Transmitters that have features like a scanner that looks for clear channels need to have a defeat switch so the user can over-ride the scanner when it malfunctions.
There should also be a lower priced version of the same transmitter for users that never want to use the scanner... people who want to do their own frequency choice.
The NAB and FCC, if they want to be real, have big noise-pollution problems from Wi-Fi, light-bulbs, static producing sources larger than the Atlantic Ocean... Part 15 radio is NOT a source of intereference that any sane person would wprry about.
The part that amazes me is when people are calling for MORE regulation than we have now. All this talk about special spectrum scanning transmitters, do ya'll really think the FCC has time for this? Do you REALLY want to esentially kill the homebrew and kit communities? Do you want what Canada has where you can only buy one or two transmitters because of the way certification is handled there? This is crazy guys, we have gotten so far away from the spirit of part 15 in the hunt for more power.
As this post's original topic proved, we already have an obvious lack of certified builders of part 15 FM equipment. Lets not make that number even lower and more expensive.
The transmitter Legacy proposes would easily exceed the $200 mark, there is no good way to build that kind of unit cheaply.
you know not only should Tim test the field strength and range of these transmitter butt also features and performance. Maybe he can test sum of these transmitter with built in scanners to see how they really do.
Also he should test some transmitter with variable output levels and tell you what level produces 250 microvolts per meter at 3 meters and what produces the 1000 microvolts per meter at 3 meters or 100 microvolts per meter at 30 meters.
It's my understanding that part 15 operators can use any transmitter but they must be responsible 4 the actual field strength. So that in mind maybe this could help widen the choices 4 FM transmitters.
I also like to see am transmitter field strength test just too see what setup produces the best field strength.
"I also like to see am transmitter field strength test just too see what setup produces the best field strength."
HB did this not too long ago, the Rangemaster was the winner.
"Also he should test some transmitter with variable output levels and tell you what level produces 250 microvolts per meter at 3 meters and what produces the 1000 microvolts per meter at 3 meters or 100 microvolts per meter at 30 meters."
The problem with this is the very nature of the FM Broadcast band. What one setup does in a certain location could be completely different in another. A certain amount of power is not guranteed to go anywhere in VHF, thats why the FCC licenses according to height and power for the FM and TV bands.
"It's my understanding that part 15 operators can use any transmitter but they must be responsible 4 the actual field strength. So that in mind maybe this could help widen the choices 4 FM transmitters."
This is exactly what I have been trying to say, and exactly what some of your proposals would take away. It is completely the end users' responsability to comply with the rules.
Mighty1650 said "we have gotten so far away from the spirit of part 15 in the hunt for more power."
The problem is that the spirit of Part 15 means different things to different people.
Some want to compete with the big boys, while some are content with very localized community radio or special applications.
Some are just content to housecast, and some just want to tinker.
One size does not fit all.
It's the guys that want to compete with the licensed radio stations to some degree that want more power on the FM band. If you just want very localized community radio, probably Canada's BETS-1 levels are sufficient on the FM band, and the existing rules on the AM band.
If you want to housecast, you don't need any more power, and either AM or FM will do.
If you want to tinker, then any band will do, including long wave and shortwave.
I consider myself somewhere between community radio and tinkering, and probably a lot of us here are a mixture.
That's why you're never going to achieve any sort of consensus in these petitions just by talking - either the guys who want something just go ahead and do it (the petition, I mean), or you have to adopt some sort of process to achieve a compromise of sorts. It's already been talked out.
"HB did this not too long ago, the Rangemaster was the winner."
Not to open a can of worms, but the Rangemaster, under the set of test conditions HB employed, was the winner. It did not prove that under every set of test conditions, the Rangemaster would have come out on top. In fact, subsequent discussions on the testing methodology showed that the AMT5000 results were probably skewed because of the minimal ground used. The AM band really isn't much different than the FM band when it comes to installation parameters affecting results.
I think perhaps the biggest potential change to the rules on the FM band (and also on the shortwave ISM bands) should be in the area of measuring compliance. Currently, only those who have expensive test equipment really know for sure if they are compliant. It would be nice to change all the Part 15 rules so that they were consistent and easily measurable , i.e., place limits on the input power to the final stage of the transmitter, or place limits on output power from the final stage.
Talking of HB testing the AMT5000, by chance did they test a AMT5000 that was owned by a member on the forum ?
