Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Adjusting ALC for ALS 600  (Read 8670 times)
WASVE7BDJ
Member

Posts: 2




Ignore
« on: June 23, 2010, 09:46:21 AM »

Greetings to the group, this is my first post.

I read in these pages, but can' t now find it again, a comment by a ham that the ALS 600 manual is badly written where it comes to explaining how to set up the ALC.

There is a potentiometer on the back that first has to be set while driving the amp to about 400 watts, and then there is the business of setting the front panel ALC set knob after that.

I don't know if it's my difficulty setting this up properly, or if it's just that I'm driving the amp too hard on SSB -- but I've caused it to go into auto-shut off mode almost every time I've used it (5 or 6 times).

Can anyone explain the procedure more straightfowardly please?

Thanks in adavance,

Brenton
VE6IE (who used to be VE7BDJ)
Logged
K0BG
Member

Posts: 9883


WWW

Ignore
« Reply #1 on: June 23, 2010, 01:36:31 PM »

ALC or no ALC, you're driving it too hard. It requires just about 60 watts to drive it to full output. If the ALC isn't hooked up, and/or  adjusted correctly, you'll eventually cause the input swamping resistor (35 ohms) to increase in value. Sooner or later, that will cause the finals to fail.

And you're correct, the manual isn't very specific about the adjustment. If you have a peak reading wattmeter you can put between them, the adjustment is a little easier. You want the ALC to cut back the power (nominal 100 watts PEP) to about 60 watts PEP.
Logged

AD5X
Member

Posts: 1436




Ignore
« Reply #2 on: June 23, 2010, 02:22:09 PM »

Hi Brenton - I don't use ALC with my ALS-600.  I drive the amp with about 60 watts, which drives the ALS-600 to close to full output.  I wonder what transceiver you're driving the amplifier with?  Some transceivers output a high-power pulse that occurs for a fraction of a second until the transceiver's ALC circuit throttles the power back to what you want it to be.  This initial high power pulse can trip out the amplifier.  This is definately a problem with the ICOM IC-706MKII/MKIIG (I have both and have verified this).  If your transciever puts out a high power pulse regardless of the output setting, you can get around this by leaving your transceiver set to full output, and then put an attenuator in line to limit the transceivers power to what is necessary for the amplifier (info on how I did this at www.ad5x.com).

Again, I don't use ALC.  But if you do, here's the procedure:

With the ALC cable connected, adjust the ALC set knob on front of the amplifier fully clockwise and the ALC limit control on the back of the amplifier fully counter-clockwise as viewed from the rear.  Key your transceiver and apply enough drive until the amplifier's power meter reads 400-500 watts.   Now turn the front panel ALC set knob fully counter-clockwise.  Key amplifier with RF applied and adjust the ALC limit control on the back of amplifier until the ALC light on the front of the amplifier just comes on.  This sets the max ALC voltage necessary for your transceiver.  Now your ALC/power adjustments can be made with the ALC Set control on the front of the amplifier. 

For SSB Operation, first set the ALC SET control fully clockwise.  While using normal modulation, increase your transceiver’s output power until the desired amplifier peak output power occurs.  The "ALC SET" control should then be adjusted until the amplifier's RF output power just begins to drop.

Phil - AD5X
Logged
WASVE7BDJ
Member

Posts: 2




Ignore
« Reply #3 on: June 24, 2010, 07:14:38 PM »

Gentlemen,

Thank you for your replies. And Phil, that explained procedure pulls together parts of the (poorly written, poorly organized) manual in a coherent way. I think I'll be able to follow that after I've had a few minutes to relax!

I'm driving the Ameritron with a Drake TR 7, and while I'm trying to crank down the mic level to keep it below 60 watts, every time the amp shuts down it's on an audio peak. I just did it again, a few minutes ago.

I did get a Daiwa swr-power meter, and it's selectable for reading either peak or  average, but it reads way way way low. Like, it tells me 20 watts is coming out of the Drake when the power meter on the Ameritron reads 80 to 100. I thought something was wrong with my Drake, at first.

At least swr looks a more accurate reading.
Logged
W5WDV
Member

Posts: 17




Ignore
« Reply #4 on: March 19, 2011, 01:14:24 PM »

Phil,

You mentioned the ALC setting for SSB operation whereas you start with the ALC set control fully clockwise then with normal modulation adjust exciter drive until the power just begins to drop.

Forgive me but I have tried this many times and have difficult time finding the "drop" point. I'm using a true peak reading meter.... Is the drop obvious? There is a place where it does a rapid drop with a steady (relatively) voice tone. Is this the drop I should be looking for? On air gets great audio reports but ther is no ALC LED activity at this setting. Should the LED be responding at this level?
Thanks, I'm becoming obsessive with my ALC!

