My plates glow red; is that ok?
 

I just got a very nice Yaesu FL-2100B, running two 572Bs in parallel. It
works great, loads 0right up, and put out about 600 watts of RF key down on
20 meters.

I typically run it at 300 watts by reducing the drive from my exciter, and
run SSTV a lot. After about a minute at 300 watts the plates of both tubes
glow a pretty bright red. It's not so noticable in daylight, but at night in
a darkened shack it's quite bright, a cherry red.

Idle current is correct. The antenna shows an SWR of 1.5 at my operating
frequency. I am not using a tuner between the amp and the antenna.

Is this glow normal? My tubes have the heavy graphite plates. They only glow
after a minute of key down CW. On SSB, or keyed with no drive, they do not
glow.

Any help will be appreciated. This is my first experience with this tube.
Thanks.

Mike, N4PDY

It is not rated continuous duty. I don't think I would run it a minute of
key down CW...or SSTV for that matter!
Just my thoughts!
....Dave

"Michael White" wrote in message
...
I just got a very nice Yaesu FL-2100B, running two 572Bs in parallel. It
works great, loads 0right up, and put out about 600 watts of RF key down
on
20 meters.

I typically run it at 300 watts by reducing the drive from my exciter, and
run SSTV a lot. After about a minute at 300 watts the plates of both tubes
glow a pretty bright red. It's not so noticable in daylight, but at night
in
a darkened shack it's quite bright, a cherry red.

Idle current is correct. The antenna shows an SWR of 1.5 at my operating
frequency. I am not using a tuner between the amp and the antenna.

Is this glow normal? My tubes have the heavy graphite plates. They only
glow
after a minute of key down CW. On SSB, or keyed with no drive, they do not
glow.

Any help will be appreciated. This is my first experience with this tube.
Thanks.

Mike, N4PDY

It is not rated continuous duty. I don't think I would run it a minute of
key down CW...or SSTV for that matter!
Just my thoughts!
....Dave

"Michael White" wrote in message
...
I just got a very nice Yaesu FL-2100B, running two 572Bs in parallel. It
works great, loads 0right up, and put out about 600 watts of RF key down
on
20 meters.

I typically run it at 300 watts by reducing the drive from my exciter, and
run SSTV a lot. After about a minute at 300 watts the plates of both tubes
glow a pretty bright red. It's not so noticable in daylight, but at night
in
a darkened shack it's quite bright, a cherry red.

Idle current is correct. The antenna shows an SWR of 1.5 at my operating
frequency. I am not using a tuner between the amp and the antenna.

Is this glow normal? My tubes have the heavy graphite plates. They only
glow
after a minute of key down CW. On SSB, or keyed with no drive, they do not
glow.

Any help will be appreciated. This is my first experience with this tube.
Thanks.

Mike, N4PDY

In article ,
"Michael White" wrote:

I just got a very nice Yaesu FL-2100B, running two 572Bs in parallel. It
works great, loads 0right up, and put out about 600 watts of RF key down on
20 meters.

I typically run it at 300 watts by reducing the drive from my exciter, and
run SSTV a lot. After about a minute at 300 watts the plates of both tubes
glow a pretty bright red. It's not so noticable in daylight, but at night in
a darkened shack it's quite bright, a cherry red.

Idle current is correct. The antenna shows an SWR of 1.5 at my operating
frequency. I am not using a tuner between the amp and the antenna.

Is this glow normal? My tubes have the heavy graphite plates. They only glow
after a minute of key down CW. On SSB, or keyed with no drive, they do not
glow.

Any help will be appreciated. This is my first experience with this tube.
Thanks.

Mike, N4PDY


I would probably back off to 1/4 of the rated power as an absolute max
since the amp is rated 600 watts on SSB. I probably would run it at 75
or 80 watts for SSTV to let it run at less than flat out.

In article ,
"Michael White" wrote:

I just got a very nice Yaesu FL-2100B, running two 572Bs in parallel. It
works great, loads 0right up, and put out about 600 watts of RF key down on
20 meters.

I typically run it at 300 watts by reducing the drive from my exciter, and
run SSTV a lot. After about a minute at 300 watts the plates of both tubes
glow a pretty bright red. It's not so noticable in daylight, but at night in
a darkened shack it's quite bright, a cherry red.

Idle current is correct. The antenna shows an SWR of 1.5 at my operating
frequency. I am not using a tuner between the amp and the antenna.

Is this glow normal? My tubes have the heavy graphite plates. They only glow
after a minute of key down CW. On SSB, or keyed with no drive, they do not
glow.

Any help will be appreciated. This is my first experience with this tube.
Thanks.

Mike, N4PDY


I would probably back off to 1/4 of the rated power as an absolute max
since the amp is rated 600 watts on SSB. I probably would run it at 75
or 80 watts for SSTV to let it run at less than flat out.

