RadioBanter - Homebrew 11 tube CB receiver info wanted

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Homebrew 11 tube CB receiver info wanted

I recently won a HOMEBREW 23 channel CB receiver. Yes I know it's
not a real boatanchor but given that it has 11 tubes plus several
diodes , I thought I'd ask about it here. It looks very well made.

I was hoping that some one would recognize it by tube line up. I just
looked at it and haven't started drawing the schematic yet. It has the
following tubes, 6EH7 (the RF amp) , 12AT7, 12AU7, 6BN8, 6HR6, 6BA6,
6BE6, 6GX6, 12AX7, 6AQ5, and an OA2. It has 6 RF and IF
transformers.

The antenna is connected directly to a transformer with the RF amp
feed by a cap off the secondary. The first oscillator(?) Uses a 29305
Kc crystal. It has a "S meter" and what I suspect is a meter adj. pot
on the back. There is a octal socket on the back labeled transmitter
that has two lines jumped as well as a voltage divider with a large
electrolytic to ground in the middle of the divider.

The tuning cap is three section with one section switched by a
control on the front panel. The tuning cap is driven by a very nicely
home made dial cord mechanism with a heavy flywheel. So far I have
figured out the RF and audio gain controls. The other two front
panels pots function are a question as well as the functions of four
multi section toggle switches. With the filter caps being bad. I have
not powered it up for more than two minutes.

Does anyone remember a home brew rig with these features HAM or CB? I
would like to find a schematic if possible. I looked at the HBR site
and it doesn't seem to match anything there. But given the limited 23
channel coverage plus channels A-D it looks like it's from the late
1960's or real early 1970's .

Thanks

Jim

Homebrew 11 tube CB receiver info wanted

Jim wrote:
I recently won a HOMEBREW 23 channel CB receiver. Yes I know it's
not a real boatanchor but given that it has 11 tubes plus several
diodes , I thought I'd ask about it here. It looks very well made.

I was hoping that some one would recognize it by tube line up. I just
looked at it and haven't started drawing the schematic yet. It has the
following tubes, 6EH7 (the RF amp) , 12AT7, 12AU7, 6BN8, 6HR6, 6BA6,
6BE6, 6GX6, 12AX7, 6AQ5, and an OA2. It has 6 RF and IF
transformers.

The antenna is connected directly to a transformer with the RF amp
feed by a cap off the secondary. The first oscillator(?) Uses a 29305
Kc crystal. It has a "S meter" and what I suspect is a meter adj. pot
on the back. There is a octal socket on the back labeled transmitter
that has two lines jumped as well as a voltage divider with a large
electrolytic to ground in the middle of the divider.

The tuning cap is three section with one section switched by a
control on the front panel. The tuning cap is driven by a very nicely
home made dial cord mechanism with a heavy flywheel. So far I have
figured out the RF and audio gain controls. The other two front
panels pots function are a question as well as the functions of four
multi section toggle switches. With the filter caps being bad. I have
not powered it up for more than two minutes.

Does anyone remember a home brew rig with these features HAM or CB? I
would like to find a schematic if possible. I looked at the HBR site
and it doesn't seem to match anything there. But given the limited 23
channel coverage plus channels A-D it looks like it's from the late
1960's or real early 1970's .

Thanks

Jim

Jim,

I'm very surprised to hear that someone would homebrew a CB rig: I'd
guess it's a commercial unit without the front plate unless the
workmanship is definitely "homebrew".

The mixer crystal is a puzzle: it implies an IF in the ~3.3MHz range,
which I've never seen before. OTOH, if it was made for 10 Meter ham use,
a 29.305 MHz crystal and a 455 KHz IF would work out to either
29.760 or 28.850 MHz, and only the lower frequency is in the 10 meter
band. It might have been a custom-made unit for CAP or other use on
29.76, but I don't have any experience with those.

I'm going to guess that you have a CB set that was modified for either
10 meter ham use or for some quasi-government use on 29.76.

HTH.

William

(Filter noise from my address for direct replies)

Homebrew 11 tube CB receiver info wanted

William Warren ") writes:
Jim wrote:
I recently won a HOMEBREW 23 channel CB receiver. Yes I know it's
not a real boatanchor but given that it has 11 tubes plus several
diodes , I thought I'd ask about it here. It looks very well made.

I was hoping that some one would recognize it by tube line up. I just
looked at it and haven't started drawing the schematic yet. It has the
following tubes, 6EH7 (the RF amp) , 12AT7, 12AU7, 6BN8, 6HR6, 6BA6,
6BE6, 6GX6, 12AX7, 6AQ5, and an OA2. It has 6 RF and IF
transformers.

The antenna is connected directly to a transformer with the RF amp
feed by a cap off the secondary. The first oscillator(?) Uses a 29305
Kc crystal. It has a "S meter" and what I suspect is a meter adj. pot
on the back. There is a octal socket on the back labeled transmitter
that has two lines jumped as well as a voltage divider with a large
electrolytic to ground in the middle of the divider.

The tuning cap is three section with one section switched by a
control on the front panel. The tuning cap is driven by a very nicely
home made dial cord mechanism with a heavy flywheel. So far I have
figured out the RF and audio gain controls. The other two front
panels pots function are a question as well as the functions of four
multi section toggle switches. With the filter caps being bad. I have
not powered it up for more than two minutes.

