marcspaz

Here are the readings on my X300 with a 30' run of LMR400. Not getting on the roof anytime soon. Did you add a ground strap to the base of the antenna? I have a run of 6 gauge going to a ground rod. May be the difference.

I'm courious about the SWR on the x300. I have the x300 repeater antenna mounted at my house. The extra height and gain contribute to extending the coverage area. I got an additional 5 miles but switching from the 200 to the 300. I'm going to go grab my analyzer and checking my SWR. You my have something wrong on your end. Last I checked, my SWR was 1.5 or 1.6.

Everything that adds height about the ground (in this case the mount itself) adds height/length to the antenna, thus impacting SWR.

You're not talking to anyone with a bubble pack radio from car to car unless you can see them anyway. Not sure a $10-$20 radio not having a scan function is a real concern in this situation.

For spring protection when offroad, I use the Comet SBB-1. Its basically a taller rubber-ducky antenna good for 60w. 100% flexable and works great for MURS, 2m, 70cm, and GMRS.

There is no "limit" on antenna height from a GMRS rule perspective. If you have a 1,500 tower, from an FCC rule perspective, you are good. Now, there are registration and notification requirements for antennas near airports and for antennas over 200 feet. However, as long as there is no safety or environmental impact, they will simply process the notice/registration into the official record. There could be state, county or local restrictions, etc. If you are dealing with an HOA... have fun getting an antenna up at all. It's always a fight.

@fremont I am in agreement with @mbrun. If the cable is NOT connected to the radio nor an antenna, and you measure between the center lead of the NMO and ground (and/or the antenna mount bracket), and it shows <1 ohm, then you have a dead short in the cable or the mount. Take the coax completely off the mount and see if the short between the center lead and the outside of the cable still exist. If it does, you need a new cable. If it doesn't, its the mount, and I would still be very suspicious of the nylon isolator.

@wrop206... LOL true story.

Hmm.. odd, why did you vote down my response? You don't believe adding the spring can cause problems? I noticed @WRAM370 gave the same advice and you agreed to try removing it.

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@DanW Yeah, like I mentioned earlier (today? don't remember. LOL) I don't think 20 is the right answer either. I really hope it gets more popular, though.

LOL... Point taken. The total population in and around the Line A is significant, for sure. I don't know if call signs start with any other letter than W, but per the FCC there are only 126,153 GMRS licenses that start with W. Seems about right since there are 842,408 actively licensed Amateurs, and ham radio is much more popular.

Oh, man! I missed the spring part. Adjusting the antenna length a couple of millimeters can throw off the SWR. Adding a 4 or 5 inch spring will definitely through it off.

There is a nylon spacer between the mount and the center feed on the 3/8x24. Make sure its aligned correctly and not crushed. If you have an ohm meter, disconnect the cable from the radio and the antenna from the mount and see if the center lead is shorted to ground.

No, I am not saying that 79 million people live above Line A. They would be packed ridiculously tight. What I am saying is, the total population of the northern states that Line A is present in, per the Census Bureau, is about 79,633,000+. That is enough people whom driving to or north of Line A is a distinct possibility, that they should be considered in a standardization proposal.

No, I'm sorry.. That is not what I am trying to say. What I mean is, none of your measurements are in agreement with one another.. Therefore I do not trust the 40 W reading. I believe that either you need to calibrate your watt meter, your amp meter, your volt meter, some combination of the three or all three.

@WROZ437... you are experiencing exactly what I would hope to avoid. Finding something other than 20 for "over the road simplex" would work much better in many cases. Maybe, there is no single channel as answer. OffRoaderX does have some entertaining content. Being a Jeep enthusiast, I love watching offroad videos.

Something I was thinking about with regard to Line A... 90% of the US population lives on the the US borders and coast lines. ~79,633,000 people live on the northern border. That means that Line A has the potential to impact communications for more than 24% of the people in the lower 48 states. As much as I like the idea of picking a channel, a channel other than 20 to avoid conflict with potential ORI type repeaters, a solution that potentially excludes almost one quarter of the population doesn't seem like a solution at all, IMHO. In fact, I would be more prone to encourage people to use 20 over 19, since many repeaters have light traffic and operators are supposed to be mindful of not causing interference as part of their license agreement, anyway. I don't know the right answer. Just thinking.

The meter should have come with a ground plate for testing HT's with antennas. I though the meter was at the base of the antenna. If you are 4 feet away, especially if the meter is inside the vehicle, that should be plenty of distance and shielding.

The number one rule of emergency communications is, the command center should never be in the affected area. If you are in the affected area, you need to have a radio relay system established to get the message to the appropriate logistics or CnC staffer inside or outside the affected area, to send help. So, if you are outside the impacted area, get the person's name, what the emergency is, where they are (to the best they can say). Basically the 5 W's. And then you or someone right next to you calls 911 and relays that information. If you are in the affected area, you gather all of the aforementioned information and then relay it through whatever stations needed or direct to CnC, logistics, or whatever unit has been established to respond to the type of emergency being experienced. If you are at an event that is just starting, you will likely be relaying that information directly to Incident Command. Yes! Exactly! Both fantastic radios. I am partial to the Icom, but you can't go wrong with either.

Eh... no one was looking for any of us. Honestly, back then it was common for me and a few friends to vanish for days or even weeks at a time while we were partying. Two days was not a red flag. These days, if grandpa is gone for more than 2 hours, my phone is ringing because the babies want to know when I'll be back. LOL

I'm going to throw this out there. I did about a year ago and it was not well received, but I hope this audience is a bit more open-minded. Just my own personal opinion, the best solution that has zero reliance on any underlying system is 40-meter Amateur radio. There are extremely lightweight, compact, battery powered radios. You can get a small foldable/roll-up solar kit for unlimited use. The antenna is just a piece of wire that only need to be a few feet off the ground. The best part is, depending on how high you make the antenna, you can talk everywhere from 1 to 10,000 miles. You are going to get help day or night and can actually talk to someone for health and welfare as well as status updates. I know we're a GMRS forum and there is some good advice on the satcom stuff, too... but I feel like they have dependencies that are failure points.

Are you using a grounding plate/shield to stop rf from the antenna soaking the meter?

@Sshannon If I were to guess, I would say it might be based on the minimum voltage needed for the radio to work. Given that they said it should be close to 8 amps (46w +/-) at full power and it has a 55% efficiency rating, the math would work out to 11.5vdc. That kind of makes sense... most 12vdc systems run on as little as 11.0vdc and max out at about 15vdc. So, you may be on to something there.

I wish I could answer that question accurately. Very little information about the radio that was given to me. As you noted, I'm not sure it matters either way, based on the math you shared.