Re: [Repeater-Builder] Motorola Pac/Rt

9 Feb 2004 20:44:43 -0000

At 07:22 PM 2/8/04 -0800, you wrote:
Mike Morris WA6ILQ <[EMAIL PROTECTED]> wrote:

At 02:51 PM 2/8/04 +0000, you wrote:

>hi
>I dont know if some one can tell me how i setup Motorola Pac/Rt
>mobile repeater, VHF, Model H13TTY3110ASP29 to stand alone repeater

The short answer is you can't.

It's a unit deigned to connect to the audio lines and PTT of an existing
mobile radio and allow use of that radio via a hand-held radio.

Picture a state police officer making a traffic stop on a highway.
Before he gets out of his patrol car he flips on the PAC/RT and
walks back to have a chat with the motorist.

His mobile radio hears a signal and that audio is transmitted by the
1/4 watt transmitter in the PAC-RT to the officer. He answers by
pressing the PTT button on the handheld, and the PAC-RT receives
the signal and keys the mobile TX.

If a second patrol car arrives on the scene and enables his PAC-RT
the first one is shut off.

All of this is done on a simplex channel.

A similar product can be found at

Read that web page for the theory of how it works.

I've had a high band PAC-RT on the shelf for 10 years. I haven't
found a use for it yet.

It's based on a low-end walkie talkie, with the transmitter castrated
back to one-quarter of a watt, with a very poor front end, and to change
the frequency you need to order a new crystal and install it into a
channel element.
High band PAC-RTs were used on low band and UHF mobiles. UHF
ones were used on high band and low band mobiles.
A few ham radio operators here in the Los Angeles area played with
them over a dozen years ago and while they did work, they were not
practical in an area with a lot of repeaters... you might as well have the
handheld talk to the repeater rather then talk to your car which talks
to the repeater.

Mike WA6ILQ


motorola originally called the pac/rt a mobile repeater in actuallity its really a portable extender  [ ie.> if your down in a gully with a portable checking out a car crash  -your car is way above you on the highway ...instead of running up the embankment to talk to your base ..you call on your portable which forces the mobile in the car to transmit with its full { lets say 100 watt mitrek} the base hears your message and responds ..your mobile in turn causes your pac/rt to transmit back to your portable } biggest draw back was its only 1/4 watt output on the portable channel...its amazing what motorola did with all those handie-com portables left over before they made the ht90/440 series radio's  huh ?

And it wasn't that hard to bump the handi-coms to amateur channels - 2m or
440 - or to put the missing final transistor back in.  And I saw more than one
that had a different radio patched in place of the handi-com - even a Midland
13-509 220mhz mobile (modified for solid-state-switching).

Mike WA6ILQ






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