Low Power on 10 meters.....?

[WX2MIG]

I have an older solid state Kenwood TS-130S, haven't really played much on 12, 15 or 17 meters, but on 20, 40, and 80 meters, with everything well in tune, and going by the meter on my MFJ-949C tuner, my out put will peak from 60 to 80 watts.
As soon as I go to 10 meters, and I've checked this with 4 different antennas, I only peak out at 30 to 40 watts......

Is this radio designed to transmit at a lower power on 10, or could there be a problem with the finals on it......????

 

[n8fgb]

Common with early solid state rigs. The PA was startiong to run out of it's frequency range of operation.
Rich

 

[295]

I have an older solid state Kenwood TS-130S, haven't really played much on 12, 15 or 17 meters, but on 20, 40, and 80 meters, with everything well in tune, and going by the meter on my MFJ-949C tuner, my out put will peak from 60 to 80 watts.
As soon as I go to 10 meters, and I've checked this with 4 different antennas, I only peak out at 30 to 40 watts......

Is this radio designed to transmit at a lower power on 10, or could there be a problem with the finals on it......????

The radio should be putting out equal power on all bands. You could possible have a problem or it could very well be the meter you are using. I don't want to down anyone's equipment, but honestly, I have not had good luck with stuff from MFJ, especially the accuracy of their watt meters. First you should check it in CW mode into a dummy load not on any antenna system. I can tell you from experience that MFJ's peak reading meters leave a lot to be desired.

If you can get access to a better quality peak reading meter such as a bird/coaxial dynamics/struthers...you might be suprised to find out that your radio is functioning fine. Nevertheless, considering the age of the 130 you may need to send it off for a tuneup and maybe minor repair.

73

 

[WX2MIG]

Knowing the quality of MFJunk products, I wondered if perhaps the meter just wasn't reading properly at that frequency range, but when I tune up in CW mode, it does indicate that I'm reaching full power, it's when I switch to SSB that it indicates I'm only peaking out at 30 to 40 watts, and I also have to turn my ALC way up because that drops out as well on 10 meters....

This leads me to think that maybe it's the radio, and not the meter.

Been thinking about getting one of those good Diawa cross needle meters just to be on the safe side.....how's the quality and accuracy of those meters.....???

 

[295]

QST did a review of a few meters a while back, I believe the Daiwa was included in the review. I will see if I can dig it up later this weekend.

73

 

[Beetle]

It's not at all unusual for an HF rig to show a bit of a power drop-off at the high end of its range. Both tubes and transistors have finite points beyond which they obey the laws of physics and their design parameters .

 

[W5LZ]

Your TS-130 appears to be operating normally. Most radios of the same vintage do the same thing, less output on higher bands. I do think a 50% reduction in power is a bit much for that though.
There are a lot of things that will affect output power so using a dummy load is a very good idea for doing that kind of checking. So is using a decent meter. 'Pin-point' accuracy is nice but really isn't all that necessary. (If you want that kind of accuracy, do the VA numbers for the finals.)

And I ain't happy unless I can 'pick' on something so...
You'd better leave that 'ALC' alone and just use the mic gain. Yeah, I know that isn't what you meant, but you don't want to give people ideas, you know?
- 'Doc

 

[295]

Knowing the quality of MFJunk products, I wondered if perhaps the meter just wasn't reading properly at that frequency range, but when I tune up in CW mode, it does indicate that I'm reaching full power, it's when I switch to SSB that it indicates I'm only peaking out at 30 to 40 watts, and I also have to turn my ALC way up because that drops out as well on 10 meters....

This leads me to think that maybe it's the radio, and not the meter.

Been thinking about getting one of those good Diawa cross needle meters just to be on the safe side.....how's the quality and accuracy of those meters.....???

I found the article on the Daiwa meter. The only daiwa review I could find was the Daiwa CN-101L, here are the numbers at 100 watts SSB, at 2 mhz the meter read 30 watts; at 14 mhz the meter read 30 watts; at 28 mhz it read 30 watts peak.

The reading at 1 kw on voice were: 2 mhz, 900 watts peak; 14 mhz 800 watts peak; at 28 mhz, 900 watts.

