The DX Zone has a huge list of SWR meters.
But, it does not list my favorite, Autek WM-1 which has dual meters (not cross
eyed) and peak hold, too.I have had no trouble with my 3 units, but u do have
to be careful with the coax 13vdc power plug from unit to unit because
occasionally they will reverse the + on the plug------between unit
versionsAlso, the maker is grumpy. I ordered my third one from Autek and asked
for a 220VAC wall wart. They sent the 115VAC one and said forget ur special
request.
Things u want on a SWR meter-read true power regardless of SWR-remote sensor
unit so your big coax does not drag the meter off the table.-dual meters-peak
reading option.-Off switch.-range switch like 20 w, 200w, and 2000watt choices.
Happy Metering, 73
Charles Harpole
k4vud@hotmail.com
> From: lists@subich.com
> To: mhughes149@verizon.net; amps@contesting.com
> Date: Mon, 5 Oct 2009 00:26:35 -0400
> Subject: Re: [Amps] AL 1500 P.O. Meter Function
>
>
>
> Based on the schematic of the amplifier, the PO function is
> not a wattmeter but a simple capacitive voltage divider and
> rectifier on the RF output. A circuit like that has no
> directivity and is easily confused by reflected power and
> common mode currents on the feedline.
>
> If you are concerned about accurate power measurements,
> get a good wattmeter and use it in a matched circuit -
> SWR = 1:1 - and use common mode chokes between the meter
> and antenna. A capacitive voltage divider/rectifier will
> only provide accurate readings with no reflected power to
> "boost" or "buck" the voltage in the line. For example,
> if the SWR is 2:1, "power" calculated by using a voltage
> measurement can range from 25% to 400% of the actual
> power depending on the distance to/from the antenna (load).
>
> 73,
>
> ... Joe, W4TV
>
>
>
> > -----Original Message-----
> > From: amps-bounces@contesting.com
> > [mailto:amps-bounces@contesting.com] On Behalf Of MICHAEL HUGHES
> > Sent: Sunday, October 04, 2009 9:50 PM
> > To: amps@contesting.com
> > 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,
> >
> > KE9AG
> >
> >
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
>
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