EMRFD Message Archive 5553

Message Date From Subject
5553 2010-12-24 10:32:29 Chris Trask WTB: VCXO
I'm looking around for a couple of voltage-controlled crystal
oscillators (VCXO) for a project that I'm bringing to a conclusion. No
specific frequency, though some even frequency of 10MHz or below would be
nice. Specific requirements are 5V, TTL output, metal DIP package, and a
mechanical tuning adjustment would be a plus.


Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE
http://www.home.earthlink.net/~christrask/
5554 2010-12-24 21:43:51 Ashhar Farhan Re: WTB: VCXO
why not try the si570? one can use them as generic building blocks. i
recently ordered a whole bunch. they have a power-on frequency of around 10
Mhz.

- farhan

5556 2010-12-24 23:54:03 Juan Carlos Berbe... Re: WTB: VCXO
Hi Fellows
Where Can I get a good price for the Si570
I am planning to send it to Cuba to work into de SDR
73's
Jc

2010/12/25 Ashhar Farhan <farhanbox@gmail.com>

> why not try the si570? one can use them as generic building blocks. i
> recently ordered a whole bunch. they have a power-on frequency of around 10
> Mhz.
>
> - farhan
>
>
5558 2010-12-25 00:17:37 ae5ew Re: WTB: VCXO
Mouser: 634-570BAC000304DG USD$21.79 qty 1
Charles AE5EW

5559 2010-12-25 01:14:30 Dave - WB6DHW Re: WTB: VCXO
You can order the exact same part direct from SiLabs on their web site for
$12.02 each quantity 1.

Dave - WB6DHW
<http://wb6dhw.com>

5561 2010-12-25 06:04:57 Chris Trask Re: WTB: VCXO
>
>>
>> I'm looking around for a couple of voltage-controlled crystal
>> oscillators (VCXO) for a project that I'm bringing to a conclusion.
>> No specific frequency, though some even frequency of 10MHz or below
>> would be nice. Specific requirements are 5V, TTL output, metal DIP
>> package, and a mechanical tuning adjustment would be a plus.
>>
>
> why not try the si570? one can use them as generic building blocks.
> i recently ordered a whole bunch. they have a power-on frequency of
> around 10 Mhz.
>

That's an interesting idea, and I'll keep it in mind for later on. For now, I just need something inexpensive and in a DIP through-hole package for a fully working prototype.


Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE
http://www.home.earthlink.net/~christrask/
5562 2010-12-25 06:08:59 Chris Trask Re: WTB: VCXO
>
> You can order the exact same part direct from SiLabs on their
> web site for $12.02 each quantity 1.
>

Anyone have the URL for that?


Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE
http://www.home.earthlink.net/~christrask/
5563 2010-12-25 07:18:05 kb1gmx Re: WTB: VCXO
5564 2010-12-25 07:28:54 aa0zz Re: WTB: VCXO
Je,
I would add a word of caution. There are many varieties of Si570 so you have to be careful to get the right part for your hardware configuration and software as well. Mouser carries only a few varieties at this time. That particular Mouser part number is for an LVDS part with 50 ppm tolerance and a start-up frequency of 167.6667 MHz. The start-up frequency is significant because it is often used by the software to determine the crystal frequency that was measured by the factory. There are many other varieties of Si570 available so you may be better off going directly to the Silicon Labs web site (www.SiliconLabs.com) and working through the menus to get the exact part that you want to use. You can get them in large or small quantities from Silic
5565 2010-12-25 07:29:34 lasse moell Re: WTB: VCXO
5566 2010-12-25 11:47:25 k5nwa Re: WTB: VCXO
Not all these parts are the same, many are
cheaper and have a lot higher jitter
specifications, an undesirably quality in a radio
receiver. Of all the parts I have looked at the
SI570 is by far the best in terms of jitter, .3 ps

At 09:29 AM 12/25/2010, you wrote:
>
>
><http://www.silabs.com/products/clocksoscillators/Pages/BuildPartNumber.aspx>http://www.silabs.com/products/clocksoscillators/Pages/BuildPartNumber.aspx
>or...
><http://sdr-kits.net/PAOKLT/PAOKLT.html>http://sdr-kits.net/PAOKLT/PAOKLT.html
>
>/Lasse SM5GLC
>
5567 2010-12-25 13:55:31 Dave - WB6DHW Re: WTB: VCXO
5568 2010-12-25 18:30:14 Tim Re: WTB: VCXO
DIP is definitely passe for VCXO's.

