[Lowfer] ZL1BPU DDS exciter

Mon Feb 23 23:18:23 EST 2009

I think the biggest problem was getting a slow enough PC to prog the
Atmel device - I ended up using an old IBM parallel port running Win
95..wonder where that is?

I did get some corruption in the registers from induced RF noise from my
transmitting array but I was dealing with 10's of Volts per meter at 137
kHz from a loop running nearly 40/50A of current and a 1.25kW tx just a
few metres away  http://www.kl1x.com/shack.jpg ; I sorted this out by
improving the filtering to the DC 12V  to the unit and adding common
mode chokes suitable for LF on the control ports. In standalone mode it
ran for weeks by itself with no issues resending the same format.

I think the only other problem is going to be how to program the sucker
seeing as I haven't powered it up/seen it in over 3 years...  I ran the
DDS and 1W 4426 PA thru a 137kHz LPF (just in case) and that drive the
Decca Transmitter directly
http://homepage.ntlworld.com/mike.dennison/index/lf/decca/transmitter.ht
m  (thanks Mike)

Laurence BY3A-KL 1 X, Tianjin China

Aka x WD2XDW and now   WE2XPQ...Wasilla AK

-----Original Message-----
From: lowfer-bounces at mailman.qth.net
[mailto:lowfer-bounces at mailman.qth.net] On Behalf Of Andy - KU4XR
Sent: Tuesday, February 24, 2009 10:36 AM
To: Discussion of the Lowfer (US, European,& UK) and MedFer bands
Subject: Re: [Lowfer] ZL1BPU DDS exciter

--- On Mon, 2/23/09, Charles W5COV <cvest at cox.net> wrote:

> The Futurlec development board would make a simple approach to it 
> and not have to do all of the point to point wiring . 
> I have one here , that I have never taken the time to build up .

Thanks for the reply Charlie; That's my next biggest question.
Lyle spoke of " adding to " or " modifying " the board with additional
components. And your term " taken the time to build up " Once I get
that little circuit board full of parts out of its box; I'm gonna
be standing there looking at it and saying " now what ? " I'm pretty
much convinced I'm ordering the board, and any other computer related
parts will probably be on hand or at Radio Shack.

> Once programmed with mode , ID , frequency , it is stand alone . 
> Just  have to hook it back up to the computer to make changes to
> these parameters 

OK; that answered those questions, so ; I've already made progress.

I appreciate your input. 73 for now:::

Andy - KU4XR - EM75xr - Friendsville, TN.
LOWfer Beacon " XR " @ 184.322 KHz ( QRSS-60 )
Coordinates:  N:  35* 43' 54" - W:  84* 3' 16"
http://www.myspace.com/beaconxr

--- On Mon, 2/23/09, Charles W5COV <cvest at cox.net> wrote:

> From: Charles W5COV <cvest at cox.net>
> Subject: Re: [Lowfer] ZL1BPU DDS exciter
> To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands"
<lowfer at mailman.qth.net>
> Date: Monday, February 23, 2009, 9:15 PM
> Andy , Peter ,
> 
>    When Lyle and I first contacted Murray about this , Lyle
> bought enough 
> parts for I think it was 10 "kits" . He sold them
> almost immediately .
>    Several of us built them and I am not aware of anyone
> that had a problem 
> with getting them up and running . Well actually I think I
> made a couple of 
> stupid mistakes.
>    The people I was in contact with , used the 12.8 MHz .
> TCXO . That is I 
> believe the single most expensive part . Even at that some
> of us were able 
> to obtain those at no cost from a list member , Stewart ,
> when I built a 
> second one . Mine were built with point to point wiring .
>    It might seem a bit intimidating just reading the page ,
> but really is 
> pretty user friendly , once you get to the point of
> programming it .
>    The Futurlec development board would make a simple
> approach to it and not 
> have to do all of the point to point wiring . I think Dex
> used the Futurlec 
> board and I have one here , that I have never taken the
> time to build up .
>    As far as spare parts , I keep a spare AT90S2313 on hand
> and the usual 
> spares used in the classic K0LR amplifier . I ended up
> using that instead of 
> the original design by Murray .
>    There is a world of wealth and knowledge on this list
> and I am quite sure 
> between everyone there is enough patience and technical
> ability to help you 
> out of any problems that you might encounter .
>    Once programmed with mode , ID , frequency , it is stand
> alone . Just 
> have to hook it back up to the computer to make changes to
> these parameters 
> .
> 
> Charlie , W5COV , WE2XXO
> 
> CV , 185.2983 kHz . , QRSS60 , 24 / 7 , EM26ex , OK. 
> 
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