- March 7, 2019 at 5:00 am #110085AMRadiolegendParticipant
Total posts : 323
I have noticed on other popular Part 15 sites that the mud continues to be stirred about H.R.5709 and its relationship with legal Part 15 operators. Please read the definition of a radio pirate HERE.March 7, 2019 at 5:42 am #110086Carl BlareParticipant
Total posts : 1540
Having some familiarity with legal writing and being aware of a sly tendency of some public officials to intentionally misapply the law I spot flaws with this document that could lead to troubles with legit part 15 operators.
However the American way of sucking up to the right people and kissing select ass should provide the usual safeguards.March 7, 2019 at 6:13 am #110087Carl BlareParticipant
Total posts : 1540
Keep in Mind
Another thing to realize is that the present extreme right wing faction is working hard to close avenues of mass communication to prevent alternative voices.
Therefore the Pirate Radio Act is a companion to the shutdown of net neutrality.March 7, 2019 at 9:38 am #110089
I’m going to combine two replies – one for this thread and one for the ground lead vs antenna thread (it seems the latter never really goes away).
I don’t see any ambiguity in the Pirate Act, and in fact, any reason to be concerned (if you are operating legally), despite fears elsewhere.
A pirate is not someone who attempts to operate within Part 15 rules. Usually pirates are pretty obvious, operating with many watts and illegal antennas, causing interference.
There has ALWAYS been discretion on the part of an FCC agent (and even local law enforcement agents, as state laws specific to unlicensed transmitting have been around for some time) in determining whether someone operating in a so-called ‘grey’ area between piracy and Part 15 is a pirate. That hasn’t changed.
By ‘grey’ area, I mean that that area in which a broadcaster might operate while attempting to comply with the rules, and not (complying, that is).
I don’t consider using an AM transmitter in an elevated installation with a long ground lead a ‘grey area’. It’s non compliant. The rules are absolutely clear on this point, and it’s doubtful that this is just a ‘mistake’, as it’s called elsewhere. What an FCC agent does with this type of install is really up to them, and is probably dependent on such factors as the range you’re achieving, your attitude towards the inspector, etc. How difficult is it to read, just about everywhere, including the rules, that you’re limited to 10 feet for the antenna, ground lead and feed line? You can do a complicated installation with electronics, antenna, audio feed, etc. and yet you can’t use a tape measure? At that point, I think that you’re just hoping you don’t get caught.
The FCC is capable of running NEC simulations, and has seen far more real world installations that most of us combined. They have a pretty good idea of what the maximum range of a Part 15 compliant AM transmitter should and would be, even under ideal conditions (we do too, as both radio8z and Rich have done the math and published it, here and elsewhere). Anything over a mile (and possibly a bit) and something is not right.
Part 15 FM is another matter, as it takes expensive test equipment to check compliancy. That being said, the FCC has come out and stated that a maximum of 200 feet to an ordinary radio is the maximum you can expect from a Part 15 compliant installation. I think that’s being generous(and that’s been verified with the math, once again by the same individuals); I’ve usually found a Part 15 signal fading away well before 200 feet with an ordinary radio (you can get more with a sensitive car radio). So you can be pretty certain that if your FM installation has range significantly greater than 200 feet, you are not compliant. Again, what an FCC inspector does if you’re caught is dependent on the same factors as for AM (although they’re probably stricter with FM due to dial congestion and potential interference).
The ground lead/antenna discussion has come up once again. The salient point is that either can radiate RF. If you have an almost non-existent ground lead to earth, then you have a vertical monopole. If you have a long ground lead, then you have some form of dipole – if the two are not the same length, then it’s considered an offset dipole.
I think the practical takeaways from the Pirate Act are virtually zero if you are using a Part 15 certified transmitter (shows intent to comply with the rules) installed in the manufacturer’s recommended way (that forms part of the certification) and monitor your range in the event something unexpected goes wrong (keeping it at or around 1 mile for AM or 200 feet for FM, maybe a bit more to very sensitive radios). Plus, don’t interfere with licensed services.
I would have thought that all that would be desirable even BEFORE the Pirate Act.
I’ve always felt the Pirate Act was more political than anything else – there’s certainly no more money being added to the FCC budget for enforcement. If anything, I think that the added administration time and costs may reduce enforcement, at least towards the little guys (i.e., us).March 7, 2019 at 10:41 am #110090MarkModerator
Total posts : 564
@Artisan, the ground/antenna lead discussion at the MBCF that has come up was about, originally, if the antenna and the ground lead radiate equally if both are above ground, not the rules or compliance, and whether height with the 3 meter antenna would be as good as a ground mounted set up with a below earth ground. And also why adding more length to the antenna would be to no advantage.March 7, 2019 at 11:33 am #110093
I understand that, Mark.
