[Elecraft] Antenna switches

[Robert Nobis]

I agree, isolation is the most important factor for antenna switches. However, I wouldn’t use a switch unless it had at least 60dB of isolation in the HF band, even with Tx power of 100-watts.

73,


Bob Nobis 
n7rjn at nobis.net


> On Jan 2, 2017, at 20:23, Don Wilhelm <donwilh at embarqmail.com> wrote:
> 
> Jim,
> 
> The most important factor when talking about connecting multiple transceivers to antennas is isolation.
> The real question is just how much RF energy will leak back into the non-transmit transceiver.
> Yes, there is the possibility of damage to the receiving circuits and T/R switch of the receive transceive that is just supposed to be listening if it gets too much RF at its receive input.
> 
> That is what the real discussion is all about.  The amount of isolation required in the switch depends on the power level.  If you are talking about 100 watts power from the transmitter, 40 dB isolation is likely OK, but at higher powers, you will need more isolation.
> 
> 73,
> Don W3FPR
> 
> On 1/2/2017 9:53 PM, Jim Miller wrote:
>> Off topic.  Sorry.  What are the functional disadvantages that make it
>> apparently undesirable to build an antenna switch that is a crossover 2
>> radios x 2 antennas?  What if you only used one path at a time but could
>> switch them easily?  Crosstalk?  Is it so strong as to damage the other
>> radio?  Is it not possible to achieve acceptable compatibility with 2 radios
>> and 2 antennas?  Or to swap amplifiers between two radios and two antennas
>> by placing one on the input and another on the output of the amplifiers?  Or
>> to swap in the better antenna for a short contact that you just can't seem
>> to make on the current one?
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