The AM sensitivity is just fine on the VX-7.

It's ALL in the antenna.

And if you want a BIGGER battery than that of the VX-7,
you will not be happy with with the smaller capacity stock battery of the VX-8

Leave it to GM to replace the simplest and most reliable charging method with a technical nightmare. LOL!

Any way you alice it, a 12 volt lead acid starting battery needs at least 12.65 volts in order to float.

Anything less and you are in discharge.

Isn't GM the same company that invented the "daytime running lights" that caused premature failure of alternators and headlights?

Hmmmmmmmmm

If you don't intend on transmitting or only intend to operate QRP you might get by using adapters.

I wouldn't waste my time myself.

PROPER coax with PROPER connectors designed for transmitting are FAR cheaper than a PA module plus labor.

By all means call Ten-Tec

They will be more than happy to guide you through it.

865-428-0364

There are many service monitors that can do what you require.

You can sometimes pick up a good service monitor on Ebay for $500 or so.

I use a Comet AS-20 for a compromise between the big antennas and the stubbys.

It's only about 8 inches in length but works well on 2 meters and 440.

You most certainly can use two mobiles and a controller to make a repeater.

And by using vertical separation between transmit and receive antennas, you could even get by without the equally expensive duplexer.

Make your own 1/4 wave stub filter.

There are many online 1/4 wave stub calculators available and all you need is a length of coax and a "T" connector.

One stub cut for 152 mhz should eliminate the paging signals.

Quad driven element is the only way to go.

Direct 50 ohm feed point and simple to build.

Cut it as short as you need to.

However, you would likely get better performance from a 1/2 wave antenna since your ATV lacks enough surface to provide a good ground plane.

Larsen NMO150-BHW

The Larsen is also a molded one-piece coil which is much more durable than the Antenex design and unlike the Maxrad and Antennex designs will not allow water intrusion.

Honestly, I wouldn't bother.

You have a very rare radio and Standard is out of business.

Sell it and buy a lesser radio like kenwood yaesu or Icom
and for what you getvout of the 5900 you could buy TWO
of those!

Primecell.com

They rebuild your BP-172 for $29.95

4.8v 2100mah

I simply went to Walmart and purchased an Everstart    MAXX-29 125AH marine battery for $69 and It is float charged 24/7 by a APC 500Va UPS.

I have both CIG lighter sockets and thumb screw terminals
mounted to the battery box so it is truly portable once
strapped onto the fold up hand truck.

I used a barbed wire fence for a SWL antenna years ago.
Coupled through a 3KV capacitor and had a 90 volt gas discharge mounted to the fence post to ground.

It was fantastic on 160 and AM broadcast.

I picked up foreign AM broadcast stations so strong they
took out state side stations.

And I could hear stations on 160 when most others heard nothing but noise.

Try keying the repeater with the LEAST amount of power.

At that point if you can't "hold" the repeater, increase your power level until you can.

THIS will be the amount of desense (IF you have it.)

Preamps will only make things worse.

In your location, I would reccomend installing a preselector filter like the DCI 145-2H for $169.95
It can be installed AHEAD of the duplexer and will dramatically attenuate out of band signals from reaching the transmitter as well as the receiver.