Racal RA17 re-born : A trip down Memory Lane

[Will_D]

More progress reports: Ian has been concentrating getting the mechanical side of things sorted before going on to the component replacement and re-alignment.

Seem to remember a brand called "Make-a-switch"
It had 12 positions on each switch wafer, so you could have 1 x 12, 2 x 6, 3x4, 4x3 combinations plus the mechanical stop plate(to limit movement) , and you could stack up a lot of wafers.

Sort of rotary switch Meccano!!

I had a lot of them salvaged from old equipment.

[awemawson]

Ian has sent me a couple of updates in the form of .pdf documents which I'll attach one by one due to size limitations


.. . . .whoops it seems that they are both too large - I'll see if I can pull bit's out and post them 

[awemawson]

And the second report

[awemawson]

Now I have received Ian's third report as a .PDF 8.8 mByte long, but oddly if I save each of the two pages that it consists of using 'PDFCreator' they are each less than 900 kByte - same happened when I did the previous two reports 

[David Jupp]

He probably generated the original using Microsoft Print to PDF - it's notoriously inefficient.

[seadog]

That's a very thorough refurb. I've just been looking on line and seen an 1154/1155 that he refurbished. Fantastic work.

[awemawson]

That's why I chose him - he has a very good reputation and his refurbished radios command a premium price from the cognoscenti. Particularly with the RA17 series he has a lot of experience getting them back to at least as good a performance as when they left the factory. His next report hopefully will show the careful work getting the correct pass band shape of the complicated filters.

Mind you it's bankruptcy territory paying him 

[seadog]

I see that the most recent prices he's posted are for 2015. Has inflation taken its toll? 

[awemawson]

Time will tell 

(but actually his price is quoted as of Jan 2018)

[awemawson]

Ian has finished waving his magic wand over the RA17 and it is looking SPLENDID from the pictures that he has sent me.

Not seen it yet as I've asked him to do a similar re-furbishment on my RA137-1 LF attachment - waiting his response.

By total co-incidence I came across a mystery parcel on the shelf in my welding shop today, and according to the label it contains a good RA17 1ST VFO unit wrapped up by me 22/10/2002 and charged with silica gel desiccant.

[awemawson]

So I'm glad to be able to report that Ian has agreed to breathe his magic over the RA137a-1 LF converter which undoubtedly needs the same attention to the aged capacitors and resistors, and a bit of alignment - though it is a far simpler affair than the RA17 itself.

Up early this morning (as loads of family descending on us soon for Easter) and packed it up sandwiched between a pair of sheets of plywood hopefully to  protect it from the ravages of couriers in transit. Awaiting collection on Tuesday after the Bank Holiday.

[Pete.]

I can't imagine the hours that's gone into that refurb. I don't suppose there are many people about now who could even do it.

The before and afters look amazing, along with the comprehensive report.

[awemawson]

Yes he turns out good work. 

He enjoys what he does, similar to me titivating various bits of CNC machinery, and certainly if one didn't enjoy it it would be quite a slog.

[awemawson]

Well I've been and gone and done it again   

An RA218 independent side band adaptor for the RA17 turned up on eBay and I won it last night. These are fairly scarce these days so although this one is not in prime condition I grabbed it.

The RA218 makes interfacing RTTY (radio teletype) equipment a doddle, and since that is what got me into computers back in the 1970's it's a bit of re-living past experiences.

The RA218 contains some unusual glass enveloped crystals - the most rare of them - an 18 kHZ -  SEEMs to be present, but the others are contained in a crystal oven so the pictures cannot tell me if indeed they are there. I can tell from the photos that two valves , VT11 & VT12, are missing from their screening cans, but they are only 12AT7's used as audio output stages for the upper and lower sidebands. 12AT7's are still easily available at sensible prices (amazingly RSComponents stock them !!!) unlike many other valves which have become trendy in the "pretentious audio" world!

This time I have totally cheated, and have arranged for the seller to send it directly to Ian who has again agreed to wave his wand over the unit. He has one of these adaptors in his own RA17 / RA117 set up, but when he got it that rare 18 khz crystal was missing and he is running on a jury rig of a different crystal and a TTL divide chain!

So that's two RA17 adaptors from me on his 'to do' list 

[seadog]

12AT7's are still easily available at sensible prices (amazingly RSComponents stock them !!!) unlike many other valves which have become trendy in the "pretentious audio" world!


