jas

Thanks! Based on what you posted I did some more research on this. I found the exact tone on a video in YouTube, although it's much louder and clearer in person. The video is about programming Illegal FRS digital radios. The signal is strong enough in most parts of our county to exclude an FRS radio on simplex, unless the radio is connecting to a repeater. Then again it could be any other radio that has both the capability to transmit on 462.700 and also digital. Then again, it still points to a repeater because of the distances. Here is the video. I queued it to start at 14:30, a few seconds before you can hear the tone: https://youtu.be/R_fYaK84VU4?t=870 Best, JAS

Hi all, This is an addendum to my original post above. I received the Laird 1/4 wave 6" whip antenna and have now done the SWR test. It's really good. Especially when compared the the Midland MXTA25 Ghost, the results of which you can refer to on the first post. Reception is also crystal clear. Very pleased. with the Laird product. Here are the numbers: Laird – “2.1 DBi” 6” Whip Channel 1 - 462.5625 – SWR 1.04 Channel 16 - 462.575 – SWR 1.06 Channel 22 - 462.725 ­– SWR 1.07 Channel 15RP – 467.5500 – SWR 1.01 Channel 18RP – 467.6250 – SWR 1.01 Channel 22RP – 467.7250 – SWR 1.01 The next step is to install a new Laird Mag mount. It has the RG8X cable vs the RG58/A/U on the Midland mount. The Midland mount/cable combo has a calculated loss of about 45% so my MXT275 has turned into an ~8.85 watt radio! The Laird low loss mount/cable should up the output of the radio to about 12.3 watts. It should be here next Tuesday and I'll report back after the install. All the Best, JAS

I'm on the West Coast of Florida so that is highly unlikely! I'm going to try to make a recording of it and figure out how to post that. Best, JAS

I was just about to post about a similar problem and found your topic. Not trying to hijack the post by any mean, the problem I have seems similar but only it's only in one channel. I 'm using a new Midland MXT275, which if I'm not talking I run on scan. It's weird but there is never anyone on channel 21 (462.700), with one glaring exception. It started as best as I can describe it, a loud machine gun like tone lasting about 3-seconds. At first I thought OK, a repeater tone and left it at that. Now it has become really annoying. I can hear it everywhere in two counties, distances up to 40 miles. And now it's very frequent, sometimes two or three bursts in a row spanning a couple three minutes. It is very loud! Then I thought well I never hear anyone on that channel so it might be the radio, or some other inside the vehicle interference (that could still be the case). I tested the radio on that channel talking to my wife on her HT and it all works perfect both ways. I'm at a loss and would appreciate suggestions. Best, JAS

Thanks so much for the tables and info. I looked at my magnetic mount to see if I could replace the cable with 8X and it can be done but it would be quite involved and would compromise the bottom of the mount to water intrusion. So, I went looking on the net and good news! RG8X magnetic mounts are rare, but I was able to find a Laird 8X mount in stock at Arcadian, the G8XPST. It's silver chrome but no biggie. Laird has a lot of 8X magnetic mount products including black ones but they are not in stock. Interestingly, these RG8X mounts are made by a company called Antenex Corporation, which was absorbed into Laird. here's the description: "High Quality NMO cable kits and NMO magnetic mounts were the flagship product of the original Antenex Corporation, founded in Glendale Heights, IL in 1990. The company's passion and dedication to designing and manufacturing high-performance coaxial cables like G8XM for Magnetic vehicular mounting of NMO antennas continues to drive the company's success today. Owned by Laird Technologies since 2006, this dedicated group of Land Mobile Radio (LMR) professionals use quality materials and workmanship to produce a superior product." On the website they have the attenuation of the RG8X at 6.09 DB/100FT, which looks optimistic compared to the tables you sent me. Either way, this will be a lot better than what I have now. It's on the way to me plus another 1/4 wave antenna (in silver stainless). That one by Pulse - Larsen. Thanks again! Best, JAS

