Alec

Oh... that explains why HT's work better for us fat people! Especially on lower frequencies. Sent from my SM-S916U using Tapatalk

Really ?? I did not infer that "Code Talker" is mentioned anywhere in the FCC rules. I'm merely using that as an example to point out that "Plain Language" is an ambiguous term, not all foreign languages are commonly understood, and that perhaps the FCC's definition is not as clear or definitive as it should be!

___ @JHENRY, yours was a very good question. I'm fairly new to this forum, but I'm quickly learning to just ignore the regular trolls...

Just like the word "unreasonable" is arguably the most important word in the 4th amendment of the U.S. constitution, the definition of the term "Plain Language" is the key phrase in the FCC rules. Actually, the precise definition wording of section 95.303 as shown above poses a very interesting question as it is being presumed that all foreign languages, by definition, are not considered coded or secretive. It says: "Foreign languages and commonly known radio operating words...". It does not say; "Common Foreign languages and ..." The public at large cannot be expected to understand the wide variety of foreign languages that may be broadcast over the air. Clearly some recognized foreign languages are not at all well-known and in fact our own military has used this strategy expressly to create "secret communications"! "CODE TALKER" Wikipedia: "A code talker was a person employed by the military during wartime to use a little-known language as a means of secret communication. The term is most often used for United States service members during the World Wars who used their knowledge of Native American languages as a basis to transmit coded messages." As @UncleYoda pointed out, it is the FCC's responsibility to make the rules clear. At this point, I'm not sure they really are.

Great information... Glad to hear that it is working well for you. THANKS!

Good advice. Thanks for that!

Thanks for that input! For occasional 2m/70cm I use a very good local linked repeater network without any problems. For GMRS, I use mostly short distance simplex when travelling with a group or at the lake or other destination. The performance from my current mag mount which I usually place on the cab directly in front of the 3rd taillight, (basically where the antenna would be if I use one of these 3rd taillight mounts) works just fine! I like that location (up and centered) because it keeps the antenna up and out of the way of getting things in/out of the truck bed and I don't have to stare at it while driving. All the discussion about the effectiveness of the ground plane, while interesting, and not at all irrelevant, is just not too significant of a factor for my purposes. That's why my OP was a question more about the antenna mount itself (water leaks, strength etc.) and less about the RF propagation characteristics associated with its location which seems to be the direction the thread drifted. I'm not going to drill into my roof and I'm sort of tired of taking the mag mount on and off, so without any specific feedback that indicates that this type of mount is structurally problematic to my vehicle, l will probably give one of these mounts a try and hope for the best.

Exactly! I believe I only received 2 posts from people who have actually used that specific type of mounting device and provided some feedback about them. Nobody actually addressed my original questions, which were "Does it leak?" and "Are they strong?". The other posts that provided alternative mounting solutions, alternate recommendations or general antenna considerations regarding ground plane etc. were all valuable answers or comments to different questions that I did not specifically ask. I am still appreciative and thanked those people for their contributions to the topic. Looking at my OP I did not ask "what is the best way to mount an antenna?" Sorry if my communications sounded dismissive of others effort to help as that was not my intention.

@WSEZ864 Thanks for the suggestion about the back rack, and for the photo! Very helpful. That is certainly an interesting option worthy of consideration. @WRUU653 Thanks for the A-Pillar suggestion. I do understand compromises... Cost isn't a primary consideration for me, but even so the 3rd tail-light mount is in itself sort of a compromise, rather than following the recommendation of the "drill-baby-drill" enthusiasts who advocate for just installing that NMO mount. While an NMO mount installed dead center of the roof of my truck cab might be the best solution for RF purposes, that isn't necessarily the best solution for my purposes. I've been browsing YouTube videos about removing the headliner as was suggested by @WRUE951 and unless you are someone who does that sort of thing all the time, it appears like it could potentially be a PITA that is not without its own considerations and complications. In the process, I've also stumbled across a great many videos regarding replacing or fixing a 3rd taillight on these trucks. Some replace it for the purpose of a cargo/5th wheel bed camera, others for brighter or flashing LED lights etc. Many people with many different reasons. However, there are also folks that speak of damaged headliners as a result of leaks from a worn 3rd taillight lens gasket. Many suggest that it is not "IF" it will eventually leak, but rather "WHEN" it will leak, and they advocate replacing the gasket and resealing these 3rd taillight assemblies with silicone as a preventative measure. Something to think about... Interestingly enough that gets me back to my original post about this type of antenna mount where I asked those with direct experience using these devices: "Do they leak?" I'm thinking of an antenna being pushed by wind or by hitting trees, etc. and wonder how that might contribute to breaking or otherwise compromising that watertight seal around the mount? IOW, if these 3rd taillight assemblies are prone to leaking, maybe introducing an antenna mount there would be inclined to make matters worse. Absolutely nothing is without compromise!! Again, thanks for the comments and feedback on the topic.

