Page 1 of 1

UHF Reception Problems...

Posted: Sat Mar 13, 2010 3:03 pm
by Buggerific
Hi all,

I have an icom UHF in my zook, I'm getting about a car-length range out of it at the moment... I think it worked on the way home when I bought the car but I've since put on an alloy bar.

I've checked the connection of the cable from the plug to the base of the antenna and all is fine, I've tried a different whip on it with no success...

Do most, or some, antennas need to ground themselves through the bar and could this be my problem because the alloy bar doesn't conduct?

I appreciate any feedback!

Posted: Sat Mar 13, 2010 3:21 pm
by thehanko
yes some antennas grount through their mount, try a seperate wire back to the body, front under the antenna mount.

Posted: Sat Mar 13, 2010 4:49 pm
by T_Diesel
By the sounds of it, your antenna is "ground dependant" which is why it's not working with the change of bull bar. As suggested, find a suitable ground and wire your ground back to somewhere suitable.

I would also check the continuity across your coaxwith a multi-meter to make sure you have no leakage anywhere along the coax aswell.

Posted: Sat Mar 13, 2010 5:39 pm
by Buggerific
Yeah I have checked the continuity from the plug end to the base of the antenna and all is fine on both the pin and the ring and i've checked for continuity between the pin and the ring and they're not shorted out so that should be fine...

Will try a ground cable when it's not raining!


Cheers!

Posted: Sat Mar 13, 2010 7:46 pm
by mike_nofx
aluminium is a conductor by the way!

Posted: Sat Mar 13, 2010 10:13 pm
by MrGrim
ive been a CB/ham operator for nearly 3 decades

1st metal is metal alloy, steel, copper, brass, lead, ect it will all ground
( running a ground wire from the base to a ground point will incept harmonics not good !!! )
2nd you need to chech your coax at the plug end for :-
A- no short from pin to outer of plug
B- pin shows circut to antenna base thread
C- the outer does show circut to ground at both ends
D- 99% of all UHF Antennas are ground dependant unless marine they are co ground dependant or independant and normaly white

you have two other options replace the coax set there around $15-$20 or have a comms store check the SWR standing wave ratio
with a meter this will diiagnose if its the coax or the radio and re signal with out even the coax pluged in you should still get at least 20-100 mtr signal
(not recomended to transmit for long periods as its harmful to the radio but helpful to just test to check if radio has a problem with out test equipment)

still have any problems you can pm me ill try to help further
Cheers
Mark

Posted: Mon Mar 15, 2010 4:22 pm
by Buggerific
As mentioned earlier, I have checked coax cable and all is good... The bar does conduct, I've now tested for that. Thought it was a valid question though.

Put a different radio in to test with all the same cables and it worked fine so there seems to be some sort of fault within my radio unit.

Receives better than it transmits but still not a good range at all.

Does anyone know if a radio repairer in Sydney... Preferably northern beaches/north shore?

Posted: Tue Mar 16, 2010 7:22 pm
by Buggerific
So...

Pulled the unit out today to find some sort of oil over the outside of it... So I opened it up, there was a little but if oil on the inside and one of the capacitors (or something similar) has exploded. Damn.

So I am now looking for a radio repairer to take it to.