FM transmitter

[Guest guest]

KenL_MCSE wrote:

Here is a link from the guys at diy all about transmitters

http://diylightanimation.com/wiki/index.php?title=FM_Transmitters

I could be wrong on this statement;

the tx-99e board is in the Mobile Black Box 4000, the Hilly; the board is build by CHZ.

I just lve how that article states TWO differeing things about the distance. In one area it says "tranmsit no further than 300'), then later on, it says transmit 201' and you're busted. And references 200'. Then folks wonder why many get confused as to how far they can transmit legally.

Pretty sure it's not more than 300', and I don't think anyone transmitting over 200' is going to "get busted" either, 301', possibly.

[Guest guest]

Orville wrote:

KenL_MCSE wrote:

Here is a link from the guys at diy all about transmitters

http://diylightanimation.com/wiki/index.php?title=FM_Transmitters

I could be wrong on this statement;

the tx-99e board is in the Mobile Black Box 4000, the Hilly; the board is build by CHZ.

I just lve how that article states TWO differeing things about the distance. In one area it says "tranmsit no further than 300'), then later on, it says transmit 201' and you're busted. And references 200'. Then folks wonder why many get confused as to how far they can transmit legally.

Pretty sure it's not more than 300', and I don't think anyone transmitting over 200' is going to "get busted" either, 301', possibly.

It's field strength measured at a specific distance, not just pure distance from antenna/transmitter, so not the proper metric in the first place...other than as a very rough guideline. You could be 20 feet from your transmitter and in violation of the FS guideline...you're correct, their explanation does more to confuse than clarify.

[KenL_MCSE]

Actually it is not distance. It is the field strength at 3 meters cannot be over 250 u/vm. According to Radio Brandy, wiki's and part15.us that is .1 microwatts transmitters (EDM).

The thing I find funny (wrong word) is that an EDM putting out .1 microwatts broadcasts futher than other units that put out 500 miliwatts, 1 what, etc.

[Guest guest]

KenL_MCSE wrote:

Actually it is not distance. It is the field strength at 3 meters cannot be over 250 u/vm. According to Radio Brandy, wiki's and part15.us that is .1 microwatts transmitters (EDM).

The thing I find funny (wrong word) is that an EDM putting out .1 microwatts broadcasts futher than other units that put out 500 miliwatts, 1 what, etc.

Correct. Point being, you cannot just say, "if you have signal at XX feet, you are in violation", or "if you contain your radiated signal to within XX feet you are operating legally".

The concept of field strength measured at a specified distance is what is misunderstood in a lot of these discussions.

[Guest guest]

DonFL wrote:

KenL_MCSE wrote:

Actually it is not distance. It is the field strength at 3 meters cannot be over 250 u/vm. According to Radio Brandy, wiki's and part15.us that is .1 microwatts transmitters (EDM).

The thing I find funny (wrong word) is that an EDM putting out .1 microwatts broadcasts futher than other units that put out 500 miliwatts, 1 what, etc.

Correct. Point being, you cannot just say, "if you have signal at XX feet, you are in violation", or "if you contain your radiated signal to within XX feet you are operating legally".

The concept of field strength measured at a specified distance is what is misunderstood in a lot of these discussions.

Now if I get an SWR meter, will this tell me what I need to know or do I need something completely different?

I do know if I DO NOT use the supplied antenna with my MBB Eclipse 4000 and use an old "Rubber Ducky" spare scanner antenna I have, my signal starts breaking up in less than 1/10 of a mile (just under the 1/2 way point), but if I use the "magnetic telescoping antenna" that was supplied, then I'm trnasmitting a clear signal almost 6 times that distnce. Almost 6/10ths of a mile, which is definitely past the range limits. Or if I use an 10Db Attnuator the range is about the same as the "Rubby Ducky" antenna using the supplied telescoping antenna.

Also just noticed there is NO part 15 sticker or written indication on the MBB Eclipse 4000 unit anywhere either.:shock:

I had thought there was on the back of the unit, nope, not there. Nothing in the documentation either, I just looked! Now I wasn't aware of this when I purchased it in Jan. 2010(on glowing recommendations and reviews of it), otherwise chances are I would have went with another transmitter if I had known the unit WAS NOT FCC Certified!

