March 25th 12, 06:06 AM
posted to rec.radio.amateur.boatanchors
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First recorded activity by RadioBanter: Jul 2006
Posts: 113
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Swamping transmitter input to amp
ND4jS wrote:
I am attempting to amplify a newly acquired multi elmac transmitter with
a henry 2kw. The power of the elmac is too high and i have tried
swamping it with a 50ohm dummy load in parallel with the amp. This
helped but the input is still a little too high. Any suggestions?
On Sat, 24 Mar 2012, Edward Knobloch wrote:
Assuming the linear requires 80W input to produce 1500W,
you need 20W carrier input to the linear in AM mode.
I would replace the 6146 with a 2E26 (same base pin-outs)
and lower the screen voltage in the exciter
for 20W carrier output. Then, no need for an attenuator
and the exciter will run cool. snip
On 3/24/2012 5:56 PM, Peter wrote:
Ummm why not just lower the screen voltage on the existing 6146 ?
Hi,
I think changing to a 2E26 instead of just cranking down the screen
voltage of the original 6146 for 20W output will result
in cleaner modulation. Starving the 6146 that much
for screen voltage may produce a varying load
to the modulator with plate (and screen) modulation applied.
Also, less risk of over-driving and possibly damaging
the tubes in the linear if the 2E26 is installed.
(A 2E26 costs about $4 new.) Cheap insurance.
73,
Ed Knobloch
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