Batboard

I bought a unit that was labled as a 5mhz reference osscilator, now its here and I am not sure if thats what it is or I have more, it seems it is from a Micor.

Part # TLB1564A
Sticker on back lists freq as 43.200, thats what makes me wonder if this is more than just the 5mhz reference, I do see the 5mhz module in it.

I know nothing about Micors, as you can see....

W4WTF wrote:I bought a unit that was labled as a 5mhz reference osscilator, now its here and I am not sure if thats what it is or I have more, it seems it is from a Micor.

Part # TLB1564A
Sticker on back lists freq as 43.200, thats what makes me wonder if this is more than just the 5mhz reference, I do see the 5mhz module in it.

I know nothing about Micors, as you can see....

That's not an issue, because that unit is not from a Micor. That looks, more specifically, like the HSO (High-Stablity Oscillator) module out of an MSR2000 or MSF5000 series.

In either case, you've got yourself a decent frequency reference at least. However, for best accuracy, you should compare it against, say, a GPS-locked standard.

I don't recall if there's anything else (an exciter?) in that drawer or not. Someone more knowledgeable about base stations than I will need to speak up.

The unit you've posted is a High Stability Oscillator from a Low Band VHF MICOR PURC Transmitter. The individual 5 MHz Oscillator would be connected +13.8V DC and left on to stabilize within 1 hour. On the oppose end of the 5 MHz Oscillator there's a small glass capacitor to set the reference frequency. You must be extra careful not to adjust that capacitor too far in either direction otherwise you'll damage the oscillator itself. /\/\ formerly manufactured these 5 MHz oscillators, then they outsourced them to an OEM but finally dropped the OEM supplier.

Also used in Micor simulcast conventional systems in Australia at one time
But as said it is a 5Mhz HSO

Thanks guys, so what would be fed into the "audio in" jack on the back?

ahhhhh... Audio ! no seriously, audio to modulate the oscillator.
One such function would be to apply audio of the correct frequency
to create a test signal that would be used to set precise deviation
characteristics using bessel null functions. Or to provide a direct
true fm signal for setup and alignment purposes. Phrawg

My recollection is that on the PURC station, the audio is "true FM", so the audio modulates the crystal in a channel element inside that HSO.
Out of the back of the HSO should be a BNC connector, that signal is run via a small coaxial cable to a "channel element" that has no components inside.
That "fake" channel element is plugged into the exciter.
That is how the high stability modulated signal gets fed to the exciter.
But, that is just going from my feeble memory.
Anybody got a better memory on those?

You are right PETNRDX I forgot how it all joined in but the fake channel element on the exiter was the clue I needed to remember.
Boy thats about 25 years ago.

Thanks guys, the paging part explains the data terminals.

I really just wanted a 5mhz reference for the shop, so the rest is excess but for under $20 I have what I need and more.

$20 here too.
I picked one of these up today. All I want is the 5MHz ovenized oscillator.
+24v @ 500ma applied, and in about an hour, I get 5.00001132 MHz on my Keithley counter. (Not recently calibrated.)
If anyone wants the case with the rest of the circuitry, PM me.

.....or tell me how to turn this into an audio noise maker for experimental music (I'm into that kind of stuff, synths and such).

=FB=