EMRFD Message Archive 4851

Message Date From Subject
4851 2010-08-04 16:17:53 brainerdd XTALs for filter
I am designing a low cost, high performance HF transceiver for the newcomers in our club. I am thinking of using ADE-1 DBM's , an Si570 for LO, and the Hycas for IF.
Does anyone know which of the many crystals from Mouser or DigiKey between 8 and 12 MHz are better for filters. Anyone have part #'s for some they have successfully used?

Dave - WB6DHW
<http://wb6dhw.com>
4852 2010-08-04 16:33:26 Nick Kennedy Re: XTALs for filter
I'm also building a receiver (eventually, transceiver) using the HYCAS.
Currently my crystal filter uses FOX080 8 MHz crystals from Mouser.

I've also purchased and tested some ECS-V 8MHz crystals from Digi-Key that
looked OK.

73-

Nick, WA5BDU


4853 2010-08-04 16:49:49 ajparent1 Re: XTALs for filter
4854 2010-08-04 17:17:37 Paul Daulton Re: XTALs for filter
I am a fan of John Pivininchy's work on filters. I can recommend his
book "Crystal Ladder Filters" by MFJ press. FAR circuits has boards for
Johns article in 73 magazine(1992 Jan I think) titled "Twin Crystal
Filters". Also included in the set is an osc board. John uses xtals in
the shunt configuration for USB filters and in the series mode for LSB
filters. The article used 9.803mhz xtals. I built the filters from the
73 article and still use them in bench models when I am breadboarding a
new project.

I have used 10 mhz xtals with no wwv feed through in my latest
project as well as a Bitx transceiver. AADE has a filter program(freee
download) that is very useful in designing filters.this program had 10
mhz xtals as one of the defaults.

Good luck with your project. Please publish data for the project on
this site.

73 Paul k5wms

Quoting brainerdd
:

I am designing a low cost, high performance HF transceiver for the
newcomers in our club. I am thinking of using ADE-1 DBM's , an Si570
for LO, and the Hycas for IF.
Does anyone know which of the many crystals from Mouser or DigiKey
between 8 and 12 MHz are better for filters. Anyone have part #'s for
some they have successfully used?

Dave - WB6DHW


Paul Daulton K5WMS
beacon WMS 185.302 khz qrss30/slow 24/7
Jacksonville,Ar 72076
em34wu


[Non-text portions of this message have been removed]
4855 2010-08-06 04:41:44 drmail377 Re: XTALs for filter
Hi Dave,

Long reply, but hopefully it contains something of use to you...

A. Crystal Filters

* I don't have specific part numbers for Digikey or Mouser crystals. But for comparison purposes for what follows, typically decent crystals run around $0.25 USD/100 or so (see Mouser P/N 815-ABL-8.192-B2, 8.192MHz, +/-20ppm).

I would buy a bag of 100 pcs or more. You can match the crystals up into sets and toss the outliers. When buying this many pieces, unit price becomes an important factor.

* I once bought a bag of 100 11.0592MHz crystals (a magic frequency, see below for more on this) from AllElectronics dirt cheap, less than a dime a piece including shipping. They worked as good as one can expect for a ladder filter at that frequency.

Deals like these come and go at AllElectronics. As of writing time the deal I got is gone. But today for example they have 9.8304MHz HC49/U (HC18/U) crystals for $0.15 USD each in 100 pcs and up; five for a buck otherwise (CAT# CRY-9830).

www.allelectronics.com

* I have heard of good results when buying crystals by the bag-full off ebaY. Here's an example:

Item no. 110469507346 (Buy-it-now), 100 pcs 8.192MHz HC49, $7.99 + $2.99 shipping by USPS. Comes to $0.11 each.

* Generally, lower frequency IF crystal filters perform better, but there are often advantages to higher frequency IF's (life's a trade-off).

