I would be curious as to what the fundamental resonance frequency is and what the high impedance and low impedance actually is at the feed point of the antenna without balanced line.
If the feed point at the transmitter end of the line is too low, add or subtract some feed line. You can also add and subtract line from the opposite side of the antenna. You mentioned earlier about opening up the opposite end. This could be a good experiment. And also consider capacitance or inductance added where you make the cut or adding transmission line at that point with and open or closed end going nowhere except to a stick to hold it up off of the ground. It doesn't take a mathematical antenna expert to experiment You only need some extra wire. Fun Stuff John, WA5BXO -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Lawson Sent: Wednesday, January 11, 2006 10:44 AM To: amradio@mailman.qth.net Cc: [EMAIL PROTECTED] Subject: [AMRadio] I'm not an antenna expert I don't even play one on TeeVee... So, in advance of a lot of EZNec work (and I don't have the experience with that program to derive much 'good' out of it right now) - I'd like to ask what may seem to be a rather obvious HF antenna question. Due to the usual reasons - my HF antenna is a loop suspended from my backyard fence - approx 430' total, closed loop, 5' off the ground, fed by 450 ohm ladder line back into the shack, using an Ameritron ATR-15 tuner to match the system to my Valiant. The tuner and transmitter are bonded to a very heavy ground system via an 8' stake less than 3' from the gear. There is no ground system under the antenna, other than that which Nature provided - and with the current winter conditions, the ground is rather wet and conductive. This antenna system exhibits the following SWR: 160M - 1.3:1 80M - 1.1:1 40M - +3:1 20M - 2:1 15M - +3:1 10M - +3:1 The tuner capacitors end up being all-the-way-meshed on the 'misbehaving' bands - not so on 160, 80, and 20. So I'll see Y'all on 3880 and just fergit the rest. ;} No but seriously folks: obviously the feedpoint resistance is outside the tuner's ability to cope with it at various frequencies. I'm thinking the first unscientific experiment might be to go to the opposite side of the loop from the feedpoint and cut it into a big horizontal bent dipole - mainly because that will take about 45 seconds to accomplish - one of the benefits of having one's entire antenna at ahoulder-height. But I'd like to get some other opinions - I know there's an electrical Pattern here from the info - and I have some other ideas based on that. And no, I can't put up a "real antenna" so I'm pretty much comiited to making this one work as well as I can. Until I move the QTH to somewhere with a few acres and room for Lots of Wire. Cheers John KB6SCO ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
