Interference testing with the Ramsey 100B

Thanks Carl. Me and Station8 were in Different locations and used different Radio's and still every 15.2 Mhz above or below your frequency you can hear a dead carrier or audio. I was REALLY coming in on 27.405 (Channel 40 on CB). I could clearly hear what song I was playing and this happened for well over 75 feet from the transmitter antenna outside (And my antenna was a magnet mount CA-200) FM antenna. Imagine what interference would had been caused if I were to have bought the comet antenna or the Ultimate FM antenna sold by Radio Brandy.

I'm thinking that Veronica TX is looking better and better all the time to block that crap. It has far better filtering and is well built. Its NOT a toy so I'm sure it has got to do way better than this crap sold to the Hobby Radio community.

You should be able to Flycast with it for those of you who are into only that. Hell just use a dummy load for the antenna and keep your power down. Remember its variable 0-30 Watts so just creep the pot till you get the range you need and leave it.

Yes Boomer rather you decide to go over the limit or not interference is a problem.

I have seen this happen even on certified part 15 transmitters like the whole house 3. But keep in mind that the whole house three can also be turned up to higher power. At the higher power it will go a mile. I did notice on my whole house FM transmitter 3.0 that at high power I can cause the entire FM band to have a loud static sound in this pretty much wiped out the entire FM band. This occurs for a good 50 foot.

Keeping this in mind and being a good neighbor this could be a real problem in these type of complexes where there are four houses to one building.

I think the real reason why some people get busted even though they are transmitting on a fundamental frequency that is far away from any license station what they're not realizing is that their transmitter is causing Spurs and interference and people begin to complain about it. They might not complain to the person who's actually doing the transmitting one of the neighbors decides to call the police or the authorities about it. And then it's game on the person gets nailed often not knowing what is really going on.

I'm going to call a spade a spade and say that not everyone follows the rules and goes exactly the limit. Rather they want to admit it or not. This is another big reason that we at the new radio Revolution is trying to stomp out this interference problem. And don't think that hiding behind the false sense of security of certified transmitter is going to get you out of the interference problems. It seems like these transmitters are the ones that are doing it.

The funny thing is that transmitter like the Veronica and several others are far more Superior and don't cause this interference problems. I would like to see what the source FM transmitter does the one that is one Watt and is supposed to be part 73 certified.

The funny thing about that transmitter is that it does come with a rubber duck and it is a SMA connector on it. I would really like to see what type of interference issues that transmitter may or may not cause and I wonder if the power of that transmitter with less interference would actually get you out further.

Look I've always been the big FM guy in this bunch. And knowing all of these things and being a big FM guy I think it's time that we do try to come up with a good solid cure for this interference problem and one that would be something affordable for everyone.

I'm sure the FCC would rather you have a clean transmitter than a dirty transmitter. And it seems to me that some of these supposed certified part 15 transmitters are one of the worst noisemakers on the FM dial that there is. I wish I did have a spectrum analyzer because I would definitely show some of the transmitter that I own and what they actually are doing.

Maybe it's time to get more members of the new radio Revolution and maybe charge dues or something like that so that we could actually do more experimentation with these transmitters and then work on modifications that will stop the interference issues. That in itself will help everyone in the long run this I do believe.

Transmitters are certified based on a number of factors. They must generate a legal field strength within the test environment of the lab, and they must have a clean signal AT THAT FIELD STRENGTH.

It's been shown in testing that even if a transmitter is certified in the lab, it may produce a field strength that is far above the legal Part 15 limits in the real world. But at least users can point to the certification as a justification for use (most don't have the requisite test equipment to check that).

You can't do that with these other transmitters. There's a reason for them not being certified (or even being able to be certified). They either produce more field strength than allowed (and are intended to do so), even in a test lab, or their signal is compromised. I'm sure that if they could be certified, the manufacturers would go through that process, as it would increase sales dramatically. So I'm not surprised at these findings.

As for the Whole House, it obviously meets Part 15 interference requirements at the legal field strength or it wouldn't have been certified (it is also RSS210 certified in Canada). Running it above those limits is just asking for trouble.

The only transmitters I'm interested in are those that are legal, and certified for a specific service.

