I'm thinking this might also act as a gate to prevent excessive rf getting
into the K3 2nd rx. I'm planning to have a horizontal receive antenna
located adjacent to my vertical transmit antenna for diversity reception. I
was just investigating the ICE196, but this idea might be better.
David
If you are planning to use closely spaced Tx and Rx antennas, I would
suggest that you consider using a Reed relay or similar fast acting relay
to short circuit the external preamp's input during transmit periods.
Without it there is some risk that during transmit periods the external Rx
Hi Geoff
I did consider that and I get your point about the diode protection, I've
had first hand experience ! To reduce my bench time creating my own
amplifier and such like I was looking into using the RPA-1 from
DXEngineering which has an automatic bypass mode. I don't know if it will
...I would suggest that you consider using a Reed relay or similar fast
acting relay to short circuit the external preamp's input during transmit
periods...
Take a look at the Omron signal relay, Mouser part number
653-G6A-274P40-DC12. These relays operate in 3ms typical, 5ms max. I use
If you are planning to use closely spaced Tx and Rx antennas, I would
suggest that you consider using a Reed relay or similar fast acting
relay
to short circuit the external preamp's input during transmit periods.
So long as the relay is accuated before RF appears, and held until after RF
Perhaps I should look at protecting the K3 subreceiver from the RPA-1, even
on receive mode :-(
I seem to recall Wayne saying the rx input could take 2W although not
recommended !
73
David
G3UNA
The RPA can output well over 1/2 watt, so don't expect it to act like a
limiter. It makes a
Thanks Phil, you have a great site and I've often referred to it, as I do
the W8JI site.
73
David
G3UNA
...I would suggest that you consider using a Reed relay or similar fast
acting relay to short circuit the external preamp's input during transmit
periods...
Take a look at the Omron
David,
Have you measured the strength of the BC carriers in the 6 MHz and 7 MHz
bands after sunset as seen at the shack end of your antenna's feeder when
terminated ?
If of any use to you I could send you some screen captures using a 1600 kHz
span after sunset this evening, with the BC
I had a thought for a future feature request. For those of us who use RX
antennas (active and/or preamp). It would be really cool if the 12v output
on the K3 could be triggered by the PTT. If the 12v output jack could be
set in the menus to 0v (OFF) on PTT we could power our preamps via that
Hi Rich,
You could control 12 V to an external RX antenna or preamp using the
KEY OUT signal pretty easily. This signal floats (open, or hi-Z)
during receive, and goes to 0 V (ground) during transmit. The timing
is perfect for such an application, because there's a delay between
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