| Author |
Message |
    
Znut
| | Posted on Friday, June 20, 2003 - 3:23 pm: | 
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Hi,
I am gonna try to make a vertical antenna for FM work on 6. I have not talked to anyone on 6m FM with my ranger yet because my yagi is only usable from 50.000 to 50.400.
My question is, has anyone ever made one with the radiator being 3/8 wave instead of 1/4? Is the gain worth the less than ideal impedance?
Thanks,
Znut |
bruce
| | Posted on Friday, June 20, 2003 - 6:58 pm: |
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znut i have made them before 1/4 wave types as for 3/8 wave dont wast your time i would put the efford into decoupling the antenna from the coax and mast...... the copper skylab works as good as anything. |
de
| | Posted on Friday, June 20, 2003 - 8:33 pm: |
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Re Z...
Might I suggest that you attempt to make a PVC 2 element quad similar to a PDL II. But rahter loading it with that orbit junk, use a quarter wave section of 70 ohm coax as a matching section. The size should be a little bigger than a 2 meter quad but it should be feasable.
AND the quad has two advantages. Firstly directivity. And most importantly a better overall performance.
Heck you probably have the scrap PVC already just laying around in the tool shed or you can get scrap practically for free.
Later
DE |
Znut
| | Posted on Saturday, June 21, 2003 - 3:42 pm: |
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Thanks for the replies!
RE Bruce. That's what I thought. I guess any gain would be wasted in matching.
RE de. I already have a 3 el yagi and intend in the future to build a 4 or 5 element quad. As of now I don't have a vert/omni for FM simplex and repeater operation.
My goal is to make a vertical out of RG 58 to pull up high in a tree so A} I don't have to mess with radials and B} because I already have 3 masts up. One has my A-99; one has my 2m/440mhz omni + my 6m beam; and the other has my 2 element quad for 11m.
Any way my next question is, do I need to wind a choke out of the coax to decouple the feedline or does the current on the sleeve(braid folded over jacket) cancel that under it on the shield?
Thanks,
Znut
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Brassmonkey
| | Posted on Sunday, June 22, 2003 - 12:03 am: |
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hey nut!
let me know how it works out, having something like that for six would be handy. i use a 300 ohm two meter jpole which does surprising well and i made an aluminum horizontal dipole for six ssb but havent caught conditions yet to really try it out. im looking at a few tri band verticals for six, two and 440 to hook to my ft8900 or i'm gonna need a really big switch box! he he he |
Znut
| | Posted on Monday, June 23, 2003 - 12:46 pm: |
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Anyway my next question is, do I need to wind a choke out of the coax to decouple the feedline or does the current on the sleeve(braid folded over jacket) cancel that under it on the shield?
Thanks,
Znut |
bruce
| | Posted on Monday, June 23, 2003 - 2:40 pm: |
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i would or get beads and put the coax through them |
Znut
| | Posted on Monday, June 23, 2003 - 10:22 pm: |
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Bruce,
If I use ferrite, should I put the beads under the sleeve up at the top of the jacket or below the bottom of the sleeve(1/4 wavelength of coax shield stripped and folded back over jacket)?
I guess at the bottom because I want current on the sleeve so it performs like a vertical dipole. I'm just guessing though.
Znut |
Tech833
| | Posted on Tuesday, June 24, 2003 - 12:33 am: |
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Ferrites go below the end of the sleeve. Use FB-43 beads.
Also, the 3/8 wave element on top of a 1/4 wave sleeve would be the same thing Shakespeare did with the ABS. Some series capacitance should be all that is required. |
bruce
| | Posted on Tuesday, June 24, 2003 - 5:07 am: |
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below the sleeve on the coax look at the ringo ranger they have a set of radials down 1/2 wave acts like the beads would keep the antenna isolated from the coax
http://www.wb0w.com/cushcraft/ringoII.htm
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Tech833
| | Posted on Tuesday, June 24, 2003 - 10:52 am: |
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Bruce-
Very good! You get an 833 Brownie Button. |
bruce
| | Posted on Tuesday, June 24, 2003 - 7:47 pm: |
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COOL and i where it next to my 1964 5 cent HAMRADIO stamp button? |
Znut
| | Posted on Tuesday, June 24, 2003 - 9:27 pm: |
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Thanks!
Wow, I'm really beginning to like this thread. I appreciate ALL OF the help.
As I've done before, I will distill this information I've recieved here and share the results of my project.
I have to run so I can think about my project and masticulate some porcine, bovine, or maybe some equine form of high protein nourishment!
Take care,
Znut |
Znut
| | Posted on Wednesday, June 25, 2003 - 5:57 pm: |
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Bruce/Tech833,
How many beads should I use? They are a little over .300" long.
I ordered the ferrite beads, 12 of them. I got the largest inside diameter I could find, .197". I am goin' to have to SQUEEZE the RG 58 through them.
By the way, I was kidding about eating horse last night. I had the bovine meat. Tonight is porcine(pork chops are one of my all time favorites) and I hope it's shake and bake this time. These pork chops are from a 150 pound boar and the shake and bake coating goes with the darker meat that a mature, uncastrated boar has.
Znut |
Tech833
| | Posted on Wednesday, June 25, 2003 - 10:24 pm: |
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Znut,
I unknowingly ate horse meat when I was in the boy scouts once. I had no idea.
You will need a lot of beads to drain all that RF. According to my chart, the 43 material will have around 18 ohms resistance at your frequency band I guesses at the thickness of material). You will need 10 to make 180 ohms resistance for instance. I suggest building up enough resistance that you do not detect any more cable radiation. That may take another shipment of beads. |
Moderator558
| | Posted on Thursday, June 26, 2003 - 8:56 am: |
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look at this info and download the COAX DIPOLE
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Moderator558
| | Posted on Thursday, June 26, 2003 - 9:06 am: |
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guess it helps to have the link? 
http://www.qsl.net/ve3sqb/ |
Moderator558
| | Posted on Thursday, June 26, 2003 - 9:08 am: |
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http://www.qsl.net/ve3sqb/coaxdpl.exe |
Brassmonkey
| | Posted on Monday, June 30, 2003 - 4:39 pm: |
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ok Znut
now that i have 6 meter ssb and fm whats the low down on local activity? i've been scanning but haven't heard much except an occasional station on ssb but they're just in and out. anything local? nets? repeaters? etc? |
bruce
| | Posted on Monday, June 30, 2003 - 5:14 pm: |
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brass.... your 300 miles from me so im out of range but lissen on 52.02 wends nights at 730-800pm there is a net in tampabay |
Brassmonkey
| | Posted on Monday, June 30, 2003 - 6:19 pm: |
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cool bruce! thanks also getting set up for packet so any local or regional info will help |
Znut
| | Posted on Monday, June 30, 2003 - 9:15 pm: |
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Good job Brassmonkey.
Monitor 50.135 USB for local and DX, 50.125 international calling freq on USB, and 52.525 FM.
I will be giving my call on the 1/2 hour or so on 50.135 USB for a couple evenings. I'll also ID on 146.52 and 146.59 FM every so often.
You are still only a few miles away, right?
Znut |
Brassmonkey
| | Posted on Tuesday, July 01, 2003 - 3:07 pm: |
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right, i mostly work evenings so i guess i miss most activity on 6 |
Znut
| | Posted on Tuesday, July 01, 2003 - 6:22 pm: |
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Monkey,
Email me to let me know when you will be on the air. I usually come home for lunch.
By the way, I got the ferrite in today. I hope to have a new antenna in the air Thurs night or Friday.
I will post some pics.
Znut |