* Choose crystal frequencies that are commonly manufactured. They are typically cheaper and the manufacturing batches are larger so you have a better chance at getting closer-matching parts. Because of RS-232 UART timing reasons, clock crystal "magic" frequencies that are commonly manufactured are often multiples of 300 or divisible by some factor of 2 at common RS-232 baud rates. Frequencies that are a multiple of 2 are quite common too.

4.9152, 5.5296, 6.1440, 7.3728, 8.192 (factor of 2), 9.8304, and 11.0592MHz are some of these magic frequencies. For more on this subject see the section "Oscillator & Magic Quartz Crystal Values" here:

http://en.wikibooks.org/wiki/Serial_Programming/Typical_RS232_Hardware_Configuration

Same link here:

http://bit.ly/aKJdDS

* Diz's KitsandParts site has a crystal filter "RFtoolkits" PCB for $4 USD. He sells pre-matched (+/-10Hz) sets of crystals at 5.0688 or 4.9152 MHz (there are those magic frequencies again) for $1 USD per crystal. You need to supply the the caps for his board. Vary the cap values to change the filter bandwidth.

http://www.kitsandparts.com/xtalfilter.php

For that matter, Diz's RFtoolkits may have all the board kits you need to prototype your whole radio if it is of the stand-alone type. He recently added a DDS VFO Development Kit to the line-up (more on that below with a link).

Look at the Erector RX project by ak2b in the KitsandParts user forum. That project at one point used the Hycas IF board too.

http://www.kitsandparts.com/fluxbb/viewtopic.php?id=16

* Dig around on Jack Smith's (K8ZOA) site for good articles on building a crystal measurement jig and actually measuring crystal motional parameters. Once you know the motional parameters you can simulate your filter easily in LTSpice which is free from Linear technologies. Look at the files area in the LTSpice Yahoo Group for examples of simulated crystal ladder filters. If memory serves Jack has some nice papers on designing ladder filters on his site too.

www.cliftonlaboratories.com

www.linear.com

http://tech.groups.yahoo.com/group/LTspice/

B. Starting points for a DDS or Si570 VFO. Here are some suggestions:

* K5JHF and K5BCQ have an Si570-based Si570 controller kit with shaft encoder and LCD. It is relatively inexpensive. Off-hand I don't know if the firmware is open or closed. It do remember the micro-controller is neither an AVR or a PIC though, but I suspect you should be able to get a copy of the source. If you are fixed on using an Si570 and want a tuning knob and LCD, this may be the best jumping off point. But (and a very big but) I'm not sure if the "Slow-tuning algorithm" is used on this VFO (see more on this below). You may want to enquire about this. If it isn't, then you may want to port Fred's (PE0FKO) code over from the ATtiny Si570 USB controller used with the Softrock radios.

http://www.qsl.net/k5bcq/Kits/Kits.html

Jack Smith reviewed an early version of the KB5BDC/K5JHF Si570 here:

http://www.cliftonlaboratories.com/si570_kit_from_k5bcq.htm

* WA7UFQ has a universal VFO controller with a shaft encoder and LCD that controls both DDS's and the Si570. Off-hand I don't know if the firmware is open or closed.

http://home.roadrunner.com/~wa6ufq/universal_vfo_controller.html

* Look at Diz's above mentioned DDS Development Kit RFtoolkit on the KitsandParts Web site. The firmware is open-source.

http://www.kitsandparts.com/DDS-Dev-Kit.php

There's an active area on the KitsandParts User Forum dedicated to the DDS Development Kit.

http://www.kitsandparts.com/fluxbb/viewforum.php?id=7

* Richard N8YSK sells the DDSV4. This is a "high-end" DDS VFO in my opinion as it is pre-built, uses an AD9859 and has a shaft encoder and LCD. The icing on the cake is that the firware is open-source and the processor is an ATMEL AVR (if memory serves). The firmware is written in BASIC using the BASCOM-AVR compiler; but it is too big to fit into the free version of the compiler. Fortunately the BASCOM-AVR compiler is affordable. Richard's firmware might be a great starting point for adding a shaft encoder and LCD to a DDS using a lower cost AD9834 for-example. You know all there is to know about building DDS boards, I'm sure.

http://www.rmt-tech.com/

* N3ZI sells a nice relatively low cost DDS VFO with shaft encoder and LCD. Alas, the firmware is not open source (I've asked). The kit uses an AD9834:

http://www.pongrance.com/

* Tom KM5H sells single Si570's and the QRP2000 Si570 USB controller (more on this below), see this page:

http://km5h.com/default.aspx

* If you are going to use a PC to control the Si570, you're almost there with your previous work on the Si570 breakout board and the UHF/SDR. All you need to do is add the USB/i2c micro-controller bridge with appropriate firmware.

