Blaise

OK, this is driving me nuts. Normal human hearing spans from 20 Hz to 20kHz (Outliers from 12 Hz to 28kHz, but those are rare). CTCSS tones are listed as ranging from approximately 6Hz to 260 Hz, all *well* within the range of the average human ear. So riddle me this, Batman(Batmen? Batfolk?): Why do we not all hear low-pitched buzzing during radio calls made with CTCSS tones in use?

OK, let's see: I've checked it on my monitor Baofeng, a Motorola Talkabout, and the Radioddity DB-20G mobile unit in my car. I pick it up around my house and in various places in my town. I've compared the frequencies to local repeaters, and only one in the MyGMRS DB corresponds to either frequency. The one that *dooes* correspond has been around forever and is actively maintained (and identifies itself when the static is gone, etc...) It's hard to know if it's always the same thing, since I'm never running two radios at once, and I haven't done a systematized survey, but they*seem* to be a real transmissions...

GMRS in my area is pretty rarely used. I scan in the car and when I'm at my desk, and pick up one or two conversations a day max. However, a few months ago, I started picking up digital transmissions on .600(17). They would last anywhere from one to thirty seconds each, and I would pick up clusters of them that would preclude any other use of the frequency for up to an hour. A few weeks ago, those stopped completely, to be replaced with what seems to be a strong signal nearly continuously transmitting nothing but some static. In the last few days, these 'nothing' transmissions have begun on .675(20) as well. They now render both frequencies completely unusable for significant chunks of every day. Any of you experienced folks have any idea what might be going on? I got a video of my monitoring unit while it was happening. Not sure if hearing the transmission is useful, but at least you can see for yourself! BadTrans.mp4

Ingener, Enjuneer, I math good...

[Removed!] - Don't post on cold medicine!

*twitch*

China has their own watts!?!?!?

Thank you for making a wonderfully concise, clear, and unnecessary-jargon-free response! Yes, I agree that we're talking about ideal case, not practicalities here. I was just trying to ensure that I wasn't missing something about the actual physics, because this whole em transmission thing is so damned convoluted I rarely know what to expect. As far as how consequential a particular increase in range is, maybe I just see it differently. To me, that "slight" 41% increase in range is pretty significant, especially if the cost of achieving it is paying an extra $12. Legal questions aside, managing almost a mile and a half in the woods rather than a mile would seem to be pretty good when you're out hunting or hiking with friends, for example. Would you get better range by climbing a tree and hanging a $150 dipole antenna for your $40 5W unit, then retrieving it and repeating whenever you need to talk as opposed to just buying an 8W unit? Sure, but how practical a way is that to get better range? Can you put a 15-plus inch antenna that costs $60 on your $40 HT and do better range-wise than paying $12 for an extra 3W? Sure, but again, between the cost and the inconvenience of trying to walk in dense brush with a 15 inch antenna, it's again not terribly practical. I'm not saying power is magic, I'm just questioning why there is such a borderline fanatical aversion to even discussing it...

Skirting for a moment that someone else already did the "I wrote twelve paragraphs to explain that if you convert to an exponential scale the numbers look smaller" explanation you just repeated, and I already responded about how it doesn't seem like converting your measurements to an exponential representation to make it look smaller doesn't change the laws of physics, I feel like this was exactly the sort of condescending, knee-jerk response that makes my point. I never said they did. I questioned why they think that constantly regurgitating what appears to be an incorrect, or at least greatly exaggerated, statement is helping anyone, and why they were so aggressive about it. Like you are, for example. So let me get this straight. I question a statement because a) it always seems to be delivered with an unthinking, nearly religious fervor, and b)it doesn't seem to jibe with the known laws of physics. I then present those physics as I understand them and ask for someone to help explain to me how to square what I know with the statement it seems to contradict. You ignore my question almost completely and respond with paragraph after paragraph of dense jargon that seems to boil down to "Decibels are exponential, so the numbers looks smaller", which a) someone else already did without being disrespectful and b) I already responded to. You characterize my questioning as pathetic "willful ignorance and dismissing people that try to explain it", in shouty bold text, even though you've done nothing to actually help explain anything. No, definitely nothing dogmatic or aggressive about that at all.... If by "the clown", you mean three different physics professors at a highly respected polytechnic institute who taught "Fields and Waves", "Fields and Waves II", and "Photonics", then I can assure you, my assignment lists alone would make it pretty clear that they very rarely told me anything I wanted to hear. What is it you think I want to hear, anyway? I'm really interested to know. Because it sounds like whatever crazed little story you've made up in your head about it is almost certainly a) wrong, and b) stupid.

