Relays in transmit path ?

[N4XD]

Are relays still used for T/R switching or does the G2 use pin diodes? If relays, any differences from the 7000 series? Specifically, is the pure signal relay still in parallel with the T/R relay so its always used even if the mode isn't SSB?

Thanks
Ron
N4XD

[w9ac]

Are relays still used for T/R switching or does the G2 use pin diodes? If relays, any differences from the 7000 series? Specifically, is the pure signal relay still in parallel with the T/R relay so its always used even if the mode isn't SSB? Thanks Ron N4XD

Ron,

Good questions, and I hope someone will respond with actual data. In case you missed it, there was a prior discussion about this:

https://community.apache-labs.com/viewtopic.php?f=46&t=4570&p=24241&hilit=w9ac#p24241

Presumably, there was a performance issue that may have precluded use of the PIN diode switching topology that's shown on a pre-release schematic. If true, it's solvable but it's also possible that the circuit became too complex to offer any added value in the minds at Apache Labs -- which it is.

I'm also not buying into the argument that a PIN diode section cannot be adequately linearized. I have designed and built many PIN diode QSK circuits. With ample diode biasing, linearizing isn't an issue -- just as linearizing is not an issue with Elecraft transceivers and amplifiers that utilize PIN diode T/R switching.

Has anyone on the list successfully obtained a complete set of G2 schematics? Apart from that, it would require digging into the unit to verify if the PS relay is wired in parallel with the T/R relay.

Paul, W9AC

[N4XD]

Thanks Paul.

From reading the other string, seems no changes have been made. That is a REAL shame since, to me, the use of relays is a downside for the radio. Perhaps I'm doing something wrong but I found that, when using the internal keyer, a VERY long delay (hundreds of ms) was needed to eliminate hot switching. Using an external winkeyer solved that problem but seems a longish delay is still needed.

I have yet to implement your changes. I get tired of working the jigsaw of removing the boards from the 7000 enclosure

Ron