Baffeled by zero swr...........

[KB1TPX]

I suddenly have a problem with my TenTec 544. When I key up, my meters all drop to zero. I suspect that it is a ground issue, because when I unscrew the antenna connector (shield only), my receive increases. However that only takes care of the receive. When I key up, the swr/s meter drops down to zero, with no output. Could it be that my balun on my G5RV got wet in all the rain and is shorting? or is it a bad coax, or....any thoughts?:headbang I was transmitting to eastern Europe one day, then nothing the next day. What duh?
Hopefully, it's not internal, TenTec gets $60.00 an hour for repairs.

 

[TonyV225]

Coax is shorted Check your ends if their ok then you have to check for pinched or damaged coax. You can uncrew both ends then check one end with a VOM (Multimeter) for continuity some meters such as mine you can be lazy and just listen for the beep or tone.

 

[KB1TPX]

I figured as much, I'll bet I closed the window too tightly, that's what I'll check first. I've got to get me a panel for the window and put a couple of connectors on it. BTY Thanks for the tip.

 

[TonyV225]

Ive also looked at those window panels but have to many antennas for all the different bands and I am eventually putting up more. I was going to say if you are running small jumpers you know drom say a meter or amplifier and such check those first because they are more often than not the coax that shorts out and has to be cut and redone

 

[KB1TPX]

Ive also looked at those window panels but have to many antennas for all the different bands and I am eventually putting up more. I was going to say if you are running small jumpers you know drom say a meter or amplifier and such check those first because they are more often than not the coax that shorts out and has to be cut and redone

Thanks for the tip.

 

[Robb]

I suddenly have a problem with my TenTec 544. When I key up, my meters all drop to zero. I suspect that it is a ground issue, because when I unscrew the antenna connector (shield only), my receive increases. However that only takes care of the receive. When I key up, the swr/s meter drops down to zero, with no output. Could it be that my balun on my G5RV got wet in all the rain and is shorting? or is it a bad coax, or....any thoughts?:headbang I was transmitting to eastern Europe one day, then nothing the next day. What duh?
Hopefully, it's not internal, TenTec gets $60.00 an hour for repairs.

First off, I would connect an external power meter and a 100w dummy load to the radio and see if it has output. I am not familiar with the TenTec radios at all; but many ham rigs will fold the power output down when/if it sees a very poor SWR match. If your radio does have this feature; then you might perform a complete reset and then re-test the radio with the meter/dummy load once again. If it shows power output; then you are OK with the radio.

Next, I would give your antenna(s) a very close visual inspection. Check the balun for water intrusion - yes. But also check the coax for water intrusion too. Make sure that the antennas you use also pass a careful and complete visual inspection.

Then; report back here please . . .

 

[KB1TPX]

First off, I would connect an external power meter and a 100w dummy load to the radio and see if it has output. I am not familiar with the TenTec radios at all; but many ham rigs will fold the power output down when/if it sees a very poor SWR match. If your radio does have this feature; then you might perform a complete reset and then re-test the radio with the meter/dummy load once again. If it shows power output; then you are OK with the radio.

Next, I would give your antenna(s) a very close visual inspection. Check the balun for water intrusion - yes. But also check the coax for water intrusion too. Make sure that the antennas you use also pass a careful and complete visual inspection.

Then; report back here please . . .

Aye aye, will do!

 

[W5LZ]

I think the idea of using a dummy load to check the radio is a very good idea. If there's no problem transmitting into that dummy load then it's a reasonable guess to think the problem is something other than the radio, right? Then you get to start checking all the other stuff besides the radio.
The only thing an ohm meter can tell you about coax is if it's shorted or not. From there, that dummy load and an SWR meter is the simplest way of checking any feed line. If connected to that dummy load and a reasonably low SWR results, then it's probably okay. (Keep in mind that RF is AC, and that's a different ball-game than DC.)
Unscrewing the 'ground' connection with a feed line and hearing more is very common, happens with almost any antenna. Basically it turns the feed line and antenna into a random/long wire antenna. You might be surprised at what you can hear with just a plain old wire connected to the center pin of that antenna connector. Receivers aren't all that 'picky' about impedance matching etc. Transmitters definitely are 'picky' about that so using it like that isn't the best idea in the world.
Narrowing things down to the radio or not the radio ought'a be your first step, I'd think. The radio being the problem isn't a very nice thought, so rule it out to start with (hopefully!).
- 'Doc

 

[KB1TPX]

Thank you W5LZ

 

[KB1TPX]

Finally!

It was just a disconnected jumper on the power socket.:laugh:

 

[KB1TPX]

Thanks for all the advice guys. Good for future reference.