I would consider using the circuit from the current Softrock Ensemble radios. The Si570 circuit is isolated from USB inexpensively and Fred's (PE0FKO) ATtiny firmware is up-to-date and stable (more on Fred's firmware below). The schematic for the current Softrock Ensemble kits can be found on this site:

http://www.wb5rvz.com

The Softrock Yahoo Group is here:

http://groups.yahoo.com/group/softrock40/

* The QRP2000 USB Si570 controller is available from SDR-Kits. Remember, this controller has no shaft encoder or LCD, it is intended to be used with a PC. The SDR-Kits site has a small application for Windows that will allow you to tune this board or any Si570 controlled with the same protocol (such as a Softrock SDR kit with Fred PE0FKO's ATtiny AVR firmware). This kit does not isolate the Si570 i2c control from USB, so ground loops may occur.

http://www.sdr-kits.net/

* If you are going to use an Si570, no matter how you control it you will likely want to employ the "smooth-tuning algorithm". This prevents the Si570 from starting and stopping as you tune it. But it only works relatively close-in to the current frequency you are tuned to (the latest Si570 data sheet has more on this). Use Fred's (PE0FKO) AVR ATtiny Si570 firmware as an example of how to do this. The source code is open.

http://home.ict.nl/~fredkrom/pe0fko/SR-V9-Si570/

That's all I have. Please share your project with us. Like with your previous projects, I'm sure this will be very interesting. I see this new project is not posted on your Web page or
4856 2010-08-06 05:37:55 Fernando Krouwel Re: XTALs for filter
Hi David, good morning:

I agree with you about using large scale production xtal frequencies for IF filter building purposes.

I have used with very good results the 4.9152MHz IF for 40M in a now classic receiver (2 x NE602, like NORCAL, 40-40, SW-40, etc). This lead us to another advantage: a low freq LO (about 2.1MHz), which assures good stability very easilly.

Please, look at the following link, which refers to a retired english xtal filter kit, that I have not built but appears to be a very fine thing (they also have other interesting circuits):

http://www.cumbriadesigns.co.uk/images/T1%20Filter%20v1.0.pdf

73´s
Fernando - PY2ETT



----- Original Message -----
4857 2010-08-06 09:30:49 drmail377 Re: XTALs for filter
I want to clarify that the N3ZI DDS VFO is quite powerful. Even though the firmware is closed-source, there is a lot you can do/customize via the serial etc. interfaces. I'm quite impressed with the product's capabilities by watching the development and deployment. There is an active Yahoo Group too...

http://www.pongrance.com/

http://groups.yahoo.com/group/N3ZI_kits/messages

This kit is definitely worth a close look.

