[Top] [All Lists]

Re: [Amps] AL 1500 P.O. Meter Function

Subject: Re: [Amps] AL 1500 P.O. Meter Function
From: "Dave Hachadorian" <>
Date: Mon, 5 Oct 2009 02:32:57 -0000
List-post: <">>
I own an Al-1500, and my buddy W7WW has two of them. We have 
found that the wattmeter is extremely sensitive to 
variations in swr or load impedance. It's a great amp 

Dave Hachadorian, K6LL
Yuma, AZ

----- Original Message ----- 
To: <>
Sent: Monday, October 05, 2009 1:49 AM
Subject: [Amps] AL 1500 P.O. Meter Function

>I need some help.  Upon receipt of my new AL 1500 I noticed 
>that the Multi Meter P.O. "Power Output" function indicated 
>1,100 watts output on 40 meters and similar low output 
>readings on 15 meters.  In all cases the load is a Hygain 
>Hytower with VSWR at 1.5"1 or less on the frequencies 
>tested.  After talking to the factory they had UPS pick up 
>the amplifier and it along with the tube were returned to 
>Ameritron.  I was given priority as it is a new unit.  My 
>contact at Ameritron couldn't find anything wrong with the 
>amplifier and promptly returned it to me after asking 
>question regarding my line voltage and whether or not I may 
>have had the ALC connected.  My drop is connected directly 
>to the electrical box, 12 gage wire and the AlC was not 
>connected.  I asked the Technician on more than one 
>occasion regarding the P.O. Multimeter and the accuracy of 
>the Power Output and was assured that it was an accurate 
>indication of power output.
> After receipt of the Amp it behaved exactly as it did when 
> it left my home.  Over the weekend I inserted an 
> additional piece of Coax, RG 8214, approximately 24' long 
> in line with the antenna and the amplifier and got 
> significantly different numbers.  I was driving the 
> amplifier in all cases with a FT 1000mp Mark V Field with 
> 50 watts indicated output power.
> The P.O. Meter now indicated somewhere between 1,500 and 
> 2,200 watts depending on the band.  All were checked with 
> the exception of 160 for which I have no load at this 
> time.
> I also used a scope, TEK 2235 connected to my EWE antenna 
> to monitor the transmitted RF of both the driver and the 
> amplifier.  Using these numbers I extrapolated the gain in 
> decibels, converted it to gain and multiplied the gain by 
> the driver power (50 watts).  Considering the drive, 50 
> watts the results seemed reasonable, if not somewhat 
> optimistic with power outputs approaching 1,500 to 1,800 
> watts.
> My guess is that the power meter in the AL 1500 is really 
> a "Relative Power Output" meter, not a Power Meter.  The 
> power meter reading should not be dependant on where you 
> place the meter in the transmission line, or at least I 
> would not think so.
> I am not complaining about the amplifier, overall, I would 
> make the purchase again, based on cost/benefit.
> My guess is that this is a RF sniffer circuit which is 
> good enough for a tune up process but not what I was 
> expecting.
> If it is truly a watt meter then there is another problem.
> Thanking you in advance for your thoughts.
> Mike,
> _______________________________________________
> Amps mailing list

Amps mailing list

<Prev in Thread] Current Thread [Next in Thread>