Maxon 8402A is pretty decent and also a commercial radio at a decent price. Hytera HM782 is a commercial radio that will work HAM/GMRS in both analog and digital. Both radios are programable, have fantastic receive ends and transmit 40-50 watts. Kenwood is another choice but i'm not familiar with their radios.. Programing the Hytera and Maxon radios are both a cat walk. Very easy learning curve..
you can save a ton of money and buy two Maxon 8402A radios, the repeater jumper cable and programing software. And of course you'll need a Duplexer. These Maxon radios are the exact radios used in the Bridgecom repeater. I use these radios for my repeater and i talk 70-80 miles.. I didn't use the repeater jumper as i installed and ICS Repeater controller using Open Repeater (open source software that works with an ICS controller) Or you can go with the two Wouxuns KG1000 radios.. The Maxons would still be a little cheaper. The programming software is fairly simple to use.. RFWiz.com and i believe buytwowayradios.com are Maxon Dealers.
Many years ago i tried a UHF antenna in an attic of a two story house and never had any luck with that setup.. Always puzzling because talking on portables from the garage down stairs worked much better.. There are lots of things in an attic that hampers single quality.. i.e. HVAC vents, wiring, vents etc.. I ended up putting the antenna in a tree next to the garage and had pretty good results.. Flag poles work well too if you can get away putting one up.. Experiment.
It may not help to run direct to battery. My mobile in my RAM 6.7 Cummins picks up electrical noise generated from either the electric fuel pump or the manifold heater element.. Not sure which one is causing it yet. It's not really annoying but you can hear it when it cycles on/off.. My mobile is ran direct to one of the batteries and yea, i checked with two different mobiles and both radios pick it up..
Bigger cities, i.e. Los Angles basin will drive you nuts.. Rural areas like Palmdale, Lancaster, Mojave Desert etc is always quite... hReally depends where your at.. I'm sitting at Lake Isabelle today and it's fairly busy with boaters and campers.. They aren't chit chatting to shot the breeze but rather sharing fishing results, camping locations etc..
if you have a 3D Printer there are tons of free files for cable clips in all sizes available on-line. Print them with ABS fillimant for UV protection.. They print failry fast and the various options will suite any need..
FYI,, After running a 'report' this morning for current updates.. it does look like many of the Repeater Linking guys are turning off 'Access Request' for their repeater sites. Meaning they are not accepting request to join their repeater circus.. Also noting that many are toggling from 'Paid Access' to 'Permission Required or Open System'.. Some are even disabling their rogue repeater.