Bill
Logged
AD5X
Member

Posts: 1436




Ignore
« Reply #5 on: March 19, 2011, 04:45:43 PM »

Bill - It just occurred to me.  I bet you're using the switching power supply on 120VAC.  Is this the case?  The switcher has an input current sense that shuts the power supply off at just a bit over 15 amps.  The problem is that the amp draws very close to 15 amps at 120VAC.  However, on 120VAC you can get voltage drop in your AC wiring.  So if the AC voltage drops, the switcher draws more current which can exceed the switcher trip point.  You don't have this problem with the linear power supply.  It is unregulated, draws more like 13 amps at 120VAC, and doesn't have an input AC current sense than can trip it off.  I had this problemm and solved it by going with 240VAC.

For the SSB ALC setting, just go ahead and the ALC in CW.  That's the easiest way.  I don't use ALC as I said before.  And if your TR7 doesn't have a power control, you might look at the in-line attenuator I have on my website at www.ad5x.com that I've been using with my ALS-600.  You don't need ALC, and you can leave your transceiver set for full power all the time.

Phil - AD5X

Logged
N1ZHE
Member

Posts: 68




Ignore
« Reply #6 on: March 20, 2011, 05:04:29 AM »

Phil,

I read some are having trouble with the amp faulting on the voice peaks. They seem to feel it has to do with the switching power supply because when they switch to the non-switching power supply the problem seems to cease. Would this be more likely to be ALC related?

I have a dedicated 240 volt 20 amp line into my shack.

What is the difference between the ALS-600 with the switching power supply and the one without the switching power supply? Would the switching power supply model be better or can I just save the extra bucks and get the non-switching model?

David, N1ZHE


Logged
W5WDV
Member

Posts: 17




Ignore
« Reply #7 on: March 20, 2011, 09:43:01 AM »

Phil, ( and others)
Thanks for the timely response. I had thought about the voltage drop but I'm using the linear power supply so I dismissed my thought knowing it was unregulated. I also watched the current/voltage meter on the PS while adjusting and while it made me crossed eyed, there was no voltage drop so when the RF deck meter has that slight drop, I noticed that I can turn back clockwise with the ALC set control and the power goes back up. If I go past that "drop" point, turning counter clockwise, the power reading goes back up. It is an obvious "dip" in reading which is probably 2-3 watts in reality. So... Is this the real drop in power that I would be seeing on a scope?

After the last effort setting of the ALC, I got on the air and found a station that recorded the signal and actually was quite pleasing in audio quality so that's the good news.

Below is a breakdown of equipment followed by current settings.

Icom IC-7000
Icom IC-20 mic
ALS-600 linear PS
LDG AT-1000pro auto tuner (use it manually)
G5RV 102' configured as inverted vee, apex at 28' drooping to 8' on the ends.

Exciter is now set for 60 watts drive, I can control output through menus
Tuner does a great job fooling the 7k and amp into believing it's a 50ohm load. Working well on all  80-10 meters.

Station is getting out worldwide, last 100 contacts or so after adding the ALS-600 have been effortless, which is a huge improvement, much more than I expected. Breaks pile-ups like I never believed I could!

I'm showing about 400-450 with the 60 watts of drive, a little flickering of the ALC LED with the setting on 5. More LED activity When I set the control on 3 to 3.5.

With the results I'm having, I don't really feel I need to run it any harder as it won't make a
difference anyway on the receive end.

Since running some power is new to me, and we know the G5RV isn't exactly a desirable load, I'm concerned I might blow it up. This paranoid condition is due to the amps wattmeter being off by about 100-150 watts compared to the tuner wattmeter. The above ouput numbers are coming off the tuner meter which is peak reading. I did switch to average just to see if the output would drop and as expected, meter swings were 30-70% lower which in theroy should be about right.

On the other hand, I have settled on 60 watts or less for excitation, I ran it up to 80 and could easily reach 600+ on the tuner meter,  800+ on the amp's meter and got scared!

Again, just concerned about over driving the amp.

Bill - W5WDV
« Last Edit: March 20, 2011, 09:48:15 AM by W5WDV » Logged
W5WDV
Member

Posts: 17




Ignore
« Reply #8 on: March 20, 2011, 10:07:54 AM »

David,

I had also read about the switching power supply causing faults in some operations and decided that the weight difference didn't matter to me as I prefer a linear supply over a switcher anyway. That being said, I have several switchers and they work well I just didn't want a serious load being supplied with one. If you can lift it, why not save a $100 and draw less from the wall in operation too!

