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Expander (Expo) 100 B version

Hawkeye351

Well-Known Member
Jun 27, 2021
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Got a Uniden Washington (8719 PLL) on the desk.

Issue:
Extras not working properly.

Evaluation:
Only one crystal in the expo kit. The 11.1125 (original radio crystal) is the only crystal inserted in one end of the row for the crystals.

I found out that the high channel crystal for this B version is 11.2595, and I have one so I inserted it in the kit. Now I need to know the mhz the low channel crystal needs to be.

I calculated the difference between the highest channel crystal and the original radio crystal to be a 0.147 spread. So I subtracted that 0.147 from 11.1125 and came up with 10.695. I have several of those but it drops me down to the middle of 25mhz instead of 26.515mhz.

10.695 low channels (10.695 + 0.147 = 11.1125)

11.1125 regular 40 channels

11.2595 high channels (11.1125 + 0.147 = 11.2595)

I may not have them in the right orientation (placed in their right socket) to produce the right frequencies.

Anyone know if the 10.695mhz crystal is the proper crystal for the lower channels from an expo 100 B version (it calculates out to be the right one)?

And what is the proper socket for the high channel crystal, then the low channel crystal, etc...?

By the way, for those that still use expo channel kits:
Over time, the crystal socket solder joints will get weak and lift off the solder connection. You must remove the switch control itself from the board by unsoldering the five tabs around the base of the switch, and then reflow the solder spots for the crystal sockets. The center one being your main focus. Then resolder switch control back to the board.
 
Last edited:

Oooops, I believe I miscalculated...lol...

11.1125 - 0.147 = 10.9655, not 10.695 as before. That's why it drops down to the middle of 25mhz when switched to the low channels.

Now to go through my parts to round up a 10.9655 crystal.
 
Here is a new kit I designed with relay switching to keep the frequency stabilized no drifting.

Will work with mb8719/mb8734 11.1125 or 11.3258 xtals.

crystals freqs you need are 11.2625 high and 10.9655 for low with the 11.1125 xtal.
remember to use trim caps and use a choke to lower the frequency or a cap to higher the frequency.
Best to open the voice lock to slide
And i always tune the radio to ssb upper and lower am will be fine.

I also have another kit that you remove the pll add a socket and plugin the new kit will give 28.045-26.515 but channels are not in succession.
No holes drilled and can always plug back in your original pll and back to stock

I have all the xtals if you need any you can message me private.
The xtals need to be cut correctly so the ssb will work.

Also pictures of the new kit in a nice box and frequency counter. of just an a box no frequency counter.

Good luck
 

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I wouldn't mind trying out a few of the crystal board products (first pic). These guys around here are spoiled on the expos, but they don't realize how old those things are, lol...

How much for 3 of the crystal boards with crystals?

And, for the crystal boards, do they install the same as the expos (remove original crystal from radio board and insert into empty slot on expo board, then solder expo board wires to the location where the original crystal was removed from radio board)?
 
I wouldn't mind trying out a few of the crystal board products (first pic). These guys around here are spoiled on the expos, but they don't realize how old those things are, lol...

How much for 3 of the crystal boards with crystals?

And, for the crystal boards, do they install the same as the expos (remove original crystal from radio board and insert into empty slot on expo board, then solder expo board wires to the location where the original crystal was removed from radio board)?
I sent you a message with contact info
 
Don't forget that the eleven-point-whosit crystal used with the 8719 is fed into a frequency-tripler circuit. What gets mixed with the VCO is 33.3375 if the crystal is 11.1125. The frequency difference between them is what feeds into pin 17 of the 8719.

This is why that kind of radio can deliver a wide clarifier range. The actual change in crystal frequency gets multiplied by three.

73
 
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