BoxCar

Codeplug is the frequencies stored in the radio. For multiple radios you normally program one radio and the using computer software copy that programming so it can be "plugged" into the other radios. '

A little 5 to 10W repeater on battery and solar with a J-pole would more than meet your needs. I'd put the antenna and solar panel on a pole part way up on a ridge or hill to limit the exposure off the property. Use codes on both the in and out frequencies to limit any unwanted users.

A copper scrub pad won't rust.

50W ERP is 6 feet of clearance in free space. There are several calculators for the new guidelines available on the net. ARRL has one that's fairly easy to use as an example. But as far as shielding goes, an aluminum ground plane is as good as steel. Aluminum converts magnetic energy to eddy currents within the metal so the RF is effectively neutralized.

If you won't have an issue with putting a connector on the coax, run it through a piece of PVC pipe. Fill the pipe with insulating foam leaving a drip loop on the exterior portion of the cable just before entering the pipe.

I would look online for a cable that matches the white connector and has the other end of the adapter cable either bare or terminated with fork or round lugs. you can then use a larger supply like https://www.amazon.com/eTopxizu-Universal-Regulated-Switching-Computer/dp/B00D7CWSCG/ref=sr_1_3?crid=ZSAO9DWX9EIZ&keywords=12v+power+supply+30a&qid=1636219326&sprefix=12v+power+supply%2Caps%2C118&sr=8-3 to power both radios.

You forgot WOAI in San Antonio

Actually, the software can be moved to multiple computers--as long as you use the same email and ID code. I have my copies on two computers, one desktop, the other a portable.

As long as the two are no transmitting at the same time you are OK. Desense is primarily passed through the antenna into the receiver so it's the antennas that are the key players.

Getting help in those situations relying on low power FRS/GMRS units will be spotty at best. While more people are installing and using these radios, they are not widespread. Portable, hand-held radios have a radiated signal of 5 watts power, just like the vast majority of radios used by others. Mobile or in-car units can have up to 50 watts of power on some frequencies. The primary issue is having another station in range which is why it would be hit-or-miss. The other radio services available to most people, CB and amateur have many more users and a greater chance of being able to reach another party. CB has 40 channels with a more structured use in that there are some channels used primarily for travel. The problem with a hand-held walkie-talkie is the antenna length needed for its lower frequencies. FRS/GMRS operates at a much higher frequency band so the hand-held antennas range from 6 inches to about 19 inches. This is off-set by the fact two stations have to be virtually in a straight line from each other or in line-of-sight. GMRS radios can use repeaters which will allow a signal to be retransmitted from another location to cover more distance. Repeaters are not real common, but there are a lot of them in-service. Amateur, or ham radio is another option. The portable, hand-held units have roughly the same power as the others but have many more frequencies or channels on which to operate and a very robust repeater infrastructure. Both GMRS and amateur require FCC granted licenses to operate. GMRS doesn't require any more than the license and equipment while amateur requires some knowledge of both radio and the regulations proven through a 35 question test. Amateur equipment is generally more expensive than GMRS, but that's off-set by its flexibility and greater infrastructure. In use, ham and CB share in the fact they both are used for talking between stations without the language found on CB. FRS, limited to very low power is often used by families and children with some business thrown in. You won't find much in the way of general conversational use on GMRS due to the low overall number of users. My recommendation is to get licensed for both amateur (Technician) and GMRS. Use both on the road but amateur on the trail.

repeaterbuilder should give you some help. You will probably need a duplexer, power amp and supply for most basic installs. Plan on adding an auto id device and an interface circuit to handle the receive to transmit audio.

Nice

this request for help setting up a radio and what if anything is nearby points up the problem of buying online. There is no local help available. My suggestion is to search for a local ham club and ask for help. Hams generally happy to offer assistance and can also offer a path toward getting an amateur license with more power and options. While I had radio experience so programming the radio wasn't difficult for me, I know how daunting a task it appears to someone with no knowledge

HF "bends" by reflecting from layers in the atmosphere. UHF doesn't reflect so is line of sight to the horizon.

If your friend has his FRN he can do the search using it and the results will be any licenses issued under that FRN.

I would be very happy with those readings. Try different channels and get readings on those so you have an idea of the bandwidth of the antenna.

GMRS users aren't organized into clubs to sponsor a sales/swap meet.

Try fleabay

Written for hams, but the principles apply to GMRS as well. What is a Repeater and How Do You Use One to Communicate? – OnAllBands 73's all K4BJW

Both can contain outdated listings. It's best to just monitor the repeater output and see if there is any traffic. You can then ask specific questions about programming your radio by giving us the manufacturer or brand and model.

Paired frequencies act as if it were a single channel. That's what paired means and repeater channels are PAIRED.

Gee Michael, I thought the OP would have enough common sense to point the dish at the repeater. I guess some people need to be led step-by-step and can't reason things out.

Use a small 1/4 wave placed about 6" in front of the center of the dish. You'll get a directional antenna with about 3 dBd of gain out of it.

If the noise was present only when driving, it may be from your car also.

Members of the same family can share the license of a licensee. Members of different families will require their own license to use GMRS. An alternative would be MURS, Multiple Use Radio Service which uses the VHF radio band. VHF will have a better range than GMRS or UHF under most conditions even though MURS is less power out. MURS, like FRS does not require a license.