Topband: Separate rcv antenna, some general notes

[kees nijdam]

Hi,

A separate rcv antenna input can be made (in many transceivers) by
interrupting the connection from the antenna relay to the rcv (=rx) input.
Both ends of the interrupted lead must be connected to two connectors, to be
mounted on the rear side of the rig. On the rear sides of many transceivers
there is still some place (maybe with a special bracket)for additional
outlets.

I did it with my TS480SAT and the TS480SAT of a good friend. The 'blind'
plate for the second blower can be used for mounting the additional outlets
(BNC or similar).
I did it also for my FT100 and some older transceivers.


The original configuration can be restored with a short coax connection
between the two outlets.

However, in some transceivers the T/R relay is between the (TX-)Low-pass
filters and the tx-final. This means that the new rcv input is bypassing the
Lowpass filters. A seperate (80/160 LP) filter in the rcv lead may be
needed. I did it for the FT100.

A second remark is the protection for the TX signals entering the rcv input.
Be sure not to overload the rcv input as it can damage the rcv. Some
separation between rx and tx antenna will help, but in some cases additional
measures may be needed.

73,

Kees, PA0CLN

Send me an e-mail if you wat a picture of the TS480SAT.