Band Reject Coaxial Stubs

[Del Seay]

John Brosnahan wrote:

> 
> You can't assume that 40M is clean -- it never is. So you will really need
> both 20M and 40M filters.  Typical transmitters only reduce their 2nd
> harmonic by 40-50 dB leaving a lot of signal on 20M from the 40M
> second harmonic.  And typical recievers on 20M don't reject the
> 40M fundamental all that well.
>

Hi John: Your comments all agree with me, except - the prudent
approach is to clean up the transmitter outputs prior to ever looking
at the stub issue! First priority would be to properly filter all
receiver inputs, all exciter outputs, and  make sure the harmonic
content and 2nd, 3rd, etc imd of the amps are all properly reduced
to an acceptable level. Then, proceed with the inter-station
problems. Your answer was well thought out. Thanks. de KL7HF

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