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Last call for my last Rhode and Schwarz polyscop. Only ?20. If no takers, I'll scrap it for the valves (EL84's) and metal for my friends machine shop Collection Hampshire UK 73, Martin M0MGA

My RA17 has been in storage unpowered since 2006. Prior to that it was in tip top condition having been serviced by Rob Filby in December 1999. I know it was unwise and neglectful of me not to power it for so long. What should I do now to bring it up? I have a mains variac. Can I use that? What is the procedure? Thanks, Andrew.

Hi Douglas A few posts ago, in a long meandering thread, I made an assertion that Racal introduced a mod to replace the spring edged covers with knitted mesh versions. You said you'd never seen any. It took a while to scan through the various RA17 documents I have. But here it is: E729 Misc Instr No 9 ...RA17L ...Change of filter covers "In order to reduce spurious oscillation below specification figures...change the covers of the 37.5MHz and 40MHz filters...new covers contain "knitmesh" cushions, and will replace existing type covers in future equipment manufacture." There is then a list of existing spring finger part numbers and the corresponding modified knitmesh part numbers. Dated Jan 1971. It may be possible to get the same effect by taping the filter seams with adhesive copper EMC tape (once the filters are aligned of course!). Craig

This is pretty much a historical curiosity. This was the "book" method of aligning the crystal and other bandpass filters on the IF strip, and IF transformers in the RA17 series of receivers. Basically described as a "High Discrimination Oscillator", it was precision set to 100kHz against an internal crystal calibrator, and had three large tuning knobs covering 10kHz, 1kHz and 100Hz total range, selected by a switch. Nothing much on the web about this boatanchor (a hefty 40kg/88lbs), no manuals anywhere. There are two references - one an old Marconi catalogue that describes its characteristics, and a similarly old Marconi price list that says it was ?328 in 1961 (around ?10k in today's money). However, as an example of the ravages of time and value, the TF144 signal generator was even more expensive - but last year I was given two. Both of which work bang on spec BTW, half a century on. Of course now a spectrum analyser is the way to go. However, for curiosity's sake more than anything, does anyone know anything about this Marconi TF1168 beast? Craig

I am trying to get this to work. 1: Interpolation Receiver hears SW signals when back tuning cap lead touched. 2: Using spectrum analyzer I can see 37Mhz signal at MHz points (Tiny SA) at V9.. This shows v4 v6 V8 and V7 V9 V10 working. 3: I can hear the chuffs on a VHF broadcast RX held nearby. 4: I have to make a RF detector probe to probe V9 to measure voltage at TP, but it seems OK. 5:KHz at 0 and MHz at 0 gives a signal. Any ideas? Lawrence

Greetings to all.I have for some time been enquiring about the availability of a manual for a Racal RA121D ISB adaptor unfortunately,to no avail.This adaptor has a 118kHz crystal oscillator installed as well as the normal 118kHz variable oscillator.I have the details of the RA98 118k crystal oscillator but need the connection details within the 121.Can any kind soul assist? Brian g

How do I remove the large knobs on my RA17? I have tried pulling them off by hand. I don't want to lever them off because I would damage the panel. I had thought of removing the fibre wesher and and putting a small short screw under the front washer and then tightening the nut to push the shaft. I might pull the nut out. A claw type puller to push against the centre could work if I could find one I thought as well I could wind string behind the knob and either pull or wedge it in. Any ideas? Lawrence

Hello Racal forum members, What in the wide world of sports is the Racal RA6338B VHF Converter? Pictures are available here (not my listing) https://www.ebay.com/itm/266773706822 The only settings on the front panel are to select bands in 1 MHz steps, although it can be remotely controlled from connections on the rear panel. We know that Racal sold Decade Frequency Generators to tune the kHz setting of the RA17 family of receivers . Is this VHF converter capable of lowering 1 MHz wide VHF bands to within reach of the MHz tuning of the RA17? Could this VHF Converter then enable the RA17 to tune to say the AM aviation bands 108 to 130 MHz by using the VHF Converter as a front end and tuning the RA17 in the range of 8 to 30 MHz? If not, a home brew VHF converters would be straight forward to design. Such devices are also commercially available. See Tech Minds YouTube video https://www.youtube.com/watch?v=JILgwTiw1cM . But it is always desirable to go with original manufacturer equipment where possible, and you can't beat a Racal. Given that this VHF Converter is serial number 4, it maybe a custom one-off order that Racal build for some unknown North American Customer. Then the RA6338B VHF Converter will likely remain shrouded in mystery, short of buying it and testing it out. Apologies is this is off topic. Kind regards, Terry.

