Crystals for the Mizuho MX-series

There is pile of the informations about the crystals and calculations for the MX-series...

 

 

MX xtals specifications:

Funamental mode
60 pF internal capacitance
0.0010 % tolerance
AT-crystal cut
HC-25 case

 

 

The formula and examples for MX-21S:

 

16.2670MHz = 21X-25 xtal label ; it covers 21.25 - 21.30 MHz range.
Generally take the xtal frequency, multiply it by 2, then subtract the IF frequency.

Fx = 2x(Fo) - 11.2735  [MHz; MHz; MHz]

 

16.2670 X 2 - 11.2735 = 21.2605 (lowest frequency)
16.1647 X 2 - 11.2735 = 21.0559 (lowest frequency)


Some examples of the crystals for MX-6Z:

 

28X30 - 13.20990 (28.30 to 28.35)

28X35 - 13.22682 (28.35 to 28.40)
28X40 - 13.24373 (28.40 to 28.45)
28X45 - 13.26059 (28.45 to 28.50)

 

The formula for the MX-6Z is in the back of it's manual:

 

       (Fo + 0.05 - 7.7975)

Fx = ------------------------ - 0.005
                3

Example: 50.10 = 14.11700 MHz

Fo = Crystal Frequncy

Fx = Lowest Operating Frequency

Example: 50.10 = 14.11700 MHz

 

The rest of the 10M crystals are:

 

28X00S 28.000 - 28.050 MHz 13.10853 MHz

28X05S 28.050 - 28.100 MHz 13.12544 MHz
28X10S 28.100 - 28.150 MHz 13.14233 MHz
28X15S 28.150 - 28.200 MHz 13.15923 MHz
28X20S 28.200 - 28.250 MHz 13.17612 MHz
28X25S 28.250 - 28.300 MHz UN
28X30S 28.300 - 28.350 MHz UN
28X35S 28.350 - 28.400 MHz 13.22682 MHz
28X40S 28.400 - 28.450 MHz 13.24373 MHz
28X45S 28.450 - 28.500 MHz 13.26059 MHz
28X50S 28.500 - 28.550 MHz 13.27750 MHz
28X55S 28.550 - 28.600 MHz 13.29457 MHz
28X60S 28.600 - 28.650 MHz 13.31161 MHz
28X65S 28.650 - 28.700 MHz 13.32866 MHz
28X70S 28.700 - 28.750 MHz 13.34571 MHz
28X75S 28.750 - 28.800 MHz 13.36275 MHz
28X80S 28.800 - 28.850 MHz 13.37980 MHz
28X85S 28.850 - 28.900 MHz 13.39687 MHz
28X90S 28.900 - 28.950 MHz 13.41391 MHz
28X95S 28.950 - 29.000 MHz 13.43094 MHz

 

The formula for the MX-6S:

 

         (Fh - 11.2735)

Fx = ------------------------
                3

Fx = Crystal Frequncy

Fh = Highest Operating Frequency

Example: 50.100 to 50.150 = 12.95883 MHz

 

The MX-3.5S:

IF : 11.2735 MHz
XTAL : 14.83700 MHz
VFO : 25kHz

3.5XX00S 3.500 - 3.525 MHz 14.83700 MHz

3.5XX50S 3.550 - 3.575 MHz ...


The MX-6S:

6X00S	50.000 - 50.050 MHz	12.92550 MHz
6X05S	50.050 - 50.100 MHz	12.94216 MHz
6X10S	50.100 - 50.150 MHz	12.95883 MHz
6X15S	50.150 - 50.200 MHz	12.97550 MHz
6X20S	50.200 - 50.250 MHz	12.99216 MHz	MX-6S標準装備周波数
6X25S	50.250 - 50.300 MHz	13.00883 MHz
6X30S	50.300 - 50.350 MHz	13.02550 MHz
6X35S	50.350 - 50.400 MHz	13.04216 MHz
6X40S	50.400 - 50.450 MHz	13.05883 MHz
6X45S	50.450 - 50.500 MHz	13.09216 MHz

 

 

Thanks to Dave, WB0GAZ we have very complete information about the MIZUHO HT range xtals from ICM (LONG)

From: David Feldman (dgf@netcom.com)
Date: Fri Jan 05 1996 - 16:35:50 EST

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--------------------------------------------------------------------------------

PLEASE FEEL FREE TO REPRODUCE/COPY THIS FILE, BUT PLEASE KEEP IT INTACT
BECAUSE IT WON'T BE VERY HELPFUL IF THE FILE ISN'T COMPLETE. ALSO PLEASE
KEEP THE REVISION DATE WITH THE FILE TEXT SO IF I GET SOME UPDATES AND
RE-PUBLISH IN THE FUTURE YOU'LL KNOW WHICH VERSION YOU HAVE!

