Blaise

You can't be serious! If people read what they were responding to, 79% of the content on the internet would just disappear!

This is super-useful! Do you mind if folks distribute it? I'm trying to set up a local group too....

Good grief, you're right! Somebody better tell OffRoaderX...

Yeah, I'm less interested in the DIY aspect than the science of it. I hate just accepting specs without knowing why...

Thank you! This, and the searches it inspired, have provided *much* digestible info...

Anyone have details on this question? It's really the crux of what I was wondering...

To clarify the click-baity question a bit: I recently watched an online debate/put-down session on someone who claimed to be able to make cheap coax just as efficient and low-loss as super-expensive stuff just by doing things like running it in copper tube, wrapping in metal mesh, etc. This seems a bit naive/uninformed, but it does make me ponder questions like: *Is* it possible to decrease losses in existing cable via external means? What is actually going on internally that makes one cable less lossy than another? Is is just thickness of conductors? Geometry tricks? Shielding? Is it possible to build something equivalent to or better than "good" coax to get your signal where it's going in controlled circumstances, like a fixed installation on a roof? Does the answer to this question include the "ladder line" I keep seeing hams post about? Do DIY ideas I've seen like extra-insulated 'cheap' coax, home-made braided wire, or a pipe with insulated grounding cable inside hold water? I have some antenna resources, but they don't go into much detail on this topic beyond 'here's what you do'. Is there an in-depth but still relatively accessible primer on the science of signal propagation in cables, etc? So yeah, just a million questions. I sound really demandy. I'd like fifteen thousands words on my desk by Monday!

You rock, man. Even when I think I know, I still always learn more when I read your write-ups. You should very seriously write a book!

Got it. So we *know* you're no riot at parties...

You must not understand the topic.

From the link: "Nonionizing radiation can cause internal body heating, which can be hazardous to a developing baby." - Which doesn't affect genotype, only phenotype, and only in a developing baby...

What exactly do you think RF does to the gene pool?

And they're apparently out of business, anyway...

Welp, now my brain has exploded. I need to go read more theory...

Oh, wow, so they filter out *ALL* sounds below that line, not just the expected tone? I mean I guess that makes sense to some degree, or you'd hear everyone else's tones on an open channel, but that's a fair chunk of our hearing range missing! I wonder why they don't use higher frequencies. Anything over 28kHz would be literally unhearable, and a frequency that high can transmit a lot of data, if need be...

Doesn't that mean that any sounds in that range that we *intend* be transmitted (like "Hey Mike, listen to the sound this machine is making. Does that mean it's going to explode?) will also be filtered out of transmission, if they happen to be within whatever range the radio electronics is unable to discriminate between of the CTCSS tone?

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.