[AMRadio] dds information


Brett gazdzinski Brett.gazdzinski at mci.com
Fri Jul 16 21:50:15 EDT 2004


Far circuits web site has a number of circuit boards for kits that
do 1.8 to 20 MHz, dds and other type vfo's...

Used to be a company making kits for a dds vfo on the qrp sites, but I think
they went out
of business.

I don't think its hard to build a good analog vfo, even using tubes.
My homebrew receiver LO seems very stable, and has a digital readout.
After a few minutes, it seems really stable, more stable than it needs to be
for AM anyway...

I have a PTO assembly out of a T368 that would work well with the digital
display.
The digital display makes it easy to build, as you don't have to worry about
any sort of dial, or dial calibration.
The display reads the exact frequency of the vfo..

 
Brett
N2DTS




-----Original Message-----
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net] On Behalf Of Brian Carling
Sent: Friday, July 16, 2004 6:16 PM
To: Discussion of AM Radio
Subject: RE: [AMRadio] dds information


How do you get one programmed to cover a wider range of frequencies than
just 
one band?

I would like to get one that would generate from 1.8 to 12 MHz

I already have an AD9850 chip here.

On 16 Jul 2004 at 13:52, Jim candela wrote:

> Bill,
> 
>  Below is the scoop on the WA1FFL version. His email address is listed  
> there at the top. Sure would be nice to have some clean sounding AM 
> rigs on the air that are also not drifting! This might be perfect for 
> a Class E solid state rig, as well as some boat-anchors.
> 
> This unit will also power up at the minimum frequency like Don was 
> saying about his unit. A more sophisticated micro-controller, or 
> computer interface is needed for more "bells and whistles". For me, a 
> plain-Jane DDS VFO is my goal.
> 
> Regards,
> Jim
> 
> 
> -----Original Message-----
> From: James Hagerty [mailto:jim at buddytone.com]
> Sent: Tuesday, May 25, 2004 7:57 PM
> To: Candela, Jim
> Subject: Re: Compact DDS VFO Information Request
> 
> 
> I still have plenty of boards and parts. Nice to hear from a new 
> reader. My "kit" is a partial one with the hard-to-get components 
> only. A programmed microprocessor is included. Note: R1, R8, and R9 
> are 1/4 watt, not 1/2 watt as stated in the parts list. Parts Kit
> Information: To make the VFO as affordable and simple as possible to 
> build, I am offering a partial parts kit that includes the following:
>      1. High-quality, commercial-grade p.c. board with the AD9835 DDS 
> surface-mount chip already soldered on (professionally done, not by
> me!)
>      2. Output op amp (AD811AN)
>      3. Microprocessor programmed for your band of choice, including
>      socket.
> This kit is available for a cost of $35.00 plus $5.00 shipping and 
> handling (overseas orders add $2.00, with payment with a bank check 
> for U.S.Dollars). The bands available as of today are:
>      a. 3.5-4.0 MHz.
>      b. 7.0-7.5 MHz.
>      c. 5.5-5.0 MHz. (reverse tuning for local-oscillator operation); 
> 5.0-5.5 MHz. also available
>      d. 10.0-10.5 MHz.
>      e. 14.0-14.5 MHz.
>       f.  1.8-2.3 MHz (160 meters +)
> The display reads 000.000-500.000 kHz  for all of these band choices.
> I also just finished a VFO with a 1 or a 10 MHz. tuning span (up to
> 14.5 MHz). I also have a 2 MHz span version.
> 
> ***I strongly advise using some filtering at the output of the VFO. If 
> you do not have a copy of the W7ZOI/K5IRK receiver article (which 
> contains some very nice lowpass/bandpass filter info) I can supply a 
> copy of the filter design data.I also have a CQ article by Doug DeMaw 
> regarding the use of solid-state VFOs with older vacuum-tube rigs, 
> which may be of interest to you. ***In addition to the above, I am 
> offering limited quantities of the following: Industrial-grade, 
> p.c.-mount BNC connectors for $7.00 each (made by Trompeter) and I 
> have one shaft encoder for $22.00.  All of the other parts are 
> available from sources like Digi-Key,  Mouser
> Electronics, and All-Electronics. The latter has very nice surplus
> displays for under $10.00. Anything by Optrex or Varitronix should
> work.
>      My parts kit has only the premium parts which builders would have
> trouble getting in small quantities.  Selling the kit this way saves
> the builder a lot by giving him the flexibility for choosing displays
> and enclosures, output connectors, using junk box parts, etc. and it
> prevents me from having to stock several thousand dollars worth of
> parts.
> 
> ***Please make all checks out to: James Hagerty.
>      My address is: 64 Nonquit Lane, Tiverton, R.I. 02878, U.S.A. I am
>      also including a short assembly and applications ideas guide
>      along
> with the premium parts kit. It's about 3 pages. I have built 6 boards 
> and I had no trouble whatsoever getting any of them working.
>       73, Jim   WA1FFL
> 
> 
> -----Original Message-----
> From: amradio-bounces at mailman.qth.net 
> [mailto:amradio-bounces at mailman.qth.net]On Behalf Of BILL WINTER
> Sent: Friday, July 16, 2004 1:09 PM
> To: amradio
> Subject: [AMRadio] dds information
> 
> 
> where can one obtain pre-programed cpu chips for either (or both) the 
> wa1ffl or the kg6cyn dds devices? I can handle everything else. Bill 
> ______________________________________________________________ AMRadio 
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