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Loud TR Relay

K5FM
K5FM Member
edited April 2019 in FLEX-6000 Signature Series
While the PIN diode/reed relay TR system used in the CW QSK mode is reasonably quiet, the  click/clack of the TR relay when in SSB mode is very annoying. At first I assumed this was some type of amplifier keying relay that could be disabled, but that does not seem to be the case. Why can the same  TR hardware used in QSK not be used in other modes?  If it is a function of  obtaining the ultimate in  noise floor we should at least have the option of choosing a silent TR mode over noise floor if that better suits our operation.   All of my amplifiers use either vacuum relays or PIN diodes for TR switching, and all of the other premium  transceivers I have owned over the last 25 years could be configured for silent TR switching,  this is  a huge step backwards and would have been a deal killer had I known about it  before my purchase. 

Answers

  • Gerald-K5SDR
    Gerald-K5SDR FlexRadio Employee ✭✭
    edited April 2019
    PIN diodes introduces transmitter IMD on linear modes like SSB.  It would be technically possible to use the PIN diode in SSB on the 6000 series but at the expense of linearity, which does not matter on CW.
  • K5FM
    K5FM Member
    edited June 2014
    ?, PIN diodes are the industry standard for RF switching  where linearity is a critical requirement. In my work  we  have been using them  for over 25 years in applications where linearity requirements far exceed that required of a amateur SSB transmitter, with proper biasing IP3 performance should be down to the level of a mechanical relay.

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