[Elecraft] Band Pass Filters for QRP

[Ron D'Eau Claire]

Once very simple solution that will provide more than 30 dB attenuation of
the undesired signal is a coax stub. It's just a length of coax connected to
the main transmission line with a "T" connector that is cut to the proper
length to attenuate the signal from the other station. And, yes, you can use
several of them in parallel. 

A couple of on-line references for building them are:

http://www.k1ttt.net/technote/onestub.html


http://www.k1ttt.net/technote/onestub.html

73,

Ron AC7AC


-----Original Message-----


Good afternoon all. I have a question and would appreciate everyone's 
thoughts. I've started trying to get to the field with a buddy of mine. We 
take a popup camper and have a day or two operating event. We keep running 
into a problem if we both decide to set up stations.

We are generally using K3s and W3EDP antennas or maybe a Buddipole. The 
antennas are 20-30 feet apart, so as you might guess, If one of us is on 40,

the guy operating on 20 knows it and visa versa. While the K3 can do alot to

minimize the interference, it's not something you'd want to listen to for 
very long.

What options might be out there. We are aware of W3NQN bandpass filters, at 
$105-$125 a band, that can get expensive quick. But that's not the real 
problem. 6 of them is almost the size of them is almost the size of the 
radio. I don't really need filters capable of 200W. I'm looking for 
something closer to QRP levels. Even 20-30W would probably work, as it would

allow for some of the backpacker type amps.

I know the W3NQN filter, or some of their cloans would do the job, but I'd 
like something smaller....IF I don't have to compromize too much in 
performance.

Any suggestions would be appreciated.

73's Jack  K5FSE
Treas  QRP ARCI

jack.nelson at mindspring.com