On Tue, Jul 31, 2012 at 7:54 PM, George Allen <[email protected]>wrote:
> Gerald provides a very interesting discussion of antennas in the > FlexInsider Issue 2; but, what is wrong with just paralleling antennas for > different bands together? > > > > Lets suppose that we wish to monitor both 20 meters and 80 meters at the > same time. If we have two antennas that are resonant respectively on 20 > and 80 meters and we parallel them together, the receiving SCU's should be > happy. Yes, even though there is a high impedance for the out-of-resonant > antenna, the receive losses will be low and we will get signals from both > antennas. But, nothing bad should happen. > Why would you assume that the antenna operating out of its normal operating frequency is high impedance? Remember that the feedline operates as a transformer and might transform a high-impedance at the antenna into a very low impedance at the feed-point. What you are suggesting might work in some instances but it by no means is guaranteed to work in another. No, if you want multi-band performance you want to use a multi-band antenna or you want to use a broad-band antenna like a log-periodic or a T2FD. (http://en.wikipedia.org/wiki/T2FD_Antenna) -- Brian Lloyd, WB6RQN/J79BPL 3191 Western Dr. Cameron Park, CA 95682 [email protected] +1.767.617.1365 (Dominica) +1.916.877.5067 (USA) _______________________________________________ Flexedge mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for posting topics related to SDR software development and experimentalist who are using beta versions of the software.
