[600MRG] Fwd: Re: Testing new Transmit downconverter

[Dave]

I also have the KX3 and initially it wasn't even stable enough for 40m wspr,
see 

http://g4fre.blogspot.com/2012/07/kx3-on-qrss.html

At one point Elecraft,  as you say were looking at locking to an external
reference but its very hard to do that with the SI570DDS so they went for a
calibration table correction lookup procedure on there web site that needs a
fridge and a hairdrier

http://g4fre.blogspot.com/2012/12/why-is-kx3-in-fridge-and-whats.html

after I did this the kx3 its stable enough for wspr and qrss decodes on 40m
so it should be good enough for LF

Dave

Ww2r, g4fre

-----Original Message-----
From: Edward R Cole [mailto:kl7uw at acsalaska.net] 
Sent: Friday, April 26, 2013 2:33 AM
To: Dave; 'pat bunn'; 600MRG at w7ekb.com
Subject: Re: [600MRG] Fwd: Re: Testing new Transmit downconverter

Dave,

This is the mixing approach I favor as one can utilize high precision 
10-MHz references as the LO.  However the IF radio has to be capable 
of transmitting on 10.470-10.480 MHz.  This is outside the amateur 
30m band.  The K3 is able to run there with no issue, but might be 
challenging for other radios (without modification).

I have the K3's little brother, the KX3.  But it is not as versatile 
and also does not exhibit as good frequency stability.  I understand 
an external reference ckt is under consideration at Elecraft which 
may fix that.  Still one might have to design a transverter that 
utilizes a standard ham band as IF.  This may require finding an 
adequate oven controlled oscillator to provide a super-stable LO.  A 
TCXO at 3.0 MHz with 0.5-ppm might suffice (3000 kHz x 0.5 E-6 = 1.5-Hz).

73, Ed - KL7UW

At 04:50 PM 4/25/2013, Dave wrote:
>I built a true transverter (ie tx and rx converter) for 474.2khz in my uk
>station and I have been very pleased with it
>
>I use the k3 as the IF at 30m and use the K3 10MHz reference as the local
>oscillator
>
>I did use it for a while with a good 10MHz oscillator as the LO and still
>got decodes
>
>To reduce the size of the LF station I have used the FT817 as the IF on
30m,
>but mine definitely needed the onboard histab oscillator to get reliable
>decodes
>
>Dave
>
>Ww2r, g4fre
>