Linear Amplifier ALC interfacing
Posted: Thu Mar 14, 2019 10:48 pm
Linear Amplifier ALC interfacing
Some Linear Amplifiers require an ALC interface from the Linear to the Transceiver. The Apache rigs do not provide a negative voltage "ALC" interface for Linear Amp equipment. This seems to be especially important for older Tube type Linear Amplifiers.
Have you come across an interface circuit or device that will work with our Apache gear?
Is there a document or discussion somewhere that speaks about the special feature of an Apache TRx that prevents it from OVERSHOOT or OVERDRIVE of a Tube type Linear Amplifier?
Can the new "CESSB" software cause any ALC problem for a Linear Amp?
For example W1AEX says "see a check box for CESSB Overshoot Control" on this webpage:
http://www.w1aex.com/anantxgain/anantxgain.html
https://www.youtube.com/watch?v=l5JmDAaDBVo
[url]anan-100d.wikidot.com/100d-am[/url]
http://anan-100d.wikidot.com/100d-daw
I thought that Warren NR0V wrote about the careful attention he paid to ALC inside the PowerSDR software and Apache firmware:
http://anan-100d.wikidot.com/100d-sp
The PowerSDR Developers are very proud about how you can NOT exceed ALC = 0.0 when driving the Audio chain with MIC or VAC Audio. This certainly is an essential feature for proper operation on digital modes like FT8 or PSK31.
W1AEX has presented some excellent guidance here:
http://www.w1aex.com/anantxgain/anantxgain.html
[Way back in March 2011 K6JCA surprised the Flex community with scope pictures to prove that overshoot destroyed the PA in a Flex-5000:
http://k6jca.blogspot.com/2011/03/tx-overshoot-on-flex-5k.html I assume Flex solved that problem and it has not come back to haunt them.]
Is there any evidence that an Apache rig could cause a overshoot or overdrive of a Linear Amp that is relying on an ALC control voltage to ensure that the Linear operates within it's intended output range?
References:
https://www.w8ji.com/ameritron_alc_adjustment.htm
https://www.qsl.net/dh1dm/alc/
https://www.eham.net/articles/15783
https://www.eham.net/articles/10183
https://www.hamradioandvision.com/how-to-use-an-alc-meter/
thanks for any info, opinions or comments,
72/73 de Ken N9VV
Some Linear Amplifiers require an ALC interface from the Linear to the Transceiver. The Apache rigs do not provide a negative voltage "ALC" interface for Linear Amp equipment. This seems to be especially important for older Tube type Linear Amplifiers.
Have you come across an interface circuit or device that will work with our Apache gear?
Is there a document or discussion somewhere that speaks about the special feature of an Apache TRx that prevents it from OVERSHOOT or OVERDRIVE of a Tube type Linear Amplifier?
Can the new "CESSB" software cause any ALC problem for a Linear Amp?
For example W1AEX says "see a check box for CESSB Overshoot Control" on this webpage:
http://www.w1aex.com/anantxgain/anantxgain.html
https://www.youtube.com/watch?v=l5JmDAaDBVo
[url]anan-100d.wikidot.com/100d-am[/url]
http://anan-100d.wikidot.com/100d-daw
I thought that Warren NR0V wrote about the careful attention he paid to ALC inside the PowerSDR software and Apache firmware:
http://anan-100d.wikidot.com/100d-sp
The PowerSDR Developers are very proud about how you can NOT exceed ALC = 0.0 when driving the Audio chain with MIC or VAC Audio. This certainly is an essential feature for proper operation on digital modes like FT8 or PSK31.
W1AEX has presented some excellent guidance here:
http://www.w1aex.com/anantxgain/anantxgain.html
[Way back in March 2011 K6JCA surprised the Flex community with scope pictures to prove that overshoot destroyed the PA in a Flex-5000:
http://k6jca.blogspot.com/2011/03/tx-overshoot-on-flex-5k.html I assume Flex solved that problem and it has not come back to haunt them.]
Is there any evidence that an Apache rig could cause a overshoot or overdrive of a Linear Amp that is relying on an ALC control voltage to ensure that the Linear operates within it's intended output range?
References:
https://www.w8ji.com/ameritron_alc_adjustment.htm
https://www.qsl.net/dh1dm/alc/
https://www.eham.net/articles/15783
https://www.eham.net/articles/10183
https://www.hamradioandvision.com/how-to-use-an-alc-meter/
thanks for any info, opinions or comments,
72/73 de Ken N9VV