VHS radio problem

[5th Tuition]

I recieve loud and clear. Looks like I'm not transmitting. Antenna must be fine if I can recieve, Right? Antenna connection must be ok in the back of the radio if I'm recieving, Right? Could the problem be in the mike? Can you replace just the mike? Is there a meter to read transmission strength?
Anyone ever have this problem, and how did you fix it? Thanks, 5th (Marty)

[2dogs]

I'm pretty sure there is a meter you can put between the radio and the antennae to check the TX strength or tune the ant to it's max. You can Rx with the ant laying down. Can't transmit worth a hoot.

[msginny]

If you have a fuse box before radio, check for corosion on tabs of fuses....mine will do that ocasionally due to oxidation? on tabs in the fuse panel.

Duane
Ms Ginny
20' CC Grady White

[Tom Powers]

What misginny said. . . Get a volt meter out and check the voltage at the 12 V wires as close as you can get to the radio. Measure the voltage click on the transmit button while looking at the volt meter.

Also a poor solder joint, corrosion, etc. on the antenna connector could give the same symptoms.

[5th Tuition]

Thanks guys. I'll be looking into it tomorrow (saturday).

[capehaze]

Marty,

Checking voltage at the radio is a good idea and easy to do. A bad connection may be able to supply 12 volts during receive, but cause the voltage to drop when more current is needed for transmitting. Check when trying to transmit...

Things to determine (if voltage is OK)...
Is the transmitter keyed (actuated) when you press the mic button? ...Indicator light?, display change?, if neither available, open squelch - does noise go away when trying to transmit? If not, could be the mic switch or inside the radio.

Is radio being keyed, but *no* RF power? (Requires meter) Likely bad transmitter.
If making power, but low, could be the radio or a bad antenna (many radios cut back power when the see a bad SWR)

Radio keys, makes power, but transmits signal with no modulation. Could be mic or in the radio.

A bad antenna or antenna connection/cable will typically affect transmitting before receiving. To check the antenna, you need one of three instruments: a VHF SWR (Standing Wave Ratio) meter, a VHF forward/reflected power meter, or an "antenna analyzer". The SWR meter is the cheapest and most common. It will show the SWR on the coax to the antenna. 1:1 is perfect an not usually seen. 1.5 or 2/1 is not as good, but satisfactory. Over 2.5/1 indicates trouble - either in the cable or the antenna. This meter will give *some* indication of transmitter output power, but is not typically calibrated so you cannot be sure the unit is making rated power. A Fwrd/Ref power is typically calibrated to read actual power output and can also determine the SWR. They are rather expensive so not so common. Radio repair techs and many Ham Radio guys (should) have these. An antenna analyzer will check the cable and antenna, but won't tell you anything about the transmitter.

I have F/R pwr meter and analyzer, but am way up in central VA :(

Good Luck!
Woody