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I need some crystal infomation for the 8719 pll chip
- Thread starter dss56
- Start date
And you may be correct on that and he should experiment with different values. The part that had me a bit unsure was the statement that he had no movement at all and that could speak to the idea that a phase issue is part of the problem which would also speak to whether the crystal is in anti-resonance which again would be more of an issue with parallel resonance than series "I THINK"? And it could/may point to its inability to change frequency even one cycle? Don't know wish I had it on my bench "the bench I had before I didn't have one" I could figure this out especially since I most likely forgot something I used to know LOL help! If you knew how unfunny that should be you would feel sorry for me, LOL
also set the radio dead on with the 11.3258 xtal. The pictures I loaded are of the 11 4758 xtal and will not tune to ssb upper or lower. So im sure the new xtals i received are not cut correctly and I'm trying to figure out what would be the correct specs for this to work on am/usb/lsb.
Well, hold on a second.
They usually provide the circuit they used to test the device.
That would end all questions as to ability to slide or stuck on resonant.
There is the issue of Xtal and support INSERTED in to that Xtal case - preventing it from getting tweaked.
The biggest hint I see of that is the required 20pF measurement versus the 10pF
So when the newer Xtal gets put in, the Varactor needs a support part to "swing" the Xtal to offset the AM to SSB "Window" - if the tripler can't simply adjust the Xtals own resonance with capacitance or inductance - then remember the Xtals need ISOLATION from each other as you work this - for any common lead will get you into trouble because the Xtals with the highest output will win over any others.
So the issue of extra means the new Xtals have a tighter tolerance (A.K.A. - higher output) - which equates to a change of banks - like capacitive or inductive "bank" to change the resonance. You'll have to look into a different approach.
They usually provide the circuit they used to test the device.
That would end all questions as to ability to slide or stuck on resonant.
There is the issue of Xtal and support INSERTED in to that Xtal case - preventing it from getting tweaked.
The biggest hint I see of that is the required 20pF measurement versus the 10pF
So when the newer Xtal gets put in, the Varactor needs a support part to "swing" the Xtal to offset the AM to SSB "Window" - if the tripler can't simply adjust the Xtals own resonance with capacitance or inductance - then remember the Xtals need ISOLATION from each other as you work this - for any common lead will get you into trouble because the Xtals with the highest output will win over any others.
So the issue of extra means the new Xtals have a tighter tolerance (A.K.A. - higher output) - which equates to a change of banks - like capacitive or inductive "bank" to change the resonance. You'll have to look into a different approach.
Andy
The stock 11.3258 xtal woks great and this is the spec sheet for it attached.
I hooked up with a company and are looking into cutting 11.4258 samples with the 11.3258 specs and see if that does it. When Done with this project I will explain what its all about for now I want to get my project working and then spill the beans.
I appreciate all who ave suggested/input to this problem.
thanks Bob in Boston MA.
The stock 11.3258 xtal woks great and this is the spec sheet for it attached.
I hooked up with a company and are looking into cutting 11.4258 samples with the 11.3258 specs and see if that does it. When Done with this project I will explain what its all about for now I want to get my project working and then spill the beans.
I appreciate all who ave suggested/input to this problem.
thanks Bob in Boston MA.
Attachments
Ok, looks like this part has a 1mW output capability - pretty high which may prevent the overtone from even being developed. The output of say a Uniden 11.325 Xtal is more along the lines of PICO-watts (pW) - not Mili (m) or Micro (u) watts - you are seeing an efficiency factor of over 100 X the usual used in a typical CB.
So I've attached a Farnell datasheet, may provide some direction...
At least it can show a test circuit...
So I've attached a Farnell datasheet, may provide some direction...
At least it can show a test circuit...
No, just use for reference - because of your need to develop a 3rd overtone, the whole mess needs to have less of Major so it doesn't swamp out the fundamental you're trying to obtain. This is what sounds like your major (forgive the pun) is...
So really, the 50 ohm impedance effect - you will need to Attenuate the Xtals output either series or parallel - to keep it from becoming the predominate, so the tripler it's used in, can actually develop the overtones (harmonics) without the major overwhelming it. There is a series of filters the PLL uses, but they can all sense-lock into the major simply by the ringing effect of RF noise on the ground plane the PLL chip is using.
