A good source for gamma match and end fed dipole??

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Elopid
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A good source for gamma match and end fed dipole??

Post by Elopid » Mon Jan 18, 2016 5:20 pm

Hey fellow necks,

I'm looking for somewhere closer and cheaper than PCS to buy gamma match dipole antennas, I'm also looking for a mono-pole endfed dipole.
Does anyone know any good places to get aerials, I don't mind buying over seas if it's not going to be £50+ each time per gamma dipole??
I've had aerials from Sandpipers and I found the quality to be very poor and didn't really rate them for their claimed performance either. I don't have time to or know anyone who builds them and eBay is like a needle in a haystack.

Cheers. :mrgreen:
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Gigahertz
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Re: A good source for gamma match and end fed dipole??

Post by Gigahertz » Mon Jan 18, 2016 10:58 pm

Sandpipers J-pole or "J-Match as it was called" was a good antenna dont know if they still offer it, but Ive have one that survived for a while.
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Elopid
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Re: A good source for gamma match and end fed dipole??

Post by Elopid » Mon Jan 18, 2016 11:16 pm

Hi thanks for your answer but as I tried to say before I don't like Sandpipers aerials, I've had them before and they don't look professional enough for the installation I require.
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TekMcr
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Re: A good source for gamma match and end fed dipole??

Post by TekMcr » Tue Jan 19, 2016 9:22 am

http://m.ebay.co.uk/itm/FM-BROADCAST-AN ... nav=SEARCH

Any good for you?
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Elopid
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Re: A good source for gamma match and end fed dipole??

Post by Elopid » Tue Jan 19, 2016 9:46 am

Thanks for your reply but that is a J-Pole so unfortunately not.
It is far too big, very ugly in appearance and far from discrete.
I need gamma match dipoles or end fed dipoles (quarter wave only with no radials)

Cheers
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Maximus
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Re: A good source for gamma match and end fed dipole??

Post by Maximus » Tue Jan 19, 2016 9:51 am

Sirio used to sell a gamma matched dipole for around £40. They're quite popular with the Dutch. The model number is DP-100.


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pjeva
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Re: A good source for gamma match and end fed dipole??

Post by pjeva » Tue Jan 19, 2016 11:45 am

Gamma match could be pain in the ass to set correctly tho. If you don't have network analyser and you need to set it up quickly


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thewisepranker
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Re: A good source for gamma match and end fed dipole??

Post by thewisepranker » Tue Jan 19, 2016 12:26 pm

They're not always fun to tune with a network analyser either. Getting them spot on can take hours.
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radio-berlin
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Re: A good source for gamma match and end fed dipole??

Post by radio-berlin » Tue Jan 19, 2016 4:40 pm

Looks like a homemade copper in spray paint job. so239 just soldered onto the side of it.
1.5kw really ????? and 97 sold, blimey! im gobsmacked
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Elopid
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Re: A good source for gamma match and end fed dipole??

Post by Elopid » Tue Jan 19, 2016 5:12 pm

Yes, a poorly constructed ugly aerial like that is exactly what I'm not looking for.
I'm always looking on eBay but so far no good.

Cheers for all your help guys, keep the suggestions coming.

As for tuning the gamma match I have a veteran radio HAM who tunes them for me 1:1 SWR.
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pjeva
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Re: A good source for gamma match and end fed dipole??

Post by pjeva » Tue Jan 19, 2016 11:04 pm

thewisepranker wrote:They're not always fun to tune with a network analyser either. Getting them spot on can take hours.
Exactly! I tuned my own for about 4 hours, but when i finished, reflection was 9W at forward power of 1003W and coverage was excelent. Also, it should be tuned on site, as tuning may change with height above ground. Anyhow, not very good choice for "mount and run" pirate installations.


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Gum
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Re: A good source for gamma match and end fed dipole??

Post by Gum » Wed Jan 20, 2016 12:01 am

radio-berlin wrote:
Looks like a homemade copper in spray paint job. so239 just soldered onto the side of it.
1.5kw really ????? and 97 sold, blimey! im gobsmacked
And only $185 delivered!
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rettimsnarT
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Re: A good source for gamma match and end fed dipole??

Post by rettimsnarT » Wed Jan 20, 2016 3:07 am

Yes that is ridiculous, you can make them out of copper piping and plumbing solder for about a score.
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thewisepranker
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Re: A good source for gamma match and end fed dipole??

Post by thewisepranker » Wed Jan 20, 2016 9:05 pm

pjeva wrote:
Exactly! I tuned my own for about 4 hours, but when i finished, reflection was 9W at forward power of 1003W and coverage was excelent. Also, it should be tuned on site, as tuning may change with height above ground. Anyhow, not very good choice for "mount and run" pirate installations.
Nice. Have you got a network analyser or did you do it the very, very hard way?

The worst bit about tuning the gamma matched dipole is that it can appear to be tuned when it isn't quite there yet. This can be seen quite nicely on a network analyser with the SWR vs frequency trace being asymmetrical - I'll see if I can get a picture next time I tune one.
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pjeva
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Re: A good source for gamma match and end fed dipole??

Post by pjeva » Thu Jan 21, 2016 12:10 am

Yes, I did it with network analyser, but... Tuning gamma matched requires tuning of both radiating element and gamma "stick". And after a few hours you realize that your results few meters from ground do not match results when you put it on the mast... That is the moment when you decide will you finish it at all or you will be a pussy and go buy nice factory made broadband dipole and give up that few extra watts ;-)


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