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

[John Langridge]

Hey Pat - sorry to hear about your experience.  The one I built based on  the 
G3XBM-design driving the GW3UEP amp worked flawlessly through the  2012/2013 
season and continues to function pretty stable even using a  3.2 rock for an 
LO.  


For CW I use a homebrew VFO and separate  amp but could use the transverter with 
good success.  I just hate  dealing with the offset that the radio automatically 
applies to the  carrier freq which is why I prefer the home brew VFO.

John  Molnar's board is very unique in that it has an option for and out board  
10 MHz GPS locked LO instead of the crystal.  That is something I will  look at 
going forward.  The board seems to do well and is good value for  someone who 
may be new to putting kits together and wants to get on  the band.  I give it a 
thumbs up so far and I am doing some tweeking  this morning to make sure I got 
the toroids wound properly.  My original  downconverter does not use toroids but 
had equal adjustments that had  to be made to make sure I was getting max power 
and best wave form.. Too  bad we can't just wind them and put them in HI!

thanks for the  comments.  SO far I like what I see on the board XKA designed.  
Its  certainly much easier than the dad bug design I used for the original  box!

73 and looking for you in the noise!

John /NJD/XIQ



________________________________
From: pat bunn <pbunn at patbunn.com>
To: 600MRG at w7ekb.com
Sent: Thu, April 25, 2013 8:58:08 AM
Subject: [600MRG] Fwd: Re:  Testing new Transmit downconverter




-------- Original Message --------
Subject:     Re: [600MRG] Testing new Transmit downconverter
Date:     Thu, 25 Apr 2013 09:45:53 -0400
From:     pat bunn <pbunn at patbunn.com>
To:     John Langridge <jlangridge at sbcglobal.net>



My experience with transmitting down converters is not all that good -
actually bad. They are easy to make from scratch, but the problem is
with stability in the transmitter or transceiver. I found my IC718 to be
worthless for WSPR, especially WSPR-15 even at 1 watt output due to
thermal heating causing significant frequency drift. I think Dex also
had the same problem with a newer ICOM tranceiver.  The IC718 set at one
watt out got physically hot to touch after a 15 minute WSPR transmission
and was impossible to decode by Dex,  80 miles away( a very strong
signal) due to drift

They are probably fine for CW, but for long QRSS or other long transmit
modes, you are likely to be disappointed.

After testing several different methods to stabilize the transceiver, I
bought a used HP signal generator to generate my transmit signal to feed
the class D Amps. I have this GPS disciplined and am very happy with
this solution.


Pat
WG2XCT
N4LTA






On 4/24/2013 8:47 PM, John Langridge wrote:
> First of all, let me say thanks to all of the stations that continue to listen
> and transmit on 630m as the days seem to get longer at an alarming rate and
> noise keeps going up.  The last month has been brutal here in NTX but the last
> few nights have shown some improvements.  Thanks again!
>
> Tonight I am testing a new transmit down converter developed and kitted by 
John
> Molnar, WA3ETD/WG2XKA.  The kit is pretty sweet, with a minimum of parts and
> appears to be capable of producing close to 20 watts using an IRF510 at 13.6v
> and around 2 amps.
>
> SO far I really like what I am seeing.  Anyway, I will be testing it tonight 
>but
> plan on letting it run in some capacity over night, whether as exciter only or
> driving the amp, I have not yet decided.
>
> 73 and again, thanks for listening!
>
> John KB5NJD/WG2XIQ
> _______________________________________________
> 600MRG mailing list
> 600MRG at w7ekb.com
> http://w7ekb.com/mailman/listinfo/600mrg_w7ekb.com
>



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