WA1GFZ
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« on: July 31, 2007, 09:42:29 AM » |
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This weekend I shot a couple ropes way up in the top of two trees at the new QTH. They are up around 70 feet and 125 feet apart. Now to decide how to make 160 meters work. 1 hang vertical off the ends 2 fold it back on itself like Frank AHE does. 3 pull ends out lile a big triangle sloping to the side. 4. feed as a Tee.
Feed point is up around 60 feet to the basement window.
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WU2D
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« Reply #1 on: July 31, 2007, 09:55:30 AM » |
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Where is the ideal feed location? Near one tree or the other or near the middle?
Mike
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These are the good old days of AM
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WA1GFZ
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« Reply #2 on: July 31, 2007, 10:22:42 AM » |
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Middle of 125 foot run or Tree at the high end of the lot. Yard is only 60 feet wide so VEE would be too tight. I have a 40 foot tree across the yard in the middle so could swing the ends over to it. Top of the lot have another 60 footer on other corner about 50 feet from end point tree.
I might even consider an inverted L on the other side of yard but would be only about 45 feet away from dipole.
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WU2D
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CW is just a narrower version of AM
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« Reply #3 on: July 31, 2007, 10:46:48 AM » |
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Frank,
In the beginning...
I will start off the fun with a real old buzzard design that will produce big signals like they had in 1910. With proper ground radials, this will produce embarrassing amounts of antenna current.
Do the XYL and Neighbors have a vote?
Mike WU2D
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These are the good old days of AM
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The Slab Bacon
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« Reply #4 on: July 31, 2007, 11:01:28 AM » |
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boy, Frank, I would just love to have the luxury of a 120' flat top!!
I'd be like the proverbial pig in szht!!
Steve, the Huzman has an interesting setup for a 120' flattop that plays well on 160. He hangs a piece ov ladda line down vertically on each end to add some linear loading length. I think he has info on it ova on the am window somewhere.
The Slab Bacon
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W1VD
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« Reply #5 on: July 31, 2007, 11:54:22 AM » |
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Mike Looks like my 136 kHz transmitting antenna... http://www.w1vd.com/XNStxantenna.htmlFrank Might make a good antenna especially since your close to the water. Jay |
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'Tnx Fer the Dope OM'.
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w3jn
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« Reply #6 on: July 31, 2007, 12:37:14 PM » |
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I feed my 120' open wire fed flat top (center fed) with a K1JJ style tuner. I used a silver plated edgewound coil out of a BC xmitter and the link is 1/2" wide by 1/4" thick copper STRAP. Vacuum Variable capacitor. I hafta tap WAY down on the coil to get it to resonate but it works pretty well all things considered. The circulating current's gotta be pretty hefty but using the GPT-750 the coil gets barely warm to the touch after an old buzzard.
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Todd, KA1KAQ
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« Reply #7 on: July 31, 2007, 01:29:10 PM » |
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known as The Voice of Vermont in a previous life
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WA1GFZ
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« Reply #8 on: July 31, 2007, 04:09:23 PM » |
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Mike,
Someday I'll have a spark rig to go with Jay's antenna configuration.
I was lucky to get off two great shots with the bow. I had to stand under the primary wires at one end to get a bead on the branch I wanted. The lot high side is only low voltage so I didn't worry.
Yup know Huz configuration. I guess I will have to put something up and see how it plays. Looks like a Need about 60 feet of feed line and have a 250 foot spool of #8. I have a couple nice matched variable inductors that are 12 uh so should work good on 75 and maybe low Z on 160. They came out of a mil TX that ran 3 KW.
I'm not worried about the higher bands right now because I could fit a 40 meter dipole across the top of the lot and be away from the larger antenna. fc
My neighbor was watching me but was afraid to ask....XYL told his XYL I was putting up an 80 foot tower a few years ago so he must be thinking the crazy man next door is moving his toys in. fc
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WU2D
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« Reply #9 on: July 31, 2007, 04:34:25 PM » |
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Mike Looks like my 136 kHz transmitting antenna... http://www.w1vd.com/XNStxantenna.htmlFrank Might make a good antenna especially since your close to the water. Jay, My heavens that is a manly antenna! Mike Jay |
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WA1GFZ
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« Reply #10 on: July 31, 2007, 05:00:50 PM » |
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John,
I'm leaning to your configuration as a first cut. Cut the wire in half and make a 60 foot open wire line with 120 foot dipole. Would you please give me the size of your inductor so I can determine the inductance. Also do you have any idea of how much C it takes and you the primary side so I don't have to reinvent your wheel. I might drop 20 or 30 feet vertical but want to stay above the roof of the house peak.
tnx
PS this one day off per weekend has a nice ring to it now that I'm almost done with the sheetrock.
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w3jn
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« Reply #11 on: July 31, 2007, 08:08:39 PM » |
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Inductor is about 3" diameter by 6", 22 turns. IIRC it's about 30-40 uH but it resonates WAY down on the taps - both taps towards the middle with only a couple turns between them. The cap is a 500 pF vacuum variable but it too is right at the end of its trvel.... I can get to 1870 but no lower.
