[time-nuts] Marginally off topic... Aircraft Automatic DirectionFinders as beacon receivers.

Robert Atkinson robert8rpi at yahoo.co.uk
Fri Dec 25 19:40:06 UTC 2009


Hi,
sorry for the late reply, I missed this in the traffic! I know the KR85 quite well, used to fix them about 20 years ago. I don't think I have a service manual but will check next time I'm in the loft. King Radio were bought out by Bendix who where subsequently bought out by Honeywell. Don't bother going to them for manuals, they only release them to authorised service centers, and even then only if you are authorised for that range of equipment. My current employer doesn't cover the GA stuff. They are also quite protective about their copyright. Might be worth contacting a local avionics repair shop, as long as they know it's not for aircraft work they might help. I'm sure you know that the goniometer in the system is in the indicator and the loop antenna connects to this. Thus you can't DF without the indicator. The indicators are paired with the receivers, if the serial numbers don't match they won't work properly.
 
Robert G8RPI. 

--- On Tue, 22/12/09, WB6BNQ <wb6bnq at cox.net> wrote:


From: WB6BNQ <wb6bnq at cox.net>
Subject: Re: [time-nuts] Marginally off topic... Aircraft Automatic DirectionFinders as beacon receivers.
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Date: Tuesday, 22 December, 2009, 22:07


Hi Tom,

I haven't seen one of those for a few years.  I don't have a manual, but have you tried going straight to the manufacturer ?  I think they may still be in business.  However, they may not be cheap either.

One word of caution before you blindly buy that manual.  Many of the "so-called" manuals amounted to no more then installation instructions.  That is they barely had enough data to understand what the connector pin outs were.  Forget actual schematics of the insides.

The big companies expected you to go their "company" shops for repair.  In the old days, to get actual service manuals you needed to be a repair "station" recognized by the manufacturer.  Not all companies played that game, but the big ones did.

Good luck,

Bill....WB6BNQ


Tom Clifton wrote:

> Approaching off topic, but possibly of interest as Loran and WWVL is on the fringes of this...
>
> ________________________________
>
> I have several dead King KR-85 ADF untis that I want to  repair and press into service as 505khz beacon monitors.  Designed primarily for receiving 200khz to 500khz non directional beacons, they came out of 1970's vintage private planes and to date I have not been able to come up with a service manual with schematics (short of paying $70 for a manual  at Esso Air). Is there any chance that anybody out there may be able to assist with at least a partial copy of a manual
>
> These things are interesting - run on 12 volts, typicaly have an IF strip in the 150kc range and have a "digitally generated" vfo that has a TTL divider chain and a PLL for generating a sine wave.  BFO included!  And the front end  on these things have pretty good input filters divided into three bands - 200khz-400khz, 400khz-800khz and 800khz-1600khz (Yup - covers the AM radio band) to reduce intermod fro out of band stuff.  Conversion to 137 or 185khz would be awkward, but theoreticaly should be possible, likewise conversion to ham 160m, or down to 60khz or 100khz for other fun stuff.  They have a balanced loop input as well as an unbalanced sense antenna - lots of  potential!
>
> 73 - Tom in St. Louis
>
>
>
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