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As kids we hung around the local RS before the TRS80 computer was even thought of. Their parent company, Tandy, used to sell leather and leather crafting tools back then. Their coax sucked and I didn't even know what good coax was. We used it for CB because we didn't know any better. Actually Lafayette was a much better and highly respected company.

I give up, what's the LEARN system?

Should have said thanks Steve for posting info from Gil.

well there sonny,,, There was a time when Radio Shack was the deal... Unless your an old timer, you have no clue...

Hi Gil, Thanks for the information. I will take another look using your information. Dave

One of the main differences between cheap coax and more expensive quality coax is the amount of shield braid used and also the materialist is made from. You will only see about 50-60 percent of the dielectric being covered by the shield braid on cheap coax where you will see 70 to 100 percent coverage in the more expensive coax. The amount of shield braid makes a difference in how it protects against RFI and will also act as a better counterpoise when the coax is used as such. It is common to use the coax as a counterpoise when using end fed half wave antennas for HF versus running a separate counterpoise wire.

Yeah, definitely best to not draw attention to yourself.

The words "Radio Shack" totally disqualifies this as a viable choice. At least you got a free battery if you joined the battery of the month club. But seriously,that cable was acceptable for CB use, that's it.

Not all RG8 is stiff.. Radio Shack used to sell a flex RG8.. I've used it many times and yes it is flexible. It was a pain to make connectors though, the dielectric would stick to the center conductor which had to be scraped with a plastic wedge and the shielding would mold into the outer sheath making that a pain to remove. But over all after spending an hour putting connectors on, it was decent cable

It did occur to me after reading some comments that because this is a NGP antenna in a NGP installation, perhaps the real difference is that the cable I changed to acts as a better counterpoise than the one I replaced. That could simply be a fluke, because I doubt either US or Chinese manufacturers give any significant thought to its characteristics as a counterpoise. Maybe they do, but I'd be a little surprised.

The stiffness of RG8 is specifically why RG8X was invented. It would be extremely difficult, if not impossible, to route LMR400 in most of the ways required in a vehicle.

Although LMR400 cable is not constructed the same as RG8 coax cable, but they do share the same physical dimensions and RG8 coax was predominantly used in mobiles several decades ago especially when a ball and spring mount was used. The minimum bend radius spec for heliax in addition to the difficulty of routing heliax throughout a vehicle would make it impractical.

I see I was wrong about this. Thank you both for the corrections!

I don’t recall ever saying that you are using the wrong coax. I pointed out that RG8x has a foam dielectric and RG58 has a solid dielectric and that’s why RG58 is frequently used for mobile installations. RG400 also has a solid dielectric and a tiny outside diameter. It’s expensive though. A person could build a Frankenstein cable using RG400 where needed and something with less attenuation elsewhere to make up the necessary length, but the splice points reduce reliability and potentially add losses. Also, nothing I’ve said has been demeaning or critical of you or in any way personal. I’ve tried to stick to factual information, demonstrating how I did any calculations.

I’ve been meaning to grab some for a long time now. I think you’ve got me motivated to pull the trigger finally.

Im just trying to help and little, but i think there is benefit to watching this video. I put it together for some new Hams in my club, but the Amateur frequencies in UHF are close enough to GMRS, that the demo is still very valid.

Exactly. So, what's the point of telling me I'm using the "wrong" coax? I'm sure ladder line would give better results, but it won't fit through the holes in the floor of the back of the cab, to say nothing of going under the side bed rail, over the top of the front bed rail, down the front of the bed, under the cab, and back up through the hole in the floor. 15' is about as short as I can go and it has to be very flexible. I'm not aware of anything "better", but I'm open to suggestions.

Hey, just trying to spread some love. I know some people here might not seem like they love each other, but think of it this way, it can be just as difficult picking the right coax. No shame in selecting the wrong coax, just admitting to yourself you made a poor choice is the first step towards inner peace.

I reran the numbers using RG-58, RG-8X, and RG-8 with the length of 15 feet since that is the average length used in vehicle installations. RG-58 RG-8X RG-8 Now most mobile antennas will not have 5 dBd of gain so you will have to adjust that number using the calculator.

I'll be civil to him when he stops being an ass.

That's nice to know, but LMR400 and Heliax aren't practical for vehicle installations.

Come on now. Please be civil as this is a family oriented forum.

I'll look at that for next time. In the meantime, I'm not having any more line loss than 99% of the installations out there. Less than most, in fact.

Kind of irrelevant since most of us won't be using 100 meters of either in our mobile instalation anyway. Again, using the right coax for the job is key.

No, you illiterate. I specifically stated that it's an NGP antenna. But even an NGP antenna can often benefit from a good ground plane.