BPL is out

| I like that Doug, 'walk of shame'..........can I use that or is it your | in-tel-ek-chew-ull property??

It's hardly mine. In case it's not clear, it often refers to what happens immediately after `hey, watch this!', and in the case of slope flying at least, it usually refers to a long walk -- either your plane went down at the very bottom of the hill, or is sitting in the top of a tree, or landed *in* the lake below the hill. And you get bonus points if everybody can see you in your walk. :)

Of course, if you're truly slope trash, and brought more than one plane with you, you may leave your plane in the tree and not bother retrieving it until either 1) it's time to quit flying, or 2) *all* your planes are now up in that tree.

is fun reading, and yet remarkably accurate!

| yup. wait and see. There will be a work-around likely when the | inteference hits the 10-6 fan.

I really don't expect BPL to create too many problems for R/C, either on the 27 mHz band now, or on the 72/75 mHz bands when/if BPL starts using those bands. If you have power lines in the back of your flying field, it'll probably create a zone around them where you do not fly, but ultimately flying near power lines isn't smart anyways, BPL or not.

But on the other hand, something that makes our current frequencies unusable might actually be a good thing in the long run, as it could push us into spread spectrum radios. But in the short run, it would suck.

Of course, the FCC may just not care. At least the hams have some rights to their bands -- the ham part 97 rules trump the part 15 rules used by BPL (and the part 95 rules used by R/C, for that matter) and yet the FCC doesn't care about that interference, as long as it fits the part 15 rules.

| > In article , | > jim breeyear wrote: | | > Most? I don't know about you, but if I'm flying out of my line of | > sight, it's because something went wrong and my plane is about to | > crash :) (Though to be fair, I did once lose my plane that way, and I | > put down my transmitter and went to make the `walk of shame' to go | > look for my plane, and suddenly it popped back up into the sky :) )

Power lines have no insulation, the 60 HZ is not a problem, the arcing is, but the power company will fix that in short order. BPL over uninsulated power lines will be a huge problem.

Total rubbish, both og you.

The p[int about broadband is that its - er - broadband.

UIts a complex hash of frequencies all teh way up teh RF spectrum. It is 'nosie' unless you have teh abiliy to decde it.

Insulatin is no barrier to RF energy.

And you need a LOT or RF energy to propagate even a couple of Mbps signal down a few tens of kilometers.

Its a complete disater.

Unless they run coaxial, the stuff will leak out everywhere, but power lines are not coaxial at high voltages - too much loss.

Guys, you need to look a little beyond the obvious stuff here:

jim breeyear wrote:

Good idea! exce-e-e-e-ept...... y'know the main precursor to coron discharge is a breakdown in dielectric strength in power lin insulators? Yup; and that little problem often creates a cutsey littl tuned circuit that doubles (or triples) the frequency of the curren running through the line. This out-of-phase "signal" starts creatin false peaks and nulls in the AC wavefront - and at sufficient voltage and currents; that in turn creates the corona discharge. Regardless o the voltage and current of the doubled- or tripled- frequency; it's no double or triple the frequnecy on which you were bothered. Let's sa that BPL suddenly "wipes us out" on 72MHz; and the FCC, using thei inimitable logic, figures "They're aircraft, put them near an aircraf frequency!" and plops us on a portion around 216MHz :rolleyes: Prett cool, huh? Until you land there and find that you've got interferenc that sounds an awful lot like BPL, because 72 MHz tripled is 21 MHz.....

Of course, this problem could easily be the solution; in one of tw manners:

1.)Triple that 216 MHz (makes a ninth harmnic, which is common), an they're suddenly smack dab in the middle of the 875-925 MHz band that' being touted as the "radio Nirvana" for public service/public safet agencies nationwide. "Gee Governor Smith; we weren't able to rescu that busload of your constituents because BPL had wiped out ou communications system...." Suddenly that state's PUC is making th Power Companies perform lots of not very cheap maintenance to kee their ISP out of the police chief's radio system. Now, will tha maintenance cost be positively offset by the income from BPL? Hmmmmm? 2.) I know a lot of Hams (being one myself - KC7BDP); and the mos devoted QRP (low-power) operators will likely become HIGH powe operators, if that's they only way they can be heard. Let me tell yo a little story: I once had problems with our local cable company an some untapped line amplifiers in the alleys. Cable channel 19 wa wiping out my receiver on 2 Meter SSB. Short story is that none o their paying customers (I don't have cable) were complaining; so the didn't see there was a problem, no matter HOW many times I called. FC Long Beach had only one complaint (mine); so it wasn't worth thei time. One night a few years ago, I was working some great DX on Meters (50 MHz); running my 160 watt amp - during some Basketbal Championship that was playing on cable channel 2 (60 MHz). Apparentl that was "bothering" a lot of basketball fans in my neighborhood. Cabl company had my phone number from all the times I had complained - an they called me. I responded to their threats ("We're gonna call th FCC on YOU!") by telling them that my little old amp was running a barely 10% of the total amount of power I was licensed to use tha close to their little basketball game - and that they could call th FCC so we could compare my license to their lack of same - they wante to work something out! Problem solved. Now, imagine 60,000 Hams suddenly finding themselves FORCED to use legal 1,500 Watts PEP not too far from their electric service (and BP customers)......