73 Dave WB0GAZ dgf@netcom.com

This file was posted JANUARY 5, 1996 from WB0GAZ at dgf@netcom.com
------------------------------------------------------------------

Last year I worked with International Crystals to develop a set of "standard"
part numbers for the range crystals used in most of the MIZUHO hand-held QRP
SSB/CW HF rigs. Through a set of analyze/duplicate/test cycles I got some
reasonable results (I guess you'd call the results reasonable - at least they
weren't awful!) I spent some good $$ at this - looking back it was a rather
crazy project, but I really am a sucker for cute little radios so it was
necessary.

Toward the end of 1995, ICM instituted a (rather high) minimum+hourly charge
to test/analyze crystals, so I gave my project up once they set that policy
in place. At this point I don't plan to try to refine the parameters any more,
so I think it's time to post the part numbers as they stand. I do hope to get
feedback from hardy soles that actually try to use this info, and based on
that perhaps we can make minor "tweaks" and other corrections that will
improve the parameter sets. I'd also like to be able to publish a set of
frequency-calculation formulas (see below) so if you have access to some of
the formulas for the various Mizuho radio models, I'd be most grateful to
accept a copy of the info and include it in a subsequent posting.

Please feel free to use this list, but at your own risk, because it turns out
Mizuho (in Japan) hand-selects range crystals they have manufactered to get
ones that track accurately the frequency dial on the radio. My results have
similarly been rather variable, and I don't have the luxury of having a whole
batch of crystals made and hand picking the right ones.

It is feasible to have crystals shipped directly from Japan but it's rather
expensive (postage, Faxing your order in and getting it confirmed, exchange
rates, Yen-denominated cashier's checks, etc.) and some of them (such as for
the 2M band, etc.) aren't made anymore at all, and others (such as for the
US phone 40M band) aren't made except by special order (really a complicated
procedure!)

I didn't investigate the MX-3.5S (I felt the radio was of really limited use
in the US as the US phone band is far above where the MX-3.5S is designed),
the MX-6S (or AEA DX Handy for 6M) as I didn't have a sample unit, or the
MX-18S as my unit arrived with two crystals to cover the entire 18.068-168
MHz band and I didn't want to spend the $$.

Please note that for 15, 10, 6 and (possibly) 2 meters there are actually two
different flavors of Mizuho radios. The "S" suffix units have 1-2 watts of
output power, were sold only assembled, and use a 11.2735 MHz IF. They are
the more common types. The MX-15, MX-10, MX-6Z, and MX-2 units (no "S"
suffix) are 1/4 to 1/2 watt, were sold either kit or assembled, and use
a 7.795 MHz IF. I have no idea why two different IFs were necessary (maybe
cost?) but the range crystals are COMPLETELY different. You can't use a
MX-10 range crystal in a MX-28S even tho both radios are intended for the
10M ham band. The AEA DX HANDY for 10M is also called MIZUHO MX-28S. There
is a 1 watt 2M rig (the Santec LT-202S) running around but I've never seen
one, so I couldn't try to get crystals made for it. If anyone wants to sell
me their Santec LT-202S..............

!!! IMPORTANT !!!
!This info DOES NOT include the formulas needed to calculate a crystal's
!frequency given the range you want to cover. For that, you're on your own.
!I discovered also (much to my chagrin) that some of the rigs don't seem to
!have a completely linear relationship between target range and crystal
!frequency, at least as well as I could determine, and some of my attempts
!backfired (off by 5-10 kHz from desired range). The ways I found to pick
!a crystal frequency were either (1) work backwards knowing the desired
!coverage and the radio IF and crystal multiplication factor, or (2)
!interpolating/extrapolating a known crystal onto a new frequency knowing
!the crystal multiplication factor. The one thing I can tell you is that you
!derive the crystal frequency by specifying the TOP END of the desired
!coverage range (i.e., if you want to cover 21.150-21.200, you use 21.200,
!the IF, and the multiplication factor for that particular radio to obtain
!the crystal frequency required). IMPORTANT: ICM DOES NOT HAVE THE NECESSARY
!FORMULAS - THEY ONLY WILL BE ABLE TO PROCESS AN ORDER WITH A PART NUMBER
!AND AN ALREADY-CALCULATED FUNDAMENTAL FREQUENCY THAT YOU SPECIFY. PLEASE
!DON'T PRESS THEM TO DO OTHERWISE AS THEY **DON'T** HAVE THE REQUISITE
!INFO ANY MORE THAN I DO! In a later version of this file, if people can
!pull together the necessary formulas based on documentation they may have,
!then this situation will probably improve (that is, if you have written
!formula docs from MIZUHO on your radio(s), then please copy me and I'll
!include in this file for a later posting). Also, if you have some "REAL"
!Mizuho crystals in your equipment, if you let me know the standard Mizuho
!part number (i.e., 14X20S) and the frequency stamped on the crystal, I'll
!accumulate a table of frequencies and that should simplify the ordering
!process by eliminating the calculation step altogether.