"Michael White" wrote in message
...
I just got a very nice Yaesu FL-2100B, running two 572Bs in parallel. It
works great, loads 0right up, and put out about 600 watts of RF key down
on
20 meters.

I typically run it at 300 watts by reducing the drive from my exciter, and
run SSTV a lot. After about a minute at 300 watts the plates of both tubes
glow a pretty bright red. It's not so noticable in daylight, but at night
in
a darkened shack it's quite bright, a cherry red.

Idle current is correct. The antenna shows an SWR of 1.5 at my operating
frequency. I am not using a tuner between the amp and the antenna.

Is this glow normal? My tubes have the heavy graphite plates. They only
glow
after a minute of key down CW. On SSB, or keyed with no drive, they do not
glow.

Any help will be appreciated. This is my first experience with this tube.
Thanks.

Mike, N4PDY




Do it this way; Tune amp up normally at full power on SSB mode, or CW
mode.

Note the Grid and Plate current readings.

Reduce drive, as you have been doing. But RETUNE the amp at the lower drive
level. Reducing the drive as needed to maintain a level of 50% or less of
the full output readings.

See if that don't fix you up.

Dan/W4NTI

"Michael White" wrote in message
...
I just got a very nice Yaesu FL-2100B, running two 572Bs in parallel. It
works great, loads 0right up, and put out about 600 watts of RF key down
on
20 meters.

I typically run it at 300 watts by reducing the drive from my exciter, and
run SSTV a lot. After about a minute at 300 watts the plates of both tubes
glow a pretty bright red. It's not so noticable in daylight, but at night
in
a darkened shack it's quite bright, a cherry red.

Idle current is correct. The antenna shows an SWR of 1.5 at my operating
frequency. I am not using a tuner between the amp and the antenna.

Is this glow normal? My tubes have the heavy graphite plates. They only
glow
after a minute of key down CW. On SSB, or keyed with no drive, they do not
glow.

Any help will be appreciated. This is my first experience with this tube.
Thanks.

Mike, N4PDY




Do it this way; Tune amp up normally at full power on SSB mode, or CW
mode.

Note the Grid and Plate current readings.

Reduce drive, as you have been doing. But RETUNE the amp at the lower drive
level. Reducing the drive as needed to maintain a level of 50% or less of
the full output readings.

See if that don't fix you up.

Dan/W4NTI

"Dan/W4NTI" w4nti@get rid of this mindspring.com wrote in message hlink.net...
"Michael White" wrote in message


Do it this way; Tune amp up normally at full power on SSB mode, or CW
mode.

Note the Grid and Plate current readings.

Reduce drive, as you have been doing. But RETUNE the amp at the lower drive
level. Reducing the drive as needed to maintain a level of 50% or less of
the full output readings.

See if that don't fix you up.

Dan/W4NTI

Probably won't help too much. I didn't in my case with that amp, when
I tried reducing the loading. 300w "1/2 power" is a bit high for
continuous duty SSTV. I would cut that in half to about 150w. I've had
the sb-200 and also the fl-2100b. They both are hot running amps. The
plate dissipation is only 320w compared to 1000w for a pair of
3-500z's. I would mount a fan on top to help cool a little better.
Heck, with my henry 2k classic, I only ran 300-400w for SSTV. "The amp
does about 1300-1400 w. " And the tubes would start to blush a little
on it. MK

"Dan/W4NTI" w4nti@get rid of this mindspring.com wrote in message hlink.net...
"Michael White" wrote in message


Do it this way; Tune amp up normally at full power on SSB mode, or CW
mode.

Note the Grid and Plate current readings.

Reduce drive, as you have been doing. But RETUNE the amp at the lower drive
level. Reducing the drive as needed to maintain a level of 50% or less of
the full output readings.

See if that don't fix you up.

Dan/W4NTI

Probably won't help too much. I didn't in my case with that amp, when
I tried reducing the loading. 300w "1/2 power" is a bit high for
continuous duty SSTV. I would cut that in half to about 150w. I've had
the sb-200 and also the fl-2100b. They both are hot running amps. The
plate dissipation is only 320w compared to 1000w for a pair of
3-500z's. I would mount a fan on top to help cool a little better.
Heck, with my henry 2k classic, I only ran 300-400w for SSTV. "The amp
does about 1300-1400 w. " And the tubes would start to blush a little
on it. MK

I would probably back off to 1/4 of the rated power as an absolute max
since the amp is rated 600 watts on SSB. I probably would run it at 75
or 80 watts for SSTV to let it run at less than flat out.

For the short time the pix is being sent the amp should take atleast 500
watts out if only only one pix is sent as per usual. It only takes 10
seconds or less to send the pix.
If using RTTY or PSK31 where the amp is keyed up for a lot longer time , it
should be derated alot.