[Radio Wrangler]

While there has been a reasonable market for SSB receivers, that for ISB has been much much smaller. So any development of an ISB machine needs to be based on that of an SSB machine for simple economies. However, the ISB stuff needs to be sufficiently separate that it can be left out of the SSB version without any significant impact on the cost of making the SSB version. The SSB version will be lower cost, higher volume and much more critical on financial margins. Using an internal tray makes it simpler. Using an external ISB adaptor saves the base model receiver having to have too big a case.

We don't know how many ISB links worked with a pair of SSB machines. This would enable better standardisation and allow the versatility of splittint their frequencies to handle different SSB channels etc... and if one broke down, you still had an entirely separate receiver to use.

David