On 05/22/2010 08:46 AM, Bert Hyman wrote:
In Bill Baka
wrote:

Can I put a noise blanker between the preamp and the radio?
I know that Hammarlund had a noise blanked circuit but these are very
hard to find and usually a lot of $$$$.
I am/was an electronics engineer for over 30 years but I find myself
at a loss as to what I should build or buy.
A noise blanker on the antenna input to the preamp seems like a good
place to put a blanker but the signal off the 25 foot 'long' wire
might not be enough to work with. My thinking is that it would be good
to intercept the noise before it even gets into thee tuned circuits
and causes ringing or some other side effect.

Noise blankers are usually inserted in the IF chain and work at a single
frequency, and on signals of relatively high amplitude. Trying to get
something to work across the complete range of frequencies you're
listening to might be a real engineering trick.

Have you considered a noise cancelling receiver like the MFJ 1025/1026?

They use a separate noise antenna (the 1026 comes with one) and combine
the signal from it and your regular receiving antenna and then apply
phase shifts to either enhance or cancel signals that are received by
both antennas. The method is effective in theory, but I have no idea how
well the theory is implemented with these products.

http://www.mfjenterprises.com/Produc...uctid=MFJ-1025

Sounds like it might be worth a try, but I don't have any $$$ to buy
anything right now. I'm on disability so my income does not go too far.
Thanks for the fast response.
Bill Baka