These are articles about my RA-117, posted in the Boatanchors list.
Well, the long awaited moment just arrived!. The Racal RA-17L I bought last week arrived on 12th March.
I have done some interesting findings about this unit:
-This model is a North American unit, as it has the calibrated S-meter, SO-239 connectors, different labels in front panel ('POWER' instead of 'MAINS', 'ANTENNA' instead of 'AERIAL', ...), american tubes, ... This is very interesting, as I got the set from UK. It sure will save some time trying to find the correct connectors :-)!.
-As the seller told me, it has NO tubes. Well, really it has ONE tube (a 6BE6) and ALL except two of the tube shields, including some IERC types.
-The manual I got is for the RA-17 Mk II, not the 'L' version I have, so the information is not 100% useful, although the working principles should be the same... Is there any RA-17L manual around?. I could swap it for a copy of the RA-17 Mk II or just pay for it. Please, let me know.
-From the Terry O'Laughlin WB9GVB Racal model list (available in the BA archives), I have got this info about American models:
RA-17 C-12 : As RA-17 but w/ American tubes except RF (ECC-189)
RA-17 C-16 : As above w/ all American tubes (6ES8 RF), beefier audio output (12AT7 and 6005 in place of two 6AU6s), SO-239 conns for IF and ant
My unit has a 9 pin socket for V23 and a 7 pin socket for V22. In the RA-17 Mk II these tubes are the audio output tubes... Could I be so lucky to have a C-16 model?.
About this model, it has 25 tubes (the power supply is solid state; a mod done in the factory, I think). The RA-17 Mk II has 23 tubes... Could you tell me the tube line-up of the RA-17L?.
I'm looking for some tubes I have not in my stock, in order to put in the receiver and have some spares for it:
6688 / E180F (6)
Also, if the RA-17L uses tubes not used in the RA-17 Mk II, I would probably need them.
The Racal is really an impressive receiver, with a depth of about 21" and that wonderful aluminum die cast chassis. Very nice!. This unit is in good condition, only missing the tubes and the 'big' covers (the small ones are also here :-) ). So I hope to be able to restore and enjoy it... I'll keep you informed on the process.
Well, I finally found which is the model I have got. Following Mike VA3MR/G3NKR suggestion, I did the obvious: looked at the back labels ;-)!. I should confess that I didn't this before because I had the receiver just over the back face, in vertical position, as my workbench was full (now I have get a bit more of space to put it horizontal... to find really good news!. I have a RA-117 !!!. It is described in the Terry O'Laughlin WB9GVB Racal model list as:
Similar to RA-17 C-16, but Quadruple conversion w/1.6kHz IF stage and filter added before 100kHz IF, two versions avail; one w/British 'valves' and one w/American tubes (including two 6688s), both have American connectors (SO-239...)
Wow, I think that this has been THE buying of my life ;-) ;-)!.
But now I'm really lost about documents, as only manual I have is for RA-17 Mk II. So, is there anybody able to copy a RA-117 manual for me?. I would gladly pay any expenses in advance.
One good thing about this unit it that it has, as the RA-17L C-16 version, a 'power' (1W) audio output, instead of the 50mW other versions have.
For your information, here is what I found written in the back panel, along with its description, from left to right:
B+ 500mA (fuse)
POWER 2A (fuse)
ANT. (SO-239 connector)
10mW, 600 Ohm
1W, 3 Ohm (this is the nice one!)
3 mW, 600 Ohm
3 mW, 600 Ohm (again!)
3 mW, 600 Ohm (and again!)
100 Kc OUTPUTS (two of them, SO-239)
In another smaller plate in the back panel, where the id labels are, you can read in one label:
TYPE No RA-117
Serial No N0229
RACAL Electronics Ltd.
And also read this other label:
AUSTRALIAN PAT. No ......
BRITISH PAT. No ......
U.S. PAT. APPLIED FOR --- hi!. I hope they have it already ;-)!
Then, just below this label, there is another 4 connection strip with a yellow label over it which says:
And the strip has this text:
There are also four BNC connectors, labeled:
And that's all!. Sorry for being so detailed, but this way you should be shure of the receiver I'm talking about ;-)
I am interested in contacting other RA-117 users, as I should do a complete alignment of the receiver, once I get all the tubes. Anybody around?.
Thanks and best regards from a lucky boy!
Well, after some nice local holidays, I have been able to start checking the Racal receiver...
I did a carefully cleaning and some minor mechanical repairs (as adding a new transparent plastic window in the dial, which was missing). The die cast aluminum chassis is free of any corrossion and has cleaned so nicely that it shines!. The overall condition of the receiver is very good. Only some small scratches in the front panel outmost part, but the lettering is intact.
Ok, let's go with the first 'electronic' test results!. I am still missing three 6688 tubes, which are the first, second and third mixers, so the checking has been reduced to some basic circuits... But has yielded interesting results so far!.
First I checked the power supply (solid state in this version), and it looked fine, so I slowly applied power... The panel light worked and the nice film kc dial showed its beautifulness. It is really a nice one to look!. As it has backlight, it is very easy to read. At the moment, is the _best_ dial I have around, IMHO.
The receiver has four BNC connectors in the rear panel, labelled '1M/s', '1.7M/s', '2ND VFO', 'RF'. They can be configured, by means of some internal wiring (BNC cables; very easy to do!), as inputs or outputs. If you use the internal oscillators, you should put them as outputs, and I put them that way. The first three of these generate signal WITHOUT needing the 6688 tubes, so my checking began here:
'1M/s': 1MHz crystal oscillator. This is the 'master' oscillator of the set. From it the system generates harmonics to cover all the HF spectrum. In my HP-5328A frequency meter, I got 1000.01kHz, so it appears to work fine. The drift, after a 5 minute warm up, was less than 50c/s in an hour.
'1.7M/s': 1.7MHz crystal oscillator. This is used in the fourth mixer to generate the final 100 kc/s IF signal. It read 1700.01kHz. Drift was also very small.
'2ND VFO': this VFO runs from 3.6 to 4.6Mc/s. It is well aligned, as in the endpoints the difference is less than 1kc from the dial indication. And in the intermediate points, it is always smaller than 1kc. Also, the tuning is very smooth, without any appreciable discontinuity.
I have also checked the RF amplifier and it seems to work fine, although I have not made any accurate check, only found that the noise is amplified.
Next step will be to check the first VFO (it runs from 40.5 to 69.5Mc/s). I could also check the audio section and some of the IF amplifiers... But I'm really happy with the current results, as it seems that the receiver is also in very good shape electrically, not just phisically :-).
I think I'm falling in love ;-) ;-) ... Perhaps it is the upcoming spring!.