[TowerTalk] TH7-DX 15M problem

[Michael Murphy]

Build a 15 meter dipole and try loading it.  Should tell the story if the
amp is really the issue.

On Thu, Aug 27, 2015 at 10:35 AM, David Robbins <k1ttt at verizon.net> wrote:

> a different antenna, like I think you said a 40m V, might not reflect
> harmonics as well as the traps on a yagi would.
>
>
> Aug 27, 2015 10:02:03 AM, kzerohb at gmail.com wrote:
>
> Don't have a second amp, but the amp plays just fine on a different
> antenna.
>
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> __73, de Hans, K0HB
>
> "Just a Boy and His Radio"™
>
> On Thu, Aug 27, 2015 at 8:51 AM, john at kk9a.com wrote:
>
> > Trying a different amp could rule it out.
> > John KK9A
> > To: "'Ham - Tower Talk'"
> > Subject: Re: [TowerTalk] TH7-DX 15M problem
> > From: "David Robbins"
> > Date: Thu, 27 Aug 2015 11:19:54 +0000
> > No, running the amp into a dummy load won't rule out the amp. A high swr
> > like
> > that caused by the amp is because the amp starts detuning and generates
> > harmonics, it’s the harmonics that would be reflected causing the high
> > reverse
> > power. Running into a dummy load would likely not show that unless there
> > were
> > a good lowpass filter in between to reject them.
> > David Robbins K1TTT
> > -----Original Message-----
> > From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
> Robert
> > Harmon
> > Sent: Wednesday, August 26, 2015 21:32
> > To: Ham - Tower Talk
> > Subject: Re: [TowerTalk] TH7-DX 15M problem
> > Hans,
> > I would have suspected the 15 meter traps too.
> > I would start doing the process of elimination to narrow down the
> culprit.
> > Disconnect the coax feeding the TH7 in the shack and put a coax jumper
> to a
> > dummy load and run the amp full bore on 15 and see if the SWR stays ok.
> > I know you think the amp is OK, but this will rule it out.
> > Then reconnect the TH7 coax and go up to the TH7 and disconnect the coax
> from
> > the TH7 connection terminals. Connect the coax to the dummy load again.
> > Back to the shack, load it up on 15 again and see what happens. If you
> still
> > have the swr anomoly, then you have ruled out the amp and the feedline.
> > It is in the antenna.
> > I had a similar problem with a KLM KT34XA one time and went thru this,
> then
> > lowered the antenna down to sawhorses in the back yard and cleaned, and
> > reconnected every element connection point and found a connection to one
> > of the
> > linear loading tubes that was squirrely. Put the antenna back up and all
> was
> > good.
> > Bob
> > K6UJ
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-- 
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*Michael Murphy - KI8R*

mike at ki8r.com

www.ki8r.com

*614-371-8265 (cell)*

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