Re: Any antenna gurus here?
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Had a 4BTV for about 19 years and it played well. Sold it off because I was moving; a freind of mine bought it and used it for several years until base rusted out. It was a decent antenna. Still have my original TA-33 which I bought 2nd hand (maybe even 3rd or 4th hand in 1979). There traps were removed and cleaned at least twice over the years. I was surprised to find that there were numerous bugs, spiders and cocoons inside the traps ! Therefore cleaning the traps was a good idea. The first time the TA-33 was mounted at 82 ft and the second time it was at 40 ft. The trap cleaning certainly helped and I saw that as a major drawback to trapped antennas. That is why I moved to a trapless antenna. So traps and coils are weak points in an antenna system. These may be unavoidable in many case, but antenna maintenance should be a must every few years on trapped antennas as well as coils which can be sprayed with coil dope or similar stuff. Not a guru... Jerry n9avy From: "Robert Johnstone shopr3@... [070]" <070@...> To: "070@..." <070@...> Sent: Sunday, October 18, 2015 9:07 PM Subject: Re: [070] Any antenna gurus here? Not trying to insult anyone. Also not believing any one antenna fits every situation. Also let's call a coil an inductor, when it is paired with a capacitor it can become a filter or trap . When tapped by whatever means tab roller etc. It can be used to tune the section of the wire past it. Since you state there is no Cap internal or (external as in the 5btv) or any other tunable feature the inductor must be used to broaden the Q of a too short wire or element past it and would not be a trap nor an adjustable tuning device. When the low dollar sheild varnish over the inductor fails and the aluminum wire oxidizes to short to itself it becomes no longer functional as an inductor and is victim to moisture. Glad you are getting good use from yours while it lasts. Exceeding the Manufacturers wattage limits in an out of resonance system is a completely different topic. Hope others are gleaning some points to ponder as I doubt Jerry, Ted and I will do more than agree to disagree while respecting different experiences. next topic? 73 Robert AD0QO 1396 From: "Jerry n9avy@... [070]" <070@...> To: "070@..." <070@...> Sent: Sunday, October 18, 2015 6:15 PM Subject: Re: [070] Any antenna gurus here? Just to add ... traps have "insertion loss" and can be a bit of a problem when the weather or if you run high power with a high SWR. Had a local ham who had a tribander. and ran too much power resulting in flaming traps. I got away from traps when I moved to "trapless" Force 12 antenna. The vertical I have looks almost trapless, but has coils with doorknob capacitors. jusy my .02 cents worth ... Jerry N9AVY From: "Ted pegduck56@... [070]" <070@...> To: "070@..." <070@...> Sent: Sunday, October 18, 2015 6:07 PM Subject: Re: [070] Any antenna gurus here? well, Robert, can't let you slide on your comments. Also, I don't think insulting me is helping Martin figure out his problem. First of all, Alpha Delta does not use traps; they use coils, and they work fine. They also work fine as an inv V. Since I got my General in July of 2009, they work like this: DXCC, WAS, WAS - Digital, WAS -JT65, WAS-PSK31, WAC and 25+ 070 endorsements. And I don't 'exaggerate' or 'Paint' anything. So, either help Martin or step off. 73, Ted K7TRK On Sunday, October 18, 2015 1:44 PM, "Robert Johnstone shopr3@... [070]" <070@...> wrote: Needing and liking are two different things. I have worked all the lower states on under 24 watts without radials on a 5btv mounted 4 inches off the grass on a 3 Ft pipe driven into Grey Clay soil that I water occasionally in the summer. I started adding copper wire radials and lost some of the near field contacts on all but 80M while gaining some increased DX stations. Having worked Australia and NZ less than 30Watts without radials from KS I disagree with "have to have" and find TED perhaps exaggerating or at least painting with a broad Paint brush. Finding a properly trimmed resonant antenna exponentially more efficient than any untuned to the location antenna. The recent Alpha Delta products purchased here are not what they once were. Several have been cut up locally saving the center and ends to make nice dipoles as the traps are not doing as advertised. Their instructions now say you will have to adjust each segment. His location is a unique situation and may take a unique solution. Possibly something like the AD away from the Mt from the tree top and a fan dipole sloping at 45deg facing the MT. My added $.02 AD0QO From: "Jerry n9avy@... [070]" <070@...> To: "070@..." <070@...> Sent: Sunday, October 18, 2015 2:08 PM Subject: Re: [070] Any antenna gurus here? The DX-EE is a much better antenna than a G5RV. I think the DX-EE can be installed in an inverted V configuration which will give somewhat of a vertical radiation pattern . Ted is absolutely correct about verticals needing radials; the more the merrier. Unless , of course, you're sitting atop a pile of iron ore. I have an Alpha-Delta DX-A which is a dual sloper for 160/80/40m and requires a metallic center support (tower) which is part of the antenna. This probably wouldn;t work for you unless you can put up a 35 ft. self-supporting metal mast. Guess you might not get that one past YL. Sound like you are pretty much limited to wire antennas. You can try a vertical, as I stated earlier, and see how well it performs or not. Guess what I'm saying is you need to experiment. (Or you can hypnotize YL to believe lots of aluminum up in air is a thing of beauty ! ha-ha !) jerry n9avy From: "Ted pegduck56@... [070]" <070@...> To: "070@..." <070@...> Sent: Sunday, October 18, 2015 1:36 PM Subject: Re: [070] Any antenna gurus here? Hi Martin, I have up now, 2 identical Alpha Delta DX-EE as inverted V's. (1 roughly E-W and the other roughly N-S) I can get a match of about 1.5 max on bands 10-80 (incl WARC bands) (80 is admittedly not great, but installed 30 meter end fed wire that handles 80-160m). All these wires are low profile and wife and neighbors are happy. I believe that unless you have an extensive radial field (which takes a lot of room, too) a vertical is just radiating poorly in all directions. The verticals that claim you don't need radials are at best, misleading, if not lying. The problem with the GR5V is that it is a design for 20m. All other bands are simply a compromise with that antenna. good luck with the project !! 3, Ted K7TRK On Sunday, October 18, 2015 11:27 AM, "Jerry n9avy@... [070]" <070@...> wrote: Try vertical and see how it plays. If it doesn't get over the mountain then back to drawing board.. . or run 2000 ft of coax up the mountain ! Jerry n9avy From: "Martin Tuip ajax@... [070]" <070@...> To: 070@... Sent: Sunday, October 18, 2015 1:11 PM Subject: [070] Any antenna gurus here? I hope I maybe can pick some brains in this group. At the moment I have a G5RV up in the trees on my property with the ends in about a 30 degree angle from each other due to the fact one end strung from the top of a tree on the bottom of a hill and the other from a tree on the top. Height is probably 60ft. I am really close to a mountain less than a mile away with nearly a vertical 2000ft risen (see my qrz page) and the back of my property has a steep hillside. The YL does not want towers so I am limited there. I am thinking to get a vertical antenna for a different radiation pattern but I think the low take off angle might not clear the hill and mountain. What are my options here? Build dedicated vertical arrays on the hillside? Regular vertical ground mounted? String vertical dipole from a tree? Use a yagi on an angle to clear the mountain? Anything else? Martin KG7HAX
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