EMRFD Message Archive 121
Message Date From Subject 121 2006-09-06 16:55:50 Jim Kortge Crystal Information
Just thought that I would pass along my statistics for matching crystals from a
lot of 200 units that I bought a while back. These are 11.0 MHz Series units
from Mouser manufactured by ECS in China. They used to be made in Korea and
those were better units terms of Q and overall spread (tighter). None-the-less,
from the lot of 200 units I got 22 sets of 6 crystals, nominally matched at less
than 10 Hz spread within the group, and 5 sets of 4 crystals with the same
spread. The remaining 48 units are destined for LO service since they have
either unacceptably low Q for filter use, or would not match up close enough for
making a good filter. In my 2N2/20 design, the main filter uses 4 crystals,
with an additional 2 crystals in a 2-pole roofing filter after the IF amp.
I don't think the parameters for this most recent group are up on my web site,
so I'll try to make some time to add those in for those who are interested.
72 and kind regards,
Jim, K8IQY
PS....I'm also cross posting this email to the qrp-tech group as I know there
are folks on that list who might be interested too.122 2006-09-06 17:07:15 Brian - KB9BVN Re: Crystal Information
You're very kind to do this.
I don't need any right now, but thanks for your efforts over the years.
You're a good ham.
73
----- Original Message -----
123 2006-09-06 17:22:18 Wes Hayward Re: Crystal Information
Many thanks for the results of your statistics. These results are
right in line with some that Bill Carver, W7AAZ, got a few years ago
when he purchased a modest quantity form DigiKey or Mouser. The
crystals he bought were made in the US and he did not see the
variation in Q that you mentioned. In fact, my general thinking in
recent times has been that we can get by without measuring Q for each
crystal. Rather, I figured that it would be good enough to do a
sampling to just confirm that Q was good enough. But my earlier
conclusion is probably not valid for the present parts. I really
appreciate the update.
73, Wes
w7zoi124 2006-09-06 19:31:00 Harry Leung Re: Crystal Information
I am interested in the matched set of 6 Xtals of 11MHz
for the 2n/20. May I have one set and 2 xtals for LO
mail to my QTH. Please let me know the amount IOU.
Cheers, 72 de Harry.VE3LCW,
E-mail harrycwleung@yahoo.ca.
QTH No. 15, IVAN DANIELS DRIVE,
MARKHAM, ONTARIO, L3S 3C5,
CANADA.
126 2006-09-08 16:41:00 kilocycles Re: Crystal Information
I Just checked to see if the 11 MHz ones I'm going to use in the
17m/12m Belthorn-based SSB transceiver are ECS...they're not, they're
Fox crystals. What is somewhat peculiar is that the 11 MHz rocks I
tested gave me lower Q's than any I've tested on the PVXO and Crystal
Test Unit. The 9 MHz "Jameco" units I'll be using in the 20m/15m
EMRFD SSB-CW transceiver had an average Q of 232k, with an Rs or
16.8(only the ones suitable for use in the rig as filter
candidates...I had a couple that were low Q/high Rs). The 4.9152
Vishay-Dales for use in the 2N2-40+ are 206k/13.3 ohms. As you know,
I've mentioned that my results typically all seem to be higher in Q
than the similar ones you've tested.
These Fox 11.0 MHz crystals averaged a Q of 158.5 and Rs of 7.3 ohms.
That's the lowest Q I've seen of any crystals, but the Rs is also
low. I have three groupings of eight crystals that would be suitable
for an 8-pole filter. By contrast, the surplus 4 MHz "pulls" I'm
going to use in a 4-pole CW crystal filter for another rig have a Q of
270k, the highest I've tested, an Rs of 20.8 ohms, and 10 Hz span
among the four selected. I actually had seven within 20 Hz on that batch.
I'm trying to see if there is a correlation between frequency and Q,
but I'm not sure I have the data to support it. I'm keenly interested
to see what your 11.0 MHz ECS results are.