You will see old stock VCXO in DIP on E-bay. But it's easy to get distracted by the cheap rubidium modules (presumably harvested from telco equipment) and end up with those :-). Do not hesitate to check out the Time-Nuts mailing list.

The surface mount 6-pin VCXO packages popular as of late work just fine with a couple of flying leads tacked on. Actually elegant compared to dead bug DIP :-) See e.g. Abrac
5569 2010-12-26 05:39:53 Chris Trask Re: WTB: VCXO
>
>DIP is definitely passe for VCXO's.
>

Better suited for my immediate needs.

>
>You will see old stock VCXO in DIP on E-bay. But it's easy to get distracted by the cheap rubidium modules (presumably harvested from
>telco equipment) and end up with those :-). Do not hesitate to
>check out the Time-Nuts mailing list.
>
>The surface mount 6-pin VCXO packages popular as of late work just
>fine with a couple of flying leads tacked on. Actually elegant
>compared to dead bug DIP :-) See e.g. Abracon ASVV, under $4 a pop
>from Digikey.
>

I found three suitable alternatives on eBay plus one fellow on another list is selling me some 10MHz units that are perfect for this demo.


Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE
http://www.home.earthlink.net/~christrask/
5570 2010-12-26 09:25:35 Chris Trask Re: WTB: VCXO
>
> DIP is definitely passe for VCXO's.
>

I'd like to take the opportunity to make some comments about the
industry trend towards SMT and the outright abandonment of leaded parts.
Yes, SMT is becoming the industry norm, and eventually there will be little
or perhaps no manufacturers producing leaded parts. NXP (née Philips) has
dropped all leaded parts production, and they have been 100% SMT for a few
years now. Manufacturing costs are less for SMT parts, and there is the
obvious size advantage.

For multi-legged critters like DSP, LPGA, and uC devices, SMT is all but
mandatory. The last gasp in leaded parts for devices such as this were the
massive 64-pin DIP packages that housed devices like the 6502 and 6800
processors and the MC14151 and MC14152 parallel programmable synthesizers.
There are other examples, of course.

SMT passive components have less in the way of parasitics, especially
the series inductance of resistors. Leaded carbon- and metal-film resistors
are a helix of resistive material deposited and etched on a ceramic form, so
the inductance problem is obvious. Older carbon composition resistors were
not much more than a chunk of carbon rod with metalized ends, and they are
still sought after for wideband RF loads.

Passive SMT devices have distinct advantages over leaded parts at VHF
frequencies and above primarily due to the much lower series inductances.
And they are mandatory when size restrictions are brought into play. Plus
there's the lower manufacturing costs.

However, for proof-of-concept breadboarding and demonstration prototypes
the usage of SMT parts can be a real pain due to the small sizes. I don't
mind using 1206 size parts when I have to make a prototype fit in a small
enclosure using Ivan Board, but when it comes to making breadboards for HF
and lower signal-processing circuitry on vector board I won't even consider
SMT components.

I keep a full stock of 1206, 0603, and 0403 passives as well as a good
quantity of SMT discrete transistors here primarily for my consulting work,
and they do get used fairly often for prototyping small RF circuitry. But
when it comes to making things such as discrete logic DDS circuitry and the
somewhat ambitious signal processing project that I'm now finishing up,
leaded parts are the only reasonable choice. So, I make certain that my
leaded parts inventory is never wanting for common devices such as 1% and 5%
resistors, 1%, 2%, and 5% capacitors, 5% inductors, and scads of TO-5,
TO-18, and TO-92 transistors, as well as plastic DIP opamps, comparators, FM
receivers, and of course HCMOS and CMOS logic. With all of this on hand I
can breadboard almost anything in a day or two.

I spent over a year looking for DIP packaged 12.8MHz TCXOs, and when I
found a source in Britain I bought all that he had, which wasn't very many.
Now I'm putting in a good stock of DIP packaged VCXOs so that I will have
something readily available when the need arises.

So, my advice to die-hard experimenters is to obtain as much as you can,
within the constraints of money and storage space. Even so, you will
undoubtedly run into situations where you will need something that you
hand't anticipated, and when that occurs you go on the warpath and obtain
whatever you can, even if it means digging deeply into the fleamarket junk
boxes and dusty surplus yard shelves and being happy with whatever you come
across.

