Yeah, I run about 600-700 on FT8 from time to time and I have assumed that I'm getting the plates to glow a little but I can't see inside the L7. I've got graphite anodes on mine so it may not show as well, anyway...
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
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On Tuesday, March 5th, 2024 at 2:39 PM, Jim Shorney <jimNU0C@...> wrote:
I've run my amps at a kilowatt out on CW (with SSB plate voltage of course) with no issues. Digital modes, well, depends on your TX time. Short contest bursts you could probably do at 1 KW. They will tolerate FT8 at not more than 700 Watts, and in fact that is a good way of getting red in the plates of classic 3-500s to activate the getter material. Back in the pre-FT days I used to run JT65 at about the same level.
W8JI has some great articles on amps at his web site, if you haven't been there yet.
73
-Jim
NU0C
On Tue, 5 Mar 2024 19:21:55 +0000 (UTC)
"amfone via groups.io" amfone20000@... wrote:
Thanks Jim for your input. I purchased my first L7 new in 1978, for years even on SSB I ran in the low voltage tune mode, only lately have I used the SSB mode when using that mode only, I always tune in the CW position or LV mode, then I will peak the amp as Drake notes using a watt meter.
I normally tune for about 500 watts on the meter, this is below of course the ratings for the tube noted by Drake in the manual. If I run AM phone with the amp using a modern rig I will have a carrier output of not more that 125 watts, running digital, mostly Olivia, when I use the amp I will run about 110 watts, all in the LV/CW position or position on the amp.
Running at the lower voltage will raise the grid current a little but you just need to keep an eye on it.
73 and thanks again.
Tim
WB8UHZ
On Tuesday, March 5, 2024 at 02:06:44 PM EST, Jim Shorney jimnu0c@... wrote:
No, NOT everyone is saying this. Always use CW mode when powering up and during initial tune up when changing bands. After that, do final tuning to the maximum power level that you expect to operate. Note that some advise to always tune up to the full 1200-ish watts output to mitigate possible "accidents" that can be damaging to the amp.
73
-Jim
NU0C
On Tue, 5 Mar 2024 14:29:15 +0000 (UTC)
"amfone via groups.io" amfone20000@... wrote:
Let me make sure I have this correct. I have two L7's and one L4B. Am I right that everyone is stating to tune these amps in the SSB position and just leave the amp in the SSB position all the time?
Also what about running digital modes I use the tune position for that but perhaps I should be using the SSB position. Please advise on both situations and many thanks.
73 Tim
WB8UHZ
On Tuesday, March 5, 2024 at 08:19:02 AM EST, John K5MO johnk5mo@... wrote:
That is a particularly nice implementation. I'll do this when I get my L7 out of service.
Great writeup too.
John K5MO
--
73
-Jim
NU0C
