Hi all,
A few days ago I bought the Whole House 3.0 transmitter to start whatever station it is that I'll be broadcasting. With so many myths about Part 15 FM around, I decided to do some real world testing.
NOTE: I did not put the device in Canadian mode. Ever.
This was brand new, out of the box from Amazon. Not used, so as not to have it accidentally set to Canadian mode. No lightning bolt on the LCD panel, and "US" in the upper left corner.
There's no real need to go into where I live in detail: it's a suburb. Trees, houses, parks.
I put the transmitter on my second floor window sill (window closed) and just ran iTunes off my old iPhone 5. I set the tuner to a known, empty frequency (I checked) and went around with the car.
You know that myth about how Part 15 FM only goes 200 feet? Total lie. The distance from my house to the farthest corner is 425 feet (south). Strong signal. Past that, to about 800 feet in the second block, I lost the signal completely.
So, I drove around the block and went perpendicular to the first street I drove down (east). So now the vector from my house to the street I'm driving down is south east, moving east. Strong signal to 400-500 feet, spotty to about 800 feet, and then dead until I picked it up VERY faintly around 950ish feet.
So, back to my house, and now I'm driving west. Strong signal about 600 feet out, and then faded to 815 feet where I had to turn.
This completely backs up my math from my post a few weeks ago.
Did the same test with my wife's car - same results with very slight variations.
Someone here (theLegacy? ArtisanRadio?) said that the WH3 should be able to go 800 feet. It's true.
I will not be testing Canadian mode. There's really no point to it for THIS test. I just wanted to see how far a Part 15 FM transmitter really goes. Besides, someone tested that for us already.
I also don't have equipment to do any kind of field strength tests.
So, there you go. Myth....BUSTED
If you have a good car radio, as you proved, 800 feet is certainly possible line of sight. Having the transmitter elevated is a big plus - I bet if you put it somewhere on the first floor, your range would be diminished. Maybe something to try out for another day.
Can I ask what kind of car radios you have - just something to put in my database of radios.
I knew it that you could legally go 800 feet sometimes 900 on legal part 15. And that TX is certified. So I can tell you that IF WE ask for 1,000 to 1050 uVm we can go 1300 feet. Thanks for stopping the myth.
Canadian mode you'd multiply those distances by 4 (assuming that it's a full 1000uv/m at 3 meters). That would be line of sight - unfortunately, the farther range you have, the more likely that obstructions and environmental noise will interfere with your signal. So 4 times the range that macdev got would be the absolute maximum (with the same radios, of course).
mac dev your result is better than mine was, but my transmitter was in the center of a brick house with other houses on either side, and all streets go uphill from here, so my location was not at all prime for FM.
The "US" on the display is not the country.....it's the pre-emphisis setting indicator. "US" stands for micro-seconds. The pre-emphisis is adjustable to North America or European standard.
Mark
Oh. haha. Well, just goes to show I never flipped the secret switch 😀
You showed that where the transmitter is located determines your coverage.
Mark
I'm going to try different tests over the next few days. I'm fully aware that I'll never get the coverage I want from it, and I have a TH5 on the way to test AM, but I'd like to know how far I *can* get with this thing.
As I did with my equations in the other thread, I wanted to do the same here. I don't do well with rumors and people telling me what's real and what's not.
The experimenter that has the same exact SainSonic AX-05B version as I do got 1300 feet. Your saying 4 x 700 we'll say that is 2800 feet. Far more than the SainSonic facing smack dab in front of a window but at first floor. So that would mean two of the possibilities. 1. The revised version of the SainSonic me and the experimenter has at high power is far less than 500mW. Maybe closer to 1mW as suggested earlier in the form somewhere that the Whole House FM Transmitter 3.0 and Decade are 1mW at high power. This also explains why the transmitter stays cold metal at the high setting. Just want to clear up a theory I have. Evidently the manual I have lied a little as it was not updated and still says 500mW for high. Maybe 1mW or 5mW but can't be 500mW as that would go a mile or more according to all the tests. If 18 nano watts goes 800 feet into a rubber duck it would not take 500 mW to go 1300 feet. Not even close to it. My math sucks but I'm not that stupid. Anyway I think the 4x 800ft will be 2400 feet. If we get the legal 2400 feet looks like I'll buy a new Transmitter. Maybe try for a used Decade or maybe not worry about it since 1300 feet is good enough for me and what is an extra 700 feet till the transmitter dies. By then the prices will have gone down and better transmitters will be made. I think we can get this legal and everyone should be happy with 4x700 feet. If not there is no hope in your future.
Have to correct my post.....the "US" on the display of the wholehouse 3 actually does mean US(the country) but is showing the setting of the pre-emphisis which can also be set for Europe and it would say EU on display. It's just changing the pre-emphisis from 75uS to 50uS(microseconds). The "US" has nothing to do with the power being US part 15.....There, I hope I explained it right this time.
Mark
Funny no one has talked about the polarization of the send/receive antennas in these Part 15/BETS FM transmitter tests.
Usually the Part 15 FM transmitters have vertical antennas.
What type antennas do automobiles have? Maybe they have horizontal antennas.
Did thw Whole House transmitter 3.o have better audio than the Decade? Does the Decade CM 10 claim to have 75uS pre emphasis? Just curious.
The answer is - it depends.
A lot of cars have vertical whips. Some are at 45 degree angles.
Some have the antenna built into the windshield for horizontal polarization.
Mismatches in polarization will result in less range.
No, the Wholehouse doesn't have as good audio quality as the Decade(CM-10 or MS100). Low end is lacking a bit and not quite as clean. The main problem with the wholehouse is the limiting it's supposed to have doesn't work....it's very sensitive to overmodulation and even with the compressor couldn't get to the volume of the other stations without it going into distortion, especially voice. The decade's work perfect with the compressor....I can actually get the CM-10 slightly louder than some other stations with no distortion.
Mark