73's David WB4ONA

4858 2010-08-06 14:06:13 Dave - WB6DHW Re: XTALs for filter
Thanks all for all the responses.
We formed a new club here last August and have licensed 30 new members
since then. SOme have upgraded to General, but can't afford the prices
of new HF transceivers. That's the motive for the design.
Most low cost designs are QRP. While that is fun for some, I think
for a new HF person it would be very frustrating. So, I want 50 to 100
Watts. Since most of the new people are used the VHF, I also think AGC
is a must have. A noise blanker would also be desirable.
I am looking at 2 or 3 approaches. The first is to modifiy my UHFSDR
design and add a 90 degree phase shift network and a audio output amp
and an agc circuit to create a stand a lone design. Also needed are the
pre-driver RF to get up to the 5 watts needed for the ARRL contest 50W amps.
A second approach is a filter design. I have been using an Atlas 180
since buying it new in 1976 and am very satisfied with it. It is a
single conversion with a DBM mixer. It switches the LO between the 2
mixers for transceive. This is also similar to the scheme used on the
TAK-40. They both use an MC1350 for the IF. A couple of changes I'm
considering to the TAK-40(besides the additional filters for the other
bands) would be using an ADE-1 DBM in the front end for better strong
signal capability. The ADE-1 is $2.49 at qty 25. I am also looking at
the Hycas for the IF for, hopefully improved signal handlying and better
AGC action than the MC1350. Any comments on comparisons between the
MC1350 and the Hycas?
I have ordered boards for the Hycas and for the TAK-40 for a test
bed. I also have some R-1 boards to use as a detector after the Hycas,
Si570 boards, and PIC microcontroller boards on hand.
I am looking at using the Si570 for several reasons:
I use them in my UHFSDR.
I sell an Si570 board.
Silicon Labs is very generous with free samples on its website.
I sell a 995x(1 to 4) board and an AD9912 board as well, but the
Si570, even if you have to buy them, is about the price of just a 9951
chip. Analog seems to be no longer giving away free samples of its DDS
chips.
I also ordered 25 of the ADE-1 DBM's, 50 12.288 MHz crystals, 10
SA612's and various other parts. I have an N2PK VNA with a program
that measures the crystal parameters. Also have 2 or 3 filter design
programs that include crystal lattice design.
I normally don't put projects on my "under development" page until i
do a pre-production circuit board.

