[Elecraft] other xmitter nearby

[Brendan Minish]

On Wed, 2008-02-20 at 10:19 +0000, Charles Harpole wrote:
> My factory bilt K3 , just out of the box, desensed nearly to zero rcve
> with 1KW xmit on different band w. ant. 70 feet away. 

70 feet is a tiny spacing in wave-length terms, depending on the
antennas you could have several 10's of watts arriving at the K3 in this
scenario.  
Before trying to operate multiple radios and multiple antennas you need
first to evaluate how much interaction you have between ALL the various
combinations.
Then you need to take whatever steps are required to keep RF arriving at
the other radios in damage inducing amounts. I am no expert multi-multi
setups but I would be inclined to keep below 0.1w returned into 50 Ohms 

Another factor is wide-band phase noise on TX and amp generated noise.
PA stages in radios and amplifiers tend to use high pass filters to
reduce harmonic content, these will do little to clean up 'crud' below
the TX frequency  

Be very careful in multi-TX setups you need to be careful about how you
engineer things or you risk rig damage.
If this is just for casual operating, adding interlocks to your band
switching so that you can't inadvertently select combinations that are
potentially risky might be a good idea

>  I want to know what filtering the VP6 guys are doing IN ADDITION to
> turning on their K3s.  73Charles 

Lots of separation between stations on the same band, use of separate RX
antennas separated by distance and polarisation, clean amps and probably
a bunch of high quality band-pass filters too. 
73
Brendan EI6IZ 

-- 
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to fix the situation yourself. It‘s dangerous. Leave it to a highly
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