@WRYZ926 Great information here. Thanks!! I was aware that the different ground plane clearances of the various conductive sections of my truck (Hood, Cab & Bed) would alter the reflective properties of the RF counterpoise. I was not aware that the vertical distance between the antenna on the cab and my truck bed, although more than a wavelength at GMRS frequencies, would effectively nullify all effectiveness of my truck bed as a ground plane!! I'll certainly need to research and read up on that... My current magnet mount has been placed very near the 3rd tail-light location and suffers from the same ground plane issues and so far the performance has been acceptable to me. I currently use a 5/8 wave GMRS antenna (although I'm not married to it - on rare occasions I swap it out for my 2M/70cm antenna) and at GMRS frequencies only about 15" of surface area is needed for an effective ground plane. So, if RF optimization were my ONLY consideration, shifting that GMRS antenna forward a few inches from the rear of the cab would probably be close to as good as it is going to get for my vehicle... Many of the comments thus far suggest just biting the bullet and drilling that 5/8" hole in the roof of the cab of my truck and installing an NMO mount as the best approach. I really do appreciate the feedback and comments! But OUCH... I just have a real aversion to that, and most likely will never do so and would rather just live with a magnet mount. Perhaps I should have mentioned in my OP that my truck has a retracting moon roof which significantly complicates things as far as drilling and mounting anything in the roof of the cab more than a few inches forward of that 3rd tail-light because of the sliding glass, retraction motor, etc. of the moon roof inside the roof of the cab. And yes, the moon roof glass too impacts my ground plane to some degree. If it's not one thing, it's another... But still I'm seeking the convenience of some kind of permanent mount, even if not optimal from an RF perspective, which as stated in the OP, is why I'm looking at whatever alternate mounting solutions I can find. Hood/fender mounts are often a no-drill option but those too often force you to route the coax thru an RF noisy engine compartment. They also tend to force you to mount them on either the right or left side of the vehicle which alters the radiating pattern to the sides, not to mention that you usually end up with the antenna being lower than the cab of the truck thus causing a certain amount of unwanted RF reflection if not some signal blockage. I conceded that there is no perfect solution, and things are never as simple as they may sound. So, while I'm not yet SOLD on this 3rd tail-light mount, and it is very expensive, thus far it seems to be a path to solve my specific problem. This is why I'm looking for folks with first-hand experience specifically with these 3rd tail-light types of mounts, even though any and all feedback is much appreciated! Thanks again...

@WRUE951 Thanks for sharing your experience. I hear you. I'm not thrilled about pulling the headliner either, as those things always turn out to be more difficult than we anticipate, but I figured that if I drilled a hole for a mount in the roof of the cab, I'd be going down that path anyway. I agree the price is very steep for an antenna mount! For my make/model/year truck the mount is no bargain @ $360 but if it avoids the potential for water leaks that can occur when you drill holes in the roof, (I've seen a lot of that with fleet vehicles) it is, from my perspective, worth the price. Also, I'll be sure to check Ebay "IF" I end up going with this type of solution. @Socalgmrs Thanks for your comment. On my 2018 GMC Sierra pickup truck (w/ a 6' truck bed) the 3rd brake light is very close to being as centered, front-to-back and right-to-left, as you can get. Thus, I don't believe this location sacrifices 180 degrees of ground plane as you suggest. I'm not wanting to direct the radiating pattern in any specific direction. If I'm not understanding your comment here, please explain... Thanks

Greetings... Does anyone out there in GMRS land have any experience with 3rd brake light antenna mounts? Like these: https://bulletproofdiesel.com/collections/antenna-mounts Do they leak? Are they strong enough for a ~32" antenna? I've been using a magnet mount on my GMC truck, running the coax out thru the rear sliding window, and placing the antenna on the roof of the cab just in front on the 3rd brake light. From an RF signal perspective, it works just fine, but I would not mind transitioning to a more permanent antenna mount. I like the idea of a no-drill solution and keeping the antenna's location more-or-less in the center of the ground plane. That makes this antenna mounting option seem like an elegant solution even though it is a bit expensive. Any feedback or personal experience is appreciated... ** UPDATED INFO: my truck has a retracting sun/moon roof which significantly complicates things as far as drilling and mounting anything in the roof of the cab more than a few inches forward of that 3rd tail-light because of the sliding glass, retraction motor, etc. of the sun/moon roof inside the roof of the cab. Besides, I really don't want to drill into the roof of my cab!!! Thanks