Does anyone remember a home brew rig with these features HAM or CB? I
would like to find a schematic if possible. I looked at the HBR site
and it doesn't seem to match anything there. But given the limited 23
channel coverage plus channels A-D it looks like it's from the late
1960's or real early 1970's .

Thanks

Jim

Jim,

I'm very surprised to hear that someone would homebrew a CB rig: I'd
guess it's a commercial unit without the front plate unless the
workmanship is definitely "homebrew".

IN the sixties (and early seventies), it was common for the hobby
electronic magazines to treat CB as a hobby. This was especially so
for "Electronics Illustrated" that had quite a few construction articles,
going from simple to quite sophisticated. So you could build a panadaptor
to check out the adjacent channels, and a receiver to monitor channel 9
(when it became a designated emergency channel) and even a grid dip
oscillator for "Class E CB" up at 220MHz, even though that service
never came to pass.

THere is nothing unique about the description. I can't recall seeing
much in just tuneable CB receivers in the hobby magazines from that
time, but it sounds like a relatively generic receiver (and he did
say receiver, not transceiver).

If it is a CB receiver, there's nothing to guarantee that it was
built from a description in a magazine article, or that it's a direct
copy of something. Someone could have made it up, or copied something
else with mods for CB. Afterall, no matter what the unit is, someone
has to create a unit before they can write it up in a magazine, so
something can exist without a magazine writeup.

And given that he says it's a receiver, if it was a commercial unit
the pickings are slim. I can think of only one manufacturer that made
a standalone CB receiver.

Michael VE2BVW

Homebrew 11 tube CB receiver info wanted

On Apr 19, 9:28 am, (Michael Black) wrote:

IN the sixties (and early seventies), it was common for the hobby
electronic magazines to treat CB as a hobby. This was especially so
for "Electronics Illustrated" that had quite a few construction articles,
going from simple to quite sophisticated.

In the early sixties I ordered one of those cb kits from an
electronics magazine. It consisted of a crudely punched chassis, a bag
of parts and a schematic. I never did get it to work.

Homebrew 11 tube CB receiver info wanted

cmdr buzz corey wrote:
On Apr 19, 9:28 am, (Michael Black) wrote:

IN the sixties (and early seventies), it was common for the hobby
electronic magazines to treat CB as a hobby. This was especially so
for "Electronics Illustrated" that had quite a few construction articles,
going from simple to quite sophisticated.

In the early sixties I ordered one of those cb kits from an
electronics magazine. It consisted of a crudely punched chassis, a bag
of parts and a schematic. I never did get it to work.

I thought building a kit CB transceiver was illegal due to the type
acceptance issue?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Homebrew 11 tube CB receiver info wanted

Scott Dorsey ) writes:
cmdr buzz corey wrote:
On Apr 19, 9:28 am, (Michael Black) wrote:

IN the sixties (and early seventies), it was common for the hobby
electronic magazines to treat CB as a hobby. This was especially so
for "Electronics Illustrated" that had quite a few construction articles,
going from simple to quite sophisticated.

In the early sixties I ordered one of those cb kits from an
electronics magazine. It consisted of a crudely punched chassis, a bag
of parts and a schematic. I never did get it to work.

I thought building a kit CB transceiver was illegal due to the type
acceptance issue?

Certainly Heathkit got around the issue with their full blown CB set(s)
by having the transmitter arrive as a preassembled module.

But I thought there was a CB "Benton Harbor Lunchbox" for a while,
and I can't imagine they would have a module for such a low end
unit.

So perhaps the type acceptance came a bit later? I can't remember (not
that I was aware of such things at the time, but I have read lots
of back issues of magazines).

In the very early days, there was equipment being made out of people's
garages. So either the rules were more lax then, or from the outside
there were companies selling things that weren't legal.

Michael VE2BVW

Homebrew 11 tube CB receiver info wanted

"Scott Dorsey" wrote in message
...
cmdr buzz corey wrote:
On Apr 19, 9:28 am, (Michael Black) wrote:

IN the sixties (and early seventies), it was common for the hobby
electronic magazines to treat CB as a hobby. This was especially so
for "Electronics Illustrated" that had quite a few construction
articles,
going from simple to quite sophisticated.

In the early sixties I ordered one of those cb kits from an
electronics magazine. It consisted of a crudely punched chassis, a bag
of parts and a schematic. I never did get it to work.

I thought building a kit CB transceiver was illegal due to the type
acceptance issue?
--scott
--

It may be now, I don't know. At one time Heathkit put out a kit called a
CB-1. This was a simple CB and not at all like the one being talked about.
There may have been others, but this is one I know of for sure.

Homebrew 11 tube CB receiver info wanted

The tube lineup is from the later generation of miniature tubes - which
means mid 60's. It looks like the first conversion oscillator is crystal
controlled and the receiver uses a tunable if stage - similar to Drake.
That means it would be easy to change thr crystal controlled first
conversion stage and cover any other range. Might be a good 10 meter
receiver - or perhaps the 12 meter band. There could be some value to a cb
collector, since few home brew receivers were made.

One of the pots might be noise limiting adjustment, or one could be for a
Q-multiplier.

Colin K7FM