The Daiwa meters don't look too good, the article was in the July 2002 QST. I thought there was a later review, I will have to look futher.

Nevertheless, as one poster pointed out, you may see less power at the top end of the band, but as he said, and I would agree, that a 50% reduction in power would be odd. Maybe a 10, possibly 15 watt reduction would be reasonable at the most.

Edit:

I was able to find the later article from the March 09 QST, they reviewed the CN-801 HP, the meter actually showed good accuracy. The numbers at 100 watts was within 5-6 watts on all bands with all testing modes (CW, 50%, Two tone). At 1kw using CW it showed on the three frequencies of 2, 14, and 28 mhz, 1030, 1040, 990 watts; at 50% duty (sending a string of dits at 60 wpm) the meter read 1180, 1300, and 1130. The 1300 watts baffles me, but it is what it is, I think for average SSB use it would be more accurate. A 1kw two tone test at 14 mhz showed 1050 watts.

73

 

[WX2MIG]

Thanks for the feedback on this one guys, mucho appreciated.....

295.....
If I get a Daiwa meter, it would deffinitely be the better model CH-801-HP...

Doc....
I ment mic gain, but you already knew that....didn't ya.....

 

[HiDef]

Your final amplifier and driver stage most likely have lower gain on 10 meters than lower bands. Output should normally still be the same though. Radios are made with extra gain in the preceding stages to take care of this and provide uniform power out everywhere. They use ALC to reduce extra gain.

Seeing as how it behaves OK on CW and not on SSB the situation is probably low I.F. gain and/or the mic input to the radio was low to begin with.

Any SWR higher than 1:1 will start another gain reduction process to protect the final amplifier. Check into a known good dummy load to eliminate this cause. Why do I say known good dummy load? Because I just spent 4 hours bench time on a rig I killed testing into an intermittent estate sale dummy load!

Try another mic with more gain.

If this doesn't work then it's time for an I.F. alignment.

If the radio has an ALC meter the readings can help understand what's going on. You should have enough gain to make ALC on each band.

 

[Moleculo]

I have the Daiwa CN-801 (original version). I've had it for years. I like the big face and needles because it's easy to see out of the corner of your eye. It makes tuning up an antenna with your tuner really easy also. This version isn't an active peak reading meter, so it's lousy at measuring PEP in SSB mode. That's OK by me as I have active peak meters in the Amp, tuner, and also a Bird43P I can hook up if I really want to. I use a tuning tone pulser anyway when tuning up the amp, so I know what the PEP is.

 

[WX2MIG]

Mole, I believe the new version does PEP, they have a 12 vdc connection that's supposed to be for a meter lamp, and for doing PEP.....

Cheapham.com has about the best price I've seen on new units at $137.95...

I'm also tracking one on Flea Bay, but it'll most likely end at a price far too high for a used meter......:closedeyes:

 

[Beetle]

Be very sure that the external 12V supply is for both the lights AND the active PEP circuitry. Lots of MFJ meters have "AVG/PEP" switches, and a jack for the 12V supply, but the 12V supply is ONLY for the meter lights.

Be a skeptic.

 

[WX2MIG]

Be very sure that the external 12V supply is for both the lights AND the active PEP circuitry. Lots of MFJ meters have "AVG/PEP" switches, and a jack for the 12V supply, but the 12V supply is ONLY for the meter lights.

Be a skeptic.

The 949C antenna tuner only has one 12 vdc connection for (I believe) the lamp.....however it may also be tapped for PEP readings....not really sure....

The Daiwa CH-801-HP uses 12 vdc for both the lamp and for PEP readings....(at least that's how I understand it to work).....

I passed on a couple of Vectronics SWR meters since they are made by MFJ and are, for all intent and purposes an MFJ product subject to all the same poor quality, and inaccuracy issues......

Much is the same with some of the cheaper meters offered by Comet, and Jetstream, they're made by MFJ, and it wouldn't surprise me if the cheaper line of Daiwa meters are too, if I got one (Daiwa) it would be the professional bench meter CH-801-HP....