Luer, Here's a cheap and easy way insure the antenna receive antenna is disconnected from the SDR (transceiver) and the antenna is grounded before the TX is keyed. Use a DPDT relay, it can be small as it switches little power. One pole has the swinger connected to ground and when energized closes the Transceiver PTT. The other pole has the deenergized connector connected to the receive antenna and the energized connector connected to ground. The swinger is connected to the receive antenna connection of the trasnsceiver. The Transceiver PTT signal energizes the relay. When the relay is energized, the first thing that happens is the transceiver receive antenna is disconnected. The next thing that happens is the Transceiver PTT and the transceiver receive antenna connection are grounded. The third thing that happens is the Transceiver starts transmitting.
At 08:28 AM 2/25/2007, Luer Luetkens wrote: >Mark, >I'm planning to install an RX only antenna. I will have a relay to >detach and ground this antenna, if the TX signal of one of the stations >goes active. This implies two things: the TX active signals have to >appear earlier than the HF power - which is the case with both the >SDR-1000 and the Kachina , I'm not yet sure with the FT817 - and >secondly you don't want to use the RX only antenna on other bands while >you are transmitting. In my case, I will leave the 817 out of this >concideration, as I use it for packet radio, plus my RX only antenna has >an over-voltage protection against too strong signals, and I would not >connect it to the 817. >I fully agree that one has to have it fool-proof. >73s, Luer, DF5TP >-------------- next part -------------- >An embedded message was scrubbed... >From: "Mark Mumaw" <[EMAIL PROTECTED]> >Subject: [Flexradio] RX only Antenna >Date: Thu, 22 Feb 2007 21:18:08 -0700 >Size: 3960 >Url: >http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070225/b315f8ac/attachment.mht > > >_______________________________________________ >FlexRadio mailing list >FlexRadio@flex-radio.biz >http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >FlexRadio Homepage: http://www.flex-radio.com/ > >FlexRadio Knowledge Base: http://kb.flex-radio.com/ _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
