I have the MFJ259B and the Palstar ZM30. These are what I see as the relative advantages: ZM30 * Better constructed * More frequency stable - synthesized * Field programmable for software updates MFJ
I developed an analysis techniques which correlates an antenna's vertical response with the Angle-of-Arrival statistics published by ARRL. Basically it gives you a "figure of merit" for an antenna at
Pete, How interesting - I was certainly unaware of your prior work. As you can see from my web site I came at this in the context of Hexbeam - I was continually being asked "what's the best height".
Dick, It seems to me that EZNEC would confirm your own experience. If I model a 40m dipole at 90ft over salt water compared to a 1/4 wave vertical at ground level, EZNEC has the vertical better at lo
Jerry, Are we sure we're looking at the EZNEC results carefully enough. If I compare a 160m half-wave at 300ft with a ground-mounted quarter-wave vertical, over average ground, the vertical has the a
Paul, I'm not quite sure what point you are making. The dipole doesn't just "cut off" below some angle. Let's suppose the vertical had a 10db advantage over the dipole at 6 degrees, and the dipole be
Jerry, My head is spinning after 30 minutes of trying to compare our figures. I'm sure you wont believe this, but I believe there is a bug in EZNEC. I loaded up the vertical model I was using last ni
Well, I'm pleased to report I'm not going senile - well, I don't think so! I'd forgotten that I saw a similar problem last year on a Hexbeam model and contacted Roy Lewallen about it. I just found th
Thanks for the suggestion, but I've now upgraded to 5.0.27 and have exactly the same error. Steve _______________________________________________ _______________________________________________ Tower
Paul, I'm still struggling with your explanation. You seem to be claiming that if the only propagation path which exists is at a lower angle than the dipole's optimum take-off angle, the dipole wont
Jerry, Thanks for the suggestion - I certainly hadn't across that particular configuration option. But sad to say it has made no difference: 10%, 1% 0.001% I still get the same gross error! Steve G3T
Jerry, Yes it is reproducible and I have sent the file to Roy. Steve _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@c
Paul, Firstly, it is presumptuous of you to say that I have not played with W6EL Prop - I have played plenty! I'm obviously not getting my point across, so let me try one more time: Assume that W6EL
Paul, Very close to the EZNEC predictions! Take a look at the full analysis here: http://www.karinya.net/g3txq/hexbeam/eznec2/ Steve G3TXQ _______________________________________________ ____________
Paul, I'm sorry I've failed to convince you. I'll now leave it for others to judge whether or not a dipole with your published elevation response will respond to signals arriving at 5 degrees! 73, St
Dan, More eloquently put than I could have - I agree entirely! The 5dBd figure can't be passed off by saying they might be referencing a dipole in free space. Take a look at the advertising. The 5dBd
Gary, If you've not already done so, you might want to take a look at the figures on my web site: http://www.karinya.net/g3txq/hexbeam/broadband/ I have no commercial interest in the Hexbeam, and I b
Bob, The answer is a little more complicated than might at first appear. Let's assume the feedpoint impedance of your dipole is 64+j0 at resonance. That will indeed result in a 7:1 SWR on the open-wi
Jim, I've seen experimental data for a Guanella current balun, wound on a #43 material ferrite toroid with a bifilar winding, which shows the efficiency as 97% (0.12dB loss) when working into its des
A recent eHam thread generated 18 pages and 175 postings on this same topic, including hot debate over Jim's claims that bifilar windings caused several dB loss: http://www.eham.net/forums/Elmers/216