[TowerTalk] Triplexor/Switch/BPF SO2R

[Richard Cariello]

Ed,
Check out the VA6AM  product line.
Rich AA2MF

Sent from my iPad

> On Feb 15, 2022, at 2:58 PM, ed_richardson at shaw.ca wrote:
> 
> Regrettably I am resigned to never having stacked monobanders on this
> suburban lot.  I have now started investigating the idea of using a
> triplexor and associated bandpass filters as a way of getting an SO2R
> antenna system operational utilizing the same 5 band yagi.  Currently I am
> using a ground mounted vertical (during the winter only) as the second
> antenna.
> 
> 
> 
> The common application recommendations are to use one of the 2x6 or 2x8
> switches to direct the 20/15/10m signals from either transceiver through the
> matching BPF and into one input of the triplexor.  I am seeing band to band
> isolation figures of the filter/triplexor combos in the 85-100 dB
> Unfortunately the 2xn switches appear to have radio A to radio B isolation
> values in the 70 dB range.   
> 
> 
> 
> Would this multiport switch isolation not be the limiting factor? Two 1 kw
> transmitters will still place -10 dBm signals at the input of the other
> radio.
> 
> How critical is it that the unselected bands be terminated in 50 ohm?  I see
> that many of the 2xn switches ground the unselected ports and this would
> effectively put a short on the unused BPS filter input.
> 
> 
> 
> Would a second set of low power BPFs installed between the radio and power
> amplifier be effective in removing another 30-40 dB of offending signals.
> This comes at the expense of another dB or so of insertion loss.
> 
> 
> 
> Does anyone have any real-world practical experience using two - 1kw radios
> triplexor/filter/switches.  
> 
> Lessons learned are much appreciated. 
> 
> 
> 
> Ed VE4VT
> 
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