View Single Post
Old 10th Jun 2008, 9:04 pm   #9
paolo67
Retired Dormant Member
 
Join Date: Jun 2008
Location: Milan, Italy
Posts: 15
Default Re: Racal RA17L BFO behaviour

Hello Al,

got you. No, it was correctly fit, that meaning the tap close to the "earty" end.

I am *very* new to the receiver, I got it from eBay for just 100 Euro. The auction had just 80 visits, I suspect the seller placed it in the wrong category or something. Looked like it was lying somewhere for years.

Actually it came with several problems:

- the three wires below 2nd VFO were badly fitted - miscontact - producing random problems
- with 2nd VFO dismounted, I checked every component. ALL the paper capacitors were bad: brown/black colour, evident dielectric leak. Several resistors largely out of tolerance. Fortunately, no problems with the frequency determining components. The 2nd VFO is PERFECTLY aligned in frequency
- deafness at any band above 500kHz - fixed after alignment of 1st IF and replacement of the two paper capacitors that showed dielectric leak. This filter looked just crazy at the beginning
- 100kHz IF checked and realigned. I own an old HP141T 110Mhz with its also old tracking generator (nixie!) that make things slightly easier
- 37.5MHz strip checked as per manual. The drive at TP3 is OK
- harmonic generator and mixer checked work fine not yet dug deeply there
- preselector roughly aligned with tracking generator, peaks everywhere on all bands. Amazing sensitivity! Do you know why Racal did not make it tracking? Other receivers of the same age and class have it. BTW the preselector is an essential element: I live very near to a hugely powerful 900kHz transmitter, without preselector I can hear it at 5.400 for example
- calibrator dead. Also here, I overhauled it completely, now it works fine (easy job here...)

Apart from BFO, the receiver is extremely accurate and enjoyable to me. The 6.5 and 13kHz filters make it perfect for HF and MW BCL. I did the procedure for overall receiver gain measurement and it exceeds specs (A3).

Of course, I am at the very beginning with it. Everything looks new and there is a lot to learn... but this is why I bought it!

Paolo
paolo67 is offline