He who has the most parts readily available is most likely the first to
have something working.

Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE
http://www.home.earthlink.net/~christrask/
5571 2010-12-26 10:40:46 Tim Re: WTB: VCXO
I think you overestimate the difficulty of breadboarding with SMT.

It is not hard at all to carve up a little piece of PCB to handle the SMT parts pretty much as they were designed to be used, and the splaying of leads to use through-hole DIP parts as dead-bug becomes unnecessary because SMT "naturally" comes that way.

Pull out a utility knife and give it a try.

5572 2010-12-26 11:00:26 Chris Trask Re: WTB: VCXO
>
> > However, for proof-of-concept breadboarding and demonstration
prototypes
> > the usage of SMT parts can be a real pain due to the small sizes. I
don't
> > mind using 1206 size parts when I have to make a prototype fit in a
small
> > enclosure using Ivan Board, but when it comes to making breadboards for
HF
> > and lower signal-processing circuitry on vector board I won't even
consider
> > SMT components.
>
> I think you overestimate the difficulty of breadboarding with SMT.
>
> It is not hard at all to carve up a little piece of PCB to handle the SMT
parts
> pretty much as they were designed to be used, and the splaying of leads to
use
> through-hole DIP parts as dead-bug becomes unnecessary because SMT
"naturally"
> comes that way.
>
> Pull out a utility knife and give it a try.
>

It's actually done easier with a Dremel tool and a 5/32" crown cutter.
I buy them by the dozen at a local jewelry findings and tool shop. But, I
go to that level after breadboarding on Ivan Board to be certain that it's
worth pursuing.

Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE
http://www.home.earthlink.net/~christrask/
5573 2010-12-26 11:02:35 Derward Myrick Re: WTB: VCXO
Chris

I agree with you. But I am now 79 years old and have way too many parts
to use the rest of my life. I just looked at a box of var ind that would be in
the VHF range and there were about 45,000 of them. I have resistors and
capacitors in the hundrea of thousands. I am now in the process of making
a selling plan. I have somewher about 1000 down converter boards (bare)
that converted (first conv) from 4Gig to 900 Mhz (low side injection) and a
900 mhz IF amp. The second converter converts from 900 mhz to 70 mhz
(high side injection) and a 70 mhz IF amp. This board can very easy be
cut into parts that will give: 70 MHZ AMP, 910 MHZ OSC, 900 MHZ AMP,
2000 MHZ OSC THAT IS VOLTAGE CONTROL. THIS OSC FEEDS A VOLTAGE
DOUBLING MIXER SO YOU COULD TUNE THE CBAND SATELLITE BAND.
This would be a good board for a hobbiest. I also have a 70 mhz IF bord
with video out. Also have video amp bords, audio detector bords that are tuneable
on the baseband signal(about 5 mhz to 7 mhz) with audio out. I have power
supply boards and ant polarity control an the same board. This is from a
C band home satellite receiver that I designed and built. I had then built in
Mexico and sold the company but Kept Thousands of parts and boards.
I also have a chanell 3 or 4 RF modulator. These are all on plugin boards
but can be used as stand along units. This is a very sensitive receiver. I
was making 1000 units a month when I sold out.

Thees would be very good boards for hobbiest to work with. I have all
the schematics and parts location for these and also have the connectors
that fit the plugin boards. Most all parts are leaded parts.

This I for information for any one that would be intrested.
I am trying to get a list of parts and quanity for when I can star to sell them.

Derward Myrick KD5WWI



----- Original Message -----
5574 2010-12-26 11:45:06 Steve Re: WTB: VCXO
Chris,

A couple of dumb questions if you would be so kind :-)

What is Ivan Board?

Do you know of a picture on the internet of a crown cutter such as you
reference in your note? A web search turned up crown cutters for rifle
barrels but nothing related to jewelers tools. I've used a dremel tool
with those little sandpaper-like discs mounted on the end of the shaft,
the crown cutter might be a better way to go?

Thanks.

