Uniden uh015sx - beep when transmitting

[Presto]

Hi All,

I have installed a new uh015sx and antenna to the my brush bar. When I try to transmit, I get a beep after 2 seconds. I read a thread I found by searching which suggested the antenna may not be ground independant? The packaging didn't refer to this at all, so it's possibly not? The Brush bar is painted, so the bracket will probably not be making ground?
Can I ground the antenna myself by running a short cable to a good ground connection?
Has anyone had a similar issue?

[adonuff]

Hi
Try slackening of the nut that holds the ariel mount on the brush bar leaving it tight enough to scratch the paint off the bar when you rotate the mount a few degrees in either direction, slightly tighten the mount and repeat until the mount has worn through the paint and created its own earth? Then give it a final tighten. it will only mark the underside of the bar.

[dmdigital]

Any idea what the antenna brand/model are?

Also the radio may be in quiet mode, group call or something else - check the manual.

[Presto]

Any idea what the antenna brand/model are?

Also the radio may be in quiet mode, group call or something else - check the manual.

It's an Axis CH5T
Packaging does not mention ground independent, but doe have a comment:

Mounting: Terminates to FME (PL259/FME adapter Included)

I bought it because it looked strong and I wanted a black antenna!! :D ...it was only later I realised I hadn't checked of being ground ind.

I just took a look at the bracket I've got (GME) and it has a small hole underneath, so I might drill a hole through the brush bar and ground it with a screw!?

Do you think this is the reason for the beep when transmitting?

[dmdigital]

Can't find anything on the web that says it is GI:confused:

I'd be looking at the radio set up first about what makes it beep during calls. Have you tried transmitting/receiving over the UHF?

[Presto]

Can't find anything on the web that says it is GI:confused:

I'd be looking at the radio set up first about what makes it beep during calls. Have you tried transmitting/receiving over the UHF?

Receiving is no problem, just transmitting, and nothing in the manual that I can find!

http://www.uniden.com.au/RESOURCES_MAIN/pdfs/uh015sx_OM_2yrWarranty-Updated.pdf

[Presto]

I'm impatient, so I drilled the bar and screwed the bracket through the hole underneath. I tested it's connection to ground inside the cab (outside of the connector to the nearest screw, and it's good. I still get the beep though when trying to transmit! :(

To test, I removed the antenna and tried transmitting (I realise this is bad, but I got frustrated!) - got exactly the same beep, so I'm convinced the antenna is at fault - and as the ground is good, it must be the centre of the co-ax right? How can I test this? It's a fibreglass antenna and seems to be fully sealed?

[PhilipA]

I am a bit confused by your post.
The grounding of the OUTER COaX of an antenna is to provide shielding from ignition and other electrical noise.

An antenna being ground PLANE independent or ground PLANE dependent has little/nothing to do with the grounding of the coax.

Ground plane independent antennas do not rely on the bonnet etc to direct the signal outward ( or in the case of a bullbar) backward, as the loading at the bottom provides an artificial radiating plane for the antenna and therefore much better forward radiation if fitted to a bullbar..

So the beep is not caused by grounding the coax.
Have you got the radio set to duplex? AFAIR this provides a beep.
Regards Philip A

[Presto]

I am a bit confused by your post.
The grounding of the OUTER COaX of an antenna is to provide shielding from ignition and other electrical noise.

An antenna being ground PLANE independent or ground PLANE dependent has little/nothing to do with the grounding of the coax.

Ground plane independent antennas do not rely on the bonnet etc to direct the signal outward ( or in the case of a bullbar) backward, as the loading at the bottom provides an artificial radiating plane for the antenna and therefore much better forward radiation if fitted to a bullbar..

So the beep is not caused by grounding the coax.
Have you got the radio set to duplex? AFAIR this provides a beep.
Regards Philip A

Hi Phillip,

You clearly know a lot more about Radio's than I do! :)
I wrongly assumed that 'ground independent' had something to do with the way the antenna was grounded :( ...thanks for your correction, which is really interesting!

20 minutes ago I suddenly had a thought - I've connected the Radio power directly to the second battery, and this being the only unit currently powered by this battery, I had no idea of it's state of charge. As you've probably guessed by now, it was this that caused the Radio to beep on transmission. I walked out to the car, started the engine, and it worked perfectly!! How stupid do I feel!! :angry: ...but at least it's fixed!

[PhilipA]

BTW a ground Plane independent antenna will have a ( usually) silver cylinder about 100mm long at the base of the antenna with the actual antenna coming out of it.

The axis CH5T is not a ground plane independent antenna so most of you signal will be rediated behind your car if mounted on the bullbar.

This may or may not be important to you as UHF is only for short distance communication.Stay at the front of the convoy LOL.This does not affect reception , only transmit.
Regards Philip A