On Fri,9/5/2014 9:59 AM, iain macdonnell - N6ML wrote:
That doesn't justify a pre-amp. If you want more acoustic noise, just turn up the AF gain. The only reason (I can see) to use a preamp is if the receiver internal noise level is higher than the atmospheric noise (coming from the antenna).
Right.
If the noise level perceptibly drops when you disconnect the antenna, a preamp isn't going to do much for you....
Perceptibly is not the right word if you care about weak signal work. The difference should be at least "twice as loud" when the antenna is added, which corresponds to about 10 dB. Use the K3's internal audio voltmeter to determine this. Turn off AGC, with the antenna connected, calibrate the dB readout to zero following the instructions in the manual, then remove the antenna.
73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