Steve K8JQ

5575 2010-12-26 13:31:50 Chris Trask Re: WTB: VCXO
Chris

,----------------------. High Performance Mixers and
/ What's all this \ Amplifiers for RF Communications
/ extinct stuff, anyhow? /
\ _______,--------------' Chris Trask / N7ZWY
_
5576 2010-12-26 14:21:44 kb1gmx Re: WTB: VCXO
5577 2010-12-26 14:51:57 Chris Trask Re: WTB: VCXO
>
> > For multi-legged critters like DSP, LPGA, and uC devices, SMT is all
but
> > mandatory. The last gasp in leaded parts for devices such as this were
the
> > massive 64-pin DIP packages that housed devices like the 6502 and 6800
> > processors and the MC14151 and MC14152 parallel programmable
synthesizers.
> > There are other examples, of course.
> >
>
> None of those ever got over 40 pins 6502 and 6800 and even Z80).
> The 151/2 were smaller and slow enough that better package was
> unimportant.
>

Yep, you're right. Still after 6 cups of coffee I'm not fully awake.
:{)

Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE
http://www.home.earthlink.net/~christrask/
5579 2010-12-26 19:14:12 kb1gmx Re: WTB: VCXO
Hi Chris,

I do embedded work mostly, also RF. When it comes to micros
I think in z80 and 8051 derivatives and oddly had the Moto 14151 synth data sheet out for a project.

Now the 68000 was a real aircraft carrier at 64pins!

With the snow and wind I"m just sitting here reading the net and
and playing with a 2M arrays (4x 6elements)
5581 2010-12-26 21:07:44 Ashhar Farhan Re: WTB: VCXO
allison, chris and others,

first, a merry Christmas to everybody. here in hyderabad india, the
tempuratures have dipped to a 'freezing' 9 centigrade (48 farenheit), which
is really cold by our standards and my dad has got all his wollens out. the
conditions here continue to be bad and a growing tree branch has ripped out
my ladder line, hence, no smoke out of VU2ESE since a month.

on smt, i am one and a half project old. i made a very small amp in
surface-mounted-ugly way, dead bugging the ICs on prototyping PCBs and
soldering the discrete components the regular ugly way. it was about 10
times as difficult and time consuming as the regular ugly way. i guess, i am
just used to 'ugly'. i can wire up a circuit almost as fast as i can draw it
using ms paint (which isn't saying much in any case).

i guess we will all have to just live with the reality of an SMD world.
however, the lego ease of DIP and leaded components will always remain. I
suppose there will always be a market for discrete leaded components, if not
the ICs. which is a relief.

as my own understanding of RF design is limited, i prefer using discrete
components anyway. it keeps things simple, playable and measurable.

- farhan (VU2ESE)

5582 2010-12-27 05:42:15 ae5ew Re: WTB: VCXO
Dang, you have a lot of parts!
Charles AE5EW

5583 2010-12-27 06:50:04 Derward Myrick Re: WTB: VCXO
Charles, You should give me a call some time and come by and see
what I have. You may find a part you want. I am about a mile off I-12
in DS.

Derward Myrick KD5WWI
281-182








----- Original Message -----
5584 2010-12-27 08:33:33 Chris Trask Re: WTB: VCXO
>
>Try Looking here...
>http://www.alltronics.com/cgi-bin/category/38
>

Yes, did look there earlier. Unfortunately, all they say is that they are oscillators with no further details. Also looked in a number of other similar places.

I did find three on eBay that are usable and bought one lot for use with this project before spending any real $$. Also got some gorgeous 10MHz VCTCXOs from Brad Thompson that are ideal except for the frequency, but well worth having. I got some 12.8MHz ones from a seller in Britain earlier for a synthesizer project which is also a part of this receiver project.

I'll probably end up putting leads on an SMT device later, but I can get planty of DIP ones for now. I will probably need 16MHz, 20MHz, or 32MHz for the final design.




Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE
http://www.home.earthlink.net/~christrask/
5586 2010-12-27 13:19:54 ae5ew Re: WTB: VCXO
I took a look at the specs. +/- 95 ppm (approximate) is not exactly precise. My FT-950 is 0.5 ppm.
Charles AE5EW

5587 2010-12-27 13:24:02 w4zcb Re: WTB: VCXO
Yup, but your 950 doesn't go from 10 MHz to 1.4 GHz either.

W4ZCB

I took a look at the specs. +/- 95 ppm (approximate) is not exactly
precise. My FT-950 is 0.5 ppm.
Charles AE5EW

5588 2010-12-27 21:52:02 kb9fko Re: WTB: VCXO
> I'll probably end up putting leads on an SMT device later,

Heh! Whenever I'm looking for a leaded R, L, or C to quickly fix or rig something up at work, I have folks tell me to just solder some leads on. I've been getting this for almost 10 years now. :-)