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Author Topic: need schematic for Browning RH-10 WWV Standard Frequency Calibrator  (Read 115 times)

N3KXZ

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I need a schematic for Browning RH-10 WWV Standard Frequency Calibrator, circa late 1940's?

I rescued this from a scrap heap and would like to bring it back to life, but I have little experience with radio electronics. I've searched online and can't find much at all about this radio.

A member of antiqueradios.com did send me rh-10 a listing in the frederic research manuals of military equipment test equipment data handbook (volume-2), but sadly that does not include a schematic or alignment procedure.

Can anyone here send me a copy or tell me where to buy a copy of the schematic and/or alignment procedure for this radio?

Thanks,
Keith
N3KXZ
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N7EKU

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Re: need schematic for Browning RH-10 WWV Standard Frequency Calibrator
« Reply #1 on: November 02, 2022, 06:55:59 PM »

From an old ad:

Full, accurate use of station WWV, the world's finest primary frequency and time standard, is obtained from the Browning Model RH-10 Standard Frequency Calibrator. The standard Browning RH-IO is pre-tuned for 5 and 10 megacycles per second reception, at sensitivities better than 1/2 microvolt on either band. A dual filter system provides selection of either the 440 or 4000 cycle modulation of WWV for use as a primary frequency standard.
Checking equipment against station WWV, at accuracies up to one part in five million, the Browning Frequency Calibrator enables comparisons to be made in three general categories:

I. Precision radio frequency standards measurements.
2. Precision audio frequency standards measurements.
3. Precision time and pulse standards for physical measurements.

The Browning RH-10 consists of a high Q antenna transformer, a sharply tuned R -F amplifier, converter, oscillator, two IF stages, detector, selective amplifier output stages and a cathode ray zero beat indicator. Although normally supplied
for 5 and 10 megacycles per second operation, any two combinations of 2.5, 5, 10, or 15 megacycles may be had on special order.

Looks like fun!  I suppose 440Hz was for the musically inclined (note A4, first A above middle C on the piano) although it is also an ISO standard.

This will be all of vacuum tube construction and also has a CRT so there will be high (deadly) voltages present.  I wouldn't work on it unless I had an experienced person to help.

73,  Mark
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Mark -- N7EKU/VE3

N3KXZ

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Re: need schematic for Browning RH-10 WWV Standard Frequency Calibrator
« Reply #2 on: November 02, 2022, 07:29:01 PM »

Hi Mark-

Thanks for responding, and for the description from the ad.

My model does not have a crt. Unless maybe the description is referring to the magic eye tube? I have worked on old Tektronix oscilloscopes so no worry about the deadly voltages present.

It would be a lot easier to work on it with a schematic... could someone help me locate one?

Thanks,
Keith



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N3KXZ

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Re: need schematic for Browning RH-10 WWV Standard Frequency Calibrator
« Reply #3 on: December 06, 2022, 02:01:37 PM »

I have this working partly. A Ham in another forum provided me with the schematic for an RMA Dummy antenna hook up that allows me to match the output impedance of my Eico 324 to the antenna input of this RH-10 WWV boat anchor. With that setup the radio does tune to and detect the modulated 10Mhz signal from my Eico. So far so good.

However, I don't know the best way to convert the 50 ohm impedance of my antenna coax to what's needed for this RH-10. I have tried adapting via one of those 75-to-300 ohm converters made for TV's, but no signal appears to get through. Partly the problem is that my regular antenna at this particular location (which is pretty noisy) does not receive WWV very well to begin with.

So... what impedance does this RH-10 expect at it's antenna terminals? I am hoping not to have to need to make a custom antenna just for this purpose, but even if I decided to do that I still need to know what this radio expects at its antenna terminals for _best_ reception. Can someone enlighten me on that?

Thanks,
Keith
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