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Ameritron AL-811 ALC Question
I have a question for anyone who owns an Ameritron AL-811 amplifier.
I have connected the Relay and ALC connections to my rig and the amplifer works great except for the ALC protection. I have confirmed for 100% certain the radio is connected correctly. When attempting to adjust the ALC limit on the rear of the amplifier as suggested in the manual I am not noticing any effect on the rig. I have driven the amplifier up to to 85W, and still do not notice and reduction of power on the radio as indicated in the manual. Perhaps I am missing something, but my understanding was when the power into the Amp was over 70W and the rear ALC control was adjusted the voltage from the Amp should kick in and power down the radio to avoid distortion. Any assistance would be greatly appreciated. Even if someone knows which is MAX and MIN on the back panel ALC adj., that would be helpful (i.e. clockwise or counter clockwise). Thank-you... Lloyd |
#2
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I think you may be a bit confused about ALC, or I don't understand your
terminology. In my world, "power down the radio" means it would be turned off. ALC, when properly adjusted, is a control voltage that should limit the power output of the transceiver to prevent overdriving and damaging the amplifier. For Amplifiers that have relatively low drive needs for full output, it can be helpful in extending the life of the tubes, as compared to the reduced life effect of driving them beyond their dissipation rating. I used to have an ameritron 811H (four tube version) and no longer have the manual, but if I remember correctly, the setting method was to transmit a known signal level into the amplifier and adjust the ALC control on the amp until the power output of the amplifier dropped (just barely), thus setting the level for protection. After it was properly set, cranking up the power output on the transceiver had little effect when the amplifier was not in standby mode. A caveat though: Even though implementing ALC is a relatively good idea, it is generally better to have really good operating habits and watch the levels, rather than relying on the Amp to protect itself. I know there is always the possibility of making a bonehead move (I'm sure we've all made one now and then) but good operating habits first are the best defense against overdriving an amplifier. Thanks --Rick AH7H wrote: I have a question for anyone who owns an Ameritron AL-811 amplifier. I have connected the Relay and ALC connections to my rig and the amplifer works great except for the ALC protection. I have confirmed for 100% certain the radio is connected correctly. When attempting to adjust the ALC limit on the rear of the amplifier as suggested in the manual I am not noticing any effect on the rig. I have driven the amplifier up to to 85W, and still do not notice and reduction of power on the radio as indicated in the manual. Perhaps I am missing something, but my understanding was when the power into the Amp was over 70W and the rear ALC control was adjusted the voltage from the Amp should kick in and power down the radio to avoid distortion. Any assistance would be greatly appreciated. Even if someone knows which is MAX and MIN on the back panel ALC adj., that would be helpful (i.e. clockwise or counter clockwise). Thank-you... Lloyd |
#3
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Hello Rick,
Your assessment matches the manual, however if you have any specifics on the adjustment that would be helpful. (When I said power down the radio I did mean decrease the output power on the radio). Do you need to drive the amplifer with 70W+ or will the ALC control work with 30W drive from the radio? I followed that same process, however did not notice the "drop" in power on the amp or tranceiver when adjusting the ALC adjustment on the back of the AL-811. Thank-you Lloyd |
#4
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What transceiver are you using? Is the polarity of the ALC voltage
compatible with your transceiver? I use an AL-80B. It has an ALC range of 0 to -10 vdc. My ICOM has a max ALC of -4 vdc. I set the AL-80B for -4 vdc at max setting. Then I adjusted the ALC SET on the front panel to activate at approximately 70 watts of drive. The point I'm making is that two adjustments were required. First set MAX ALC voltage, followed by setting ALC SET threshold. wrote: Hello Rick, Your assessment matches the manual, however if you have any specifics on the adjustment that would be helpful. (When I said power down the radio I did mean decrease the output power on the radio). Do you need to drive the amplifer with 70W+ or will the ALC control work with 30W drive from the radio? I followed that same process, however did not notice the "drop" in power on the amp or tranceiver when adjusting the ALC adjustment on the back of the AL-811. Thank-you Lloyd |
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#7
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When attempting to adjust the ALC limit on the rear of the amplifier as suggested in the manual I am not noticing any effect on the rig. I have driven the amplifier up to to 85W, and still do not notice and reduction of power on the radio as indicated in the manual. I have an external power meter between my rig and the Ameritron Amplifer and have noticed the power output of the rig is less with the amp on. If I follow the normal tune up procedure using about five watts of drive then increase in increments, I can get the max output at about 45 to 50 watts. I cannot get the rig output more than 55 to 60 watts with the amp ON. Is this normal? Dick AA5VU |
#8
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Dick, AA5VU wrote:
When attempting to adjust the ALC limit on the rear of the amplifier as suggested in the manual I am not noticing any effect on the rig. I have driven the amplifier up to to 85W, and still do not notice and reduction of power on the radio as indicated in the manual. I have an external power meter between my rig and the Ameritron Amplifer and have noticed the power output of the rig is less with the amp on. If I follow the normal tune up procedure using about five watts of drive then increase in increments, I can get the max output at about 45 to 50 watts. I cannot get the rig output more than 55 to 60 watts with the amp ON. Is this normal? Dick AA5VU Either your ALC is working or the VSWR is too high! If VSWR is too high someone may have 'fiddled' with the input tuning to the amplifier. |
#9
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Try it on several bands. It may be the ALC is set a tad too high and it is
limiting the transceivers output just as it should. In which case readjust the ALC. It may also be bad tuned input tanks and/or a bad tube(s). My AL-80B had high vswr on 15/17M tuned input b ut the problem was a soft 3-500Z. Fortunately it was covered under warranty. I made a night light out of the old tube. See here... 1. http://deepsouthnet.net/images/3-500Z-NiteLite.jpg -- Charlie-AD5TH www.ad5th.com "Dick, AA5VU" wrote in message ... When attempting to adjust the ALC limit on the rear of the amplifier as suggested in the manual I am not noticing any effect on the rig. I have driven the amplifier up to to 85W, and still do not notice and reduction of power on the radio as indicated in the manual. I have an external power meter between my rig and the Ameritron Amplifer and have noticed the power output of the rig is less with the amp on. If I follow the normal tune up procedure using about five watts of drive then increase in increments, I can get the max output at about 45 to 50 watts. I cannot get the rig output more than 55 to 60 watts with the amp ON. Is this normal? Dick AA5VU |
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