Just read this post and decided to look at my mobile setup. Found a calculator online and my first thought was: "this has to be wrong!". So I dug some more. Found more info and they all seem to match. If this is true, in essence my 15 watt MXT275 radio, coupled to the Midland magnetic roof mount (MXTA12), which comes precabled with a 6 meter (19.7 feet) RG-58A/U coax is really only a 8.85 watt radio, not counting connector losses! That's a 45% loss. I'm still finding that hard to believe. If that is indeed true, I also find it hard to believe that here we are in the 21st century and no one has seen it fit to come up with a better cable in a number of generations.... I will be buying a cable splicer and pliers to shorten the cable. I wont be able to make it shorter than ~8 feet so I'll end of with a ~12 watt radio . Live AND learn..... Thanks for the post! Best, JAS

Excellent post Michael. A great read with a lot of valuable information. Your cutoff distances sure point to a worst case scenario testing, and those are the kind of tests I like to see. I find there is a lot of stuff out there like "I can hit our local repeater from 45 miles with my XYZ HT" possible, but utterly unrealistic, to say the least! With the GSX Midlands if we are on the road .5 miles away and an 18 wheeler gets in between us, it's over! Thanks so much for taking the time! All the best, JAS

Excellent video! And excellent channel! Best, JAS

Thanks Michael. Another reason to not use the MTXA25. When I read what you said about the high numbers on the repeater channels. I went looking on the web. I found an article on the subject of antenna matching, albeit on an Amateur Radio site, where this came up: "Matching a mobile antenna to the requisite 50 ohms is a requirement for several reasons. For example, modern solid state radios are designed to reduce their output power when the input SWR reaches ≈2:1. Some will handle a little more, some a little less. Once matched, the SWR doesn't have to be flat, so anything below 1.6:1 is close enough. Remember too, if the unmatched input impedance of your antenna, is less than 1.6:1 at resonance, you need a better antenna and/or mounting scenario." He goes on to mention, and as I infer from your comment of staying under 1.5:1, that: ".......Once the matching is complete, whatever the SWR is (assuming it is under ≈1.6:1) is irrelevant....." I'm now wondering if GMRS radios are also built to throttle power for anything over 2:00:1 and if they do and we don't know about it then there could be a lot of perceived radio issues that have to do only with that throttling. That article is here: https://www.k0bg.com/match.html Thanks again, JAS

I'm not an expert on this topic by any means but as WRAK968 said in his post it makes sense that the antennas are too close. You might be overpowering the receiver on the scanner causing feedback. Squeals are usually feedback based, as opposed to say Hums, which are electrical - ground loop based or such. Can you adjust the output wattage on the transmitter? If so drop it to the lowest setting and try it again. If the squeal diminishes you have your answer. If that's the case then you might not be able to eliminate all feedback if you have a lot of transmit wattage, and might have to relocate the scanner antenna. Best, JAS

Hi All, As a followup to the tests I wrote about in an earlier post, today I hooked up my Surecomm SW-102 to the Midland MXT275 and ran tests with both of the antennas. I didn’t expect the SWR variation I got using different frequencies. Maybe someone more knowledgeable than I can forward a possible explanation…. All the test were performed in an open area, using the Midland MXTA12 Antenna Mag Mount with the original cable length. The antenna is mounted behind the moon roof in the center of the rear portion of the roof with steel dimensions of 14 x 40 inches. The rear tailgate/spoiler roof is behind that steel roof, and is about the same dimensions. That portion of the roof is non magnetic (some sort of plastic), and houses all the vehicle antennas (GPS, Wireless, AM/FM, Cellular) with a flat aerodynamic, raised hump in the center. The distance from the hump to the antenna mount is about 10 inches. All those system radios were operating at the time of this test, except for Cellular. I still have not received the 1/4 wave Laird whip I ordered. I will test that antenna as soon as I receive it. Should have it in about ten days as it seems to be back ordered. The results: Midland MXTA25 – “3 DB” Ghost: Channel 1 - 462.5625 – SWR 1.08 Channel 16 - 462.575 – SWR 1.14 Channel 22 - 462.725 ­– SWR 1.15 Channel 15RP – 467.5500 – SWR 1.72 Channel 18RP – 467.6250 – SWR 1.74 Channel 22RP – 467.7250 – SWR 1.74 Midland MXTA26 – “6 DB” 32” Whip Channel 1 - 462.5625 – SWR 1.11 Channel 16 - 462.575 – SWR 1.24 Channel 22 - 462.725 ­– SWR 1.21 Channel 15RP – 467.5500 – SWR 1.01 Channel 18RP – 467.6250 – SWR 1.01 Channel 22RP – 467.7250 – SWR 1.01 All the best, JAS