Hi Frank, I can understand your frustration but try to not get discouraged and stay excited. Things will get resolved. A random consideration: In many areas, depending upon the number of GMRS / FRS users in the area, communicating via simplex can be a real challenge. The 462Mhz/467Mhz frequencies used for GMRS channels are typically only capable of line-of-sight communications. Factor in buildings, trees, foliage, terrain and other things that tend to absorb signals in that frequency range and distance for 2 respective ground stations becomes quite limited. Obviously, this is why so many GMRS users tend to focus a lot on mountain/tower/building top repeaters. But in terms of getting an accurate signal check and test of your equipment, you are, IMHO, probably better off using simplex because when you do, people will be hearing your radio signal directly and not the signal of some presumably higher-powered, elevated repeater. If you can hear people talking on the non-repeater channels 1 thru 14 then you are almost certainly hearing simplex radio transmissions and chances may be good that if you are in range to hear them, they would be in range to hear you! If you hear someone on a simplex channel and attempt to communicate with them but do not get a response (assuming they are not just ignoring you!) the issue may be the other operators are using CTCSS or DCS sub-tones. IOW, it may not be your radio that is the issue, it may be the other person's radio that is the issue. The use of these sub-tones or "privacy codes" as they are often improperly called, restrict the user's radio to only hearing (breaking squelch) when that specific matching sub-tone is detected by the receiving radio. This creates the illusion that the conversation is private because unless the transmitting radio is sending out the correct matching sub-tone the receiving radio won't open squelch and play any audio. The majority of repeaters require a specific CTCSS or DCS sub-tone. So, your radio may be transmitting just fine in terms of distance, but the other GMRS users are not hearing you because of a specific setting on their respective radio. While the use of CTCSS or DCS codes on simplex is routinely discouraged many people do use them because they think it makes their conversation private. Additionally, some radios ship from the factory with CTCSS or DCS codes pre-programmed, so people just take the radios out of the box and start using them having no idea that these sub-tone codes are in use. So don't get discouraged too quickly. Some GMRS radios or scanners have the ability to display if a CTCSS or DCS tone is being transmitted by another radio and if you can detect this, it may allow you to set your radio to use the same sub-tone and make it "heard" by others. Doing tests of your mobile equipment with another handheld radio and a friend where you control the settings is the easiest path to take. If you need to rely on the assistance of other random people, then you must consider how the other person's radio might be configured. Good Luck! BTW, there is nothing wrong with talking to random people via GMRS! A random person may turn out to be a friend you just haven't met yet.

Hi Paul, Many radios on the market, including the Tidradio H8, ( I own one too) have the ability to receive on frequencies or bands that they do not have the ability to transmit on. This is why you were able to program frequencies into the radio that you can only receive and not transmit and it allows the device to be used as a frequency or channel scanner. At the risk of stating things that you may already know, here is a bit more explanation. The transmit frequency range(s) are locked by the manufacturer in the firmware or software of the radio. This is most often done so that the radio remains compliant with the certification for that device which has been granted by the regulatory agency for your country under their respective rules. I am not familiar with the regulatory entity in Australia so I cannot speak to that entity or their rules, but for example here in the USA frequency allocations and things such bandwidth, as how much transmitting power may be used etc. are defined and regulated by the Federal Communications Commission, aka the "FCC" and often radios sold here in the USA are FCC certified for use in a specific band that is defined by a "part" or section of the FCC rules code. For example, a GMRS radio here in the USA would be authorized under part 95 of the US FCC code and in order for the device to be Part 95 compliant or certified the radio would be required to adhere to certain frequency restrictions, band widths and power levels, etc. In many cases the radio might be capable of transmitting on other frequencies or bands or use more power etc., but these software imposed restrictions prevent that from happening so that the device can be compliant with those rules associated with specific uses. Some devices can be "Unlocked" to remove these artificial, software imposed, restrictions. You mentioned that you were considering getting your HAM radio license. In the case of the Tidradio H8, if you purchased the HAM version of the radio and not the GMRS version, that specific device does have the ability to be unlocked (Google it). However, while unlocking the device may allow it to transmit on the HAM frequencies and GMRS frequencies (or as you referred to the CB frequencies) that does not mean that the device is certified or authorized for such use by your communications regulatory authority, and you may or may not be licensed to use all the frequencies that the device is capable of working with, so be sure to do your homework about your local rules and requirements.

I agree with the previous posts that the most probable culprit is that the RT15 radios are using CTCSS or DCS Codes (see page 6 of your RT15 manual - I found it on the Retevis website here: Retevis RT15 Mini Lightweight FRS for Business Radio, usb charging, license free walkie talkie). Page 1 of that RT15 manual shows a diagram of the radio and according to that diagram the radio has a "Monitor" button on the side just below the PTT key. If you long press that button, it should, temporarily bypass any pre-programmed CTCSS/DCS tone code squelch. So, if you have all radios on the same channel (avoid channels 8-14 as your base station probably will not transmit on those channels) then long press that Monitor button on the RT15 while you transmit on the Midland GMRS base station and you hear the base station radio transmission come thru the speaker on the RT15 you will have pretty much confirmed that the issue is that your RT15 FRS radios have factory pre-programmed CTCSS or DCS Codes enabled. To solve this issue, you will need to reprogram these RT15 FRS radios to remove the use of CTCSS/DCS tone codes. As has been suggested by @AdmiralCochrane, you could also program your Midland 105 base radio to use the same CTCSS/DCS codes as the RT15 are using, but personally, I would not recommend that approach as doing so will limit your ability to communicate with others. Hope that helps.