CB radios

[Bruce Kerney]

All,
I have been in contact with GME and they are more than happy to have one of their sales reps attend a club meeting to explain radios and everything related. I have pasted their phone number on to Reg for him or someone on comittee to follow it up.
It would be an interesting club meeting to attend but would be a let down if organised and not backed up or supported by members. Anyway out of my hands now, let me know how or if it goes ahead.
Bruce

[casey]

with the desert trip being on the agenda for the next meeting - i think most the people interested in setting up a good permanent UHF system will be there for the GME guys

[Steve F]

The next meeting we have Chris coming to talk to us about helping out at Tuff Truck, maybe the meeting after for GME?

Cheers
Steve

[jeepthing]

this is good timing. ive been thinking about buying a proper UHF....

[Bruce Kerney]

Was doing some homework regarding 477MHz UHF Base Station Antennas for a mate and came across the MobileOne web Page. It has goo basic explanations of different antenna types you might like to read about before April meeting.

http://www.mobileone.com.au/antennas/default477.htm

[jeepthing]

So I probably should have asked the GME lady these questions, but I only thought of them as I was driving home last night... so hopefully someone else might be able to answer them

If I have 2 antennas with the same dB gain but different lengths/heights, whats the difference?

The difference between the fibreglass antennas and the thinner flexible antennas is purely strength for different driving conditions e.g. corrugations or tree branchs, etc, and both types have pros and cons over each other- correct?

And what are 'unity gain' antennas?

[sbadman]

And what are 'unity gain' antennas?

Unity gain is 0 gain, what goes in is what comes out.

Not sure about the length question though, might have something to do with quater wave/half wave/etc. Two quarter wave antenas of different formates ie UHF and AM would be different lengths though.

[Bruce Kerney]

Be careful when reading about "Gain" , Proper gain is amplification, which takes power in the form of an amplifier, Db "Gain" in Antenna, is what I call actually "less loss", a better aerial just picks up signals that lesser antenna can't but are in the air anyway. On transmit it does convey the electrical signal to radio more efficiently but not in amplification just more effectively.

[casey]

i was filling out my door prize card when they were explaining the different kinds of aerials at ARB the other night, so i wasn't giving my full attention :P

from what i think i heard, the fibreglass ones were good for corrugated roads, but bad for thick bush - if they hit a tree, they snap.

the steel whips are good in thick bush, but weren't so good for corrugations because their tendency to bend generates heat in the whip when being constantly bending, causing it to eventually snap.

- is this correct?

[Steve F]

That was pretty much it, although I think it was only the smaller of the stainless ones that was prone to cracking on corrugations. In saying that mine has done 110,000km now and there's a few long distance trips in there with plenty of corrugations and it's no worse for wear. She also said something about only the ute muster guys getting the big fiberglass ones and there was no real need for them.

Cheers
Steve