Minitor V External Antenna

FireDawgEMT22 · Feb 1, 2012

I have searched and searched and found nothing for this, so hopefully someone knows. I have a Minitor V with a standard charging cradle. Has anyone hooked up an external antenna to this? What I guess I really need is the pin out for the pager so I can add a pin in the cradle and put a connector on to hook up an antenna to it. It should be relatively simple to do as they sell the amplified charger with external antenna. I just do not want to buy one if I can make it myself. Any help would be great, thanks.

alphacommnj · Feb 1, 2012

Motorola Minitor V Amplified Charger RLN5705/5706 $108.50

I guess you could rig something up on your own but I would stick with the Motorola amplified charger with a whip antenna for the Minitor V pager.
VHF: RLN5075
UHF: RLN5706

A fellow firefighter has used the amplified charger for a Minitor IV and it does improve reception but only marginally. It is good for use in a fringe area or where the signal is just not strong enough to break the squelch on the pager. Since the Minitors do not have an external antenna port you will have to put in some time to fabricate your own charger with an external antenna, and even then, I'm not sure you will see stellar results.

FireDawgEMT22 · Feb 2, 2012

Well one of the pins has to be for an antenna, otherwise the amplified charger would not be able to have an antenna, the pager has all the radio circuitry so the antenna of the charger has to have some way to get to the pager ie a pin on the bottom. And what my problem is, I live far enough away that my pager will activate, but I cannot get the voice after it activates. I have to listen to it on the scanner and at night I do not want to get out of bed and go downstairs to hear the scanner whenever my pager goes off. I was going to run a cable off the same antenna my scanner is using on the roof.

cmdrwill · Feb 2, 2012

You may find that a good quality handheld radio has much better receiver sensitivity and has an adapter available for external antenna. Just make sure that the hh does the same tone decoding scheme that your Minitor has.

SteveC0625 · Feb 2, 2012

Here are the known Minitor V pinouts:

I looked all over the net and did not find any additional info. But, if someone you know has a charger amp for the V, you should be able to figure out the antenna and reset pins by examining it.

FireDawgEMT22 · Feb 2, 2012

Yeah, but i didn't want to spend the money on a new handheld. I have a portable that does not have the qcii, and the area i work is in the process of going digital.

That being said i took a leap of faith and experimented. I hooked up an old coax extension cable to two pins i added into the charger base and it is working. So for those interested, it seems the antenna pins are the two pins directly above the row of three that the charger uses. I hooked my antenna up to those pins and the pager receives traffic and alerts in a location it never did before.

FireDawgEMT22 · Feb 2, 2012

Using that picture, i hooked my antenna into the pins directly below the power and ground and it receives a better signal than it ever did before. I have it hooked up so that the antenna is on the outsider most and the antenna shield is on the inner pin.

FireDawgEMT22 · Feb 4, 2012

Just so everyone knows I have completed the project of adding the pins to the charger base and it works like a champ. So using the two pins underneath the power and gnd for antenna and shield works

jhsands · Feb 7, 2012

so, like this?

those looking at this image, it is not confirmed by the project completer.

FireDawgEMT22 · Feb 7, 2012

jhsands said:
so, like this?

those looking at this image, it is not confirmed by the project completer.

That would be correct.

During experimenting I also swapped the leads of the shield and antenna and while it did increase the signal it was noticeably better with the configuration pictured. Which leads me to believe that this is the correct pin out. I also think that the single pin left is a reset pin that, I would assume, is put to a low input and it resets the pager/amp.

I took it a step further and turned spots on the circuit board into pads for the added pins to rest on and soldered the leads from the antenna to those pads. I now have a charging/programming cradle with external antenna.

krokus · Feb 8, 2012

I have two V amp bases that have died, and I am making one of them into a programming cradle. I will trace out the antenna connections, and confirm. This won't be for a few days, at the least.

krokus · Apr 20, 2012

I got around to ripping into the amp base, today. I can confirm that the center pin of the coax input connects to the Minitor pin shown. The antenna shield connects, in parallel, to a small chip resistor and capacitor, which ties to the ground pin.

My guess: The RC "network" is for static dissipation, while still being at RF ground. (I haven't tried measuring either component.)

lafd55 · Apr 20, 2012

I've heard that Motorola amplified chargers aren't good for the pagers. Has anyone heard this? Or if it is true was it fixed?

krokus · Apr 20, 2012

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lafd55 said:
I've heard that Motorola amplified chargers aren't good for the pagers. Has anyone heard this? Or if it is true was it fixed?

Since there is a constant charge applied to the battery, it might be bad it.

One of these units suffered a lightning strike, so I no blame can be placed on the maker. The second one sounded the hose bells constantly, and the internal relay was not shorted.

jhsands · Aug 5, 2020