The range crystals are all fundamental types, and usually have 60 pF load
capacitance (yes 60, not 32), and there is another parameter that ICM calls
"C1" which determines the amount of "pullability" of a given crystal - that
is how far it will cover in the VXO circuit. If you don't specify this
parameter when you have a crystal made (that is, if you specify only the
frequency, holder and load capacitance) then ICM will choose a "C1" value
by default which is usually much too low. I think this is what has lead to
frustration in some prior efforts at getting range crystals made - the result-
ing crystal would cover (say) only 30 kHz of the band rather than the desired
50 kHz. My first ICM crystals had this problem, along with some crystals I
have that were made by JAN CRYSTAL. I chose ICM for this project because I
got very good support from one of their engineers.

Anyway, after considerable thrashing/expense/time ICM and I concocted 8
"standard" part numbers that are reasonable attempts at getting sufficient
VXO coverage. Some of the formulas seem to overshoot (beyond the lower end
of a given range) but that's not entirely bad - the radio's don't have
digital readout or even very fine mechanical readout, so it's a bit of a
shot in the dark. I'd suggest before actually putting your MIZUHO on the
air with any given crystal that you pre-test it on a frequency counter and
make up a little table that maps the (5 kHz) knob divisions to the actual
frequencies you get with your particular radio and crystal.

The MIZUHO radios don't have an elaborate set of adjustments to help each
crystal properly track the knob markings. There are no independent trimcaps
for the crystals. You plop in your crystal and pretty much take what you're
given.

If all of this sounds like too much trouble and you want a SSB/CW HT for
HF, then the only other choice I'm aware of is the Tokyo Hy Power HT-750
(see October 1994 QST page 60 or so).

Anyway, here are the part numbers I have and the results of the LATEST test
crystal I had made. As you can see some of the crystals didn't meet the mark,
but perhaps you can improve on it...

                                        (RESULTS OF LAST TEST ATTEMPT)
ICM # Description Attempt Actual Freq
----------------------------------------------------------------------------
725677 MIZUHO MX2 T/R 144 MHZ BAND PENDING (update next time)
725678 MIZUHO MX15 T/R 21 MHZ BAND 21.250-21.300 21.255-303 9.70513
725679 MIZUHO MX14S T/R 14 MHZ BAND 14.300-14.350 14.282-352 12.81307
725680 MIZUHO MX7S T/R 7 MHZ BAND 7.175-7.200 7.167-197 9.23975
725681* MIZUHO MX6Z T/R 50 MHZ BAND 50.090-50.140 50.082-141 (later)
725682 MIZUHO MX10Z T/R 28 MHZ BAND 28.350-28.400 28.333-391 12.06667
725683 (not part of this series)
725684 MIZUHO MX21S T/R 21 MHZ BAND 21.250-21.300 21.257-299 16.29025
725685 MIZUHO MX28S T/R 28 MHZ BAND 28.400-28.450 28.403-450 13.24283

*NOTE! THE MX6Z IS *NOT* THE SAME AS THE MX-6S. DON'T TRY TO USE THIS FOR-
MULA FOR YOUR AEA DX HANDY/6 METERS - IT WON'T WORK AT ALL DUE TO DIFFERENT IF.

There you have it. This posting implies no relationship I have with ICM other
than being a customer for this project. If you have another way of getting
range crystals, I'd be interested in hearing of your experiences so I can
add information to this file and post it again. Also, you CAN get most of
the common range crystals from Japan if you're making a trip over there.

P.S., you may wonder if I have some of these radios.
Yes, I do.
No, they're not for sale ;-)

Good luck!

73 Dave WB0GAZ dgf@netcom.com
All rights reserved to Dave / WB0GAZ

 

 

Thank you very much to Dave, WB0GAZ for his effort and good job in order to sumarizing the information about the ICM supplier third-party xtals for Mizuhos.

 

Please be noted that in original text was the bug > marked in red. The correct IF frequency is 11.2735MHz instead of 11.2785MHz which seems to me like the typo error.

 

73 - Petr, OK1RP