Oh absolutely, that's fair, stuff gets in the way. To antennae 6 feet off the ground, the horizon is roughly 3.1 miles away, so the maximum possible range the two of them can communicate at LOS is just over 6 miles, and obstacles between normally make it much less. But the argument rarely comes from that perspective, or at least not until someone pushes back on the "all things being equal" phrase that accompanies the original statement. I don't know, it just seems unnecessarily aggressive and not really accurate as generally presented...

I'm still not following. I don't see how representation changes anything. Just representing field strength in an exponential way doesn't change the power at distance x. If I decrease your salary by only one order of magnitude, using the number 1 looks a lot smaller than saying I've taken 90% of your pay, but did I take any less? If a signal is still "lost in the noise" after a power increase, it would be *less* lost in the noise by the root of the increase in power, meaning the range still increased, you were just still too far away, right?

> VHF and UFH are primarily line-of-sight. The signal essentially propagates until it runs into something (trees, horizon, big warehouse). But the amount of those obstacles that you can propogate through or reflect around still increases with the root of the power increase, right? I understand that completely blocking a signal is completely blocking a signal, of course, you can't go through mountains etc, but every attenuating material will still allow propogation to *some* depth, so if you increase power it will come out the other side of relatively more stuff than before, no?

I don't see the problem. Don't you want to keep them toasty warm?!?!? I mean, it's not like it's ionizing radiation...

I really don't understand that this keeps getting repeated over and over in GMRS-land. I'm new, so maybe I need to be schooled, but I've been reading stacks of antenna resources, and I started out with an engineer's education in fields and waves theory, and I just don't get this point! According to everything I understand, rf signal strength, all other things being equal, follows the same inverse square law that all electromagnetic fields do. This means that the distance at which signal strength drops off to unreadable levels increases proportional to the square root of any increase in power. So on a direct line between two antenna, assuming proportions of open air, obstructions, reflections, etc remain constant, doubling the power of a transmission provides more than 40% more range, quadrupling it provides twice the range, etc. Now, I can certainly understand providing a caution to new users that range isn't proportional to radiated power, because that's an easy mistake to make that will confuse a lot of newbs, but saying things like "Going from 5 watts to 8 watts is a relatively small increase in transmitted signal" that produces "very little difference in signal performance, all things being equal" when in fact a 60% increase in transmitted power results in more than 25% increased range, all things being equal, seems at best sloppy and at worst disingenuous. And people repeating it constantly across an en entire community seems... well, I won't say religious, but at least dogmatically ideological, anyway... What am I missing?

I just posted a work in progress last week that might help:

The difference being, I suppose, that I actually acknowledge the need...

