T-368 low output on 15 meters

[W9BHI]

Hello all,
My T-368 has low output on 15 meters compared to 160 thru 20.
There is plenty of grid drive on 15, (12Ma, about the same as the other bands).
Ouput on other bands is 400 watt carrier at about 200 Ma. and has 1500 watt PEP.into a 50 ohm load.
On 15 meters there is 350 watts at 225Ma, but only swings to about 800 watts PEP.
Dipping the plate and reloading to get 400 watts yeilds a plate current of over 350Ma.
I have done an alignment to the multiplier deck according to the manual and no difference on 15 meters.

Soft 4-400A maybe?

Thanks,
Don W9BHI

[N2DTS]

That might just be normal as you go up in frequency.
Stray L and C builds up, coil taps and unused roller inductors suck power, some tube perfomance falls off at higher frequencies.
Rigs could be built to have the same efficency on say 10 meters, but most multi band rigs fell off there.

[flintstone mop]

I had the same problem with a T-3...just runs out of steam past 20M.
Fred

[K6IC]

Don,

On 15 M,  the T-3 is standing on its tippi-toes.  The speced frequency range on all of the ones I've seen is;  1.5 - 20 Mcs.   Think that you are lucky to get anything on 15 M.

Know that many military rigs do have some overrun,  though.

Have Fun,     Vic

[W9BHI]

I'm gonna try a different 4-400 and see what happens.
If there is no difference, then it is what it is.
Thanks for the reply's,

Don W9BHI

[W2VW]

Try tuning slightly away from the plate dip while looking at peak power under modulation.

That tx has no neutralization.