After I completed my "drive test" with the WH 3.0 up in the second story bedroom window, connected to the ipod (playing Christmas music LOL) curiosity got the better of me.
I may have said something like "what the hell" and went up stairs, put on the included longwire antenna, strung it up through the top of the window and over the ceiling fan. Then, I may have switched the transmitter to "Canadian Power" and gone for a drive.
Now, had I done this 😉 I would have discovered that it came up just short of what my Procaster does on AM. I went to the parking lot 7100 feet away from my house and could find a good spot to park in and hear the WH 3.0 just fine. Granted it wasn't a "solid" signal, I had to park in a "good spot" and I doubt it would have been heard that far away with an indoor radio, but seeing as how the illegal US settings couldn't be heard to the end of the block that was pretty impressive. My town is 1/4 mile long and four blocks wide. I could drive around the permiter of town and hear it everywhere, although with some expected drop outs in various places.
I think if some sort of miracle were to happpen, based on this brief alleged test I don't believe the Canadian limits would be too far off base for something to shoot for. It would still be a heck of a battle, and would need a lot of good engineering paperwork behind it, and a lot of documentation and positive comments from people in the public eye. But it does turn what is basically good for yardcasting into something similar to what Part 15 AM does. Although we do have to keep in mind that the WH 3.0 was well above the Canadian limits as well. Also worth noting -- after runing on Canadian time for a bit the transmitter gets mighty warm.
On a positive note I will say the WH 3.0 did sound quite nice. It doesn't do well with ANY overdriving of the audio, but with the levels set nicely it does sound pretty darn good. Now, remember I have no experience with Part 15 FM so I have no experience to compare it to, but it sounded mighty good.
TIB
Maybe you should inform the FCC of your interesting findings? If it's so much over as your tests show, innocent people are at risk and the company, not the innocent purchasers should be held accountable.
Mark
I can see the incentive for manufacturers to want to 'push it" with power levels, and maybe they are in a way leap frogging each other. A company wouldn't want to put out a product that would get a reputation of having a weak signal, then no one would buy it.
Users do talk about these things - alot. I go to stores on line and there are many reviews comparing the range of oen transmitter to another, that's a very important statistic if you go by reviews.
I first noticed it after the FM broadcast power was cut back in Sirius radios some years ago. Those were useful at normal power, you could listen to a station on Sirus on radios in your house by rebroadcasting it. Apparently someone complained because of Howard Stern, so the company cut the antennas out of the radios, and they could only reach a few feet. In the car, the Sirius FM TX might not be heard on the car's radio with the antenna a few feet away.
People were angry and wanted their range back, and found ways of plugging in external FM transmitters like the CCrane and Wholehouse, and others, and there was a lot of talk about which one was best.
Could another thing be manufacturing tolerances, the tester only had one unit to go by right? A dollar store in the area had a bunch of FM transmitters in their phone accessories area, cheaper than any name brand like Belkin, more features like temperature display, and their range seemed to be better than others, and they also tuned to as low as 87.5 FM.
I got two or 3 of those and friends got several after seeing mine. One thing we noticed was that range was different for each one, by a good bit too. Cracking one open, there wasn't much inside, just FM BHXXXX chip, mircocontroller, function buttons, display. A few bucks worth of parts? Maybe that.Cents more likely.
I was thinking they're made by the millions, and there can't be any calibration or quality control here. There's not even a brand name, or website address, I think they just said FM TRANSMITTER, that was it. I plugged it into my computer's front audio jack and let it hang, then listened to streams on FM radios in other rooms, it did what I was looking for.
When you go to Amazon, Light O Rama forums and other forums talking about FM transmitters they sometimes all say that these FM transmitters ae not worth the money for they can't even get across your room. Some christmas light shows started to use transmitters of 1 Watt or higher. Even the SainSonic was talked about on some forums and people would talk about its great range. Look at the reviews on Amazon about the C. Crane and the whole house. All talk about jacking up the power because they can't be heard to the end of their driveway by passing cars that look at the light show and tune into the station.
