Dale, I second that. Recommend it highly. I was just about to suggest it when your message popped up. Also get your TO92 J310s while you still can. Andrew
> Date: Wed, 1 Aug 2012 06:46:45 -0400 > From: [email protected] > To: [email protected] > Subject: Re: [FlexEdge] The Flex Insider - Issue 2...re antennas a thought > > If you're looking for an extremely broadband receive-only antenna, I > highly recommend this active antenna design by PA0RDT. Don't be > dissuaded by the 'whip' antenna reference. The whip is not a whip at > all; rather it is a 2" x 3" (or so) copper foil trace on a pc board > which capacitively couples to the electric field. It's a very > interesting and elegant design that works well, and is easy and > inexpensive to build. It's also -very- stealthy. > > http://www.radiopassioni.it/pdf/pa0rdt-Mini-Whip.PDF > > ... and other useful references are here: > http://carconline.blogspot.com/2009/05/pa0rdt-active-antenna.html > > I have built two of them so far. They work very well as half of the > antenna system for diversity reception, and I also use them in > conjunction with the DX Engineering NCC-1 to eliminate local powerline > noise problems which have been particularly severe this Summer due to > the extreme hot weather and lack of rain. > > I built mine into a 6" length of 2" i.d.PVC tubing w/ caps on each end, > and so far have just been suspending them from tree branches, but I plan > to put two of them on a PVC boom on the tower to play around with beam > steering via the NCC-1. > > 73, Dale > WA8SRA > > > > On 8/1/2012 1:55 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. _______________________________________________ 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.
