[Premium-Rx] 100 kHz output devices

[Michael O'Beirne]

A propos the 100kHz output devices mentioned by John tonight, could I 
mention the fairly rare DK43 bargraph made by Tewkesbury Electronics for (I 
believe) GCHQ, more or less up the road.

The display has 100 LEDs giving a resolution to 10Hz on the 1kHz range and 
is completely linear over the entire display whereas that of the similar 
Racal MA1105 is significantly non linear, not that that makes a lot of odds 
for tuning, but it is a lot more difficult to measure the shift of a data 
signal accurately with a non-linear scale.

Maddeningly, the LEDs run backwards when used with an RA17L and with the 
100kHz IF converter for the RA3701.

My simple "brute force" answer is to open up the lid, unscrew the the whole 
strip of LEDs and scale from the panel (4 screws), turn them round by 180 
degrees in a vertical plane and screw up.  Thankfully the beautifully built 
cable harness from the main board to the display strip is sufficiently long 
to enable you to do this.  The scale is now upside down but you quickly get 
used to that, and it is so much nicer that the display sense now matches the 
tuning sense.

73s
Michael
G8MOB

----- Original Message ----- 
From: "John Graham" <john.graham02 at btinternet.com>
To: <Pat1McA at aol.com>
Cc: <premium-rx at mailman.qth.net>; <john.graham02 at btinternet.com>
Sent: Monday, August 16, 2010 12:44 PM
Subject: Re: [Premium-Rx] Racal 1782, 178x series


> Hello Pat,
>
> Thanks for the info. Yes, they are very rare: the only time I've ever seen 
> anything about them was a passing mention in Technical Topics some years 
> ago.
> Both mine have single-digit serial numbers and are in good condition 
> cosmetically.
>
> Keith Thrower confirmed that they were "specials" for the ministry.
>
> There are plenty of useful accessories for the 100kHz outputs: among other 
> things, I have an MA1105 bargraph adapter and an MA2232R Tuning Aid [FFTs 
> at an IF of 6.4kHz!] and a Redifon VTA-1. I still have an ancient 
> Eddystone EP15 panadaptor, too, with dual inputs for 100kHz (fixed) and 
> 400-800kHz tunable.
>
> regards,
>
> John RS86946