[R-390] Question from a newbie...

[John Saxon]

Hi folks:

I just recently obtained 3 R-390A and 1 R-390 and am now starting to work on one of them.  Don't have any prior experience with these beauties.

It just occurs to me that I haven't seen any reference to extender cables.  Are there such things out there?  I assume they would not be difficult to build if plugs were available.  Are plugs available?

Thanks,
John
K5ENQ