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

drmail377 wrote:
> Hi Dave,
>
> Long reply, but hopefully it contains something of use to you...
>
> A. Crystal Filters
>
> * I don't have specific part numbers for Digikey or Mouser crystals. But for comparison purposes for what follows, typically decent crystals run around $0.25 USD/100 or so (see Mouser P/N 815-ABL-8.192-B2, 8.192MHz, +/-20ppm).
>
> I would buy a bag of 100 pcs or more. You can match the crystals up into sets and toss the outliers. When buying this many pieces, unit price becomes an important factor.
>
> * I once bought a bag of 100 11.0592MHz crystals (a magic frequency, see below for more on this) from AllElectronics dirt cheap, less than a dime a piece including shipping. They worked as good as one can expect for a ladder filter at that frequency.
>
> Deals like these come and go at AllElectronics. As of writing time the deal I got is gone. But today for example they have 9.8304MHz HC49/U (HC18/U) crystals for $0.15 USD each in 100 pcs and up; five for a buck otherwise (CAT# CRY-9830).
>
> www.allelectronics.com
>
> * I have heard of good results when buying crystals by the bag-full off ebaY. Here's an example:
>
> Item no. 110469507346 (Buy-it-now), 100 pcs 8.192MHz HC49, $7.99 + $2.99 shipping by USPS. Comes to $0.11 each.
>
> * Generally, lower frequency IF crystal filters perform better, but there are often advantages to higher frequency IF's (life's a trade-off).
>
> * Choose crystal frequencies that are commonly manufactured. They are typically cheaper and the manufacturing batches are larger so you have a better chance at getting closer-matching parts. Because of RS-232 UART timing reasons, clock crystal "magic" frequencies that are commonly manufactured are often multiples of 300 or divisible by some factor of 2 at common RS-232 baud rates. Frequencies that are a multiple of 2 are quite common too.
>
> 4.9152, 5.5296, 6.1440, 7.3728, 8.192 (factor of 2), 9.8304, and 11.0592MHz are some of these magic frequencies. For more on this subject see the section "Oscillator & Magic Quartz Crystal Values" here:
>
> http://en.wikibooks.org/wiki/Serial_Programming/Typical_RS232_Hardware_Configuration
>
> Same link here:
>
> http://bit.ly/aKJdDS
>
> * Diz's KitsandParts site has a crystal filter "RFtoolkits" PCB for $4 USD. He sells pre-matched (+/-10Hz) sets of crystals at 5.0688 or 4.9152 MHz (there are those magic frequencies again) for $1 USD per crystal. You need to supply the the caps for his board. Vary the cap values to change the filter bandwidth.
>
> http://www.kitsandparts.com/xtalfilter.php
>
> For that matter, Diz's RFtoolkits may have all the board kits you need to prototype your whole radio if it is of the stand-alone type. He recently added a DDS VFO Development Kit to the line-up (more on that below with a link).
>
> Look at the Erector RX project by ak2b in the KitsandParts user forum. That project at one point used the Hycas IF board too.
>
> http://www.kitsandparts.com/fluxbb/viewtopic.php?id=16
>
> * Dig around on Jack Smith's (K8ZOA) site for good articles on building a crystal measurement jig and actually measuring crystal motional parameters. Once you know the motional parameters you can simulate your filter easily in LTSpice which is free from Linear technologies. Look at the files area in the LTSpice Yahoo Group for examples of simulated crystal ladder filters. If memory serves Jack has some nice papers on designing ladder filters on his site too.
>
> www.cliftonlaboratories.com
>
> www.linear.com
>
> http://tech.groups.yahoo.com/group/LTspice/
>
> B. Starting points for a DDS or Si570 VFO. Here are some suggestions:
>
> * K5JHF and K5BCQ have an Si570-based Si570 controller kit with shaft encoder and LCD. It is relatively inexpensive. Off-hand I don't know if the firmware is open or closed. It do remember the micro-controller is neither an AVR or a PIC though, but I suspect you should be able to get a copy of the source. If you are fixed on using an Si570 and want a tuning knob and LCD, this may be the best jumping off point. But (and a very big but) I'm not sure if the "Slow-tuning algorithm" is used on this VFO (see more on this below). You may want to enquire about this. If it isn't, then you may want to port Fred's (PE0FKO) code over from the ATtiny Si570 USB controller used with the Softrock radios.
>
> http://www.qsl.net/k5bcq/Kits/Kits.html
>
> Jack Smith reviewed an early version of the KB5BDC/K5JHF Si570 here:
>
> http://www.cliftonlaboratories.com/si570_kit_from_k5bcq.htm
>
> * WA7UFQ has a universal VFO controller with a shaft encoder and LCD that controls both DDS's and the Si570. Off-hand I don't know if the firmware is open or closed.
>
> http://home.roadrunner.com/~wa6ufq/universal_vfo_controller.html
>
> * Look at Diz's above mentioned DDS Development Kit RFtoolkit on the KitsandParts Web site. The firmware is open-source.
>
> http://www.kitsandparts.com/DDS-Dev-Kit.php
>
> There's an active area on the KitsandParts User Forum dedicated to the DDS Development Kit.
>
> http://www.kitsandparts.com/fluxbb/viewforum.php?id=7
>
> * Richard N8YSK sells the DDSV4. This is a "high-end" DDS VFO in my opinion as it is pre-built, uses an AD9859 and has a shaft encoder and LCD. The icing on the cake is that the firware is open-source and the processor is an ATMEL AVR (if memory serves). The firmware is written in BASIC using the BASCOM-AVR compiler; but it is too big to fit into the free version of the compiler. Fortunately the BASCOM-AVR compiler is affordable. Richard's firmware might be a great starting point for adding a shaft encoder and LCD to a DDS using a lower cost AD9834 for-example. You know all there is to know about building DDS boards, I'm sure.
>
> http://www.rmt-tech.com/
>
> * N3ZI sells a nice relatively low cost DDS VFO with shaft encoder and LCD. Alas, the firmware is not open source (I've asked). The kit uses an AD9834:
>
> http://www.pongrance.com/
>
> * Tom KM5H sells single Si570's and the QRP2000 Si570 USB controller (more on this below), see this page:
>
> http://km5h.com/default.aspx
>
> * If you are going to use a PC to control the Si570, you're almost there with your previous work on the Si570 breakout board and the UHF/SDR. All you need to do is add the USB/i2c micro-controller bridge with appropriate firmware.
>
> I would consider using the circuit from the current Softrock Ensemble radios. The Si570 circuit is isolated from USB inexpensively and Fred's (PE0FKO) ATtiny firmware is up-to-date and stable (more on Fred's firmware below). The schematic for the current Softrock Ensemble kits can be found on this site:
>
> http://www.wb5rvz.com
>
> The Softrock Yahoo Group is here:
>
> http://groups.yahoo.com/group/softrock40/
>
> * The QRP2000 USB Si570 controller is available from SDR-Kits. Remember, this controller has no shaft encoder or LCD, it is intended to be used with a PC. The SDR-Kits site has a small application for Windows that will allow you to tune this board or any Si570 controlled with the same protocol (such as a Softrock SDR kit with Fred PE0FKO's ATtiny AVR firmware). This kit does not isolate the Si570 i2c control from USB, so ground loops may occur.
>
> http://www.sdr-kits.net/
>
> * If you are going to use an Si570, no matter how you control it you will likely want to employ the "smooth-tuning algorithm". This prevents the Si570 from starting and stopping as you tune it. But it only works relatively close-in to the current frequency you are tuned to (the latest Si570 data sheet has more on this). Use Fred's (PE0FKO) AVR ATtiny Si570 firmware as an example of how to do this. The source code is open.
>
> http://home.ict.nl/~fredkrom/pe0fko/SR-V9-Si570/
>
> That's all I have. Please share your project with us. Like with your previous projects, I'm sure this will be very interesting. I see this new project is not posted on your Web page or
4859 2010-08-07 06:46:03 Brooke Clarke Re: XTALs for filter
Hi:

