Batboard

hi folks, just looking for any information on narrowbanding the maratrac uhf or vhf recievers. i know that com spec has several kits however they have never done a maratrac. the first mixer in the uhf maratrac produces a 45.1 first if signal which is amplified before it passes through a 4 pole crystal filter. then theres another stage of amplification before the rf signal passes into a subsystem ic, where the 45.1mhz signal is mixed with 44.645mhz to produce 455kc then it goes to a quadrature detector.
anybody got any ideas or have worked with this before? comm spec has a 45.05 crystal set available and several 455kc grades. i would appreciate anyone's sugestions thanks warbirdf4

It's been a while, but I put conversion kits in a couple of GM300s which have pretty much the same receiver. As far as I recall only the 455 filters were changed. There were also a few resistors that got changed to reduce the tx mod levels, and increase the rx audio level.

i have found out that the big "m" has kits available for the gm300 in either uhf or vhf which is interchangeable with the maxtrac and naturally the maxtrac is interchangeable with the maratrac
vhf = hln9575 uhf= hln9576

Hello I am looking for the part to convert a VHF Maratrac can i still get these parts from Motorola to convert it to 12.5kc

The part numbers you're asking for are shown in a post above; one for VHF and another one for UHF. You should contact Motorola for further information as to availability and pricing.

VHF HLN9575A $84.53 list
UHF HLN9576A $84.53 list

Both still show as available.

Regards

Allen

Or if you have a few old 900mhx maxtracs use the filters out of those. Thats about all the radios are worth. Done a few for our towns radios.