[Elecraft] Thoughts of K2 xtal prefilter

[Stewart Baker]

Hi Benny,

Thank you for your comments.
Yes, I think that a diplexer in front of the pre-filter and and a 5dB amplifier 
after it would work.
I do not have the necessary test equipment here to show the before and after 
results, so I will probably wait until someone like yourself (or Elecraft) makes 
those modifications.
To date I have found no IMD problems caused by the Pre-filter, but there again I 
am not resident in a country where we are 'legally' allowed to run kW's.

73
Stewart G3RXQ


 On Mon, 21 Mar 2005 20:27:44 +0200, Benny Aumala wrote:
>
>
> Dear OM Steward,
> how about using a diplexer in front of prefilter.
> If impedance there is 150 ohms, try 4,86uH and 213pF combination.
> If not, I would like to simulate other impedances.
> Between prefilter and 2N5109 amplifier this could save the 5dB attenuator
> loss for
> prefilter.
> Looking components, the hi-Q coils are not necessary, but care must be taken
> to
> choose a ferrite without IMD. I am looking for 15mm tubes of Siferrit U17.
> That is a component very hard to find now. But 30 years ago I made the best
> minimum-loss
> bandfilters with them.