Reason i ask is that i bought an AMT5000 that had the external fibreglass enclosure that i bought from Canada, and it had previously been owned by a member of this forum.
When i inspected this transmitter, it had a dry joint on the ground connection on the pcb, this caused reduced performance.
Paul.
I'd like ot know what field strength (In Real World Testing) would give you 1 mile to a Radio of 0.9 uV. Now I know Tim id the tests with the Whole House 3 with the power on High and the wire antenna connected but I can't remembe the field strength. That is the exact number I'd start with.
At least BETS-1 can go 1,000 Ft and that is not bad. But I'd also like a regular Radio to hear my signal for ½ mile. This would then be perfect. Really field strength and range tests would have to be done. And a good variable transmitter without harmonics is a good thing to test for.
Tim also needs to check harmonics and spurs for some of these transmitters. This is something no one has done that I know of. I'm sure we all want clean transmitters. So harmonics and spurs is of importance.
Boardmaker, the AMT5000 that was tested by Hobbybroadcaster was loaned to them by an individual. It did not come from any official source, and as such, there is no way to know if there were any issues with the construction. That too was one of the criticisms leveled against those particular testing conditions. I believe that all of the other transmitters used, and certainly the ProCaster and Rangemaster, came from official sources (they were from a local distributor).
All that being said, it was an interesting test. Now we need is a test to determine what the maximum field strengths of these AM transmitters could be under ideal (but legal) conditions (which is something that is being asked for by Thelegacy for FM - see how adeptly I got the thread back to the original topic?)
I'd like ot know what field strength (In Real World Testing) would give you 1 mile to a Radio of 0.9 uV.
Unfortunately there is no simple answer to that question.
For VHF-FM signals, the correct answer (mostly) will depend upon:
- ERP, height above the earth, and polarization of the transmit antenna
- Gain, height above the earth, and polarization of the receive antenna
- Path Length Between those Antennas
- Frequency
- Earth Conductivity
- Obstructions and Reflections for that Propagation Path
- Co- and adjacent-channel interference from other FM stations
- Local r-f noise
- The capture ratio of the FM receiver
- Listener tolerance for poor signal-noise ratios
The USA has the advantage of being able to use kits that you build yourself which is a hobby in the basic sense. A very good point was made here about having so much more regulation. There is a web site that you can look up in any area of the USA for open frequencies. Here in Canada if transmitter had a smart system that decided where you could transmit there's this senereo....the smart scanner may see a very weak station with some noise as an unopen frequency but if the weak station fading in and out is an out of country station...like in Toronto where buffalo stations can be recieved, you could legally go on top of it because no out of country stations are protected. If you don't pay Industry Canada and the CRTC for a licence you get no protection But the smart scanner wouldn't let you. I know this because I used to listen to a Rochester oldies station which I could get on a HI-FI receiver and one day a new more local station came and killed it(actually CBC radio2) and I called Industry canada to complain and was told too bad....out of country stations are not protected.
Mark
The whole point on making it mandatory for a scanner is so that if a station can be received by a good HiFi Stereo one person can't possibly transmit on top of that station.
This is why I would like some of those transmitters tested for their accuracy. I doubt that the Belkin is going to be accurate, but it may surprise all of us here.
I agree that if someone is not smart enough to scan their frequencies first they should not own/operate a transmitter. But there is always the Johnny problem child.
As for AM it would be nice to have an unbiased test to see how we can get the best field strength for AM and field strength will equal range. There should be an indoor test too.
But that doesn't make any sense? Why the heck would normally distant unreliable signals need protection? Common sense dictates not to use it, trust me that full power FM would cause way more problems than the part 15 ever could. The scanner is unnecessary.
I'm not trying to be mean or derail this topic, I just really don't want to see everything get so complicated.
This is supid s__t> Sorry, You will see less of me.. on this and other sites. Radio is technical and POLITICAL. Selling the FCC on issuning smart cards is.....Are you a troll?
The GOgroove FlexSMART’s can have their frequency set manually. They also tune in 0.1MHz steps, so for example 101.2MHz is available. That leads to the auto channel select sometimes picking a frequency an even channel that most radios can’t tune to that is sandwiched between full power stations. For example near me are full power stations on 103.7 and 104.3 and the GOgrove will pick 104.0.
That is bad. It should only scan 1,3,5,7 and 9. Otherwise I bet it is pretty accurate. How is the sound quality of that transmitter? I assume only 3 feet in range Right?