Problem solved

-- DesertDaw

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| Let's say that BPL suddenly "wipes us out" on 72MHz; and the FCC, | using their inimitable logic, figures "They're aircraft, put them | near an aircraft frequency!" and plops us on a portion around 216MHz | :rolleyes: Pretty cool, huh? Until you land there and find that | you've got interference that sounds an awful lot like BPL, because | 72 MHz tripled is 216 MHz.....

So, you've hard of harmonics. Good.

However, harmonics generally get exponentially weaker as you go from main signal to 2nd harmonic to 3rd harmonic to 4th harmonic, etc.

72 mHz doubled is 144 mHz -- inside the ham 2m band. And yes, you can pick up your R/C transmitter's 2nd harmonics with a 2m HT -- but the range is very short, and you probably won't be able to pick it up more than 50 feet away at all. The third and higher harmonics will be even weaker. Yes, it's *possible* to have problems with certain higher harmonics, but it's very rare.

Don't worry too much about the BPL harmonics. If BPL starts interfering with the airplane 108 - 136 mHz band, the FAA (through the FCC) will smack them down. The airplane radios use AM, so they'll certainly hear that interference.

| 1.)Triple that 216 MHz (makes a ninth harmnic, which is common)

Common? Sure. But generally incredibly weak.

BPL and harmonics are not the gloom and doom for the entire spectrum that you make it sound like. Good thing, too -- otherwise the

550-1600 kHz AM stations would basically stomp on *everything* above them.

| and they're suddenly smack dab in the middle of the 875-925 MHz band | that's being touted as the "radio Nirvana" for public service/public | safety agencies nationwide. "Gee Governor Smith; we weren't able to | rescue that busload of your constituents because BPL had wiped out | our communications system...."

Nice, but the harmonics at that range will be so incredibly weak that they probably won't even be detectable. The airplane 108-136 mHz band is in much much more danger, and it probably won't even notice.

BPL is supposed to be weak. It's supposed to fit under the FCC rules that allow you to transmit a weak signal on pretty much any frequency. I don't doubt that some BPL setups will exceed these limits, but they shouldn't be exceeding them by so much that the harmonics will have any signifigant strength at all.

| Suddenly that state's PUC is making the Power Companies perform lots | of not very cheap maintenance to keep their ISP out of the police | chief's radio system. Now, will that maintenance cost be positively | offset by the income from BPL? Hmmmmm?

This doesn't have to happen to the 800-900 mHz bands. The hams alone can keep them busy by reporting interference on their 2-54 mHz bands. Of course, reports from the police (or the FAA) would carry a lot more weight, but the FCC is obligated to pay attention to all of them.

| Short story is that none of their paying customers (I don't have | cable) were complaining; so they didn't see there was a problem, no | matter HOW many times I called. FCC Long Beach had only one | complaint (mine); so it wasn't worth their time.

Cable companies are generally very carefully watched by the local governments, since they generally have a local monopoly. Going to the local PUC or city council (whomever oversees the cable company) can suddenly make the cable company VERY cooperative.

| Now, imagine 60,000 Hams suddenly finding themselves FORCED to use a | legal 1,500 Watts PEP not too far from their electric service (and BPL | customers)......

And yes, hams will interfere with BPL, and in theory the BPL system has *no* recourse from the FCC -- they have to accept the interference. But since for now, BPL runs 2-30 mHz, you'll need to pass the element 1 test (if you haven't already) and maybe element 3 if you want to really mess with the local BPL system [1/2 :)]

| Problem solved?

Alas, if you've got BPL right in your neighborhood, you'll have a hard time picking up even 1500 watt stations more than a few hundred miles away if the BPL is using the same frequency.

And if the local hams are the sole reason that BPL doesn't work somewhere (because they're all using 1500 watts into dipoles that are right next to and parallel to the local power lines), well, it would be interesting to see how the FCC responds. Yes, the hams have rights to their frequencies and the BPL users do not, but with big money involved ... who knows?

Uh, ok, whatever you say! :-)

They do, if you get close enough to the antennae carrying them.

Tell me how many watts you need to shove a 140Mbs signal down a power line for 20 miles.

Weak it ain't...

Good.