Hi I have an RA17 receiver and a RA-98 ISB adapter, both in a 19inch rack. Both working. Allegedly they came from BBC Monitoring at Caversham. I also have a matching Racal SWR unit which incorporates shut down circuitry to protect PA finals. I also have a vandalised RA17 (spray painted front panel and no knobs) for spares. I am interested in selli g as a job lot from my Hereford QTH. I could deliver by arrangement. Given all the units are working (except the vandalised unit) but may require alignment due to age related drifting, what would be a reasonable price ? Thanks Adrian M1LCR Sent from Outlook for Android<https://aka.ms/AAb9ysg>

Looking to buy a Racal LF converter such as the 237B and other add-ons for my Racal RA 117 Rx. I already have a RA 298 SSB/ISB Adapter and MA168B Diversity Switch Happy to ship world wide if needed. Thanks for reading, Kind regards, Terry.

I have for sale a Racal RA17. Good condition, fully working. All the paper cap have been replaced, and any resistor that were out of spec have also been replace. Asking just ?50. Buyer must collect from Farnham, Surrey. Post code GU9 9AY. Philip de G7JUR.

Dear All, Is it possible to measure the output from V4 by connecting a Hantek oscilloscope to V6 pin1? It maybe be better put by saying I'm seeing VFO1 and XTAL signals going into V4, but see a sub 20mV sketchy signal on V6 pin 1 without the valve in. Am I using the wrong equipment (20mV on the scope is just a bad flicker) , I know there's a problem somewhere as there is no peaking in noise turning the Mcs dial and no signal on TP3. I do need to swap out some paper caps around this section but the voltages all look good. One of my problems is I've never played with it working, it was just given to me to see if I could fix it. Much appreciated -- Many thanks Dave

Hi. I have an RA17 in bits. The intention was to restore it but circumstances have changed. Free, if you can collect from Anglesey, North Wales. John

Does anyone know the disposition of R119 in the RA.17C-12 ? R119 appears in the bill of material, but not in the schematic. In the -2 version, it was connected to the anode of V18.2 and the AVC short/long switch (S6) but it appears to have been shorted through in the -12 version; is that correct ? Referring to Illustration 9 in the -12 manual, "100 KC/s I.F. Strip (Right Side)," it does appear that a jumper is placed in lieu of R119. Thanks in advance, 73 Steve, K0SF

I've been electrically upgrading a Racal RA .17C-2 (SN: N1484) up to the '67 RA.17C-12 version. I am nearly done with the audio upgrade of V23 (from 6AU6 to 12AT7) and V22 (from 6AU6 to 6AQ5). I would like to obtain a pin out of audio transfromer T2 if anyone has that handy. If not, I will need to unsolder some leads to confirm connections. I am also wondering if there is a later schematic set that supersedes my latest revision of 22 Aug '67 and whether those modifications are worth pursuing. Other than for pulling oscillators and completing the audio mod, I'm nearly done. I'll just say that I have large can of out-of-tol resistors and leaky paper caps ! Thanks in advance, Steve, K0SF Maple Grove, Minnesota

Is my memory failing me, or are the slugs in the preselector not supposed to be hex cores so one can tweak the bottom, as it were, without taking the top one out? I'm sure I once linied one up with the VNA to get really tight peaks. The one on the bench, which had that special moment his afternoon when the front panel went back on and everything still worked, first time with no smoke, has slotted slugs. Not a show stopper but less convenient. than I think I remember... 73, Colin.