If this post ends up double I'm sorry I am visually impaired and didn't see my reply to an older post talking about the CZH-05B which that one didn't have 75uS pe emphasis. I tried to reply to:
I have seen the SainSonic AX-05B's image of the circuit board compared to the Decade CM-10 which costs twice as much. If the SainSonic too is certified part 15 as well as the Decade then I suppose that means that the SainSonic AX-05B is not a dirty transmitter that causes harmonic spurs am I Correct in that assumption? if correct then here is the thing. I did ask SainSonic by phone if they sell theirs with 75 uS pre emphasis and they told me that their transmitter uses 75uS pre emphasis instead of 50uS.
My setup is gonna be like this for my Album Rock (Progressive Rock, Deep Tracks), Classic Rock station http://thelegacy.shorturl.com which with the software NextKast which has a nice Audio processor with it that compaires with Breakaway Broadcast along side Radio automation. It has a prevision for a FM Transmitter which does allow for the second USB sound card to receive the same audio that I'll use for the Internet stream encoder. I'll pipe this into the transmitter using the 3.5 mm audio cable. All in all I hope this will work for me as I also looked at the Whole House FM Transmitter 3.0 but I think that one is made cheap. What is your teke? I know it might go a little past part 15 without the Attenuation as posted when ever anyone talks about this transmitter but again reports say it only went 61 meters on low power (Sometimes even high). Something to consider on youtube a man was advertising the Whole House FM transmitter 3.0 on the 50 yard line at MSU football field received on a analog Radio (Not Digital) so with a Digital Radio that range will double if not triple on something like a Rotel, Yamaha, Sony Elite. Part 15 can be useful just wish we could get field strength meters for more accurate detection.
I would venture to say that any FM signal that can be heard more than 200-300 feet from the transmitter is NOT Part 15 legal in the USA. Watts has nothing to do with it. 1/4 a watt, 1 watt, 50 watts, doesn't matter. It's field strength that counts. A 50 watt transmitter with a crappy enough antenna that comes in under the legal limit field strength would be fine, but a 1 watt transmitter with a good antenna would be illegal. In reality even a 100 milliwatt transitter with an antenna would probably be illegal. Simply put the legal limitation for Part 15 FM is 250uV/M at a distance of 3 meters from the antenna. Doesn't matter how many watts or how big your antenna is, or how efficient your system is, or anything else. You are limited to that field strength. Generally speaking, on a good day, this legal limit gets you 200-250 feet into a typical radio. That fact that you may be heard further with a really good receiver is moot, unless you plan on equipping your potential listeners with really good radios. Probably with external antennas, too.
No matter what people advertise, or what advertisers and sellers offer up, you are limited to 250uV/M at a distance of 3 meters. Which translates to 200-250 feet typical to a normal consumer radio. Maybe better in a car radio, but remember, cars move, so it doesn't help much if they can listen to you for 30 seconds before they're out of range. The advertising of power output in watts, or milliiwats, or whatever is irrelevant. You can still only have the maximum signal of 250uV/M at a distance of 3 meters. The FCC has placed no limits on power, antenna, ground, or anything else for Part 15 FM except for 250uV/M at a distance of 3 meters. Which is nearly impossible for the average guy to measure in real life. There are no inexpensive consumer grade devices that will measure this accurately, but as a general rule if you're hitting 500 feet you're probably illegal.
Tim in Bovey
The Decade CM-10 is the same as the Sainsonic AX-05B. A modified CZH-05B transmitter to be FCC and Industry Canada certified. Also to be certified it has to meet standard for no interference in other bands.
I paid $200 for the Decade CM-10 which I have and have used and the Sainsonic is $50 if you get it directly from Sainsonic web site...NOT Amazon.
If I had known this I sure wouldn't have gotten the Decade CM-10.
If you read the features of the AX-05B you will see the FCC certification # on the rear and it has been modified so the low power setting meets the rules so was certified. Since the certification is with the rubber duck stock antenna using a 30 inch length of wire would bring it to Canada allowable signal strength. This is annoying that I paid $200 originally!
Based on my use this works good with good sound quality and can get to the volume of the other stations(almost) and with a compressor you will get louder on air with no distortion. A 12 volt block computer style power supply will work best with no hum.
Mark
Thanks Mark I got the answer I'm looking for. I know how to change the power by holding down the Power button and plug in the SainSonic AX-05B (CHZ-05B modified and fixed to kill harmonics like the guy @ SainSonic says). But ou eased my mind on the SainSonic.
If I get it and it hums what is the brand of power supply I need to replace this with? My Laptop has one but with a USB mic that hums on my Internet Radio station which I do have a compressor/limiter built into NextKast.
Thanks again you saved me a lot of cash. Again going with SainSonic AX-05B from the SainSonic website and PayPal or even call them by phone and order when I'm ready to order. Gotta get paid first woo hoo can't wait man I'm stoked about this transmitter made of aluminum instead of plastic.
Best Regards
Most block type adaptors with the power cord plugging in at one end and the connecting cord to your device at the other like the power supplies that come with lap tops, tablets, etc are much better and work with these transmitters with little hum. But since most laptops run on 20 volts or so the ones that power the LCD monitors(with desktops) are 12 volts and work good. The brand dosen't really matter. Any electronics parts and components store has them and ebay has pages of them. But sometimes the hum can be from before the transmitter like your compressor for example. Most of the time putting those small ferrite clamps on the power cord near where it powers your device stops hum.
Mark
If the SainSonic transmitter's power supply does cause hum and I find it does come from that power supply I'll have to find another 12 volt one that does have the same size barrel jack that the SainSonic power supply has. Yes when I go to talk on my station I have to un plug my laptop. May try replacing my USB headphones and see if I can find better ones anyway before I buy the transmitter or at the same time. I'll probably go with a pair of Turtle Beach headphones. I had some before that actually were gaming headphones for a Ps3 but they got damaged. I'll have to buy another pair as they had great shielding.
Just have to let you know I'm not on the second floor of an apartment. I'm on the 1st floor of a house but the house is smack dab next to a complex just wanted to clarify that. I'll let you know when I get all saved up and the transmitter is in action.
Best Regards.
Gentlemen,
Some of the posts above in this thread were edited to remove allusions to operating outside the rules of Part15 and speculation as to what the FCC inspectors may or may not accept.
No one here is accused of promoting illegal operation but some of the posts' content could be misconstrued as doing so, so it was thought best to avoid this by edits.
Each operator is free to operate his/her station as they deem acceptable but this site does not want to promote over-power or other possible illegal acts in appearance or in fact.
Please do not comment on this here. If you have questions or comments please do so with the CONTACT button on the front page.
Neil