You have to experiment with what you have first then decide, for the "notes" from back then are long gone off the desks of the engineers that developed that circuit to make the tripler work - the engineering that went into something like the 148 or Grant is decades old, their kids may not even have a spare spiral-bound in the closet or in a 3-ring binder up in their fathers old attic.
So really, the 50 ohm impedance effect - you will need to Attenuate the Xtals output either series or parallel - to keep it from becoming the predominate, so the tripler it's used in, can actually develop the overtones (harmonics) without the major overwhelming it. There is a series of filters the PLL uses, but they can all sense-lock into the major simply by the ringing effect of RF noise on the ground plane the PLL chip is using.
You have to experiment with what you have first then decide, for the "notes" from back then are long gone off the desks of the engineers that developed that circuit to make the tripler work - the engineering that went into something like the 148 or Grant is decades old, their kids may not even have a spare spiral-bound in the closet or in a 3-ring binder up in their fathers old attic.
Let's address kopcicle's idea of using a tone instead lets offset the balanced modulator enough to get a reading on that Pride don't know how sensitive the pride is but it should work.
And Andy is looking at what I suspect the issue could be first the fundamental frequency of the crystal will be its strongest point all harmonics after that fall off and if the crystal is aged as a 30+-year-old crystal may well be, Well the crystal may not get along with the old ones especially if there is any interaction on their crystal board that would lead to swamping.
Of course, if you place these crystals in the radio where the original crystal was it may shed some light on that idea that the board or it's Leeds are causing an issue.
And Andy is looking at what I suspect the issue could be first the fundamental frequency of the crystal will be its strongest point all harmonics after that fall off and if the crystal is aged as a 30+-year-old crystal may well be, Well the crystal may not get along with the old ones especially if there is any interaction on their crystal board that would lead to swamping.
Of course, if you place these crystals in the radio where the original crystal was it may shed some light on that idea that the board or it's Leeds are causing an issue.
I did put the 11.4758 xtal directly in the radio and same problem. Its a new xtal and also the 11.3258 are new xtals. The 11.3258 needs to be in there for the mb8719 radio to work regular 40 channels I'm sure you all know that.
I'm sure the xtal was not cut properly and hope the company I contacted yesterday will shed some light and will be able make a 11.4758 sample xtal to the specs of the 11.3258. I think the 11.4758 was cut as a regular oscillator xtal and no 3rd overtone cut or any specs from the 11.3258
I'm sure the xtal was not cut properly and hope the company I contacted yesterday will shed some light and will be able make a 11.4758 sample xtal to the specs of the 11.3258. I think the 11.4758 was cut as a regular oscillator xtal and no 3rd overtone cut or any specs from the 11.3258
The switch board it diode switching so no oscillation there it works well I moved the 11.4758 xtal to the 11.3258 position and the 11.3258 to the 11.4758 slot and same problem. And of course move the 11.4758 to the radio no switch board and same results no SSB offset but AM center slot. I will take some more pictures tomorrow with the 11.3258 and switch to usb/lsb and you all can see it works well.
Again thanks to all who has been helping and suggesting info
Bob
Again thanks to all who has been helping and suggesting info
Bob
I'm thinking the Xtals resonate power output - is the problem - so perhaps the 3rd-overtone in this would work.
The thing keeps coming back to the original premise, no shift.
So either the Xtal is unaffected due to internal construction (shunt or otherwise)
OR
This design using Fundamental xtal needs to be changed to 3rd order types.
Man, wish I had that old Xtal tester - the one that used to be at R/Shack proper retail to test your Xtals - like for scanners and stuff - even had a simple analog meter that showed weak, low or good or fail for power levels. Similar to their tube testers.
The thing keeps coming back to the original premise, no shift.
So either the Xtal is unaffected due to internal construction (shunt or otherwise)
OR
This design using Fundamental xtal needs to be changed to 3rd order types.
Man, wish I had that old Xtal tester - the one that used to be at R/Shack proper retail to test your Xtals - like for scanners and stuff - even had a simple analog meter that showed weak, low or good or fail for power levels. Similar to their tube testers.