Radio Test Set TS-3957/PRM-34

[Cdub]

As I start playing around with my radios, I often wonder how they are performing. The only test I can do at this point is to use another radio. Which isn’t saying much at all, I believe the radios are working fine? Lets see what happens when I put them through a few tests and see what the results are through these different stages of the tests.

I was just handed a radio test set TS-3951/PRM-34 to try out for the first time. This test set seams to be just a basic tester that even a novice / beginner like me can use. At least I can see if the radios are performing like I believe them to be.

Looking at the results and being able to understand what the tester is telling me maybe a different story. That's where the experts come into play. I can set up the radio, run a few test, but reading the results can be difficult.

Hopefully I'm on my way to understanding radios more and how they work.

Test results to follow............

Cheers,

C'dub

 

[Cdub]

Well the testing went well.........the test set is very easy to use and set up. Just basiclly two antenna connections. One to the radio and one to the antenna.

Radio:

SINCGARS with Power Amplifier (frequency set to 51.000 MHz)

1. Receiver Sensitivity Squelch Test

This test didn't go well......I don't know if it's the right test set for the radio or if the test set is working properly or if it was me....??...Haha

2. Forward Power Test

PA - 43.3 watts
HI - 3.3 watts
M - 0.3 watts
L- Blank / no results

3. Reverse Power Test

PA - 9.5 watts
HI - 1.1 watts
M - 0.0 watts
L - Blank / no results

4. Frequency Test

Radio tested Perfect through a number of different frequencies.



All in all, I think the test went very well and the radio should perform up to par in the field.

I did notice variation in the forward power with the Power Amplifier while changing frequencies.


Radio:

PRC - 126

1. Receiver Sensitivity Squelch Test

This test didn't go well either with the PRC-126.

2. Forward Power Test

1.2 watts

3. Reverse Power Test

0.4 watts

4. Frequency Test

Radio tested Perfect through a number of different frequencies


All in all, I think the test went very well. I'm currently using a 10 pack of ' AA ' batteries. The Forward Power may increase with a different battery set up...dunno......something I'll have to give a try latter on.

I would like to add that anyone newly interested in radios to get this test set. Well worth the knowledge of knowing if your set is working properly like expected..........

Cheers,

C'dub

 

[Cdub]

Is the reverse power to much........?? will it cause damage to the amp or radio set.....??

3. Reverse Power Test

PA (power amp) - 9.5 watts

Thank You,

C'dub

 

[ONTOS66]

This link might give you a little more insight into using the equipment.

http://www.prc68.com/I/PRM34.shtml

 

[m38inmaine]

I have the same test set. The reflected power is a factor of the antenna being tuned to the frequency selected, the more it's out of tune the more power reflected back to the radio which causes it to heat up and also loss of actual radiated power. The reflected power you have is about 25%, not good at all, very high. I suggest you make sure the feed line is correct as well as the antenna for the frequency you are operating on. That's like a 5:1 vswr, most ham radio's won't allow you to transmit with that kind of mis match.

 

[maddawg308]

I got the same test set. Never used it, but I know the manual is a gold mine of info. What I always wondered, though, is: The tester works great IF YOU KNOW THE TEST IS WORKING and CALIBRATED 100%. But what if it's not? How can you tell?

I guess worst case scenario, you can always use a self-calibrating oscilloscope.

 

[Cdub]

Hi Mike,

The test set has a BIT built in.....in the begining of the manual it will tell you how to test it......Basicly......you leave it in the off position and push the ' Push to Test " button as in the picture here.........It should read.......' 1.000 '

Try it out and see what happends.

Cheers,

C'dub

 

[Cdub]

I have the same test set. The reflected power is a factor of the antenna being tuned to the frequency selected, the more it's out of tune the more power reflected back to the radio which causes it to heat up and also loss of actual radiated power. The reflected power you have is about 25%, not good at all, very high. I suggest you make sure the feed line is correct as well as the antenna for the frequency you are operating on. That's like a 5:1 vswr, most ham radio's won't allow you to transmit with that kind of mis match.

Hi,

Thanks for the info........

How about if I change out the Antenna with a new one and see if that makes a difference..............??

Cheers,

C'dub

 

[m38inmaine]

You can try, but there are alot of factors involved. Is it the correct antenna mast/base?, is the base grounded?, how close to another object is the antenna? etc. Without knowing the variables it's hard to give sound advise.

 

[Cdub]

That's all very understandable..............

All the cables and equipment is correct as per the TM.....no issues there.

I just swaped out the antenna with a NOS one and I got.........

Reverse Power Test @ 51.000 MHz.

6.7 watts antenna UP ( straight up position)
11.3 watts antenna DOWN (bent down position with tie rope)

I did notice a wide difference when I used different frequencies through out the test.

Thanks,

C'dub

 

[m38inmaine]

You can see because the antenna was closer to ground(tied down) that the swr increased which is normal. Still seems a bit high but unless you have a ham license or such you will just be receiving(legally) anyway.

 

[Cdub]

...............unless you have a ham license or such you will just be receiving(legally) anyway.

I'm not sure what you mean by that.......can you explain a little more please......

Thank You,

C'dub

 

[m38inmaine]

You need a license to transmit with the radio, either commercial or ham or for official military/government use. Ham radio would use 50-54 MHz. The military has full use from 30-76/88 and has priority use.

 

[Cdub]

Roger that............

C'dub
KC2UCZ

 

[SCSG-G4]

The difference between the forward power and the reverse power is known as the SWR, and should be ideally adjusted down as close to unity as possible (1 going out, zero coming back in). There are antenna matching units that can help considerably, and, yes, the SWR will change a good bit as you shift frequencies. The matching unit varies the length of the antenna electrically so it most closely equals a specific portion of the electronic wave (usually 1/4 or 1/2 wave) of that frequency. Brooke's site, previously mentioned (PRC6 is a great place to learn more.

 

[ONTOS66]

I got the same test set. Never used it, but I know the manual is a gold mine of info. What I always wondered, though, is: The tester works great IF YOU KNOW THE TEST IS WORKING and CALIBRATED 100%. But what if it's not? How can you tell?

I guess worst case scenario, you can always use a self-calibrating oscilloscope.

Check our friends at LOGSA to download this manual (I'll also upload it to our Resource section)

TB 9-6625-2171-35
CALIBRATION PROCEDURES FOR RADIO TEST SET AN/PRM-34(), RECEIVER TEST SET AN/ARM-186, AND COLLINS, MODEL 972Q-4