UHF Radio (general info)

[Steveyb]

Go switch (bout $80) for 2 antennas, co-phasing as I have mentioned in other posts is completely impractical for any of you guys (a strong knowledge of rf characteristics and appropriate test equipment is needed).
Also, you can get a coil driven coaxial switch so that it can be mounted out of sight and just use a switched 12v supply for the coil. They are around $150+

In summary. Forget co-phasing. It's useless to you.

[WinM70]

So the go switch lets you switch between two aerials, correct?

Lee.

[Steveyb]

Correct, this one here would be ideal for you guys

CX-210N 2-position, handles 1.5kW (0.05dB loss to 500MHz, 0.2dB to 3GHz) $89

its under the heading coax antenna switches at this address under the TAB DIAMOND ANTENNAS

http://www.andrewscom.com.au/site-section-08.htm

[RonBacardi8]

The Antenna page is now updated:
http://www.4-wheeling-in-western-austra ... tenna.html

[Loosey]

Awesome, I'll check it out.

Edit: so a 4.5db aerial would be a good compromise?

[Qwerty]

That was my thinking on going for 5db. I'd rather have tolerance for hills / dunes / angles that I'm imminently playing in. (Ie car to car) over longer range.


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[Steveyb]

4.5db ground plane antenna mounted in the centre off you roof is about as good as it gets IMHO.

[Loosey]

What about the difference between dBi and dBd?

I read an article on it when I was searching for an aerial but can't recall where it is at present.

[RonBacardi8]

What about the difference between dBi and dBd?

I read an article on it when I was searching for an aerial but can't recall where it is at present.

That's explained in the link provided on the antenna page, I didn't put all that info on the page as it kinda goes off topic.

From the page: quote "dB or Decibel is a logarithmic unit (a scale of measurement) that indicates the ratio of a physical quantity (for scientific details see wikipedia.org )." click on the wiki link, but you have to do it from the page.

[Loosey]

Sweet as

[highoctane]

how far does the 3db reach compared to the 6db in meters approx.?

[butcha87]

Mate there are so many things that dictate how far signal travels (obstructions, weather, humidity etc) that there is no answer to that. Could be 500 meters when vehicles are facing each other could be -200 meters when facing away.

TBH this whole 3db vs 6db fiasco really amuses me and the beamwidth argument with these pretty pictures exaggerates the effects of antenna gain. Its all marketing if someone is really crackly changing down to a 3db isn't going to make him crystal clear.

In general a 6db will work better than 3db. Not twice as good. But a little bit better.