Bob, I was monitoring SWR externally, into a dummy load.
I intend to seriously clean all module contacts as well as those within the
radio.
The cause of the problem was indeed the LPF.
I scraped the pins on just the LPF barrel connectors on the 40m module and
the output power was immediately normal.
So now I know what to do. I just have to get in there and do it.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Bob McGraw
- K4TAX
Sent: Wednesday, July 16, 2014 12:21 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Scout has vy low Pwr out on some bands
The radio is oscillating and not on 40M when the output drops to 2W. Thus
the high SWR on a resonant antenna indicates the RF to the antenna is not
near the antenna resonant frequency.
I'd do some serious cleaning and trouble shooting before I put that radio on
the air. The SWR detection circuit is after the Band Pass Filter, thus the
last thing before the antenna connector.
73
Bob, K4TAX
----- Original Message -----
From: "Rick - DJ0IP / NJ0IP" <Rick@DJ0IP.de>
To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Sent: Tuesday, July 15, 2014 9:39 AM
Subject: [TenTec] Scout has vy low Pwr out on some bands
>I received my new (used) Scout yesterday.
> After a long search, I finally found a power plug and 9A Airpax circuit
> breaker in my junkbox.
> I built a cable with the breaker and am powering it from a 963.
>
> The Scout came with band modules for all bands except 17 & 12.
> There is no NB.
> The RX seems to work fine on all bands.
>
> On two of the bands (160 and 40m), I get very low output power - about 8w
> and 2w.
> On all other bands it easily brings 50+ watts on my cheap watt meter (10%
> accuracy).
>
> I changed modules quite a lot, making tests first on a dummy and then on
> an
> antenna.
> At one point 40m suddenly worked, with full output power.
> I made several 40m SSB QSOs with it.
>
> Later when I plugged the 40m band module back in, the power was again 2w.
> When I get the 2w, the SWR also shoots up. When it was working properly,
> the SWR was good.
>
> I have studied the diagram of the band modules.
> Since the RX seems to work properly, I assume the oscillator and mixer of
> these modules are working OK, as well as the HPF on the 160m module and
> the
> LPF on the 40m module.
>
> The only thing left is the actual Bandpass Filter for the TX. It is
> encapsulated in shielding and I can't really get at it.
> I have re-soldered all connections on the bottom of the PC board but no
> change. Still 2w.
>
> I can't see how it would be anything but the BPF - or am I missing
> something.
>
> Any tips?
>
> 73 - Rick, DJ0IP
> (Nr. Frankfurt am Main)
>
>
>
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>
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