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UHF ariels

Posted: Sat Jun 26, 2010 3:54 pm
by Barno111
G'day guys

Quick question, i brought a new uhf ariel, i knew it was going to be big, but once i got it the actual size of it is alot higher then i thought and now can get into my shed. So question time. Can you cut a ariel down? Im happy with it, its just too high. Or should i just sell this one and start again??

Cheers barno!

Re: UHF ariels

Posted: Sat Jun 26, 2010 4:05 pm
by Bush65
The aerial will have a wire inside or wound around the core that has a length tuned to the desired frequency range. AFAIK you will adversely affect this by cutting it.

I suggest you change it to something more suitable for your purposes. Being tall, it may be a high gain model - remember that high gain aerials do not perform as well unless you are principally using it in flat open areas such as outback.

Re: UHF ariels

Posted: Sat Jun 26, 2010 4:11 pm
by Barno111
well its a 6.6 db gain! trying to get the best inbetween ariel. But yer once i got it, the size of it was just too big!

Re: UHF ariels

Posted: Sat Jun 26, 2010 4:45 pm
by familybus
Barno111 wrote:well its a 6.6 db gain! trying to get the best inbetween ariel. But yer once i got it, the size of it was just too big!
bigger doesnt mean better when it comes to arials and simply no you cant cut the one you have!

Re: UHF ariels

Posted: Sat Jun 26, 2010 5:43 pm
by T_Diesel
6.6 dB gain is considered a high gain which transmits a narrow beam (no good for mountenous terrain).

For an "all rounder" I would be looking for around a 4.5dB.

Re: UHF ariels

Posted: Tue Jun 29, 2010 7:21 pm
by ferrit
How high is too high?

I run two RFI CD900 elevated feeds on both our 4wds, and on the lux, the antenna tip is juuust above the canopy ridges. Tops wire, bottoms solid brass, sproing mount and its been fantastic! :armsup:

Re: UHF ariels

Posted: Tue Jun 29, 2010 9:43 pm
by T_Diesel
ferrit wrote:How high is too high?
Depends how high the roof of your garage is I guess. :finger:

Re: UHF ariels

Posted: Wed Jun 30, 2010 10:14 am
by RO8M
ferrit wrote:... sproing mount...
Cool! That is probably the best ever typo.

Re: UHF ariels

Posted: Wed Jun 30, 2010 12:16 pm
by Bush65
If all else is equal, a taller antenna will give better performance than a lower one.

But some need a ground plane.

Higher gain is a different issue, and 6.6 db is about as high a gain as a UHF antenna can come in. High gain is achieved by concentrating the low power of CB UHF rigs into a narrow envelope. In hills the direction of the antenna changes and the narrow envelope changes and often leads to the signal not reaching receivers nearby - they are most useful in flat country.

Re: UHF ariels

Posted: Wed Jun 30, 2010 3:55 pm
by Big_DP
get one of these ??

Image

Re: UHF ariels

Posted: Fri Jul 02, 2010 5:56 pm
by Barno111
I sold the ariel so all my problems are solve! Now just have to find a new one! Also for anyone looking at buying a new ariel. The DB gain rating is now taken from the middle of your roof! So the 6.6 db gain is actually a 4.5 db gain once on your bull bar! Just so you are all aware of this change. 6 db gain to the old standards is apparently a good intbetween ariel as some ariels go up to 9 even 12. 6db gain is said to give the best of both worlds!

Re: UHF ariels

Posted: Sat Jul 03, 2010 12:31 pm
by crispy
Salesman told ya that didn't he..

Re: UHF ariels

Posted: Thu Jul 08, 2010 6:29 am
by Barno111
crispy wrote:Salesman told ya that didn't he..
Nar research told me that! And the gme rep told me about the change in ratings :finger: :finger:

Re: UHF ariels

Posted: Thu Jul 08, 2010 8:45 pm
by crispy
Yeah GME have changed there ratings so what your saying applies to GME Antennas.
I did often wonder what GME's dB rating was referenced to as dB is a ratio and technically needs to be referenced to something, which they now have included the i to make it dBi, which is isotropic radiator, which is a perfect (but not possible) sphere that radiates equally in all directions.

I'm pritty sure you'll find most ratings are taken from the centre of the roof as this is the most ideal place for an antenna, once you move it else where then everythings a compromise so i dunno about your 6dB on the roof then 4.5dB on the bullbar.

Personally i think people get all too carried away with worrying about gain when whats more important is installing the correct antenna for the position its in

Also Rep = Salesman :finger:

Re: UHF ariels

Posted: Tue Jul 13, 2010 9:21 am
by the_king
Dick smith. $127 dollars, 6.5db/3.5db combo. About 900 long with the 6.5 tip on there. I'm in Brisbane Northside(cashmere) and I can pick up from Yatla Pies with 6.5, havnt tried out the small one yet