I'm learning all about this amp, will be happy to share my experience if you want. So far, am thrilled with the performance. So much so, I bought a second one to use on my portable operation at the ranch. While you are shopping, it's easy to fall for the EVEN MORE is better but for once in my purchasing equipment history, I bought what was reasonable performance at a reasonable price and could not be happier. I've got a good group of operators and we compare on-air power from barefoot to full legal and while the true QRO stations have a different perceived signal, it's not necessarily better in quality in my humble opinion. In my old age, unless it's an emergency call, if the station sounds like it's about to explode, I'd rather not answer the call. Kinda wish more hams would listen to their stations...... SSB isn't supposed to sound like a jet aircraft landing in the background! Maybe they should look up what linear actually means, but then those that sound like that probably don't sound good when they don't run power!!

73's, good luck on your quest for an amp.

Bill - W5WDV
Logged
W5WDV
Member

Posts: 17




Ignore
« Reply #9 on: March 20, 2011, 04:54:51 PM »

Phil,

I may have stumbled on the cause of my confusion..... If the ALC is limiting exciter drive output, why does the LED activate LESS when you turn the front panel ALC set control clockwise i.e. (as I understand) increasing the amplifier output level?

It seems reversed too me. When I get the most flicker, I am reducing power. I thought the flicker was actually indicating a level of RF compression while the power was being increased. Am I crazy or did I totally miss something?

More clarification.... Blinks heavy from 3.5 down to 1, and the output is being reduced on all wattmeters. Progressively less blinking from 4.75 up to 5.5 with no blink above that that point all the way to 10, and the output is increasing on all wattmeters.

Bill
Logged
KE3WD
Member

Posts: 5689




Ignore
« Reply #10 on: March 20, 2011, 06:44:09 PM »

You are perceiving the action of the ALC backwards. 

The LED comes on when the ALC action kicks in. 

ALC is not compression, it is more like a servo circuit that limits the output power at a certain threshold inside the exciter. 

73
Logged
W5WDV
Member

Posts: 17




Ignore
« Reply #11 on: March 21, 2011, 06:32:59 AM »

I may have miss spoke calling it "compression". When reading the ALS600 manual, a reference is made to the "desired amount of ALC compression" while adjusting for SSB. If anything, typing out the process in this thread is making it a little more clear, Thanks for the motivation!

Bill
« Last Edit: March 21, 2011, 06:43:09 AM by W5WDV » Logged
W5WDV
Member

Posts: 17




Ignore
« Reply #12 on: March 21, 2011, 07:02:21 AM »

To all who are trying to follow the original instruction from Ameritron on the ALS-600 amplifier:

I finally got throughout and spoke to John who was gracious enough to email the following revised method of setting the ALC.


1. Set radio to FM, RTTY, or CW.
2. Set radio power output to 100W
3. From the point of view of the back of the amplifier, turn the ALC knob on the rear panel fully counter clockwise.
4. Set the knob on the front panel to 0.
5. Make sure the amplifier power is on and in STANDBY.
6. Connect a dummy load to the amplifier or make sure the antenna is tuned in properly.
7. Put amplifier in OPERATE and key up.  NOTE : the amplifier should be putting out close to 0 watts.
8. While keyed up, turn the knob on the back panel until the yellow light ALC light just barely starts to flicker.  NOTE : at this point, the amplifier is now calibrated to the radio and should be putting out approximately 100 watts.
9. Slowly turn the knob on the front panel until the output power reaches approximately 500 watts.

If you have struggled withe the original method, you will notice that this set of instructions actually contradicts a few steps. One of which is actually reversed! Which is why my results were the opposite result of what I was expecting. Amazing, I'm not crazy after all!

This was copied and pasted from the original email sent this date so even though you may have a late manufactured amp, (mine was built in 02-2011) this instruction sheet was not included. Good luck, hopefully this will put the confusion to rest.

73's

Bill - W5WDV


******IMPORTANT UPDATE******
seems Ameritron forgot 1 step with the latest instructions!

10. After completing the above 9 steps, turn the drive DOWN on the exciter or your signal will flattop. I reduced to 35 watts of drive on the Icom 7000 and was still putting out 500 peak clean watts in SSB. Good amplifier, poor instructions. once I dropped the drive down, had a mini pile up with stations telling me how good it sounded vs the flat topped signal.

Adding this step actually puts me back where I started but since it sounds good and clean, I'm done with it.

Good luck to all and remember turn all knobs left until you figure it out!

Bill - W5WDV
« Last Edit: March 21, 2011, 03:12:46 PM by W5WDV » Logged
K4AX
Member

Posts: 34




Ignore
« Reply #13 on: June 02, 2014, 08:16:35 PM »

I just got to say THANK YOU for posting this.  First time in several years I've actually had the ALC on this amp working decently. Though I generally just drive it with 45 watts.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!