There is synergy in the two posts here, though.
I also thought I (as well as others) answered some of the questions, as in an elevated transmitter install, there really is no difference between the ‘antenna’ and ‘ground lead’. After all, in a dipole antenna, the other half of the antenna is essentially an elevated ground lead. Both sections radiate.
As to whether there is a difference between the field strength in an elevated vs ground mounted antenna, you would have to do some real world testing. That was the subject of quite a contentious thread here a while ago, and the corollary to the question is whether nearby structures obstruct the signal. You would have to use a dipole antenna, and measure the field strength at ground level, at elevation, and with a building nearby (in fact, probably several types of buildings nearby, made of different materials).
I suspect that the reason a lot of people see huge increases in range with an elevated install is that something is radiating, and turning what should be a monopole with a short or no ground lead into a dipole. That being said, I also suspect, from real world testing, that obstructions do play a part in reducing the range of ground mounted installs.March 7, 2019 at 3:14 pm #110095timinboveyParticipant
Total posts : 671
First, I would like to say that I agree 110% with both of Artisian’s posts above.
Second, in reference to the second post, there is real world testing on the way. I wasn’t going to say anything, but since it’s here again …
I am in the unique position of having an elevated Procaster install with no gound lead connected. I also happen to be conveniently located in a neighborhood where moving the transmitter to the ground directly below would put various obstacles in the way, depending on direction, from an aluminum sided manufactured house, to a wood house, lots of trees, and brick commercial buildings. As well as wide open. As many of you know I also have regularly calibrated field intensity meters with which to take actual, precise readings. Once all this snow is gone I have plans….
Which, BTW is one of the reasons why I have an elevated install. If my transmitter was ground mounted, right now it would be under 4-5 feet of snow.
Also, mentioned again, above, the concept that perhaps my audio/power cable creates a a ground, or half a dipole. Haven’t done a hardcore study of this. However, whether my transmitter is mounted elevated or on the ground, it would still need to have audio and power cables going to it. In fact, were it ground mounted these wires would be about 25 feet longer than in the elevated install, since my studio is 2 1/2 stories above ground level. It’s almost a straight shot across the attic to the transmitter with it elevated. I’d need 25-30 feet more wire (at least) for a ground install, most of which would be a vertical wire. Any transmitter is going to need power and audio. My transmitter is installed with all parts provided from Procaster, including the cable that carries power and audio. Which is the same type of cable they provided for certification to go between their studio unit and the transmitter.
If you know of someone with a ground mounted install who is getting their audio and power from an underground source please let me know. Otherwise I assume all transmitters need cables for this purpose.
TIBMarch 7, 2019 at 3:33 pm #110096timinboveyParticipant
Total posts : 671
Just a footnote: The manual that came with my certified Procaster (five years ago) clearly showed an elevated installation nearly identical to mine and clearly showed a long ground lead from the transmitter to a ground rod directly below it! Fortunately I had read the rules and knew that couldn’t be right. I have no ground lead. The the manual that contained the certification information, which I assume was part of the approved certification, clearly showed this type of installation!
TIBMarch 7, 2019 at 5:35 pm #110097
Tim, some real world testing of your installation, both elevated and not, would be greatly appreciated. It would certainly set the record straight, as it were, regarding obstructions and elevated installs.
There are obviously many factors for absolute range, and that’s why any statement that you will get ‘x’ feet or miles range has to be taken with a grain of salt. Location is a huge influence, as it includes such factors as background noise, ground conductivity geography, both artificial and natural obstructions, etc.
But keeping everything the same, and just checking out the difference in field strength while varying one factor, such as height, is certainly valid.March 8, 2019 at 4:30 am #110098AMRadiolegendParticipant
Total posts : 323
@Tim: You mentioned some time back that you were thinking about adding a second transmitter for your daughter’s location? Did you do this and if no, how about leaving your installation intact and do the ground mounted test when you purchase the second transmitter? Just a thought.March 8, 2019 at 5:04 am #110102RichParticipant
Total posts : 189
My post at https://part15.org/forums/topic/fields-radiated-by-an-elevated-pt15-am-dipole/#post-110101 is appropriate in this thread, as well.
I posted it with a new thread title to make it easier to search for (and find) in the future.
- You must be logged in to reply to this topic.