This is why I prefer to purchase items I can PHYSICALLY see the unit BEFORE I buy it instead of "on-line" for items like this.

Ah well, I'll just use my rubber ducky antenna, easier to use than the magnetic telescoping one anyway. Plus it's a little more hidden and less accessible to damage.

[KenL_MCSE]

My thoughts,

I broadcast about .4 mile. I used the radio locator website to pic a frequency that 50 miles away in two different directions is used by two different radio stations. Depending on weather I can barely pick up either/both of them as I drive around.

What gets the men in black out to your house is a compliant. I only broadcast during my show and pre-show. I am taking the chance that no neighbors are trying to listen to either of these stations. I want the extra strength for a few reasons, mainly sound quality.

You decide what your situation is. If you are not affecting anyone either by blocking their station or bleeding through their other communication devices, you probably won't get a visit from the men in black.

No one here is trying to make money by selling advertising on their radio station like that guy in Miami was. Plus he was pushing some wattage so other radio stations complained.

By the way, part 15 also talks about antenna. the antenna's designed for the MBB4000 don't increase gain which is one of the stipulations. Look up the case of FCC vs Ramsey. FCC did not go after purchasers, the went after Ramsey for being too powerful.

[KenL_MCSE]

My thoughts,

I broadcast about .4 mile. I used the radio locator website to pic a frequency that 50 miles away in two different directions is used by two different radio stations. Depending on weather I can barely pick up either/both of them as I drive around.

What gets the men in black out to your house is a compliant. I only broadcast during my show and pre-show. I am taking the chance that no neighbors are trying to listen to either of these stations. I want the extra strength for a few reasons, mainly sound quality.

You decide what your situation is. If you are not affecting anyone either by blocking their station or bleeding through their other communication devices, you probably won't get a visit from the men in black.

No one here is trying to make money by selling advertising on their radio station like that guy in Miami was. Plus he was pushing some wattage so other radio stations complained.

By the way, part 15 also talks about antenna. the antenna's designed for the MBB4000 don't increase gain which is one of the stipulations. Look up the case of FCC vs Ramsey. FCC did not go after purchasers, the went after Ramsey for being too powerful.

[Guest guest]

I find a lot of Ramsey names, but I'm not finding anything about the FCC vs a Ramsey FM transmitter producing company. That is, if that is what you're referencing. The Ramsey I found was for licensing CBS, a commercial entity.

So if someone could point me in the direction of such a case with an url link, would be much appreciated.

[Alan C]

DonFL wrote:

KenL_MCSE wrote:

Actually it is not distance. It is the field strength at 3 meters cannot be over 250 u/vm. According to Radio Brandy, wiki's and part15.us that is .1 microwatts transmitters (EDM).

The thing I find funny (wrong word) is that an EDM putting out .1 microwatts broadcasts futher than other units that put out 500 miliwatts, 1 what, etc.

Correct. Point being, you cannot just say, "if you have signal at XX feet, you are in violation", or "if you contain your radiated signal to within XX feet you are operating legally".

The concept of field strength measured at a specified distance is what is misunderstood in a lot of these discussions.

Correct. What you need to remember is that the concept of the field strength measurement includes the antenna gain. You can take a perfectly legal FCC part 15 transmitter, fit it with a "better" antenna with a bit of gain, and find that the combination of transmitter and antenna has now put your setup in breach of the FCC requirements.

Regards,

Alan.

[Guest guest]

KenL_MCSE wrote:

My thoughts,

I broadcast about .4 mile. I used the radio locator website to pic a frequency that 50 miles away in two different directions is used by two different radio stations. Depending on weather I can barely pick up either/both of them as I drive around.

What gets the men in black out to your house is a compliant. I only broadcast during my show and pre-show. I am taking the chance that no neighbors are trying to listen to either of these stations. I want the extra strength for a few reasons, mainly sound quality.

You decide what your situation is. If you are not affecting anyone either by blocking their station or bleeding through their other communication devices, you probably won't get a visit from the men in black.

No one here is trying to make money by selling advertising on their radio station like that guy in Miami was. Plus he was pushing some wattage so other radio stations complained.

