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Ameritron AL-80B help

Heavy Metal

Heavy Metal

Active Member
Aug 23, 2014
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here are some pics. What The readings and settings are and the input from exciter is 50 watts. Any suggestions? Or is this right on? the other thing is sometimes the Grid reading goes far left and has no reading at all but plate does. And swr,s on radio go up too 2:1 and 3:1 but not on the tuner or see any reflective wct on with yet without amp on xmit the radio is flat to 1.1:1-1.2:1.







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Hope these pics are ok to see some of what's going on.

HV is @a shade under 3000 sitting when Keyes looks like @2800-2900 it's right around were the two lines for forward and relent intersect.
 

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I'm not familiar with the AL-80B but if no one else here is either you should join the Ameritron Amplifier Yahoo group. It's very active there and you'll get a response very quickly by folks who know that amp inside and out.

First thing I would do for intermitttent readings, all other things remaining constant, would be to change my jumpers between the radio and amp. If that's not it then it could be an issues with the input section or a tube. You are testing into a known good dummy load aren't you?
 
Looks OK to me but you might have it loaded a little heavy. You're below 150 on the grid and 400 on the plate current. 55 watts into mine gets 600 to 700 out depending on the band. If you touch up the input match you may see a bit more out. I've honestly never keyed mine on 11 meters...not that I'm above that but I use other stuff. It does fine on 10 and 12 though.

There are adjustments on the back of the amplifier for the input tune. If you're only using 11 meters tune it so the radio sees a 1:1 swr. The maximum carrier I will run for AM service is 125 to 150 watts from the amp.

How are you tuning up? A solid 50 watt carrier with no modulation? What are using for a radio? If the alc cable isn't hooked up turn the alc up to max and forget about it.
 
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The first picture shows an SWR a bit over 5:1. Second picture 1:1. Third picture seems to be infinite. Try a good piece of coax to a good dummy load (rated for the amount of power from the amplifier).
 
Beetle said:
The first picture shows an SWR a bit over 5:1. Second picture 1:1. Third picture seems to be infinite. Try a good piece of coax to a good dummy load (rated for the amount of power from the amplifier).
Click to expand...



First and third pics are on HV second pic I'm on REF. Does that make a difference or does it matter it shows SWRs anyway?

Coax is LMR 400uf
 
543_Dallas said:
Looks OK to me but you might have it loaded a little heavy. You're below 150 on the grid and 400 on the plate current. 55 watts into mine gets 600 to 700 out depending on the band. If you touch up the input match you may see a bit more out. I've honestly never keyed mine on 11 meters...not that I'm above that but I use other stuff. It does fine on 10 and 12 though.

There are adjustments on the back of the amplifier for the input tune. If you're only using 11 meters tune it so the radio sees a 1:1 swr. The maximum carrier I will run for AM service is 125 to 150 watts from the amp.

How are you tuning up? A solid 50 watt carrier with no modulation? What are using for a radio? If the alc cable isn't hooked up turn the alc up to max and forget about it.
Click to expand...



I'm using CW at 50 on 11 to tune it, like you though Ameritron recommends no to exceed 200 watt carrier on AM I'd go like you @125-150 rather have good swing and not over modulating on it.



I did make a local contact this morning on ssb amp on S7-9 amp off S2. And as you see in last 3 pics think it's @500-600. But observe the load and plate settings, what I've read they do t seem right?
 
When the knob is set to HV it is not reading reflect. HV only.

The tune and load knobs look to be in the right neighborhood.
 
Heavy Metal said:
But my grid goes dead off for some reason at times? That concerns me.
Click to expand...

Sorry, I completely missed that part and was mainly looking at the pictures. So you have an intermittent issue while transmitting. The grid current drops to nothing, SWR on the radio goes high and while this is happening you are still drawing plate current?
 
543_Dallas said:
Looks OK to me but you might have it loaded a little heavy. You're below 150 on the grid and 400 on the plate current. 55 watts into mine gets 600 to 700 out depending on the band. If you touch up the input match you may see a bit more out. I've honestly never keyed mine on 11 meters...not that I'm above that but I use other stuff. It does fine on 10 and 12 though.
Click to expand...


Should it be at 150 grid and 400 plate or can I go higher for am ssb CW what's the max for these to go and MAX drive for this amp sounds like in manual 100 watts drive then some say 80 some 70 which is which???

Most who have chimed up here with exception of one or two are v b b knowledgable and your input I would take over a manuals anyway( sucking up does good too, kidding am serious ) .
 
If you go by the spec sheet the max plate current for a 3-500z is 400ma. If you go by Ameritron's tune up procedure in the manual they have you run the hell out of the tube to make 1kw...I thought that was a CB thing. I don't push mine past 750 watts out which is 55 to 60 watts input. I keep the grid current at 150ma or less and the plate current below 400ma when I tune up so during normal operation they are less. There's always other opinions and someone that's been doing it differently for years.

You want to run a 3-500z hard enough to make the anode show some color to keep the tube from getting gassy but an occasional AM QSO will do that for you and makes a lot more sense than beating it on SSB. Mine's on the wrong side of the desk to see the tube...I need a mirror on the wall.

I'm still not sure about the issue you're having with the grid current and SWR. Maybe a bad solder joint or something simple. All the pics you posted look OK. You will have HV at all times when the amp is on, HV will sag a bit when you transmit (not as much on 240vac), you will have no grid or plate current until you transmit. The bias in these amps switches on and off between voice peaks so if you key it on SSB with no modulation there will still be no plate current until RF is applied.
 
No not all max out their things, that's stupid to Do, yeah power is a lot but modulation I think and from what I been taught LONG ago is better with a good signal.
 
OK - got it now. Wasn't looking at the switch positions. Seems like a screwy way to meter the HV, though - using the meter with the movement sort of backwards from standard.
 

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