By the way, as a note to the group, the Belthorn-based rig will be
sharing the same EMRFD design elements for all but the IF and product
detector/audio stages. I've switched out the 74HC4053s in the HFOs
with DPDT relays, due to concerns pointed out here in the group with
respect to resistive losses. I bought some SMD FST devices to try to
work in some of the other switching stages, based129 2006-09-09 14:21:21 Jim Kortge Re: Crystal Information
> Hi Jim,Greetings Ted and others who are interested in this subject,
> I Just checked to see if the 11 MHz ones I'm going to use in theI've had very good results with FOX brand crystals in the past. In fact, I just
> 17m/12m Belthorn-based SSB transceiver are ECS...they're not, they're
> Fox crystals.
got done measuring a sample of 6 from the latest lot of 100 that I bought from
Mouser a few months back. They are Mouser part number 559-FOX049.
What is somewhat peculiar is that the 11 MHz rocks I
> tested gave me lower Q's than any I've tested on the PVXO and CrystalI find several like that in each lot of 100. I guess that's why I've come to
> Test Unit. The 9 MHz "Jameco" units I'll be using in the 20m/15m
> EMRFD SSB-CW transceiver had an average Q of 232k, with an Rs or
> 16.8(only the ones suitable for use in the rig as filter
> candidates...I had a couple that were low Q/high Rs).
drive every crystal in the test fixture and look at its output relative to the
"lot average". They seem to be fine in oscillator circuits for LO service, but
would sure add to the insertion loss of a filter if used.
The 4.9152
> Vishay-Dales for use in the 2N2-40+ are 206k/13.3 ohms. As you know,Yes, I don't seem to get Q value that high. 100K to 150K seems to be about the
> I've mentioned that my results typically all seem to be higher in Q
> than the similar ones you've tested.
Q range I get with my test setups. I say setups as I've just built a prototype
all resistive test fixture. Used 5% carbon film resistors, so it isn't spot on.
Those will be replaced with 1% metal film units on the next Mouser order. I get
nominally the same results with it as I do the test fixture with the 4:1 step
down/up transformers. I'm thinking of modifying that unit to go from -3dB
attenuators on the high Z sides of the transformers to -10 attenuators for more
isolation. Easy to rebuild it, but will wait to do that when I have the right 1%
resistors for that job.
>To my eyes, those look really good!
> These Fox 11.0 MHz crystals averaged a Q of 158.5 and Rs of 7.3 ohms.
> That's the lowest Q I've seen of any crystals, but the Rs is also
> low.
I have three groupings of eight crystals that would be suitable
> for an 8-pole filter. By contrast, the surplus 4 MHz "pulls" I'mHere they are on the last batch of 200 that I reported about on EMFRD.
> going to use in a 4-pole CW crystal filter for another rig have a Q of
> 270k, the highest I've tested, an Rs of 20.8 ohms, and 10 Hz span
> among the four selected. I actually had seven within 20 Hz on that batch.
>
> I'm trying to see if there is a correlation between frequency and Q,
> but I'm not sure I have the data to support it. I'm keenly interested
> to see what your 11.0 MHz ECS results are.
ECS brand 11.0 MHz series crystals, Mouser part number 520-HCA1100-S
You can only buy these in quantities of 100 or more, they are special order
items from Mouser for some reason. The values shown are the average for a sample
of 6 units from this lot.
Fs 10.999851 MHz DeltaF 392 Hz
Rs 8.0 Ohm
Co 3.28 pFarad
Lm 0.0135 Henry
Cm 1.559E-14 Farad
Q 114,800
>I for one am anxious to see how this rig plays. Keep us posted Ted.
> By the way, as a note to the group, the Belthorn-based rig will be
> sharing the same EMRFD design elements for all but the IF and product
> detector/audio stages. I've switched out the 74HC4053s in the HFOs
> with DPDT relays, due to concerns pointed out here in the group with
> respect to resistive losses. I bought some SMD FST devices to try to
> work in some of the other switching stages, based on recommendations
> from the group. The HFO and receiver RF stages' designs for both rigs
> is complete, and I'm ready to build those.
72/73 for now and thanks for the interesting info,
Jim, K8IQY