On Wed, Jun 1, 2011 at 4:53 PM, Steven L Hess <[email protected]> wrote:
> The noise level on 30 meters does drop it doesn't drop by much when I > engage Pre1. It's between a half an S-unit and a 1 and moves closer to the > half maybe. It's hard to judge. I guess I should really be looking a dBm and > not the "conventional" S-meter? It will be easier to see the change if you look at the dBm display. One S-unit is exactly 6dB in the Flex radios so the dBm display is a lot easier to read. > Looking at dBm with the AGC set to fixed It's about the same between -120 > and -123 dBm when connected to a 50 ohm resistor/Ten-Tec dummy load and > Pre-1 engaged and -119 and -122 with the "Preamp" off. That dummy load > could be acting as a antenna though. > You don't have to do anything with AGC. Unlike most receivers the S-meter is not a part of the AGC so it doesn't matter what you do with the AGC -- the meter always reads the stronger of either the noise or the signal+noise in the receiver passband. So the key is what the noise level does when you turn on the preamp with a dummy load connected. If the noise level goes down, it means that you are noise-limited in the receiver with the preamp off. Go ahead and turn the preamp to pre2 if you like/can. That will give you an idea of how much the noise figure goes down with the preamp. I really like these radios. They work like a radio should work. -- Brian Lloyd, WB6RQN/J79BPL 3191 Western Dr. Cameron Park, CA 95682 [email protected] +1.767.617.1365 (Dominica) +1.931.492.6776 (USA) (+1.931.4.WB6RQN) _______________________________________________ FlexRadio Systems Mailing List [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/