I like the way you think! In my business, the mantra is: "....What do you think? What do you know? What can you prove?....." In that order Best, JAS

I agree with both previous responses. If you have the wireless modem in there and also have Bluetooth switched on that might have a small impact, but it would be your radio interfering with them . Double pane windows with metallic solar coatings. if you have those they are not going to help either. I have 180 MPH hurricane windows and sliding doors on my home. All of them double glass with metallic solar coatings (they look like green mirrors from the outside). I can be out on the patio all happy with my HT listening to everyone, and if I walk inside and close the sliding door it's like turning the power off on the HT! Instant silence.

It's not that the MTXA25 is that bad. It's just that in a worse case test the difference between the antenna that came with the radio and the ghost is not enough to justify the cost of the new cable and the cost of the antenna itself. And as I mentioned, in best conditions the ghost might outperform the 1/4 wave factory antenna. I don't have that information. If there is one thing I've learned about UHF so far is that when transmitting in all kinds of different situations, going up in elevation beats everything else. I remember using AM radios on boats back in the day. Some special days we could transmit and receive over 100 miles (all over water). UHF is clearly a different animal. Line of sight is basically the limit. Even an extra foot or two in antenna height, as was the case in the test with the MXTA26, and maybe coupled with a bit of extra power from the antenna's directionality could account for extending the range by another 20% or so..... Best, JAS

Hi all, New here but have read a lot of you all’s posts. Great advice, thank you. I'm an older pseudo-retired guy and with this COVID thing still going I have a lot of free time on hand. I forgot, and my GMRS license expired so I had to get a new one, new call sign and everything. Had the original since the mid '90s. Living in hurricane alley it was the best option then and still is. Whenever you have to leave your house behind, it’s convoy time. So, after doing that, and replacing the HT radios (from the 90's) I decided to get a mobile radio. I went with the midland MTX275 because of what I drive (see below). As most of you know it comes with a 1/4 wave 6-inch antenna, although I was surprised by the how thin the cable was, not like any coax I'd ever seen. As I found out, it's not a bad thing. With lots of time on hand I decided to run some tests of the Midland antenna lineup. The test was limited by my application. I'm driving a leased 2019 Lincoln Nautilus Black Label. Look it up - NO holes allowed anywhere! It has a moon-roof, meaning I had to go magnetic and only have 14 inches of ground plane North/South, with the width of the roof for the sides. Mounted the radio under the driver's seat – remember, NO holes anywhere . I live on an island in Florida. Lots of homes, 5-story condos and such = lost of interference and no high spots except for bridges. So, for the tests I bought the MXTA12 magnetic mount, the MXTA25 Ghost and the MXTA26 "6DB" antennas. The antenna that comes with the MXT275 comes pre-wired, so I needed Midland’s bigger NMO mount for the new antennas. The mount is three times as big, very secure, rubber booted, and with a real coax cable. Off I went to test… I’m a business analyst by profession, which means that when I analyze stuff I always start with worst case. And that’s what I did here. The tests were done by driving away on the mobile and transmitting, starting from the front of the house and then every ¼ mile. The receiver, a lowly HT was set up outside in the worst possible location and just high enough off the ground as to mimic a sitting position. To record the test, I set the HT right in front of my iPad and set the iPad memo app to record. Each test took about 15 minutes. The results? Reception on the HT in these worst of conditions, transmitting with the antenna included with the radio was all static at 3.5 miles and cut off completely at 3.75-miles. Had a lot of static at 2.5 miles when I drove by a 2-story small shopping center adjacent to a 4-story condo in the line of sight. I went over a 25-foot-tall bridge at 3.25 miles where the transmission was perfectly clear. With the MTXA25 Ghost antenna installed, the difference in the results were measured in feet (not good). In the clear it is clearer, but it has a lot of static in the same places as the little 6-inch included antenna. It is possible that in a best-case scenario, the opposite of what I did, it will outshine the ¼ wave antenna. In my opinion it’s not worth the extra money for that cable and antenna combo. The difference is that small. The MXTA26 ran away with the test. I believe it is a 5/8 wave antenna and it’s all of 32-inches tall and so I must stop when I get home and take it off to go in the garage (raining?). Not a reasonable thing for everyday use. I quit that test at 5-miles, it didn’t cut off like the other two, just unintelligible static. It outperformed the two other antennas both in clarity and distance by a mile. That’s a big number when trying to hit a HT in the worst conditions distance percentage wise. I did other tests, 100-mile loops with all three antennas, that was a reception test, not a transmit one. The MXTA26 still won the day. The other two were about the same. After this test, and for every-day use I just ordered a Laird ¼ wave antenna, the QWB450. Only reason I did that is to keep the MXTA12 magnetic mount so I can swap between the ¼ wave and the MXTA26 when needed. I have no use for the MTXA25 Ghost. Well, that’s it for me. Hope this was helpful. All the best, JAS

