Hi Jonathan,
Wattmeters are most accurate at their designed input and output impedance
(50 ohms for our communications stuff). Even a BIRD is not accurate for
forward power when a high SWR is present.
Also make sure the 40M dipole is not interacting with the 15M portion of you
TH-7. If it is mounted close to the TH-7 and in the same plane you may
experience some interaction on 15M as the 40M dipole is 3/4 wavelength on
15M. Many hams avoid these interactions by mounting the 40M dipole 90
degrees off of the 15M yagi (40M element parallel to the TH-7 boom).
73, Dan Magro W7RF, (President WARC 1999, member SCDXC, SCCC)
Manufacturers Rep & Distributor for HENRY RF Power Amplifiers.
www.radiodan.com <http://www.radiodan.com> ??? RFpower@radiodan.com
<mailto:RFpower@radiodan.com> A trip to our web site is worth the click!
> -----Original Message-----
> From: owner-amps@contesting.com [mailto:owner-amps@contesting.com]On
> Behalf Of Jonathan Kaplan
> Sent: Thursday, September 09, 1999 6:52 AM
> To: Amps@contesting.com
> Subject: [AMPS] Have Cake & Eat it too
>
>
>
> Hi All,
> I've been slowly putting on line my tower installation with a
> TH7DX and a M2 40 mtr dipole atop a 55ft crankup. I've noticed
> a strange behavior since switching from a tuned dipole. My
> Clipperton L amp will tune either for power or SWR on all bands
> but 15mtrs, but not for both. In other words, when I tune the AMP
> the power meter (a RS model) will either show greater power at
> a high SWR or low power at low SWR. But not high power at low
> SWR! What does this mean is wrong? Does it neccessarily
> mean the final output into the air is limited, and that the antenna
> system is out of tune?
>
> I just need confirmation of that theory and how to test it.
>
> Thanks for any help.
> 73
> Jonathan KO6XS
>
>
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