On 12/12/2016 10:01 AM, Michelle wrote:
I have converted a Drake L4B to 6 meters and I seem to be stuck at
> 750 watts output, I have tried a PI input (no change) , different
> tank coils (less output), The current setup listed below I have
> checked both input and output with a antenna analyzer at 50.125 and
> they both seem to be right on spec. Thanks in advance for your
> comments.
Plate volt 2300 under load
plate current .650
Grid 220
Drive 100 watts
Output 750 watts
Input circuit T match (works as it should, flat match)
Plate cap 3-30 pf vacuum variable
Load cap 25-350 pf (original Drake plate cap) 1/3 meshed at max output.
Tank circuit PI-L, L1 3 1/2 turns 1/4" copper tubing 1 1/2" id, L2 4 turns
> 16 gauge 1" id.
RF choke 42 turns of 22 gauge on 1" porcelain form
Bifilar choke Stock Drake 20 turns each leg of 10 gauge on 5/8 ferrite rod
All grid pins directly grounded to chassis
Parasitic suppressors are 47 ohm 2 watt with 1 turn 16 gauge
T/R relay changed to vacuum relays
What am I missing here? Has to be something really simple I'm overlooking,
Thanks again for your comments,
You don't say your modulation mode. (CW - FM or SSB whatever that is)
I'm no expert, but you are achieving 50% efficiency, that doesn't
sound bad to me for 6 meters, to get more power out you need more
power in.
I would double the plate Voltage.
That increases your gain and output power capability. <-- changed
--
Ron KA4INM - Youvan's corollary:
Every action results in unwanted side effects.
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