By the way, part 15 also talks about antenna. the antenna's designed for the MBB4000 don't increase gain which is one of the stipulations. Look up the case of FCC vs Ramsey. FCC did not go after purchasers, the went after Ramsey for being too powerful.

What I think you are ultimately saying, correct me if I misinterpreted, is..."legal or not, I'll take my chances no one complains, and odds are, the FCC won't visit me.."

I can assure you, dealing with the FCC as part of the day job, they are understaffed, overworked, and have a lot bigger things to worry about than Joe Christmas Light's fm transmitter that may be a bit too hot.

However...they still have the letter of the law on their side...so it's ultimately your choice of how much risk you want to take.

[Guest guest]

Orville wrote:

I find a lot of Ramsey names, but I'm not finding anything about the FCC vs a Ramsey FM transmitter producing company. That is, if that is what you're referencing. The Ramsey I found was for licensing CBS, a commercial entity.

So if someone could point me in the direction of such a case with an url link, would be much appreciated.

Ramsey Electronics...here's one link..this whole deal goes back 5 years..involved their "export only" transmitters...

http://www.mediageek.net/2006/01/micro-transmitter-manufacturer-fined-by-fcc/

[Guest guest]

DonFL wrote:

Orville wrote:

I find a lot of Ramsey names, but I'm not finding anything about the FCC vs a Ramsey FM transmitter producing company. That is, if that is what you're referencing. The Ramsey I found was for licensing CBS, a commercial entity.

So if someone could point me in the direction of such a case with an url link, would be much appreciated.

Ramsey Electronics...here's one link..this whole deal goes back 5 years..involved their "export only" transmitters...

http://www.mediageek.net/2006/01/micro-transmitter-manufacturer-fined-by-fcc/

Thanks Don!

Now from all I have been reading on that issue, it would appear to me that MBB is "illegally" selling UNCERTIFIED transmitters in the US. As there is NO certification, FCC or otherwise on the unit, in the documentation OR on their website. They don't make you sign a form, but they are using pretty much that same disclaimer of: "the end user is responsible for the legal use of the equipment".

So I'm somewhat surprised their is no FCC vs Mobile Black Box issue!

Since it appears that to sell or manufacture ANY FM trnsmitter, wether fully assembled or in kit form REQUIRES PART 15 CERTIFICATION by the FCC to be legal in the US! Otherwise it IS NOT even supposed to be sold or available in the US!
(at least that is my understanding from reading all the information at that site and links from it).


Someone must have either sent in a complaint to the FCC about the Ramsey unit or somebodies neighbor complained because of interference to their favorite radio station to start that investigation.

But it sure puts me in question of MBB and their transmitters now that I've read that.

Again, thanks for the link, it has made for some very interesting material to read!

[Guest guest]

Orville wrote:

DonFL wrote:

KenL_MCSE wrote:

Actually it is not distance. It is the field strength at 3 meters cannot be over 250 u/vm. According to Radio Brandy, wiki's and part15.us that is .1 microwatts transmitters (EDM).

The thing I find funny (wrong word) is that an EDM putting out .1 microwatts broadcasts futher than other units that put out 500 miliwatts, 1 what, etc.

Correct. Point being, you cannot just say, "if you have signal at XX feet, you are in violation", or "if you contain your radiated signal to within XX feet you are operating legally".

The concept of field strength measured at a specified distance is what is misunderstood in a lot of these discussions.

Now if I get an SWR meter, will this tell me what I need to know or do I need something completely different?

I do know if I DO NOT use the supplied antenna with my MBB Eclipse 4000 and use an old "Rubber Ducky" spare scanner antenna I have, my signal starts breaking up in less than 1/10 of a mile (just under the 1/2 way point), but if I use the "magnetic telescoping antenna" that was supplied, then I'm trnasmitting a clear signal almost 6 times that distnce. Almost 6/10ths of a mile, which is definitely past the range limits. Or if I use an 10Db Attnuator the range is about the same as the "Rubby Ducky" antenna using the supplied telescoping antenna.

