Specifications

by LNXAUTHOR on February 8, 2005 Mail this to a friend!
- who uses ALC anyway?
:-)
- seriously, tks for the article...
RE: ALC Adjustment Procedure
by NO9E on February 8, 2005 Mail this to a friend!
Overdriving an amplifier by a cheap transceiver INCREASES readability. Here it is why.
Cheap radios have AF processor, which is not terribly useful. A radio with speech processor off has an average power of
only 5% of peak power, a miserable 5W out of 100W. By contrast, an expensive radio with RF processor can have an
average power up to 40%, or 8 times higher. With cheap radios, the manufactures allow for deliberate
overdriving at some
stages so that the average power increases to 10-15% at low splatter levels. One can achieve even more by overdriving
an amplifier to have RF processing at the QRO level. Then the average power can increase perhaps to 30%, of which
perhaps 5% will be splatter but the rest 25% would be RF-processed power.
Many users of cheap radios noticed that overdriving helps them make that DX... (while driving everyone else nuts).
RE: ALC Adjustment Procedure
by NO9E on February 8, 2005 Mail this to a friend!
Overdriving an amplifier by a cheap transceiver INCREASES readability. Here it is why.
Cheap radios have AF processor, which is not terribly useful. A radio with speech processor off has an average power of
only 5% of peak power, a miserable 5W out of 100W. By contrast, an expensive radio with RF processor can have an
average power up to 40%, or 8 times higher. With ch
eap radios, the manufactures allow for deliberate overdriving at some
stages so that the average power increases to 10-15% at low splatter levels. One can achieve even more by overdriving
an amplifier to have RF processing at the QRO level. Then the average power can increase perhaps to 30%, of which
perhaps 5% will be splatter but the rest 25% would be RF-processed power.
Many users of cheap radios noticed that overdriving helps them make that DX... (while driving everyone else nuts).
ALC Adjustmen
t Procedure
by WA2JJH on February 8, 2005 Mail this to a friend!
ALC, A MUST, for on the air anyway.
I got my 600W all solid state (4 mrf-150) up to 200W out with 4 W in.
Next jump is 400W as soon as cooling fans are in. Then the rated 600W
I have found that mil rigs wll otimise the ALC for better peak power with less distortion.
I built a -12V supply for the ALC back to the driver rig. I am going to use a summing op amp.
Alc will be a function of SWR, heatsink temp, amd a simple demod of the SSB envelope circuit. Excessive peaks will be
summed into the op amp.
Yup I know a CPU is a nicer way to go. However I think my 4 parameter methode by simply summing error voltages will
work just fine.
I have decided not to fold back power until I have greater than 2:1 swr.
Many times ALC can act as a type of RF speech compression.
The original kenwwod Ts-520 DX switch simply reduced the delay and attack time of the ALC to the 12by7a driver tube.
The result was clean but punchier sounding TX audio.