I forgot to mention my dipole is in a fan configuration (2 wires each leg fanning out from the center, and connected at the center). For this service (160 on a 75M antenna) the two wires in parallel on each leg probably help a bit due to the low impedance.
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W1GFH
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« Reply #12 on: July 31, 2007, 09:11:56 PM » |
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I feed my 120' open wire fed flat top with a K1JJ style tuner.
I used a silver plated edgewound coil out of a BC xmitter... I think that should be added to the lyrics of: I walk forty-seven miles of barbed wire, I got a cobra snake for a necktie
I got a brand new house on the road side, and it's made out of rattlesnake hide
I got a brand new chimney put on top, and it's made out of human skull
Come on take a little walk with me child, tell me who do you love?  |
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KB2WIG
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« Reply #13 on: July 31, 2007, 09:28:43 PM » |
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ham to the bone???
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What? Me worry?
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WA1GFZ
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« Reply #14 on: July 31, 2007, 10:36:32 PM » |
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John,
TNX for the information. The trees are big enough to do a fan configuration and both ropes are on one side of each tree. I knew you had a fan and had that in the back of my mind. I have a pair of 12 uh variable inductors that are pretty heavy. I could do another balanced balanced tuner. I also have another 30 foot hunk of RG393 for a balun and a choice of large bread slicers or vv caps.
I would think a fan would lower the Q and help support the center.
Most people I talk so far to say don't do more than 30 feet vertical.
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W1VD
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« Reply #15 on: August 01, 2007, 06:35:16 AM » |
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Frank
The fan sounds like a good idea. You can always tie the feeder together and use it as a vertical. A good sized fan will provide 10 - 15 pF per meter of top loading. Looks buzzardly as well...
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'Tnx Fer the Dope OM'.
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w3jn
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« Reply #16 on: August 01, 2007, 06:39:12 AM » |
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I feed my 120' open wire fed flat top with a K1JJ style tuner.
I used a silver plated edgewound coil out of a BC xmitter... I think that should be added to the lyrics of: I walk forty-seven miles of barbed wire, I got a cobra snake for a necktie
I got a brand new house on the road side, and it's made out of rattlesnake hide
I got a brand new chimney put on top, and it's made out of human skull
Come on take a little walk with me child, tell me who do you love? tell me WHOOOOOOOOOOO do you love |
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WA1GFZ
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« Reply #17 on: August 01, 2007, 08:50:49 AM » |
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XYL doesn't let me bring pets home
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The Slab Bacon
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« Reply #18 on: August 01, 2007, 08:54:59 AM » |
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XYL doesn't let me bring pets home
How about food items?? I nice big pot ov rattlesnake chili would sure hit the spot!!  |
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WA1GFZ
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« Reply #19 on: August 01, 2007, 09:24:01 AM » |
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I can fan out the ends up to 40 feet. John have you tried connecting the ends. BTW My inductors are 12 turns each and I think 3 inch ID.
Strap is not 1/2 inch I think more like 3/8.
My tuner in Enfield has a pair of 22uH but the antenna is full size with about 70 feet of open wire line so Z is a lot higher.
WHO DO YOU STRAP?
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The Slab Bacon
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« Reply #20 on: August 01, 2007, 10:51:46 AM » |
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WHO DO YOU STRAP?
I walk 47 miles of feedline, use a 4x1 for a neck tie. I got a brand new shack by the roadside and its made of black wrinkle steel. Its got little chimney up on top made from an 833. C'mon take a walk with me now, tell me WHO DO YOU STRAP!! |
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W8EJO
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« Reply #21 on: August 01, 2007, 11:08:25 AM » |
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How about a 1/4 wl inverted L?
I would guess that might give you the best all around (local & DX) signal with the your real estate restrictions on 160.
Of course you'll have to do the radial thing.
Terry
W8EJO
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Terry, W8EJO
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w3jn
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« Reply #22 on: August 01, 2007, 11:38:19 AM » |
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No, I haven't Frank, that would be an interesting thing to try to see what the difference (if any) is.
I suspect the feedline length is gonna make quite a bit of difference. In my case my tuner happens to be at a very high current/low impedance point hence the very low taps on the coil.
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WA1GFZ
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« Reply #23 on: August 01, 2007, 12:40:45 PM » |
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Terry,
I could do an inverted L easily and have a good ground without radials. Low side of the lot is 5 feet above water under one of the support trees. A balanced antenna on the higher bands is what I am shooting for and could drive it as a TEE om 160 if I had to. Just outside the basement window I have a good connection to ground that runs down the sewer line trench into water at the bottom of the lot. It is also tied into the water and a loop around the footings.
Balanced antennas seem to be less of an RFI problem but with a second tuner it would be easy to change.
John I will also have about 60 feet of feed line #8 spaced 4 inches so Z should be low.
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« Reply #24 on: August 01, 2007, 01:34:38 PM » |
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OM,
The August 2005 QST has a design that looks like a perfect fit: it's intended for a 120' distance and offer a 50 ohm load.
HTH.
73, Bill
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