Also just noticed there is NO part 15 sticker or written indication on the MBB Eclipse 4000 unit anywhere either.:shock:

I had thought there was on the back of the unit, nope, not there. Nothing in the documentation either, I just looked! Now I wasn't aware of this when I purchased it in Jan. 2010(on glowing recommendations and reviews of it), otherwise chances are I would have went with another transmitter if I had known the unit WAS NOT FCC Certified!

This is why I prefer to purchase items I can PHYSICALLY see the unit BEFORE I buy it instead of "on-line" for items like this.

Ah well, I'll just use my rubber ducky antenna, easier to use than the magnetic telescoping one anyway. Plus it's a little more hidden and less accessible to damage.

SWR meter is not what you want. You need a true field strength meter. Its not a piece of equipment that will directly connect to your transmitter.

Interesting comments on the web re MBB, their connection to HLLY, part 15 compliance, and wide-ranging comments about quality of the product. But there is definitely some question re their selling a non-kit transmitter in the US, and it not being certified. It also raises some interesting debate regarding certification needed for "kits", versus "homebrew"..

I've not taken the plunge as yet, but after all is said and done, the EDMs still seem to come out on the top of the heap...and, it looks like, the price list. But at the end of the day, that will likely be my choice.

[Guest guest]

double post.

[Guest guest]

Orville wrote:

DonFL wrote:

Orville wrote:

I find a lot of Ramsey names, but I'm not finding anything about the FCC vs a Ramsey FM transmitter producing company. That is, if that is what you're referencing. The Ramsey I found was for licensing CBS, a commercial entity.

So if someone could point me in the direction of such a case with an url link, would be much appreciated.

Ramsey Electronics...here's one link..this whole deal goes back 5 years..involved their "export only" transmitters...

http://www.mediageek.net/2006/01/micro-transmitter-manufacturer-fined-by-fcc/

Thanks Don!

Now from all I have been reading on that issue, it would appear to me that MBB is "illegally" selling UNCERTIFIED transmitters in the US. As there is NO certification, FCC or otherwise on the unit, in the documentation OR on their website. They don't make you sign a form, but they are using pretty much that same disclaimer of: "the end user is responsible for the legal use of the equipment".

So I'm somewhat surprised their is no FCC vs Mobile Black Box issue!

Since it appears that to sell or manufacture any FM trnsmitter, wether fully assembled or in kit form REQUIRES PART 15 CERTIFICATION in the US! Otherwise it IS NOT even supposed to be sold or available in the US!

Someone must have either sent in a complaint to the FCC about the Ramsey unit or somebodies neighbor complained because of interference to their favorite radio station to start that investigation.

But it sure puts me in question of MBB and their transmitters now that I've read that. Very interesting material to read too.

It would appear you're right about MBB.

Re your antenna question, a certified part 15 transmitter must use the antenna supplied, as that is part of the certified design.... In the case of MBB, it's a moot point...and again, all up to how legal, or "not legal" you want to be...

Ramsey and the FCC have clashed a few times...I sense the FCC watches them closely...and its a lot easier to go after them since they are stateside...

I've built some of their non-RF products, not bad kits at all..just looks like their is a cloud over their transmitter products.

[clyfe]

Caleb Linburg wrote:

I wanted the MBB transmitter but it has been sold out for a long time does anyone know when the new one will be out?

http://www.mobileblackbox.com/content/view/42/76/

I bought a MBB4000 for my 2010 show and was very disappointed. I had it running on an analog timer to automatically turn on and off during my show. However, on Christmas Eve, I got a call from a friend, he was out front and said there was no audio on the radio, just silence. I went and checked, sure enough, wasn't working. I contacted MBB and told me I was a few days out of warranty(90 day) and there was nothing they could do. I will never do business with them again!

[Guest guest]

DonFL wrote:

It would appear you're right about MBB. If I'm reading things correctly, re your antenna question, a certified transmitter must use the antenna supplied..but I could be wrong there. In the case of MBB, it's a moot point...

Ramsey and the FCC have clashed a few times...I sense the FCC watches them closely...and its a lot easier to go after them since they are stateside...

I've built some of their non-RF products, not bad kits at all..just looks like their is a cloud over their transmitter products.

