[TenTec] rick's recalcitrant 515

[Katz Ajamas]

Sorry Joe-

We'll have to wait for Rick to get back to his bench to know if it's a good
guess.

Here's how I arrived at the guess.

80 bad 40 OK suggests that the LSB line is not 'stuck'. Toggling it to
change 80 but not 40 while still providing reverse sense is difficult to
figure out, never mind having a reason to, so not likely.

Recalling that older rigs tune backwards on 80 to save a crystal and
passband filter prompts a look at how the 515 mixer is tickled on 80.

Seeing a common inductor and the same value trim cap for each bands LO
passband filter was the AhHah!(If 5-5.5 can be peaked for 20, it can be
peaked for 80!)

I'll not post the travails of making a Chinese "Octopus" 40m(7023kHz)
transceiver work. It is supposed to give 8W out and was about 1/2W before I
fried the final. So far I've spend almost $100 on doodads to help me
diagnose a problem with a $12 kit :-). Mentally, it's got me to the point
of gicing serious consideration to purchasing a VNA.

More relevant to Tentec as it's for antenna and filter work is which VNA to
get.

I've narrowed it down to. MFJ225 $289, minVNAPRO $490, MiniVNAPRO clone
$330, MinVNATiny$590, MiniVNATiny clone $425, VNWA3-E $600.

The Pro or Pro clone looks to be the most versatile a it has bluetooth and
can hang from an antenna. It's supposed to have 90dB dynamic range to
170MHz.
The MFJ is similar but has a built in display, no bluetooth, and about 70dB
dynamic range.

Has anyone used the miniVNAPRO with bluetooth in the manner of dangling
from an antenna feed with the antenna at it's final resting place? I can't
imagine things getting much better.

73, -Bob ah7i/w4





On Tue, Sep 6, 2016 at 12:00 PM, <tentec-request at contesting.com> wrote:

>
>
> ------------------------------
>
> Message: 8
> Date: Tue, 6 Sep 2016 07:21:28 -0400
> From: k8mp at aol.com
> To: tentec at contesting.com
> Subject: Re: [TenTec] rick's recalcitrant 515
> Message-ID: <156ff3b3ce2-22ca-e70a at webprd-m69.mail.aol.com>
> Content-Type: text/plain; charset=utf-8
>
> I was dismayed to read Bob's email because I figured it probably meant an
> end to The Great 515 Mystery. Shucks!
>
> Joe, K8MP
>
>