I can understand it being an issue even at legal power with some uncertified FM transmitters (although it's difficult to tell if you're legal unless you have expensive test equipment). Part of the certification process is the lab ensuring that the transmitter has a clean signal.

That's why it's unwise to use uncertified transmitters unless you really know what you're doing.

WE've found out after Carl left the meeting and Bob came on that there is a 7.6 Mhz crystac in the oscillator section of the Ramsey 100B TX. Giving that knowledge 7.6 X 2 = 15.2 Mhz (Tada Folks we may have a winner winner chicken dinner). Now what needs to happen next is to find a way to stop this second harmonic of the oscillator 15.2 Mhz from causing these image frequencies every 15.2 Mhz. Thank GOD I'm on 87.7 Mhz cuz 100.1 + 15.2 = 115.3 Mhz and where is that? The Aircraft band. Like I said THE CERTIFIED WHOLE HOUSE 3.0 DID THIS AS WELL and ALL OF THE TRANSMITTERS WE TESTED USED THAT BH1415F FM/compressor/limiter chip again some so-called certified TX's use.

Remember that the Decade is an expensive rip off of the CZE-05B(Same as Signstek CZE-05B, Fail-Safe CZH-05B with a bypass of the Hi Power capability and instead of the reverse TNC connector has a telescopic antenna). I can almost Guarantee this TX is doing the same thing that we experienced with several transmitters using that BH1415F Chip.

Now if I get enough donations I may prove a point and buy for testing that Source FM 1.2 Watt certified LPFM TX and see if it does the same thing as I'm willing to bet my bottom dollar it is using that BH1415F chip which again we see as a possible problem if their oscillator section is too using that 7.6 Mhz crystal. And I'm confident that our official engineer of the New Radio Revolution knows what he is doing as he has been in broadcasting for several years running.

Defeating this issue is now our goal before trying to ask for more power at this time. We had him do his authorized test and some findings were of alarming news that needs immediate attention FIRST! If we solve it we may post how to correct it.

One ALPB member mentioned he had a Ccrane FM1 and FM2 TX and said he never experienced any of what we have described. To what we want to know is what are they using to tune/transmit on FM? Is it the same Japanese Rohm BH XXXX chip set or did they use a proprietary chip no one else uses?

I guess if we can get folks to join and pay dues we could find out by purchasing a Ccrane and do our own investigation to see if indeed they may be using something different. Also they may use a different crystal in the oscillator section of that TX. We may have to test them to see if we get the image as well as crank them up since there are all kinds of images of the pot needed for that and then see if it starts to throw dead carriers or spurs at these multiples of 15.2 Mhz.

I think I'm gonna save for the Veronica TX that way I KNOW I'm clean. It is well filtered and has a nice clean sound as reported by many including a New Radio Revolution member. Yes its very expensive, but there is a reason its not cheap. They made sure that it didn't cause noise all over the spectrum unlike some other transmitters using the BH14XX chips.

I know there is a NEW BH1417 chip but we have not seen a manufactured transmitter using this one yet. The interesting thing about this NEW chip is that it has the 1 Watt capability right out of the chip (which makes me think that the 1.2 Watt SourceFM transmitter may be using) this is why I want to try this and see what it does but before I do I'll try and get the specs on it and see if they reveal if that is the case that they use the 1417F chip and indeed we can count on some cleaner transmitters in the future (Lets hope for the later).

We at the New Radio Revolution will be vigilant in solving this to help everyone in Radio from the Hobby Broadcaster to the listeners to public safety. This is a problem we'll not just sweep under the rug and forget about it and hope it magically goes away.

Remarkable Day-After Development

At last night's SPECIAL MEETING called by Jeff Station8 to report on "New findings regarding FM transmitters" I was lost in fog because we were hearing about a problem that seemingly made no sense and had no estimated cause nor foreseeable solution.

But today comes this later news: "WE've found out after Carl left the meeting and Bob came on that there is a 7.6 Mhz crystac in the oscillator section of the Ramsey 100B TX. Giving that knowledge 7.6 X 2 = 15.2 Mhz (Tada Folks we may have a winner winner chicken dinner)."

All of a sudden things make sense and Jeff wasn't imagining things and there really was a problem in need of a fix!

This ALPB has the best members!