Does anybody know of a small, easy to obtain receiver that can receive 85
kcs? Tube type, surplus OK.

I have an old Lear ADF that was cut out of a plane decades ago. The cables
were whacked off, and I can't find a schematic. Someone did send me a
schematic of a set very close in model to the one I have, so I do have
that. However, most of the circuitry in the radio is dedicated to the DF
capacity, which I don't need or want. There are three subchassis, and
probably 15 tubes.

I want to use the small tuning head, which has an 85 kcs IF output, to feed
something like a Q-5er that would serve as IF and audio.

If I can't find one, I have an R-11a that I could feed the tuning head
output into it's IF strip.

I'm trying to kludge up a homebrew longwave/BCB DX rig.

In article , elaich wrote:
Does anybody know of a small, easy to obtain receiver that can receive 85
kcs? Tube type, surplus OK.

Take an AA5. Keep the 455 KC IF strip, but change the tuning on the front
end and the local oscillator.

Otherwise you are probably in frequency-selectable voltmeter territory.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

A BC-453 tunes 455 kHz and converts to 85 kHz. The selectivity can be
increased by pulling out the plastic inserts. Audio is high impedance, but
can be used to feed into another audio amp or back into the receiver audio
chain. Lots of info available on the internet. Today, it is easy to build
a 24 volt supply, and they like that.

Used to be $4.95 - oh wait, that was 1959. But they are still available.

Build a double conversion converter and you can tune a few hundred kHz. Or
build a converter with a synthesized oscillator. Makes a great mobile
receiver for your 1954 Buick Special. Build a solid state inverter onto
that dynamotor plate. In fact, you can use one of those cheap $6 12 - 120
volt inverters and use a voltage doubler to get the correct voltage.

Colin K7FM

On Fri, 10 Oct 2008, COLIN LAMB wrote:

A BC-453 tunes 455 kHz and converts to 85 kHz. The selectivity can be
increased by pulling out the plastic inserts. Audio is high impedance, but
can be used to feed into another audio amp or back into the receiver audio
chain. Lots of info available on the internet. Today, it is easy to build
a 24 volt supply, and they like that.

Used to be $4.95 - oh wait, that was 1959. But they are still available.

But are they still cheap?

I bought my one and only Command Set transmitter in 1972, for ten
dollars here in Canada. It was actual surplus, rather than bought
from someone who'd bought it surplus.

It's now been longer since I bought it than 1972 was from the end of
WWII.

Michael VE2BVW

Build a double conversion converter and you can tune a few hundred kHz. Or
build a converter with a synthesized oscillator. Makes a great mobile
receiver for your 1954 Buick Special. Build a solid state inverter onto
that dynamotor plate. In fact, you can use one of those cheap $6 12 - 120
volt inverters and use a voltage doubler to get the correct voltage.

Colin K7FM

Michael Black wrote in
ample.net:

But are they still cheap?

No, they are not. One just went on ebay for over $100.

"Michael Black" wrote in message
ample.net...
On Fri, 10 Oct 2008, COLIN LAMB wrote:
But are they still cheap?


Michael VE2BVW


Ones that have been butchered or modified are still inexpensive.
Modifying a pristine example for a direct IF input would be
a no no; but I've just aquired a few ugly duckings for the IF
transformers fairly cheaply.

Pete

An HRO 7 will tune down to 50 Kc with the proper coil set and I'd guess
that some of the other HROs will too!

--

73
Hank WD5JFR
"elaich" wrote in message
...
Does anybody know of a small, easy to obtain receiver that can receive
85
kcs? Tube type, surplus OK.

I have an old Lear ADF that was cut out of a plane decades ago. The
cables
were whacked off, and I can't find a schematic. Someone did send me a
schematic of a set very close in model to the one I have, so I do have
that. However, most of the circuitry in the radio is dedicated to the
DF
capacity, which I don't need or want. There are three subchassis, and
probably 15 tubes.

I want to use the small tuning head, which has an 85 kcs IF output, to
feed
something like a Q-5er that would serve as IF and audio.

If I can't find one, I have an R-11a that I could feed the tuning head
output into it's IF strip.

I'm trying to kludge up a homebrew longwave/BCB DX rig.

"Henry Kolesnik" wrote in news:qK0Lk.5910
:

An HRO 7 will tune down to 50 Kc with the proper coil set and I'd guess
that some of the other HROs will too!

Jeez, if I had an HRO 7, I wouldn't need to do this to begin with! LOL!

I'm going to use the Lear tuning head to feed the 85 kc IF of the R-11a. My
big problem will be voltages. The R-11 uses 14 volt tubes, wired in series
pairs. That was for the plane's 28 volt system. I'll have to rewire them in
parallel and feed them 12 volts. I haven't looked at the Lear yet, but it
probably uses the same idea.

Weren't R-11's fairly common? A Google search turns up only one page on the
entire Internet that even mentions them. There are a couple of the Lear
tuning heads on eBay. That surprised me.

On 20 Oct 2008 18:30:57 GMT, elaich wrote:

"Henry Kolesnik" wrote in news:qK0Lk.5910
:

An HRO 7 will tune down to 50 Kc with the proper coil set and I'd guess
that some of the other HROs will too!

Jeez, if I had an HRO 7, I wouldn't need to do this to begin with! LOL!

I'm going to use the Lear tuning head to feed the 85 kc IF of the R-11a. My
big problem will be voltages. The R-11 uses 14 volt tubes, wired in series
pairs. That was for the plane's 28 volt system. I'll have to rewire them in
parallel and feed them 12 volts. I haven't looked at the Lear yet, but it
probably uses the same idea.

While you're rewiring the heaters consider replacing the metal-cased
caps under the chassis. They will have to be removed to access the
tube socket bases.

An alternative to rewiring the filaments is to build a power supply
using a 24 V transformer. My Q5-er supply uses back-to-back 25.2V
transformers to feed the rectifier/filter circuit. The filament
voltage is taken from between the two transformers. A 6.3-0-6.3V
transformer supplies 6 & 12 volts.

Registered User wrote in
:

An alternative to rewiring the filaments is to build a power supply
using a 24 V transformer. My Q5-er supply uses back-to-back 25.2V
transformers to feed the rectifier/filter circuit. The filament
voltage is taken from between the two transformers. A 6.3-0-6.3V
transformer supplies 6 & 12 volts.

If I'm going to use the remote rotatble ferrite bar antenna (and I
definitely want to) I'm going to need 28 VAC 400 Hz. Does anybody know of a
schematic for an oscillator circuit? I looked online and couldn't find
anything.