Removing mag mount coax and attaching my own coax?

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Apr 17, 2011
What is RG-58C and RG-58C/U? I've heard of RG-58A and RG-58A/U but not RG-58C or C/U.

Okay, RG-174 kinda lossy. Maybe I should look for an antenna that uses different coax.

Any idea what the lowest loss coax I could get would be? Just curious.
RG-213 Mil spec?

So impedance is a non issue with receivers? Wouldn't a mismatch cause standing waves that would impede incoming signals?

That'd be nice having free pickings at the sattelite installation. :)

Is there any bad effects from using different grade feedlines connected together?

Indeed, I listen to 800 MHz regularly.
I've never found an impedance mismatch to be a problem with a scanner receiver.

As an example, I'm using RG-6 on a home made 1/4 wave to listen to local police and aircraft in and out of KSTL. I can hear aircraft down to 1500' and I'm 50 miles from the airport.


Premium Subscriber
Aug 29, 2017
Good stuff to know. An antenna designed for specific bands or frequencies is something I'd like to try. I listen to 800 Mhz regularly but I also like to try to cover everything so all band is definitely the way to go right now. That's also why I want an all band antenna because it's cheap and I'm not sure if it will magnetize to my roof or not, not sure if I have a metal or fiberglass roof. I could try sticking a fridge magnent or neodyne on it to see but if it doesn't work I"ll probaly use it on another vehicle. It's for my semi truck and I haven't bothered climbing up there yet.

I think maybe I've heard of 10base2 ethernet. Interesting. Sound like the c/u could come in handy.

We are really starting to get into the weeds here, but your questions are valid concerns. Yes they are. :)

Okay I understand what your saying about impedence changing across frequencies and why an antenna would perform better if it is resonant for the intended frequency of use.

By grades I just meant coupling RG-174 with RG-58 or whatever else kind of coax they have available out there that's good for mobile use. Maybe that's about it, idk.

Glad you like the RG-213, think I"ll get some of that when I get my base station set up.

Yeah that interesting about the 1:1 VSWR. I heard 2: 1 or less is good to shoot for but at least I know now that I don't have to worry about that with the scanners.

Thanks for the antenna examples and brand info.

Welp, sounds like the 32db amp would just kill my signals so I"ll take your guys advice and go with the 10dbm, only a fool wouldn't.

Looks like I'm back im the market for some amps and double shielded foil coax.

Yeah I would prefer to buy an amp with an attenuator so I could tweak the amplification as I saw fit. I'm sure they must make some with attenuators. I suppose different equipment responds differently.

Your saying to stay away from the 10dbm amp also Ubbe? How does it put out 30db if it says 10dbm? P1? I don't understand db that much at all yet.

How well do mag mounts hold up to inclament weather? I need to figure out how you protect an amp outside the vehicle as well. There's no where close where I could put it inside the vehicle like you could with your trunk.
The 10db amp has not exhibited any issues that make me think it has a high noise figure. In fact, I expect it has a low noise figure from the performance I get. For the price it is worth a try. Some mag mounts I have had did very well in weather staying on my car, but others have had water get into them and ruin the coax connection. The large ones can be taken apart and repaired, but those small molded ones are often glued shut. The one I am using now I got from Amazon. I thought I bought it from eBay, but found I had gotten it from Amazon. So far it has done well for about 2 years. I had to glue the magnet back in place once. It is under a piece of Mylar.


May 22, 2018
Well, I"ll give it a try. I"ll be sure to check out the shielding, I do want to try out some coax with that foil double sheilding sometime. Hopefully that spectrum force mag mount holds up against the weather just have to give er a try. I will also try out a mag mount antenna with RG-58 a/u.

Sounds like your quarter wave antenna is doing just fine, good to know the impedence shouldn't really matter. I"ll still try to match stuff up if it's on a certain frequency with an antenna that's resonant for that frequency and maybe I"ll try unmatch to just to see if there's any noticeable difference.

When I get my mobile setup completed I"ll have to post some pics of it.
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