One of the first technical idea that we learned as amateurs was that antenna gain is the same in transmit as in receive. Yes, that is true...but...it doesn't seem to be true. Why can I hear stations that I can't talk too? Or, why did I get this card from someone who said that they could hear me but I wouldn't go back to them?
There is a wee bit of a problem here that should be given a look. It's a little thing called NOISE. Many times a signal is there but noise blanks it out. It doesn't take much noise to cover up signals and that is why when we
look at operators on the lower bands, we often find them using a different antenna for receiving than they use for transmitting. Attempts to nullify the problems with noise for the amateur usually take one of several forms.
Using a receiving antenna that is positioned to be least bothered by noise, such as ignition noise is one way, Another is to use antennas that are directive for receiving while using a omnidirectional one for transmitting is another. There are of course some electronic techniques that narrow band the signal or move the passband or notch out noise (an interfering signal is just noise as far as anybody attempting to copy through that signal is concerned.)
PSK and DSP are examples of this.
Yes, Antennas are reciprocal in gain, but not necessarily so in performance.

Here's an interesting site that leads to several ideas:
http://www.boingboing.net/2004/06/28/evolved_antenna_desi.html

If you'd like to understand more about DXing, the Yankee Clipper Contest Club has a lot of information:
http://www.yccc.org/Articles/articles.htm

With digital radio becoming a greater part of amateur radio, a good source of info is the Green Bay Professional Packet Radio club.
http://www.qsl.net/n9zia

A loaded source of material can be found at:
http://www.deforest.org/~hamshack/

I read the info put out on the Antenna site for some outstanding discussions about antennas:
http://antennex.com/

Finally, a very interesting article "On the Origin of Circuits" may be found at:
http://www.damninteresting.com

If you have found others that SMARS members might like, Send them to the editor for including in "Feedback."

George A. Guerin, K8GG, of Ceresco, MI, reminds us of one of the fine services ARRL offers to members.  Members are eligible to receive notices when it is time to renew their ham licenses.  The notice also gives direction on a quick and easy way to renew them online.
George said it took only 12 minutes for him to renew, even though he uses dial up.  George is all set for 10 more years.
If you haven't signed up for this free ARRL member service, go to the Membership Modification Form (Member Data Page) in Members Only on www.ARRL.org.  Make certain the box in front of "Notification of license expiration" is checked.  Just as George received an e-mail reminding of his pending license expiration, HQ will e-mail a reminder of this to you.

Lifted from the SM newsletter.