Too Cool?

[W5BIB]

I operate a Swan-500cx as a dedicated rig on 40 meters. Question; Is it possible to remove too much heat from the finals (6LQ6's) during operation (CW only). I run it at about 300-400 mls. I get about 300-350 watts out. I use an external fan to remove heat. Sometimes while operating, ...the area above the finals is actually cool to the touch. This is after a 30-45 min warm up. Just receiving, I use no fan. When transmitting I use the fan when it feels pretty warm to the touch. Is there such a thing as too much cooling?...

[WB2WIK]

Nah.

The rig could run outdoors when it was 32F and it would be a lot cooler. It will work fine that way (although its "warm up" time to reduce drift would be a lot longer).

[W5BIB]

Nah.

The rig could run outdoors when it was 32F and it would be a lot cooler. It will work fine that way (although its "warm up" time to reduce drift would be a lot longer).

Yep... I've noticed the "cooler" it runs, the more 'drift'. I'm fortunate to also have a Swan 410C external VFO to use with it (virtually drift free) and a SP-600JX for a rx. Tnx fer info.

[KE3WD]

Those things you call tubes are THERMionic valves, which means that they actually need a certain amount of that heat in order to do their thing. While cooling can be desirable and can serve to extend component life a certain amount, overdoing it would likely cause premature component failures of a different kind due to expansion/contraction considerations and such.

All things in moderation,

73

[W5BIB]

Those things you call tubes are THERMionic valves, which means that they actually need a certain amount of that heat in order to do their thing. While cooling can be desirable and can serve to extend component life a certain amount, overdoing it would likely cause premature component failures of a different kind due to expansion/contraction considerations and such.

All things in moderation,

73

That's kinda what I figured. I allow it to remain pretty warm during operation by adjusting the fan blowing across the unit. It just doesn't get "hot enuf" to keep my coffee hot (just warm)...

[WA7KKP]

Sounds like you're really pushing that Swan . . . they were notorious for being overrated as per input power. If you read the fine print in the manual, you'll find out that normal operation on SSB should be at most 100-125 ma on peaks.

Keep the fan on -- the #1 killer of sweep tube finals is heat, and now that sweep tubes are going for a king's ransom, you want to keep them going as long as possible.


Gary WA7KKP

[W5BIB]

Sounds like you're really pushing that Swan . . . they were notorious for being overrated as per input power. If you read the fine print in the manual, you'll find out that normal operation on SSB should be at most 100-125 ma on peaks.

Keep the fan on -- the #1 killer of sweep tube finals is heat, and now that sweep tubes are going for a king's ransom, you want to keep them going as long as possible.


Gary WA7KKP

Hi Gary. I only use it on 40 CW. The manual says 450 ma for full power on CW. I typically run it about 250-350 ma. which gives me a peak about 300 watts out. You 're correct on the SSB settings. I never operate SSB with it.