[SCCC] 6 mtr Transverters Query

[N6KI Dennis Vernacchia]

Sorry for wide post but this is an obscure query.

A ham friend recently acquired an ICOM-775DSP HF XCVR
made in the early and mid 1990s

He would like to get on 6 mtrs and I am sure the the transverters that
may have been available when the 775 was new are as scarce as hens teeth,
if they even existed.

Does anyone make an after market transverter that will work with the 
ICOM 775.
Are they I.F. Specific for that rig? etc etc

Any ino appreciated.

73, Dennis N6KI
San Diego