SWR Problem

[lancerice]

I am tring to tune in VHF antennas, the SWR meter that I am using is a Zetagi HP201 I am on 165Mhz but when I key up the meter will not stedy, it keeps moving down the scale, so I end up holding a key for about 2 mins before it will stop and by then I have a swr of about 10, should this happen, Im sure the meter should go stedy stright away, any help PLEASE.

Thanks Lance

[Jim202]

I am tring to tune in VHF antennas, the SWR meter that I am using is a Zetagi HP201 I am on 165Mhz but when I key up the meter will not stedy, it keeps moving down the scale, so I end up holding a key for about 2 mins before it will stop and by then I have a swr of about 10, should this happen, Im sure the meter should go stedy stright away, any help PLEASE.

Thanks Lance

Sounds like you need to borrow another meter to see if your meter is fibbing or the transmitter is changing power.

Some radios will back down the TX output power with a high SWR. Other transmitters heat up the final output stage with a high SWR and this will drop the output power as it heats up. You really need to find out just what the issue is before your repairing the transmitter PA stage.

Jim

[Bill_G]

Agreed. You need a second meter to confirm. The next best thing is to connect your meter and test cable to another station to see how it behaves.

[Will]

I do not think your Zetagi HP201 meter is rated for anything but CB, 27 mHz and HF. So that would explain the weird readings.

[rc50won]

The specs call for it to read SWR up to 200mhz. This device was made for non commercial use so its accuracy/quality is in question. I suggest trying a different meter.

Marshall

[AEC]

I doubt being for commercial use or not probaby has little to do with the meter, but the error the meter reads within the frequency range is.
Commercial or not, the error factor plays more into this than commercial or 'hobby' usage.
How good is the meter, how well contstructed, or is it built really cheap with cheap components?
There are errors in every meter, a fact most do a good job dealing with, like Telewave and Bird.
Others, not so much, and this is where the problems stem from.
Frequency ranges, and measuring near band edge coverage can and does introduce certain errors ito the reading/display.
Direct reading meters suffer more from transmitted energy than do meters like Bird and Telewave as the measuring components are not in direct connection to the transmitted energy, and are 'passive' in respect to the direct method that places the sensing elements in the transmitted energy's path', which causes heating and errors.

[Will]

We even get big errors with pro meters due to close by high power transmitters like broadcast stations screwing up the readings.

[AEC]

High power RF travels down the coax nicely.
I think it has a love for creating havoc, especially wth poorly shielded equipment in the wrong place, such as where you described Will.