[TenTec] rick's recalcitrant 515

[rick@dj0ip.de]

Joe, are you sure you ordered that Chinese radio from a ham radio source.
Sounds to me like you were on a different kind of web site!  ;-)

73
Rick, DJ0IP

-----Original Message-----
From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Joe
Papworth via TenTec
Sent: Tuesday, September 06, 2016 10:40 PM
To: tentec at contesting.com
Cc: K8mp at aol.com
Subject: Re: [TenTec] rick's recalcitrant 515

Good info Bob. 
I built a Chinese QRP kit from Banggood (what a name! ) about a  year ago.
The kit was under 5 bucks, including shipping, from China and it  actually
works, although the RX leaves a little to be desired.
Regarding Ricks radio, I think you probably nailed it. 
Later, Joe
 
 
In a message dated 9/6/2016 4:03:02 P.M. Eastern Daylight Time,
ajamas.rn at gmail.com writes:

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
>
>
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