Motorola Alert Receiver

[KB2ZTX]

OK Folks. I'm looking for some help here. A friend dropped this unit off at my shop to re-crystal. I have searched high and low for a book on the unit. I have some info off the receiver chassis. Does anyone recognize this or know what the model actually was ?

The numbers on the the Receiver chassis are TU103H-5 and 63E823736-E

Here is a picture of it - http://www.leomac.com/monitor.jpg

[Andy Brinkley]

That's an oldie - early 1960's vintage. Lots of tubes, IIRC the receiver is based along a GGV radio, had a oven for the crystal. Should have the crystal frequency stamped on the oven.

The ones I maintained had a Quik-Call (2+2) decoder in them, the firefighters had them connected to a bell that would ring when they had a call. If I ever had a manual it's long gone by now.

The paging word has made some progress in the last 50 years !!!

[bundy125]

Man does that bring back some memories. We had one of those in the station house of a fire department I was volunteering back in the mid 70s. I was lucky that we had one plectron receiver left or that monster would have been going to my house. It worked well, but I didn't have a great deal of cabinet space (or a strong enough shelf) to put that on.
Bundy125

[WB6NVH]

This is a Motorola LO1FNB or LO3FNB monitor receiver from 1960, more or less. If you look carefully, the date should be ink stamped somewhere on the chassis on the component side, usualy on the apron somewhere. It uses the same tubes as a G-series receiver but is otherwise totally different. Most of them were used by fire departments as alarm bell receivers, and by civil defense organizations. Sometimes police chiefs kept one in their office.

For some stupid reason the model number was on a plate riveted to the flimsy rear cardboard cover, and over the years, the cover gets lost, and with it the nameplate.

LO1FNB is low band and LO3FNB is the high band version. The Motorola crystal type number is on a label on top of the crystal oven on the VHF high band models. The low band models did not use an oven. Motorola changed model number systems about 1956 so there was an earlier model series called LO-1F and LO3-F which are otherwise identical except that they had a white knob with ribs on it and the old Motorola cursive-script logo emblem.

You can get crystals from International Crystal in Oklahoma City. Bear in mind that this is not something which you can just plug a crystal into and it will work. It is not broadbanded and it uses a derived IF. In other words, trying to tweak it without the roadmap will lead to a dead receiver. The alignment bandwidth is about 400 KHz on high band and a lot less on low band. It has to be aligned to whatever specific channel you want to place it on.

Also remember that the low band ones come in band splits, so that for example a 34 MHz set won't work on 49 MHz.

I can look for the manual to see if I can cross the 63- prefixed chassis number when I get back to the office next week... I think the number you are looking for should actually be a TA- something or PA- something or TRD- something, not TU- prefixed.