You can also build a box with multiple series-tuned circuits to
multiplex multiple single-band antennas to one transceiver. I believe
QST had an article on something like this last year, used in reverse to
share a multi-band antenna with several transceivers for contesting.
George, PJ5/KJ6VW
On 08/01/2012 01:55 AM, Brian Lloyd wrote:
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)
_______________________________________________
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.
