EMRFD Message Archive 5937
Message Date From Subject 5937 2011-03-21 17:58:38 kilocycles Custom crystals
Ted, KX4OM6284 2011-05-14 12:00:26 rcbuckiii Custom crystals
I only need 2 crystals for 2 different frequencies and 1 of another frequency. I wonder if the low quantity will make them $50 crystals. Or will the price range be a more reasonable $15-$20?
I realize they have setup costs involved. But I do not know the process for manufacturing crystals. Possilbly it is a computer controlled process where they just enter numbers for etching times so setup is minimal. Or it may be more involved than that.
I've considered using programmable oscillators similar to the Epson SG-8002 but the noise figures look too bad to be used as a local oscillator.
Ray
AB7HE6285 2011-05-14 12:07:15 bobtbobbo Re: Custom crystals 6286 2011-05-14 12:16:32 w4zcb Re: Custom crystals
specific overtone operation) adds 5-6 bucks to the tab.
W4ZCB
----- Original Message -----
6287 2011-05-14 12:19:31 bobtbobbo Re: Custom crystals 6288 2011-05-14 14:22:09 dave Re: Custom crystals
that's good to 160 MHz. Phase noise is good, though not as good as a fixed crystal.
Dave - WB6DHW
<http://wb6dhw.com>
6289 2011-05-14 14:34:29 Tim Re: Custom crystals
Not quite custom but many "common" ham radio frequencies are stocked and sold by AF4K for reasonable prices e.g. $14 at http://www.af4k.com/567MHz_crystals.htm
Otherwise most of us are picking through the microprocessor/standard crystals in the Mouser/Digikey catalogs and designing the rig around those frequencies for IF etc.
6290 2011-05-14 15:03:19 n7net Re: Custom crystals 6291 2011-05-15 08:36:41 rcbuckiii Re: Custom crystals
Dave, I've thought about playing with the Si598 before but have not had much luck in finding a distributor to the part.
Ray
AB7HE
6294 2011-05-15 10:02:55 AD7ZU Re: Custom crystals
finding a distributor to the part.
Silic6296 2011-05-15 11:47:01 dave Re: Custom crystals
You can buy Si598 from the Silab web site. I ordered 10 for the club build.
Took about a month to get them.
Dave - WB6DHW
<http://wb6dhw.com>
6297 2011-05-15 12:01:12 dave Re: Custom crystals
Sadly, Silabs no longer provides free samples of the Si598 or the Si570.
That happened shortly after I started selling the UHFSDR, which is based on a
grade A Si570! You can buy samples starting from the page you referenced.
You can get free samples of the non-programmable oscillators. We got free
samples of the Si595 and the Si550 for our BFO's.
Dave - WB6DHW
<http://wb6dhw.com>
6298 2011-05-15 13:52:09 AD7ZU Re: Custom crystals
I wanted one each Si514/Si570/Si598 to eval for a project i was working. but had
not ordered.
Randy
________________________________
6299 2011-05-15 20:32:44 Darrell Bellerive Re: Custom crystals
www.westcrystal.com
Not sure what their current prices are, but they were reasonable a few
years ago when we ordered them.
Darrell Bellerive
Amateur Radio Station VA7TO
6301 2011-05-16 04:02:43 drmail377 Re: Custom crystals
www.km5h.com
His newer site:
http://km5h.softrockradio.org/
If you want to experiment with the Si570, I suggest you read the latest data sheet carefully (www.silabs.com). I also suggest you use a micro-controller development environment that supports double-precision out of the box (unless you want to write your own extended precision routines!) If memory serves, for sub-Hertz control you need be able to calculate the value of a 38-bit register.
There's a nice working example of a USB Si570 controller in the ATMEL ATtiny85 8-bit 8-pin based controller for the latest Softrock Ensemble-II SDR's. The documentation, binaries and source code is available on Fred's (PE0FKO) web site. This software includes the Si570 "slow tune" algorithm.
http://home.ict.nl/~fredkrom/pe0fko/SR-V9-Si570/
If you need to program the ATtiny, go to ATMEL's web site and download AVR Studio (free, not crippled, Windows, not open-source) and buy yourself and ATMEL AVR Dragon programmer/debugger. Don't buy an el-cheapo AVR programmer from the likes of Adafruit Industries! These crummy programmers can't program the fuse bits on the AVR's, that means you can't program (or reprogram) the ATtiny85. The AVR Dragon is $50 - well worth it, trust me!
The schematic for the Ensemble-II SDR's is available on Robby's (WB5RVZ) Builder's Notes site. The ATtiny85 controlled Si570 in the latest Softrock SDR has isolation from the USB port (finally). This helps ensure a single grounding point, which eliminates ground loops which often result in spikes in the center of the SDR bandpass.
http://www.wb5rvz.com/
There is another USB Si570 controller that is similar to the one for the Softrock SDR's (the source code may be the basis of Fred's code - I'm not sure though). But last time I looked, this one did not have USB isolation. I think these are also sold through Tom's (KM5H) Web site (link above).
http://www.sdr-kits.net/
If you dig around on this site you can find a little application to change the Si570's frequency in Windows. I think this application works with Fred's firmware too.
I think you're better off building a stand-alone version of the Softrock Ensemble-II Si570 circuit with Fred's latest firmware.
Dave Brainerd (WB6DHW, who has replied in this thread) may still have a nice Si570 breakout board for sale that you can use with your own Si570 controller design. Check his site.
www.wb6DHW.com
73's, David WB4ONA