[CQ-Contest] results auto sw bandpass filters for all bands
hs0zcw at gmail.com
Sun Jul 26 01:07:04 EDT 2015
My own and perhaps unique solution is to depend on the isolation of the
Radio 1 and Radio 2 and SO2R wiring inside the Expert 2K-FA. That is the
SO2R RF socket on the amplifier can be either shorted or further isolated
to aid in bandpass interdiction for the "other" radio set on receive during
a high 1.5KW transmission by the "first" radio.
Consult the block diagram at
to see the chance to get access to the signal chain for more isolation via
the SO2R socket (which I will not otherwise be using).
Factory says about 25db isolation at worse case, without SO2R shorted to
Sounds ok to me if "other" radio is on a different band from "first" radio.
On Sun, Jul 26, 2015 at 10:49 AM, Mark Ketchell <k5er at arrl.net> wrote:
> Hi Charly,
> From the two BPFs in my example, you could follow with a simple
> remote A/B switch (Dow-key, etc.). The "A" side from the regular bands is
> normally connected. When a warc band is selected, a diode matrix added
> inside the band decoder could output a voltage to switch the A/B to the
> "B" side. The common of the A/B goes to one input of your SPE. Duplicate
> for the other radio.
> Unfortunately, this is now many more pieces than your original
> request for a single box. Before I lead you too far down this path, you may
> want to check out the book, "Managing Interstation Interference" by George,
> W2VJN, available from Inrad(.net). May help you decide what is most logical
> for you. Good luck.
> Mark, K5ER
>> Great suggestion Mark.
>> However, where does your RF output from the two filters go? If directly
>> antennas and antenna switches, ok, but what if one puts a linear amplifier
>> to follow the BP filters?
>> My SPE amp allows two RF inputs, switchable, so the one input could be
>> regular bands and the other input be for WARC. That could work great.
>> But, then where is the OTHER transceiver/amp? No need for the filters if
>> there is no second source of huge levels of RF. Seems then one would need
>> two SPE amps and a second transceiver??
>> I thank all with suggestions. 73, Charly
> Charly, HS0ZCW
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