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View Full Version : 80 ch UHF - how loud when received on a 40 ch unit? Length of antenna cable.



Silver
13th October 2011, 09:53 PM
Silver's old Connex UHF has not worked since we bought Silver - receives but does not transmit, among other issues.

On advice of auto leccie, bought a new 80 ch unit - would have liked an ICOM or even an Electrophone, but the budget ran to one of those little Unidens. Came with an antenna for $299 - and doubtless can be bought for less if one looks around.

This 80 ch radio comes with circuitry that recognises a 40 ch transmission, and cuts the volume back. I guess, but don't know, that the transmissions from the 80 ch will sound quiet on a 40 ch unit. Does anyone know??

Antenna Cable - this deal included a 6.5 DB ground independant antenna. It has 5 metres of cable. That is only just enough to go from bullbar, through grille and radiator support panel, down the left guard behind the washer bottle, through the firewall on the only grommet on that side, around the fan motor (can't be a good thing) across/under the dash, and up the RHS A pillar, to the roof centre console. there is about 15cm spare - not enough to plug everything in with the roof console resting on the centre console, and then lift the roof console up.

Apparently one can buy extensions for the antenna cable.

Up the left hand side A pillar, someone has fed the 27 meg antenna - the holes over the door are a lot smaller on the left hand side than the right. Must be set up for left hand drive with antennas on the right. When I say the holes over the door, pull down the door rubber channel trim, and ease back the vinyl hood lining, having first removed the 'Holy Cow' handle. On the right hand side there is a bigger hole closer to the windscreen.

Maxhead
14th October 2011, 08:13 PM
I haven't heard anything about the volume being lower on the 40ch. All they have done is squeeze an extra channel in between the old channel frequencies. I don't think the volume will be effected but could be wrong.

It's a pity the cable is just to short, can you find a different path to feed it to the console? It's better not to have lots of connections as you will have loss on each one but if you have to then put a plug on the end and make an extention with a plug and socket. tape up the joining connection.
6.5db will be a good all rounder

the evil twin
14th October 2011, 10:16 PM
40 versus 80 channel Volume - "Technically" in the Lab an 80 channel set will have a slightly lower audio level on a 40 channel reciever (the engineering reasons why this is so are pretty heavy and aren't worth discussing)... BUT... out in the field with the varying quality of installations, antenna's and how people actually use the mic the difference can be pretty much ignored. I have been using a split of 40 and 80 channel gear since 2010 and no-one can pick it out in the field.

Antenna cable length - Nisspat is correct, Yes, you can extend but like everything it "technically" comes at a price due to the apparent lost transmit power used by the extra cable and the extra plug (insertion loss).
Again, out in the field and not in the lab, you will probably hardly notice the lost range unless you are out on the flat lands. If you are in any "terrain" you normally lose UHF Comms due to terrain getting in the way loooong before you actually run out of range of each other.
I do suggest that unless you are comfy working with co-ax and RF connectors maybe pay a couple of bucks for a Comms guy to make up the extension cable for you and use quality connectors

Silver
15th October 2011, 12:40 AM
Thanks NissPat and evil twin, very useful info on the cable extension and the volume.

If I need to take the console down again, I'll go to a comms bloke and get an extension made. I'm sorry that it wasn't clear from my original post that the standard cable was just long enough - would have been great if Uniden made it a metre or so longer, but I guess there is a tradeoff there, too, as well as cost.

Thanks again for your informative and helpful replies