Call them an ECC81, plate the legs gold and put the name Mullard on the envelope and you are talking silly money.

I sold 5 untested, other then the heaters, mixed ECC valves in 2015 - £50 
They came in a mixed box that I bought from a car boot for £15. I must have taken well over £100 out of that box tp date 

[Will_D]

Weren't ECC81's common as chips in TVs? I had a box full!

[seadog]

Indeed they were. The EF80 was another. I sold three dozen of them, untested, to a chap in Malaysia. It cost more to post them than he won them for (£7-55). It was interesting packing them.

[awemawson]

When I was at school I was befriended by a chap in the TV shop in the town, and can remember cycling home one day with my push bike saddle bags FULL of EF80's, PL84's and ECC81's that had been pulled from sets that he was scrapping. Back then before common sense had been banned and children were allowed to DO things we had a Radio Club at school where we regularly dived into the back of mainly Black and White but very occasionally colour TVs.

But then, in the CCF signals section at school we had a C52 transmitter that we regularly netted with other school CCF's, and the aerial for that TX would kill any careless sparrow that put a foot wrong 

Children these days miss out on SO much - bending plastic just isn't the same.

[seadog]

What was the C52, Andrew? I had a C50 for a while which I ended up scrapping due to lack of interest and space     

[awemawson]

C52 was a 19 set on steroids - C denoting made in Canada

[seadog]

Very nice. I've never heard of that rig before.

[Will_D]

But then, in the CCF signals section at school we had a C52 transmitter that we regularly netted with other school CCF's, and the aerial for that TX would kill any careless sparrow that put a foot wrong 

I ended up as signals sergeant in our CCF. Our call sign was 4Charlie (Llandovery College in Carmarthenshire).

We used a 19 set but with some extra booster/amplifier. We managed QSL contacts with a lot of public schools even oin Scotland.

We also had a mobile system - a 19 set and some very large lead acid batterys mounted on a large hand cart. A couple of junior ranks had to push this round the back roads around the school. That was c/s  Foxtrot4Charlie.

I bought a 19 set with PSU etc and managed to bring it home on a double decker bus and carry it the last half click to my parents house. I built a mains power supply for it in the old rotary converter box and so another F4C was alive in Abergavenny. I took it to Salford when we bought our first house and somehow lost it!!

Thanks for the memories Andrew

[awemawson]

One memorable CCF camp was at a place called 'Whiteworks' on Dartmoor - down a very long track just opposite the prison. One day on exercise I had to establish 'base camp' on top of a local 'high bit' called 'Gutter Tor' - iirc I had an 18 set and the other platoons were using WS38's. Managed to erect an aerial mast and got everyone 'netted up' - all was working extremely well until some other 'mob' broke in on our frequency. I (aged probably 15 or 16) ripped into them questioning their forebears and pointing out how they had totally ignored standard operating practice (ie listen before swamping people). I Assumed they were another school CCF platoon.

Oh no - they were regular Army 

Didn't stop their CO flogging all the way up Gutter Tor to make an abject apology 

Then the thunder storm broke and he helped me strike the aerial mast  - oh the power of the spoken (irate) word.

 . . . . I suppose I was bolshy even then 


https://en.wikipedia.org/wiki/Whiteworks


https://getoutside.ordnancesurvey.co.uk/local/gutter-tor-west-devon

[Will_D]

What were those little mobile sets called? Were they 88's?

 They used a 22v and 1.5 dry battery combo and fitted into two belt pouches

[awemawson]

Yes WS88 - there were two variants usually differentiated by   the lower 4 channel sets being painted green, and the higher ones were black iirc Very nicely made and crystal controlled.

Post WW2 they were more Korean War vintage - totally immersible hermetically sealed and they floated! I had several pairs of them back in the  1980's. When demobbed they had to be made inoperable so they cut off the pressel switch that was on an umbilical cord which was used to switch from receive to transmit. Every now and again the pressel switches turned up in the junk shops in Old Compton St and Little Newport St so you could re-unite them 

My first home made inverter was to power those sets - as you say 1.5 volts for heaters and (not 22v) 90 volts for the anodes. I could never get the invertors to be electrically noise free so the set whined !

*** Later edit, that must have been late 1960's not 1980's