Where can I buy a ready built synstesised 1-30 Mhz vfo ???

wrote:
Where can I buy a ready built synstesised 1-30 Mhz vfo ???

------------------
This is an NG for radio amateurs who are interested in building their
own equipment including equipment from kits NOT for buying ready
built equipment.
Conclusion : Wrong NG for you.
Advice to you : Do a Google

Frank GM0CSZ / KN6WH

On Fri, 01 Jun 2007 23:33:25 +0100, Highland Ham wrote in :
wrote:
Where can I buy a ready built synstesised 1-30 Mhz vfo ???

------------------
This is an NG for radio amateurs who are interested in building their
own equipment including equipment from kits NOT for buying ready
built equipment.
Conclusion : Wrong NG for you.
Advice to you : Do a Google

I'll differ with you, OM.

He may want to build something that, except for the DDS VFO, is entirely
within his capabilities. If he's homebrewing something less complex, and
finds the VFO to exceed his skillset (as it might exceed mine), his query
is entirely on-topic.

,

Don't let the grouches turn you off to homebrewing. They're everywhere.
Sometimes -- particularly when my back's bothering me -- I'm one of 'em,
but I try not to be.

--
Mike Andrews, W5EGO

Tired old sysadmin

On Fri, 01 Jun 2007 23:33:25 +0100, Highland Ham
wrote:

wrote:
Where can I buy a ready built synstesised 1-30 Mhz vfo ???

------------------
This is an NG for radio amateurs who are interested in building their
own equipment including equipment from kits NOT for buying ready
built equipment.
Conclusion : Wrong NG for you.
Advice to you : Do a Google

If someone wants to experiment with a high (power)level mixer, I do
not understand, why that person would have to suffer all the problems
of generating a stable specific frequency.

In fact getting a good frequency source cheaply might in fact be a
good thing to encourage people to do some home brewing.

Paul OH3LWR

In message , Highland Ham
writes
wrote:
Where can I buy a ready built synstesised 1-30 Mhz vfo ???

------------------
This is an NG for radio amateurs who are interested in building their
own equipment including equipment from kits NOT for buying ready
built equipment.
Conclusion : Wrong NG for you.
Advice to you : Do a Google

Frank GM0CSZ / KN6WH


You'll be telling him next to make his own resistors and capacitors!
Ian.
--

On Fri, 01 Jun 2007 23:33:25 +0100, Highland Ham
wrote:

wrote:
Where can I buy a ready built synstesised 1-30 Mhz vfo ???

------------------
This is an NG for radio amateurs who are interested in building their
own equipment including equipment from kits NOT for buying ready
built equipment.
Conclusion : Wrong NG for you.
Advice to you : Do a Google

Frank GM0CSZ / KN6WH
I would also like to have such a device on my workbench.
I will Google it.
I really hate it when I get half way through a HB project and find out
I could have acquired one for cheap!

John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"

Personally, I'd experiment with the AD9951 DDS chip, it's spurious
outputs are very low....

http://www.radioamatore.it/i0cg/add9951.html

However, if somebody wants a DDS for direct conversion experiments, the
AD9854 DDS has built in quadrature outputs which make it tempting. This
website discusses a complete design and, the kit can be gotten from Kanga.

It is pricy, but in my opinion, it has everything I would need.....

http://home.comcast.net/~aa0zz/index.html

The only drawback is that it's spurious outputs are higher.


Jim Pennell
N6BIU


--

10:59 Pacific Time Zone
Jun 2 2007

International Time
17:59 UTC
02.06.2007

There are dozens of kits ... the combination FCC1/FCC2 from Norcal is one,
AA0ZZ's has been mentioned as another. Kanga has a board called the PIC-EL
II that will accept AmQRP's DDS-60 daughtercard and in conjunction with
software available from AA0ZZ's website will do the same, plus, it has the
PIC programmer on board, so you can play with various versions of the
software. All 3 end up costing about the same. FAR Circuits has a board
for the old WB2V model which works reasonably well and ends up considerably
cheaper.

If you are concerned about soldering the AD985x chip, there are dozens of
folks who do that for a small fee. In fact, if you graze the QRP lists you
will discover that there are probably hundreds of folks who love to build
kits so much that they are floating in them, and a looking satisfy their
addiction by building kits for other people so their XYLs won't scream at
the increasing pile of unused electronic gear.

The PIC-EL path is probably the most conducive to experimentation, but the
most poorly packaged if your intent is to include it in one of your
projects. AA0ZZ's has I-Q outputs if you are interested in exploring SDR.
The FAR Circuits board of course includes none of the parts, the Norcal kit
is lacking the expensive parts (switches, connectors, etc.)

Already built choices do seem fairly lean.

...

wrote in message
ups.com...
Where can I buy a ready built synstesised 1-30 Mhz vfo ???

Jim wrote:

Personally, I'd experiment with the AD9951 DDS chip, it's spurious
outputs are very low....

http://www.radioamatore.it/i0cg/add9951.html

However, if somebody wants a DDS for direct conversion experiments, the
AD9854 DDS has built in quadrature outputs which make it tempting. This
website discusses a complete design and, the kit can be gotten from Kanga.

It is pricy, but in my opinion, it has everything I would need.....

http://home.comcast.net/~aa0zz/index.html

The only drawback is that it's spurious outputs are higher.


Jim Pennell
N6BIU



If you want quadrature LO signals, and you are operating below half (or
ideally below quarter) of the DDS maximum output frequency, then you might
find that the best approach is to use the cleanest DDS chip that you can
find with a single output, then filter that to remove the harmonics, DAC
images etc. and then square it up with a LVDS receiver or comparator, and
divide by 2 or 4 using the flipflops of the divider to generate quadrature.
The challenging part would be ensuring that propagation delays don't spoil
the quadrature, but it probably wouldn't be any harder than making two
matched re-construction filters to use with an I-Q DDS chip. The fact that
you end up with quadrature square waves rather than quadrature sine waves
is a good thing (not a disadvantage at all) with most kinds of mixer.

Chris

On Jun 1, 6:33 pm, Highland Ham
wrote:
wrote:
Where can I buy a ready built synstesised 1-30 Mhz vfo ???

------------------
This is an NG for radio amateurs who are interested in building their
own equipment including equipment from kits NOT for buying ready
built equipment.

Well, a VFO is not a complete piece of equipment. It's something that
might be integrated into any number of different devices. Yeah, you
could hook one straight to an antenna and make a QRP transmitter, but
he didn't ask for a QRP transmitter, he asked for a VFO.

Saying that buying a VFO module is not in the spirit of homebrewing
may be right for the old-timers who used to make their own resistors
by baking carbon and build their own capacitors from mica sheet they
dug up in their backyard. Yes, I've met folks like that. But they're
remarkably rare.

Even getting away from the issues of lots of homebrewers being
uncomfortable with laying out a SMT DDS synth, doing a very well-done
temperature compensated LC tuned VFO is something that requires
considerable skill. In fact I've done both and found the DDS route to
be easier, if less satisfying in the end!

Even manufacturers of major reputation often buy their VFO's and
canned crystal oscillators from other sources.

Tim.