RA117 serial number N0489 (/cont)

As can be see, the RA117 cleaned up rather nicely. Performance is also quite astonishing. As usual, SSB reception is more than acceptable provided you don’t overload the detector. For this reason it is sometimes necessary to add in attenuation at the front end and/or back off the IF gain. According to the manual, the signal-to-noise figure at 1.5MHz should be at least 18dB. I have checked and double checked my test setup and repeatedly get a figure of close to 27dB. The same is also so for an RA17L that I have just refurbished. I can only surmise this improvement is due to the use of modern, higher quality resistors.

So this completes my Racal collection for the moment:

Below the bench, left to right … RA17 N664, RA17L N8854 and RA117 N0489

Above the bench and going up … MA197 Pre-Selector, RA1217, RA1772, RA1792, RA3701

I also have an RA218 ISB adapter which is missing the 18KHz crystal. These obscure LF dual crystal devices are virtually impossible to come by, so I have designed and built a modern solid-state circuit which derives 18KHz from a 12.6MHz monolithic oscillator. I just have to fit it into the RA218 in such a way that it doesn’t detract from the original build. Once that is done, there is just enough room on top of the big Racals under the bench.

Job done!