So people often push it not knowing about part 15 AM as a solution for their light show. Most don't get busted unless they are too close to another station. But we have the data to ask for more strength as we have proof it does not cause interference unless people are super careless. This is why (but its too late) the FCC should have considered 87.7 and 87.9 when doing a repack and saved those frequencies for part 15 FM. But the deed is done. Lets see what we can do.
I kind of like the idea of using AM for a Christmas Light Show, it would be different than all of the ones with FM for a change, run old Christmas classics that would have been heard on AM radio in the past.
The shows I've seen are at nightime though, to better show of the lights, so you'd want a quieter AM frequeny that doesn't get taken over by strong brodcasters on skip. It might be good to do a coverage check, but it might not matter much because your AM signal would be strong. You could even disguise the antenna mast as a xmas tree or candy cane and wrap garland around it in the front yard. Mmm, lots of ideas there.
One thing FM transmitter manufacturers could perfect would be remote transmitters, like some AM uses. There are AM transmitters that have the transmitter section in a box that goes on your roof or a tower, with an audio and power cable that runs inside to your equipment, because they realize that getting the antenna outdoors and away from other objects is the way to go.
FM could start to do this too, putting the signal where it would do the most good, closer to receivers. That might even help to not have to use higher power transmitters to reach somewhere and get the job done, they won't need to overdo it trying to get a signal from deep in a house to outside, due to multipath from people walking in the house or when other cars go by.
The remote transmitter could be put on a fence along the property, hidden in a bush, or mounted to a pole lamp that everyone seems to have in front of their house, which would be right by the street where cars are parking. It couldn't be much bother to use a remote transmitter, the people at the house are already taking lots of time to put their display in.
The transmitter could even run on batteries and be fed wirelessly, like wireless headphones are.
Since WiFi goes further than part 15 FM you can use it to send the audio to the transmitter. May work. I truly love the idea of that.
Correct. I only had one to test. And I've certainly considered manufacturing tolerances as a factor for sure. But this was WAY over the limit. It's not like it was *almost* legal. But I've got half a mind to buy another one and see how it stacks up. I noticed, as I mentioned before this one has basically a reverse thread bolt to screw the antenna to, but some online appear to have an actual SMA brass connector. This one came with the "international wire antenna" but that is not listed as an included accessory, and this one came with a power adapter that produced no power. I'd like to have a dozen random ones to compare and test but my "screwing around with FM transmitters" budget doesn't allow for that! I have no intention of using any of these, I'm gathering data only more out of curiosity than anything else. My original intent was to offer up for sale at half price any I buy to do tests on but I can't in good conscience sell a transmitter I know is not legal. Heck, on batteries with an audio cable plugged in, through my walls from inside the house to my front yard it was nearly 8 times over legal. At the three meter range the FCC specifies it was over by more than 20 times if I recall. That's a hell of a tolerance!
TIB
I then did a quick range test using the Tecsun PL310 as long as I was in an open area. I didn't have the ambition to run a marathon to various points so I went out to 220 feet. At US power at 220 feet signal was readable only by positioning the radio for the "hot spot" where the signal was strong and clear.
Tim - What were the polarizations of the transmit and receive antennas when the set of tests was made using your Tecsun PL-310?
If the tx and rx antennas were cross-polarized, that would explain why the coverage radius was less than expected for the maximum fields you measured from the WH3 at a distance of 3 meters.
Missing form your test parameters was music selction when the Ipod/Ipad device was connected. Was it Polka?
Hi Tib, maybe you could attenuate it down to normal, or sell with the disclaimer that the buyer has to follow the rules when using it. I don't know why it would have a bolt connector and not an SMA, which would seem to be a better option, especially if someone wanted to attenuate it for their country. Sell it to another scientist.
It does seem like too much tolarance for a circuit. I just remembered how the dollar store transmitters we tried had all different radiation levels, with some you could tell right away that the signal was more potent than others, it was just in there and the stereo seperation was strong, that was before you left the room or even went to the car. They were really the cheapest transmitters though, where Wholehouse is a known name.
We can ask for the strength this thing puts out at the USA level in your tests. Since probably 75 percent of the part 15 population already has this transmitter it would make sense for the FCC to raise the limit rather than the other which would be to give 75% of the part 15 FM transmitter user base a NOUO. But then again its the USA our guvernment does not do what makes sense.