Uniden 980ssb HOT!!

[John Doe 55]

Hey guys, new here and could not find any info on the topic. I have a Uniden 980 which I use in my mobile with a two foot fiberglass antenna. I opened up the radio today and noticed that the "grease" that is around the final (L203, on the rear left of the board) seems to have mostly melted off. Does this mean that I have too much reflective power back into the radio which has caused this, due to the short antenna? Is there some "grease" that I can buy to re-grease it? Thank you for your help!

[231]

Welcome to the forum.

To answer your question, there are videos on Youtube that talk about how to better set up the heat exchange of the finals. If you do a search on Youtube it should come up on the mods for it.

But that really doesn't address your real problem which is obvious. The 980 has an okay SWR meter in it, what is the radio seeing for an SWR? Honestly, 2' is just too short an antenna to be very effective. I've bought and tested them before and they will always be a problem between horrible performance and being unable to get even a 2:1 standing wave. The impedance is the issue. If you are using one of those through the glass antennas throw it away and get a decent 3' antenna minimum. In that 2' antenna you have 8-1/2' of wire crammed in there. Move just a few channels any direction from where it's tuned, and your standing wave will be horrible again. Did I mention the performance is horrible compared to even a 3' antenna?

Good luck.

231

[John Doe 55]

Thank you for the response. I am aware that with a two foot antenna performance is minimal. I use the radio to communicate with other 4x4's while out on the trail (so I have not had any problems in that regard). I will look into the videos on youtube, do you know what type of grease I should use to regrease the final?

[MDYoungblood]

Hello John Doe 55,
Welcome to the forum. When using a 2ft antenna you adjust the SWR to the frequency you use the most and never go to far either way from it. If the heat sink compound (the name of the grease) is melting there is a big SWR problem overheating the final. I go a little farther then 231 and say a minimum length for a CB antenna is 4ft, it will at least give the radio a fighting chance with a good SWR over the bandwidth. Add a little compound behind the voltage regular too if none is present.
As a new member could you post a intro in the "Welcome to the Forum" topic, http://www.cbradiotalk.com/viewforum.php?f=89 , so others can say "Hello", thanks.

3's

Greg

[Deleted User 14541]

The thermal paste you speak of it put between the final and heat sink. The stuff around the edges is just what squeezed out when the mounting screw is tightened. A trail rig antenna either has to be short or a 102" whip, you will break anything else. Most of us don't run a nice radio in our trail rigs because of the poor antennas we use and how the rigs are treated.

Has the radio been peaked and tuned? Since you are talking in such close proximity you could turn the power way down and keep the final cooler. Running a radio at max power with a poor antenna isn't good for it.

[sonoma]

it is a thermal paste. just do a search and you will find it all over the place. looks a lot like tooth past when you install it. comes in little tubes and jars.

[drdx]

It is interesting that this came up here. I just got a new 980 and when used just a few minutes on ssb, the back final area gets super hot. I was thinking of just putting fins and a fan on it. My radio has never been opened, so it is doing that in bone stock form. Other than that is is a great radio.

-drdx

[MDYoungblood]

I have been hearing about a hot final for some time now, I think a heatsink would help. I'm beginning to think it is an inheritant problem with single mosfet radios. I have noticed a couple and I've seen the regulator gets hot too.

3's

Greg

[John Doe 55]

Thank you all for the responses. I tried two different antennas today a three foot fiberglass antenna as well as a five foot wilson 2k. When talking on ssb the radio got pretty darn hot with both of these antennas as well (yes my swr was set). Using an external astatic swr meter the needle was sitting all the way to the left (1.1 I guess it is, on channels 1 and 40.) The meter on the radio itself would "peak" sometimes to 1.6 but then level out to a 1.0

[silvereagle1]

Ive got 2 980's and they both get hot. I put a heat sink on them. posted a pic somewhere on here but it's been a while back. the heat sink I used was a galaxy heat sink cut to fit the 980. I think I paid 7 dollars for it on the flea market site.

-- Thursday, 11 December 2014, 18:52 PM --

found the pics for my heat sink mod.

[drdx]

Does that heatsink have a smooth surface where it attached to the radio? I think there are a few screw heads that would keep a flat surface from mating to the back but I'd have to look again. Did you have to mod that fin any?

And, not to hijack, I see your other rigs listed, if you get bored, post a 980ssb vs grant II general and receive performance comparo report.

-drdx

[Deleted User 14541]

Looks good. I think it would be best if the heatsink has a smooth flat surface to mate with the chassis with a light coating of thermal paste. The heat sink can be drilled just deep enough to fit over any screw heads on the chassis.

I do something similar with the Uniden Grant or Chinese 148 to keep the AM regulator cool. Same with an old 148 but the regulator has to be relocated.

[silvereagle1]

Does that heatsink have a smooth surface where it attached to the radio? I think there are a few screw heads that would keep a flat surface from mating to the back but I'd have to look again. Did you have to mod that fin any?

And, not to hijack, I see your other rigs listed, if you get bored, post a 980ssb vs grant II general and receive performance comparo report.

-drdx

Galaxy heat sink cut to butt into the serial number plate.
the heat sink had a small screw hole in the back of it so I bored it out larger than the transistor screw head on the back of the radio. the bored out hole slid right over top of the screw head perfectly. then I screwed it in place.

a quick comparison grant vs 980
transmit: Grant is much better. it will key low and swing around 12-15 on AM. I get great reports on SSB.
The grants SSB receive not as good as the 980. the 980 sounds much better. it's consistant with the noise level whereas the grant is agrivating to listen to. you might have a 1 on the noise level then all of the sudden it will spike up to 8 like a lightning strike. does it pretty much all the time. this is sideband mode only though. I've saw videos on the grant and a few of the videos show the same thing so it must be a grant thing. too sensitive? maybe all it is but agrivating to listen too.

[rich33]

It is interesting that this came up here. I just got a new 980 and when used just a few minutes on ssb, the back final area gets super hot. I was thinking of just putting fins and a fan on it. My radio has never been opened, so it is doing that in bone stock form. Other than that is is a great radio.

-drdx

If the back of the radio is getting hot pretty quick, chances are the transistor bias is way off.

[drdx]

Maybe so, I certainly wouldn't know for sure. On mine, it got hot to the touch but performed great. But unless it was a warranty repair, which I would have a weak case to plea with no failure or laboratory scientific evidence of lacking promise of, or similar to the like, I will live with it as cheap as it was.

I have had many radios get hot in the back. This one was just a little more noticed since it was out in the open and ran on a battery source and is not some hot rod style export. Are you saying that heat at the rear of radios is commonly indicative of that issue? Is it something that is a design flaw or just a matter of alignment or the like?

-drdx

[silvereagle1]

I believe that all the 980's get hot like that. I've got 2 of em and they both heat up fairly quick. I've read the same complaints on other sites about the 980 heating up. just the nature of the beast with this radio in my opinion. the heat sink works nice.