Hey folks, I've been distracted from my antenna studies by a more immediate need to build practical, interoperable systems for my family, and I've discovered that it's not nearly as simple or rational a process as I originally imagined. I started using prepper resources to grab info on various radio services just because I'm a packrat, but when I discovered that while most manufacturers make an effort to comply with the rules of channelized services, you explicitly can't trust manufacturers to agree on code values for CTCSS and DCS, this turned into a more serious project. It turns out that when you start trying to get your kid's Retevis walkies, your Motorola talkabouts, an FRS-based intercom system, two different mobile units and a handful of Baofengs (kept for emergencies) to all interoperate at more than a basic level, you spiral down a nigh inescapable rabbit hole! Anyway, I'm attaching a spreadsheet I've been working on (mostly of stuff stolen from across the intarwebs, but some hand-transcribed from manuals or Amazon product photos). The first sheet is a frequency-ordered list of channels for FRS/GMRS, CB, and Marine bands (which I actually needed) plus a whole bunch of other frequencies in other services probably only interesting in an emergency (which I just grabbed because I'm a packrat). The second and third sheets are lists of CTCSS and DCS codes for different radios from different manufacturers. The frequency list is at least of interest because seeing where the "channels" actually lie in a band is a bit eye-opening, but probably of no interest to anyone experienced. However, the CTCSS/DSC code charts are super useful at least to me, and I hope useful to others! In any event, I'd love it if anyone interested would check my work for errors, fill in gaps, or find new code lists to add! (Did I mention I'm a packrat?) Common_Frequencies.xlsx

I've been reading about antennae rather a lot lately to try to understand this exact issue. I assure you I believe myself to be nothing remotely like well informed on this topic, but from what I'm reading, it seems like this has multiple possible solutions: If you separated the two antennae with a metal sheet about 5 degrees wide to each antenna, you would have a dead spot on a narrow line (which might be made up for at distance by reflection/diffraction), but the bulk of the transmitted energy would miss the receiving antenna, and lessen or eliminate the problem. If you mounted the two antenna colinearly one above the other, maybe also with a metal disc separating them, you could solve the problem similarly with no dead spot at all. Please help me understand how I am wrong! (I assume I'm wrong, since no one else said it...)

Yes, I thought I made it clear I understood that by starting with "Now I realize that transmission power is less important to range in this band than antenna placement, gain, etc., but..."

I've read 'til my head aches, but still can't find an answer. Can someone set me straight? I'm trying to spec a base-station, and I'm looking at the '50 Watt' requirement. As near as I can tell, virtually none of the commercially available GMRS transmitters really output 50 watts. It's usually somewhere between 45 and 48, from what I see. But even if they *did*, antenna cable and connector losses seem like they're going to eat a minimum of 10% of your power, even over fairly short runs, so really, there's no hope of ever transmitting anywhere *near* the 50 watt limit, and realistically you'll be closer to 40 watts. Now I realize that transmission power is less important to range in this band than antenna placement, gain, etc., but all other variables being equal, if I'm not mistaken, transmitting with 25% more power is going to get you as much as 11% more range and 25% more coverage area. That's a lot more than nothing! Is this just a loss GMRS operators accept, or is there more to it? Are folks using amps to bump their unit's output power up over 50 watts to make up for losses? Is there a trick to this that I'm missing?

It worked a treat on mine. So much more convenient and usable. And I can listen to marine band as I drive up and down the Hudson Valley!

Well, I think it's pretty cool. I got my wife and I a pair of Motorola T801s for a cruise we took in southern Europe, and being able to text with each other in five different countries without having to buy phone service was actually phenomenal. We've used them camping when out of cell/wifi contact for significant time, too. The best part? I did all the pairing and programming, and then I just had to show her how to turn it on and hang it on the back of her bag. All the rest was on the phone that's already glued to her hand anyway! (It *was* challenging to deal with her frustration with not having perfect, 100% connection, but it still got the job done)

I already have a nanoVNA v4. I needed it to sort out issues with my car antennae. Now I'm trying to figure out antenna placement for a base station, along with how it will interact with nearby antennae, and potentially buying a repeater (and maybe building a mobile one from HT's). It turns out that the number and complexity of the questions you need answered increases exponentially with the number of things you are trying to do!

Thanks, folks. I've got The ARRL Antenna Book, 23rd Edition (all 1000 pages!) and Reflections III. Looks like about three months of reading. Well, I asked for it!?

So I've been building a huge list of questions about how antenna layouts might work, and I've realized that onesie-twosie answers are always going to leave me wondering about the next thing, and annoy the folks I pester, so what I really need to do is go back to school. Anyone have recommendations on how to teach myself to fish in the sea of antenna theory and practice?