Why the heck don';t yey do what we did here, and rewire teh earth coindictor with an optical fibre. It costs net to nothing to rig a light ppe over groaund when you already have towers and sirtes and rights of wayleave...

>

| > BPL and harmonics are not the gloom and doom for the entire spectrum | > that you make it sound like. Good thing, too -- otherwise the | > 550-1600 kHz AM stations would basically stomp on *everything* above | > them. | | They do, if you get close enough to the antennae carrying them.

Sure. But the zone is relatively small.

| > BPL is supposed to be weak. It's supposed to fit under the FCC rules | > that allow you to transmit a weak signal on pretty much any frequency. | > I don't doubt that some BPL setups will exceed these limits, but they | > shouldn't be exceeding them by so much that the harmonics will have | > any signifigant strength at all. | | Tell me how many watts you need to shove a 140Mbs signal down a power | line for 20 miles.

Three watts. One to hold the electrons down, one to move them around, and another to ... oh, nevermind. | Weak it ain't...

The emissions are relatively weak. Well, they have to be -- the part

15 rules that they operate under require them to be. Well, the overall emissions will be pretty srong, but they'll be spread out over many mHz of bandwidth and 20 miles, so the emissions that are affecting your specific transmission are supposed to be relatively weak. Supposed to be, anyways.

The people who are most going to be affected are ... the hams. Even if BPL does extend to 80 mHz, your R/C transmitter is transmitting at

0.5 watts to a receiver 0.5 miles away. Compare to the ham trying to pick up a 0.5 watt signal from 500 miles away (and they do this on a regular basis. It's called QRP.) The R/C signal will be millions of times stronger (and perhaps billions or trillions or more) than the QRP DX signal. (If 0.5 watts isn't interesting, 100 or 1500 watts fits too, you just have to get further away.)

If you're one hundred yards away from the power line, the R/C signal ought to be much stronger than the BPL signal. But the ham signal will still be much much weaker than the BPL signal.

| Why the heck don';t yey do what we did here, and rewire teh earth | coindictor with an optical fibre. It costs net to nothing to rig a light | ppe over groaund when you already have towers and sirtes and rights of | wayleave...

Why don't they lay optical fiber? Well, in many places, that optical fiber (or at least coax) is already there, and being used for Internet access. Somebody seems to think that cable modems, DSL, WiFi ISPs and satellite Intenet need more competition -- BPL. If you're out in the boonies and can't even get cable, then maybe it makes sense. But not in the city where you can get all these things already.

I never said they were smart ...

Hey D.H., Most of the REAL pilots I know stay out of the high tension lines and away from antenna farms. But I guess your way is better for the scare'em all bunch.

I pretty much agree with what you said here , but I cant get over the the part in the other response that the power company is practically half way up the pole fixing the offending noise source, before you put the phone down. Some power company.

There is not only loss in passive frequency conversion but siganl path losses as well.

Keep the transmitter battery charged, antenna fully extended (no rubber duck), and the airplane in close. Maybe monitor the channel to check for, burps , squeeks, pops, and buzzes.

Doug McLaren wrote:

|

Your point?

I'd take this page more seriously if it didn't say

Liverpool Chat room - Im OuTgOiNg, BuBbLy aNd vErY LiVeLy!! Im DoWn To EaRtH aNd Im OuTgOiNg, BuBbLy aNd vErY LiVeLy!! Im DoWn To EaRtH aNd HaVe A GrEaT sEnSe Of HuMoUr!!

Yes, we know how to use google and find pages of advertisements with a few ham radio related links too. I don't see how this page is at all relevant to the conversation, however.

(And for the record, 50 mHz is hardly the only VHF ham band. VHF extends from around 30 mHz to 300 mHz, which includes the 50, 144 and

220 mHz ham bands, FM radio, TV channels 2-13, NOAA weather radio, a few (full scale) aircraft bands, lots of police and fire department frequencies and the R/C bands, 72 mHz and 75 mHz. And a lot more.)

Yes, "Oh good, (I) know about harmonics." Just a little bit....spent

good portion of my life on mountaintop repeater sites; dealing wit IMD. And when you're trying to track down what ultimately turns out t be a ninth order multiple of the 1st IF in an old Johnson repeater fiv sites away that's buzzing your receiver (okay, it was mixed with th

2nd of a paging transmitter's output only TWO sites away); you find ou that "weak" signals can eat your lunch! This experience comes fro being a professional tech before becoming a Tech-Class Amateur.

Somebody already touched on the most salient point - that low-powere stuff, coming in on several frequencies which then beat togethe (mixing); and add in miles of antenna in the form of power lines you're gonna hear it. I don't care if you're on 50MHz, 144MHz, or 1. gig, you will hear it; whether you're listening to the QRP op or th guy running the "full legal gallon".

Daw

-- DesertDaw

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