hey guys i just got a new amp al-811hd and i am having a problem when i key my rig yaesu ft-897 at 100 watts with the amp in standby my swr on my mfj-998 tuner says its flat and the radio says the swr is flat but when i turn the amp on and tune it to reseonance the swr on the radio says high swr and i cant back it down without derading the tune of the amp ,,, any suggestions..
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High swr on radio with amp on
- Thread starter 317
- Start date
The amplifier has a tuned input and the SWR meter in that radio is seeing that as being high. The thing to do is to re-tune/adjust the amplifier's input circuit for the band that's in use.
Before you do any adjusting, those input impedance circuits in the amplifier should be at least in the 'ball-park'. Go through the manual for that amplifier again, especially the part about the input circuits.
- 'Doc
(It's a very good idea to be very familiar with the manual before ever turning that amplifier on! Yeah, I know, I didn't do that either, but it's still a very smart idea.)
Before you do any adjusting, those input impedance circuits in the amplifier should be at least in the 'ball-park'. Go through the manual for that amplifier again, especially the part about the input circuits.
- 'Doc
(It's a very good idea to be very familiar with the manual before ever turning that amplifier on! Yeah, I know, I didn't do that either, but it's still a very smart idea.)
Boy do i feel stupid i just rechecked all my connections and i found i put my ground wire on the wire antenna conection on the tuner instad of the ground. there right next to eachother thats what i get for just reaching in the back and doing it blind so now i get about 400 wats out still not the majic 600 and still high swr on my radio but tunet is happy 1.0 swr
BJ radionut
Supporting Member and 6m addict
317: That tuned input should be adjusted with no more than 20-25 watts out from the radio(internal tuner OFF)...Adjust input coil for min. swr... then retune the amp with same drive...readjust the input circuit... repeat sequence until you have it right...
You may have to do this on each or maybe several bands...hope you have a dummy load!
ALSO that 811HD should require maybe 50-60 watts MAX drive power...
I load mine at 25 watts keydown...
45-50 watts drive when using SSB (that's 650+ peak output)... pretty close to rated output....She will live a long happy life!
Driving that amp with 100 watts your first priority will be to save up $175.00 for a new set of tubes...your dime OM
Enjoy
All the Best
BJ
You may have to do this on each or maybe several bands...hope you have a dummy load!
ALSO that 811HD should require maybe 50-60 watts MAX drive power...
I load mine at 25 watts keydown...
45-50 watts drive when using SSB (that's 650+ peak output)... pretty close to rated output....She will live a long happy life!
Driving that amp with 100 watts your first priority will be to save up $175.00 for a new set of tubes...your dime OM
Enjoy
All the Best
BJ
Yea i just did that before i read your post it was the only thing i didnt adjust yet. i just thought it was pre tuned from the factory .. I got the swr down and full output on 20 meter so far. i cant seem to get full output on all bands yet on my Hustler 5BTV i have a dummy load that was built out of a paint can and HT resistors but i havent found the right oil to put in it yet...
i get full 600watts on FM but AM says only 100 on my mfj-998 i guess when i modulat it swings but my meter is a bit slow to show i guess