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Message |
    
Joey_migs
Member
Username: Joey_migs
Post Number: 59
Registered: 9-2009
| | Posted on Friday, November 27, 2009 - 4:49 pm: | 
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I have been catch sporadic skip lately. I want to put it up horizontally, High high?. I use 72 ohm RG-6 coiled on PVC pipe 5 ~ 6 times close to feed-point, to prevent energy from running down the shield. At the shack I use a 75 to 50 ohm transformer to SWR meter to RF amp to transceiver. Does that sound right, Should I slope it? Anything else I should know?
'ppreciate it.
73, we're out.
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Tech237
Moderator
Username: Tech237
Post Number: 1261
Registered: 4-2004
| | Posted on Friday, November 27, 2009 - 7:29 pm: |
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Get rid of the 75:50 Ohm transformer - it wont make much difference to the SWR but will get rid of a potential signal loss..
Simon
Tech237
N7AUS
.
I thought he said, "there was no rust for the wicked, and I own an MGB"
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Patzerozero
Senior Member
Username: Patzerozero
Post Number: 4734
Registered: 7-2004
| | Posted on Saturday, November 28, 2009 - 12:27 am: |
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try building a moxon. not all that big on 11m & gives you some gain, as well as directivity. a rotor or the armstrong method to point towards the skip is required. i have 1 set of spreaders that i was experimenting on 10, 11, 12 & 15 with, as well as the desire to build 1 for 20m. built 1 for 6m, but decided to go back to a yagi, same with 2m, but put a quad on the 6m yagi boom instead. |
Joey_migs
Member
Username: Joey_migs
Post Number: 61
Registered: 9-2009
| | Posted on Saturday, November 28, 2009 - 2:44 pm: |
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I never heard of a moxon, being fairly new, so the first thing I did was google it.
I am sold, starting research and this project's logistics today. You know I have several lengths of 1/2" copper pipe(type m I think.) Could this be used as a suitable replacement in lieu of the aluminum tubing.
Another thing, does anyone know if the ICOM IC-7000 is a good radio?
73, we're out.
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Patzerozero
Senior Member
Username: Patzerozero
Post Number: 4736
Registered: 7-2004
| | Posted on Sunday, November 29, 2009 - 12:06 am: |
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i've probably read 500 articles on the moxon i found on google. a recent issue of qst gave some incite into 1 for 10m, so that started the google-ing. i built several different ones for 6m, & after realizing how simple it was, i decided on using pvc tubing & copper wire. stealth being the name of the game on my suburban antenna farm, i went with some fiberglas fishing poles my neighbor threw out when he moved last month. perfect fit for the 13' x 4' footprint on 10 or 11m. based on my 6m findings, i'm gonna assume that for 10/11m, the copper pipe will shorten the sides SLIGHTLY, probably broadband it a fair amount-to cover 10 & 11 without a tuner? maybe, maybe not-and increase power handling capabilities to that of the feedline. and the biggest plus, is the feedpoint of a moxon comes awfully close to 50 ohms nearly every time. messing with yagi's confounded the gain sometimes when adjusting the spacing for 50 ohm impedance, and quads are even a bigger hassle, 4 elements are far easier to feed with coax minus a balun then 2 or even 3 elements.
bang for the buck, a moxon is most desirable at lower freqs, on 2m & higher, forget about it, even 6m i went back to a yagi. 10m & down.....play with moxons. |
Airplane1
Senior Member
Username: Airplane1
Post Number: 1374
Registered: 5-2004
| | Posted on Sunday, November 29, 2009 - 8:57 am: |
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I have a IC-7000 and I can say it is very good. Never had a problem with it and get great reports all the time. It is a do it all radio so it is all you need for all bands.
Did I say I Love my 7K, Well I do.
AP |
Tech237
Moderator
Username: Tech237
Post Number: 1263
Registered: 4-2004
| | Posted on Sunday, November 29, 2009 - 10:46 am: |
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I have even seen plans for a multi-band Moxon - each band nested inside the others - and might try one at this site.
I have used monoband Moxons on 10 and 6M during Filed Days,and have been impressed with them.
Simon
Tech237
N7AUS
.
I thought he said, "there was no rust for the wicked, and I own an MGB"
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Joey_migs
Member
Username: Joey_migs
Post Number: 62
Registered: 9-2009
| | Posted on Sunday, November 29, 2009 - 12:12 pm: |
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Thanks all for the feedback. PatZeroZero, I decided to abandon the copper pipe idea for the Moxon since I dug out an old TV rotor that won't be able to handle that kind of weight. I decided to use # 12 AWG copper wire and a cross-member support frame made of a lightweight insulating material (maybe fiberglass or bamboo.) I know that the antenna's workable bandwidth will suffer using the # 12 wire but I think the SWR will remain tolerable at +/- 240 KHZ ( I plan on using 29.205 MHZ as the resonant frequency.) Using 29.205 MHZ each diagonal will be approximately 14 feet in length. My concerns are two-fold. What type of material should I use for the diagonals? And how should I secure the mast to the bisect point of the diagonals?
Airplane1, I love the 7000 too, and I don't even own one yet.
73
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Patzerozero
Senior Member
Username: Patzerozero
Post Number: 4738
Registered: 7-2004
| | Posted on Sunday, November 29, 2009 - 7:24 pm: |
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google google google.....that said, 29.205, while within the generally accepted phone, or most often SSB, bandplan, is pretty quiet. for FM, the preferred polarization is vertical, and AM is usually found just under 29.200. most 10m SSB activity centers around 28.400, with low 500's being popular with south america. anyway, i think you'll see 2:1 swr probably around 500khz, or even better. off the top of my head, the long side was just over 12' & the short side about 4 & 1/2'. i 1st used the bamboo that is so invasive to my backyard & was satified that i could make an effective antenna. it grows tall enough where i could make an 'X' with it. my next design was '[' shaped, made from pvc pipe, attaching #12 wire to the 'u', & just hanging it across the open end. other then using fiberglas fishing poles, that seemed to be usable & cost effective for the short length required on 10m. definitely going with 'glas for larger antennas. problem is, found a place down south that sells bare crappie poles in 16' lengths for a mere $10 each, want to get at least 4, but they are out of stock til february & currently only have carbon/graphite in stock-NO GOOD for electrical/RF! mine have not been permanently mounted, so not really sure how strong the '[' shape will be in the wind, the 'X' with 'glas will probably be best. u-bolt them to a flat piece of....wood, plexiglas, trex deck material, then put a threaded coupler on a flange & bolt to plate. length of threaded pipe, OR use threaded pvc coupler & pvc pipe to short piece of pipe in rotor & through-bolt pvc & metal pipe....lots of 'FREE' mounting ideas came about during design.
once i get my 2m quad mounted to my 6m yagi's boom, i'll decide on what 10/11m moxon to build because i really want 15 or 20m moxon as 1 of the 'permanents' up on the roof. the 10m will be a 'portable' installation. |
Joey_migs
Member
Username: Joey_migs
Post Number: 63
Registered: 9-2009
| | Posted on Sunday, November 29, 2009 - 10:36 pm: |
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Would these crappie poles /Cabela's Classic Crappie Pole Item:IK-115799
work?
73
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