3560 Crystals from eBay


Jim Sheldon
 

I ordered a 10 pack of 3560 crystals (HC/49 style) from 3rd Planet Solar
on eBay. Got them yesterday and finally had a chance to check them out.
NONE will oscillate in the Cricket. The crystals aren't bad (they
oscillate & check good in my crystal checker) they just won't run in the
Cricket. I don't know if it's a feedback problem that needs a component
change or if it's just that there's not enough drive. They will
sometimes try to start and once in a while one of them would run in RX
mode but as soon as you hit the key to transmit (good 50 ohm dummy load
attached). The crystal would stop oscillating and it would be necessary
to cycle power to shock it back into oscillation. Maybe Dave, NM0S
would chime in on this since I'm not an engineer and don't know for sure
which component values to change in an attempt to make these crystals
work.

Jim - W0EB


wa2cky
 

Ouch.  Not good news but hopefully someone will find a cure.  Ah, well.  Switching to 3560 is a good idea - we just have some implementation problems.  Thanks for your work.

Bob, WA2CKY

On Thu, May 4, 2017 at 3:34 PM, 'Jim Sheldon' w0eb@... [4sqrp] <4sqrp@...> wrote:
 

I ordered a 10 pack of 3560 crystals (HC/49 style) from 3rd Planet Solar
on eBay. Got them yesterday and finally had a chance to check them out.
NONE will oscillate in the Cricket. The crystals aren't bad (they
oscillate & check good in my crystal checker) they just won't run in the
Cricket. I don't know if it's a feedback problem that needs a component
change or if it's just that there's not enough drive. They will
sometimes try to start and once in a while one of them would run in RX
mode but as soon as you hit the key to transmit (good 50 ohm dummy load
attached). The crystal would stop oscillating and it would be necessary
to cycle power to shock it back into oscillation. Maybe Dave, NM0S
would chime in on this since I'm not an engineer and don't know for sure
which component values to change in an attempt to make these crystals
work.

Jim - W0EB



Curt
 

I have the same behavior with my 3560 crystal.  Sometimes it works, sometimes not.  I ordered some from the auction site, hope wasn't a waste of time.

Still trying for first QSO...

72, Curt KB5JO


Tom Sevart
 

On 05/04/17 19:11, rhulett1@consolidated.net [4sqrp] wrote:


I have the same behavior with my 3560 crystal. Sometimes it works,
sometimes not. I ordered some from the auction site, hope wasn't a
waste of time.
Don't feel bad, I have that issue with my 3.579 crystal. Takes several tries of hooking the battery up to get the circuit to oscillate.


--
Tom Sevart N2UHC
St. Paul, KS


Lee
 

Looking at the circuit – the oscillator is not loaded too heavily by the PA (it ‘sees’ a high impedance at the input of the PA), so no changes there. One simple thing to try is to pull the 2N3904 and replace with a 2N2218, 2N5179, or something NPN and metal-canned with a higher alpha….use a transistor tester to pick a suitable one. Another option is to replace R1 with a slightly lower value; this pulls up the voltage at the base of the 2N3904 and may help it kick on…………this is a non-engineers look, but an oscillator is simply an amplifier with at least unity gain and feedback into the input…..

 

Lee KX4TT

 

From: Bob Groh bob.groh@... [4sqrp]
Sent: Thursday, May 4, 2017 20:43
To: 4sqrp@...; Jim Sheldon
Subject: Re: [4sqrp] 3560 Crystals from eBay

 

 

Ouch.  Not good news but hopefully someone will find a cure.  Ah, well.  Switching to 3560 is a good idea - we just have some implementation problems.  Thanks for your work.

 

Bob, WA2CKY

 

On Thu, May 4, 2017 at 3:34 PM, 'Jim Sheldon' w0eb@... [4sqrp] <4sqrp@...> wrote:

 

I ordered a 10 pack of 3560 crystals (HC/49 style) from 3rd Planet Solar
on eBay. Got them yesterday and finally had a chance to check them out.
NONE will oscillate in the Cricket. The crystals aren't bad (they
oscillate & check good in my crystal checker) they just won't run in the
Cricket. I don't know if it's a feedback problem that needs a component
change or if it's just that there's not enough drive. They will
sometimes try to start and once in a while one of them would run in RX
mode but as soon as you hit the key to transmit (good 50 ohm dummy load
attached). The crystal would stop oscillating and it would be necessary
to cycle power to shock it back into oscillation. Maybe Dave, NM0S
would chime in on this since I'm not an engineer and don't know for sure
which component values to change in an attempt to make these crystals
work.

Jim - W0EB

 

 


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John Clements
 

I would have to concur with the last few posts.  C10 seems to light to me.  I used up to 470pF for C10 (and 270pF for 40M) and even lowered R2 down to a 330 ohm 1/2W resistor when playing with an SVXO circuit using my crystals.  Of course my schematic is a little different as a PZT2222 transistor is used and tap the output off the emitter area instead of the base.   http://kc9on.com/ham-radio/crystals/svxo/

I'd love to be sitting at the bench tweaking that part of the circuit. Unfortunately I'm down state this weekend with some family care taking.  Maybe later next week when I get back and catch my breath I'll build up the osc circuit and play around.

Does anyone know the specs of the xtal that comes with the cricket or the source?  Would be interesting to put them on my crystal impedance meter and compare them with mine.

72 John kc9on (3rdPlanetSolar).


Mike WA8BXN
 

I don't have a cricket yet (its on order). I put together the oscillator on a test board here to try out some crystals I had. To simulate the load of the final, I used a 10K resistor to ground. I first tried out a number of 3579 crystals of various sizes and could hear all of them in my test receiver and keying sounded good. I then tried a few 3560 crystals of various sizes and could not hear any of the oscillating until I tuned the test receiver down to that frequency.Keying sounded good.  The crystals I used for testing came from a variety of sources including e-bay. 

My plan was to try some different feedback capacitor values if I had some that didn't work, but since they all do I can't. My short test here suggests that other 80 meter rocks should work for the most part. 

73/72 - Mike WA8BXN


Curt
 

I ordered 4 small crystals from 3rd Planet.  3.535, 3.550. 3.560, 3.5797.  None oscillate in the Cricket.  All oscillate in my G3UUR crystal oscillator ( 2n4401 ).  The colorburst crystal that came with the kit works fine, so that's all that counts. 

72, Curt KB5JO