EDIT: If I use the supplied antenna and no 10Db attenuator, this thing can broadcast up to a 5 mile radius! Even with the attnuator, range is 6/10ths up to 1 mile depending on weather conditions! And why I think I'll just use the little "rubber" scanner antenna. Barely get a half of 1/10th of a mile with it.


From what I've been reading at the FCC site and some others, the supplied antenna to a "certified part 15" transmitter is supposed to have a special antenna connector that would only be available from the manufacturer, and could not be bought at your local radio parts house or radio shack store!

Most often, it states the antenna should be HARD-WIRED directly to the certified transmitter!:shock: That was a surprise!

So any tranmitter that has a standard antenna connection(like BNC) from what I've read thus far, would also be considered in NON-Conformance to part 15 of the FCC rules!

And I think most transmitters have a BNC type connector to connect their antenna too. So unless there is another document somewhere that supercedes/changes that aspect, then there sure are a lot of FM transmitters operating out here that are in non-conformance.:shock: Now just how screwy is that?

[Guest guest]

clyfe wrote:

I bought a MBB4000 for my 2010 show and was very disappointed. I had it running on an analog timer to automatically turn on and off during my show. However, on Christmas Eve, I got a call from a friend, he was out front and said there was no audio on the radio, just silence. I went and checked, sure enough, wasn't working. I contacted MBB and told me I was a few days out of warranty(90 day) and there was nothing they could do. I will never do business with them again!

Clyfe, did you ever try changing out the main power cord from the ~AC~ outlet to the power brick?

My power cord went bad (just recently) and I found an old computer power cord, they fit the power block pefectly (which is also a lot olonger than their SHORT power cord), chnaged that out, turned the power switch on and it worked fine.

If you haven't tried replacing the power cord, try that, it may bring it back to life.

I thought mine was dead too, and I was going to really ticked if it had died before it was even a year old! Just glad it was nothing more than a bad power cord.

Their power cord doesn't hold up well to a lot of flexing or movement, a computer power cord is much sturdier, and again, longer. Which a longer cord for me is a plus!

EDIT: BTW, the part of the cord that went bad was right behind the female receptacle that plugs into the power brick. The male end was just fine (I cut the female end off after using a continuity tester and found when I flexed the female end, it would be internmittent), so I cut off the female end and will use the good part of the cord for some other project in the future. I never toss out anything if I think I can find a use for it for something else. LOL

[clyfe]

Orville wrote:

clyfe wrote:

I bought a MBB4000 for my 2010 show and was very disappointed. I had it running on an analog timer to automatically turn on and off during my show. However, on Christmas Eve, I got a call from a friend, he was out front and said there was no audio on the radio, just silence. I went and checked, sure enough, wasn't working. I contacted MBB and told me I was a few days out of warranty(90 day) and there was nothing they could do. I will never do business with them again!

Clyfe, did you ever try changing out the main power cord from the ~AC~ outlet to the power brick?  

My power cord went bad (just recently) and I found an old computer power cord, they fit the power block pefectly (which is also a lot olonger than their SHORT power cord), chnaged that out, turned the power switch on and it worked fine.

If you haven't tried replacing the power cord, try that, it may bring it back to life. 

I thought mine was dead too, and I was going to really ticked if it had died before it was even a year old!  Just glad it was nothing more than a bad power cord.

Their power cord doesn't hold up well to a lot of flexing or movement, a computer power cord is much sturdier, and again, longer.  Which a longer cord for me is a plus!

 EDIT: BTW, the part of the cord that went bad was right behind the female receptacle that plugs into the power brick.  The male end was just fine (I cut the female end off after using a continuity tester and found when I flexed the female end, it would be internmittent), so I cut off the female end and will use the good part of the cord for some other project in the future.  I never toss out anything if I think I can find a use for it for something else. LOL

Its not the power cord or brick. The unit powers up and the display shows the correct info. I have tried multiple audio sources with different audio cables. I know it is broadcasting because when it is on, there is no static on the channel I am broadcasting on.

[james campbell]

I think that as long as you stay reasonable,ie not transmitting a mile or more what kind of antenna you use won't alarm the fcc. also if you are just using it for holiday displays and stay reasonable don't think you will have an issue.