There's a pdf document that has the factors for common crystal
frequencies at:
http://www.prc68.com/I/Xtal.shtml#Freq

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
4860 2010-08-07 11:51:11 victor Re: XTALs for filter
Dave, I used the Juma - TRX2 (http://www.nikkemedia.fi/juma-trx2/) as a base for my design. I made changes according to my needs and my junk box. I am using it with a 20W PA similar to G6ALU design ( http://www.radio-kits.co.uk/radio-related/20W_PA/index.htm).
LO is the K5BCQ Si570 controller ( http://www.qsl.net/k5bcq/Kits/Kits.html ) however it does not support split work and its BPF switching is not done in a way that I like.
I am very satisfied with this little XCVR as it gives very good performance for a phasing XCVR. You can see its picture in breadboard state in my page in QRZ.COM .
Victor - 4Z4ME

4861 2010-08-08 05:38:03 Tom Re: XTALs for filter
Dave,



Both of the HYCAS boards I've built have work as specified and are my
standard IF/AGC board. The MC1350 obviously needs external agc and I've
tried a few audio derived methods that worked, but poorly. The K2 uses the
MC1350. Elecraft taps the IF output to mix with a 5.068 MHz crystal in a
NE602 down to 150 KHz to drive a low noise op amp for generating an agc
voltage. I used the Parts and Kits MC1350 IF amplifier at 5.068 MHz and a
4.9 MHz crystal for the NE602. I never did get the required agc voltage I
needed but this doesn't mean that it can't work since there are tons of K2's
out there with excellent agc. J



Tom, ak2b



[Non-text portions of this message have been removed]
4865 2010-08-08 17:10:05 WeiweiZheng Re: XTALs for filter
4868 2010-08-08 19:55:35 R Wall Re: XTALs for filter
I've just received a email saying they are; USD$40.00 for 8 crystals. They say the crystals have been tested whatever that means? May mean that the crystal parameters have been selected for crystal filters, but not sure.

Roderick Wall, vk3yc.

----- Original Message -----
4870 2010-08-08 21:30:36 WeiweiZheng Re: XTALs for filter
Roderrick,

I asked BG2RAQ about xtals few minutes ago. He said we bought about 1700 xtals and we have to measure these xtals one by one. The surplus xtals can be delivered after October.


Weiwei Zheng, BG6RDF