National Aeronca Association Bulletin Board

They are common HAM radio / commercial radio adapters. Let us know how the test goes on the current antenna and the repair. Maybe a picture.

Bob

Ok fellas I need a bit more guidance. So I hooked up the SWR meter and if I'm doing it right the readings are way up in the red. The power output showed to be in 6.5W range and the SWR reading showed to be about 12....If i'm supposed to be in the 1.6 or below I'm in trouble likely. I am attaching links to the meter pictures so can confirm or tell me I did something wrong. You can look at the switch settings to see which scale to be looking at. Two shots of the power reading and two shots of the SWR reading.

https://photos.google.com/share/AF1QipM ... JWbGNNTzB3

Sorry I think I included one picture that with no reading on the meter. Easier to tell you than take it out of the album.

Thanks,
Justin

Well that's a fine piece of test equipment. I am comfortable with a Bird Truline wattmeter that you turned the sampling element forward or reverse. The meter has a FUNCTION and POWER position. Each seems to have Forward or Power and Reflected or SWR. Are you sure the meter was calibated and operated correctly?

The reflected power should be relatively low or a small ratio of the output power otherwise you expose the radio to damage and of course marginal range on transmit. I need to get smart about that meter.

So I took a moment and found this video https://www.youtube.com/watch?v=TZ2Nj_s36pA

Richard,

Thanks for the video. I am not sure of anything honestly. I did calibrate the meter but had it on forward power setting when I did it and also I didn't have the dial turned all the way to the left before I started the calibration, but did calibrate full scale as it said. Also it was in forward power when I ran the SWR test and it appears from the video that maybe it needed to be on the reflective setting.

I will try to calibrate starting with the knob all the counterclockwise and it on the switch on the reflective setting and see if that changes things.

I'll see if I can do it again in the morning before I leave town for work otherwise it will be Saturday morning before I can get back to it. I'll update after.

Thanks again,
Justin

That SWR Meter is very easy to use and unlike the Bird, directly reads the SWR. (The Bird reads Forward Power with the slug in one direction and reflected power with it turned the other way.) What you want is almost 100% forward power and 0 reflected, or 1:1 SWR. If you really have 1:10 or 12, stop transmitting on that antenna until it is fixed or replaced as most of the handhelds do not have reverse power protection and you could cook the final output transistor.

You can also read the forward and reflected power on the Kenwood (Diamond Name Plate) without auto calculation of the SWR. Just depends where you have the switches and use the low power setting sine the meter is accurate to about 3% which in the 200 watt mode could be just in error.

Set the power switch on 5 watts ( most handhelds have 5 watts AM Output. Put the next switch in CAL - Transmit and turn the calibration dial until the need goes all the way to the right onto CAL. Now put the switch into SWR and transmit again and you will read the calculated SWR as a percentage of reflected to forward power.

Bob

Thanks for the info and reply guys. I tried it again the way that video shows and I am getting the same 1:12 and right at 7 watts on the power which is correct. So I ordered another antenna, delivered today so should be able to put it on tomorrow and give the test another shot. I'll update when I know something.

Justin

Make sure you check the antenna cable (I would try an SWR reading with new cable) and the connectors as both can also cause high SWR.

Bob