Dosy TC3001P meter problems...?

[jimbowilly]

Hi,
My Dosy TC3001P meter's SWR meter will not adjust to the Set Line on channel 40.
But will adjust to Set Line when on channel 1.
I reviewed the Dosy manual for this meter and I'm doing exactly what the manual says to do.
Please help.
Thanks,
jimbowilly

[Bluerunner]

Sounds like you don't have enough power to get to the set line on the lower channels.
What is the difference between the output power levels at 1 and 40?

[MDYoungblood]

It sounds like an antenna SWR problem,, best check it on a dummy load. You can adjust the meter, there are potentiometers inside but you will need a true 50ohm load to do so.

3's

Greg

[jimbowilly]

It sounds like an antenna SWR problem,, best check it on a dummy load. You can adjust the meter, there are potentiometers inside but you will need a true 50ohm load to do so.

3's

Greg

Ok. I tested with a 50 Ohm dummy load and dead key swr's are 1 for channels 1 and 40 on my Dosy TC3001P. I checked both ends of my 50 ft - RG8X coax with the other end attached to my 50 Ohm dummy load. The Ohms were slightly over 51 Ohms(+ a few thousandths). So I disassembled my antenna and inspected and cleaned all components. I found my ground plane radial end connectors are corroded where they attach to the radial wire ends( I have issues with metals corroding around my house due to salt spray emanating from near by state road). My antenna set up is a 102" stainless steel whip elevated to 10ft, with two 10 ga. coated copper wire radials cut to 102", each set at about 37°. This antenna set up originally tested 7 yrs ago at just over 51 Ohms. And I was able to tx and dx during skip to California, Main, Virgin Island, Puerto Rico... And normally I can clearly converse with locals up to 40 miles away. Even with using a 50 Ohm dummy load, attempting to adjust the Dosy TP3001P is like trying to catch a kids balloon on a gusty/windy day. I intend to contact Dosy for re-calibration of this meter. I will be replacing the ground plane radials and retesting tomorrow. I will post the results of the new ground plane wires/connectors once they are installed.
Thank you,
jimbowilly

[jimbowilly]

I'm truly disappointed with the Dosy TC3001P. I have two of them and both have similar issues. After testing, disassembling, cleaning, I dug out a Astatic PDC7 swr meter. While using two different radios and the Astatic PDC7, I am able to adjust the needle to the set line on both channel 1 & 40 and calibrate the swr . So I did all this work because the Dosy TC3001P is malfunctioning. At least I found the problem. And I had fun doing it.
Thank you for your replies.