*** Killfiling google posts: http://jonz.net/ng.htm

3 tube am 75 meter mobile
 

On Dec 9, 5:26 pm, Allodoxaphobia wrote:
On Sun, 9 Dec 2007 07:15:04 -0800, W7CXA wrote:
I am looking for information on a 3 tube 75 meter am transmitter that was
around about 1958. Two of the tubes were 6146, one for modulator and one
for final. I cant remember what the oscillator was.

I see nothing close to your description in the 1957 ARRL Handbook -
in either the "Mobile Equipment" section, nor the "HF Transmitter"
section.

Or, are you referring to a piece of commercial gear?

There was no osc. buffer, and no mic. preamp?

(I did run across an ad for Burstein-Applebee.
Now, _that_ *really* brings back memories! )
73
Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
*** Killfiling google posts: http://jonz.net/ng.htm

Yup, good memories...
However, ARRL was not the sole source of info... I vaguely remember a
quick-n-dirty mobile AM with 3 tubes... But, why worry about what was
published then.. We can cobble up something similar today on our
own... Use a VXO for the vfo oscillator to make it stable under
modulation peaks... Use screen grid modulation... Won't need a 6146
for the modulator, a 12AX7 should do (I'd have to research that, so
don't take it for gospel)
OTOH, the nice nursey says I need to take my pills now...

denny / k8do

3 tube am 75 meter mobile
 

I do not remember a 3 tube transmitter using 2 6146 tubes. I question that
arrangement, because the 6146 modulator would be running class A and very
inefficient.

However, I am familiar with a 2 tube transmitter using a 6146 final. It was
very effective and a lot of hams built one. It was called the "Golden Gate"
circuit, because it was popular in San Francisco.

Using1/2 of a 12AT7 for a crystal controlled oscillator, driving a 6146, it
was screen modulated by the other 1/2 of the 12AT7. Used a carbon mike and
step up transformer.

It appeared in the "New" CQ Mobile Handbook, second edition - 1956.

73, Colin K7FM

3 tube am 75 meter mobile
 

It appeared in the "New" CQ Mobile Handbook, second edition - 1956.

73, Colin K7FM

I said the memory was vague... But I believe you have described what
I vaguely remembered...
Yup, that should work... And it will work today, still... A VXO will
give you a bit more flexibility fro todays crowded bands...

denny / k8do

3 tube am 75 meter mobile
 

And, remember that when you find an old carbon mike, rap it hard on the side
of the desk to shake up the carbon granules, that may have caked up sitting
for decades. This is one mike that wants to be almost swallowed.

Have fun.

Colin K7FM

3 tube am 75 meter mobile
 

On Dec 11, 9:36 am, "COLIN LAMB" wrote:
And, remember that when you find an old carbon mike, rap it hard on the side
of the desk to shake up the carbon granules, that may have caked up sitting
for decades. This is one mike that wants to be almost swallowed.

Have fun.

Colin K7FM

Of course it has to be in transmit while you loosen the granules so
that there is good current flow through the granules...

denny / k8do

3 tube am 75 meter mobile
 

On Dec 9 2007, 7:15 am, "W7CXA" wrote:
I am looking for information on a 3 tube 75 meter am transmitter that was
around about 1958. Two of the tubes were 6146, one for modulator and one
for final. I cant remember what the oscillator was.

J. Andy Thompson
W7CXA
Yakima, WA


Back in the 50's there was a very popular TWO tube mobile transmitter
used by several mobile operators on 3995... Developed by Bob Carter,
W6NTU who lived up on the side of Mt. Hamilton near San Jose... It
used a12AT7 driving a sweep tube... Several of the fellows in addition
to a variant of sweep tubes, used a 6146 and an occasional 2E26 in the
final as well depending on available plate voltage... Half of the
12AT7 was the Oscillator, the other half was modulator... Carter
Modulation transmitters were very popular due to their simplicity and
performance. When loaded a bit on the heavy side, the audio sounded
quite good... Go to:

http://www.geocities.com/ResearchTri...13/carter.html

For a bit of History and a schematic of the transmitter... Remember
load that lil sucker fairly heavy with very little perceptible plate
dip for best audio results...

Good Luck de Grady K6IXA