That loop is 30m high. I'd try modelling it at 4m above ground.Quote:
Originally Posted by WØTKX
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That loop is 30m high. I'd try modelling it at 4m above ground.Quote:
Originally Posted by WØTKX
Yes, that link was not perfect, but it shows the feed-point vs polarization issue.
Picky, picky, picky. :roll:
Don't have modeling software here at work, but folks I know who use low mounted delta loops on 40 and 80 move the feed points around based on their installations and the distortions to the equilateral triangle. It ain't gonna be ideal.
That being said, I think Ron will have better luck with some sort of a vertically oriented vertically polarized loop for his current situation, right? So there we go. Unless he can do a separate RX and TX antenna setup, typically a lot better for top-band.
Right Jim?
But............I was always told size doesn't matter. Who Gnu?
since you already got a HF2V (and if it works well) why not just get the 160m add on for it?
I have the TBR-160.Quote:
Originally Posted by W2IBC
It does not work well the the Butternuts.
First, it drastically affects the bandwidth on 80 & 40 meters. The nominal 2:1 bandwidth on 40 is over 200 kHz; it's about 100 kHz with the TBR coil. The nominal 2:1 bandwidth on 80 is about 80 kHz, with the coil, about 50 kHz.
Second, the usable bandwidth on 160 is about 20 kHz. Some don't get more than about 16 kHz.
Third, to get even that much performance, you have to lay down a sh... lot of radials. At least 24 to 32.
Fourth, if you plan on running power, it's well known that as the coil assembly heats up, the frequency shifts. So you can very quickly go from a reasonable SWR to an unreasonable one.
And finally... look, the HF2V is a full 1/4 wave on 40 (the HF6 is electrically a 1/4 wave, although physically a little shorter), and 1/8 wave on 80/75. But it's only a 1/16 wave on 160. That's just plain not much of an antenna on the band.
The TBR-160 is just plain not worth it. The best that can be said about it is that if you have no other choice, it will (probably) get you (just) on the band. If I could only have one antenna, I'd put it back on. Since I have other options, though... nah.
Update...
Current plan is to go with the Delta Loop. I simply have to decide how (mechanically) to hang it. One thought would be to simply use the top of the mast to support it; another would be to use the two legs as guy wires (electrically isolated from the mast, and tied together to form the loop). Right now, I'm favoring the first option for the sake of simplicity.
Saturday afternoon, after the ladies head down to DC for the rest of the weekend, I have a couple of "prep" things to do. One is to take down the HF2V. Then I'll assemble the mast into two 20 foot sections (using stainless steel bolts, of course) in the garage. The "tricky" part is going to be what I'm doing at the base of the mast. Current thought is to cut down a 4 foot fiberglass mast to act as an insulator (ie, be the feed point for the Inverted L part of this project). What I'm also considering is to cut down one of the 4 foot aluminum masts... use about 2 feet of it in the ground for mechanical support. This would let me put the "ring" that will hold the guy wires and the top of the Delta at the very top of the mast, and then use the remaining section of the cut mast above that. That extra 2 feet or so would be the separation between the L's horizontal wire and the top of the Delta. Not an ideal spacing... but I have to work with what I have.
Sunday morning, I take the pre-assembled mast sections out into the back yard, combine them into the net mast, and get the wire for the Delta ready, along with any guys.
Then, Sunday afternoon, when W3WH & K3VX come over, we re-attach the L horizontal wire (or throw up a new one), raise the mast, bolt it in place, and spread out the Delta.
That's the plan. Let's see what really happens.
Glad to see the antenna will be up on Sunday; your neighbors tree trimmer is due back on Monday.Quote:
Originally Posted by W3WN
Good. He owes my neighbor $50 to cover the cost of replacement aluminum on the HF2V. :twisted:Quote:
Originally Posted by K7SGJ
explains a lot actually on the bnut &160 guess that is a route I won't be taking in the future.
All antenna's we set up are compromises.
Even my inverted L 77 feet high and 77 feet to the side with 3000 feeet of radials and 0.003 Ohm resistance fed at the base with the MFJ 998 is a compromise, full bandwidth on 180 to 20 meters .
The Frizel OCF Windom with added coil and 30 feet of wire works on 160 centered at 1.850.
For 17 -10 there is another vertical on the roof, so i can pick horizontal/vertical antenna on all bands.
Homebrew receive loop in the back of the yard adds receive choice extra so for receiving i have for each band 3 different antenna's to chose from.
Having an Windom at 45 feet above ground doesn't really work on 160, bar as receive antenna, the L does the main work there.
For 80 the OCF works fine in Europe, the Inverted L does much better long distance for the vertical radiation, same as 40.
20 is a toss up, the L starts to open up and depending on where the lobes are it works or not.
The Windom does fine on the higher bands, the vertical there adds DX better as the windom.
For 50 MHz there is the 5 element beam... ;)
Closed loops i dabbled with on Jota/Joti's 160 meter horizontal polarised and 30 feet up, quiet in listening and working quite well multiband.
You do need a lot of space though.... a Delta loop vertically will also be quiet and add DX multiband.
Good luck with your set up ;)