Thanks so much! I stand corrected. I was looking at DAT files in excel and the numbers were huge, all with real people and addresses in them. I've been driving around in a specific ~100 mile loop in my area testing different antennas for reception with my mobile set to scan mode. It cover all different kinds areas from undeveloped to farms to very congested cities, over water, and on tall bridges. The traffic on GMRS is non-stop. It's mostly all businesses with some long chats on repeaters and a smattering of personal stuff thrown in mostly in the FRS shared channels. This is what got me curious and asking myself - how big is this GMRS thing now? I'll probably take the tech exam anyways. I'm pseudo retired so have time on my hands. Learned a LOT about antennas so it was worth it!

Source? Pretty please...

If you don't want to use the cheaper handheld radios from companies like Midland (which I do) I would recommend the Wouxun KG-805G. It's just becoming available and is FCC approved. Personally, I've done A LOT of careful tests on GMRS, and putting the ruggedness and durability aside, Handheld radios are all pretty limited - the differences in performance are small. The difference between say 3 watts, as in the Midland radios, and 5 watts on the Baofeng, is negligible in all but the worst environments. If you're on the move, and not walking, you should have both mobiles and hand held radios. Mobiles get out further, and more importantly, can listen from a lot further away. Listening is always good in emergencies.

Hi, newbie here. first post. I'm old, as old as I would like to be . I started with radio in the mid late 60s on my dad's boat. AM and SSB with a 20 foot antenna. Since then I've lived in Florida for ~40 years. Had a boat, VHS and so forth. It wasn't until Hurricane Charlie (2004) that I realized some kind of mobile radio was a critical necessity. I live on the left coast of Florida, one street from an open pass to the Gulf and Charlie (a CAT4) was heading straight for us. We were "forced" to evacuate and at the time, with 4 and 6 year old daughters I did. Wife and I took both vehicles to go inland, and it took us 11 hours to go 100 miles to Orlando. My vehicle had a lot bigger gas tank than my wife's minivan and she almost ran out of gas. Story short, Charlie missed our area but went right over us in Orlando. The next day we decided not to go back home on I-4. Big mistake. We went through Kissimmee to get south to HWY 60 so we could get home. It didn't work. Worse, everything was pretty much destroyed. No power, no gas, no cell service. Already committed we kept going south and my Wife started running out of gas again and even worse, we got separated, with no comms. It's a lot longer story but I'll cut it short and say we got home safely, And after seeing the devastation in some of the towns we went through I made a large donation to the Salvation Army, which ran hot food canteen trucks to those areas. I saw it first hand. No comms, separated from my wife in different vehicles, two little kids, and she was running out of gas. Never again! I jumped on GMRS right then and there. Nowadays, GMRS in my area is pretty much a Business radio. that's what I hear most while driving. So, I thought an Amateur license might be a better way to go. But then I started looking at the numbers. I might be wrong, but according to the ARRL license counts they show 774,127 Amateur licensees in the whole USA. http://www.arrl.org/fcc-license-counts So, I wondered how many GMRS licenses are out there? I'm not very good at opening strange zip/dat files but the FCC has statistics on GMRS. It seems to me, and correct me if I'm wrong but currently there are ~1.3 million GMRS licenses out there. I found that information here: https://www.fcc.gov/uls/transactions/daily-weekly If this is true, for a "teotwawki" I'll stay with GMRS for the time being, After all, the M stands for mobile. All the best, JAS