Jump to content
Light-O-Rama Forums
Sign in to follow this  
jonstacey1

FM Transmitter Requirements.

Recommended Posts

I have been to all my local electronic supply stores, and none of them carry a FM transmitter that will broadcast like 1/2 mile or so, like the EDM or the WHOLE HOUSE TRANSMITTER.. I am not for sure how to obtain one, the reps at the store said that If I bought a transmitter that I may not be able to use it due to FCC or some federal regulations. They seem to think I need to obtain a Amatuer Radio liscence, IS this correct? Those of you that have one, did you get the Liscence? Where would the best place be to Buy A transmitter, "GOOD DEAL".

Thanks for your Time

Jon

Share this post


Link to post
Share on other sites

Hi Jon,

You do not need an amateur radio license to broadcast very low power on 88 - 108 Mhz. You will more than likely be operating illegally if you do broadcast 1/2 mile though unless you get a low power FM license which is only available to certain organizations that broadcast throughout the year and they're not cheap either.

Are you sure that you need 1/2 mile? The EDM may do it with a good antenna without any obstructions, but the whole house transmitter won't. I use the FM100B from Ramsey and I can reach about 500 feet or so operating at midlevel which is about 12 to 13 uW.

What kind of conditions are you trying to broadcast in terrain wise?

Steve

Share this post


Link to post
Share on other sites

jonstacey1 wrote:

I have been to all my local electronic supply stores, and none of them carry a FM transmitter that will broadcast like 1/2 mile or so, like the EDM or the WHOLE HOUSE TRANSMITTER.. I am not for sure how to obtain one, the reps at the store said that If I bought a transmitter that I may not be able to use it due to FCC or some federal regulations. They seem to think I need to obtain a Amatuer Radio liscence, IS this correct? Those of you that have one, did you get the Liscence? Where would the best place be to Buy A transmitter, "GOOD DEAL".

Thanks for your Time

Jon


http://www.intertechfm.com/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=87&category_id=34&option=com_virtuemart&Itemid=1



i came close to get this one, the price is up there. but one of my radio tech bubby said it looks to be a good, i got a 2 watt mono one, but looking into upgradeing it

Share this post


Link to post
Share on other sites

The link below will take you to the part on Ramsey's site that explains the FCC rules.

I can get about a 1/2 mile with my Ramsey FM25B if the antenna is fully extended. But I live in a very rural area with no interference at all. I normally use it with the antenna all the way down since the road is less than 100 feet from the house.



http://www.ramseyelectronics.com/resource/default.asp?page=fcc

Share this post


Link to post
Share on other sites

I am in town, flat terrain, house backs up to a field, heck I dont even need 1/2 mile, 500 ft, would be plenty, but the more coverage area the better. maybe enough to broad cast for the town, the town is only .5 Square mile. What would you recommend.

Share this post


Link to post
Share on other sites

jonstacey1 wrote:

I am in town, flat terrain, house backs up to a field, heck I dont even need 1/2 mile, 500 ft, would be plenty, but the more coverage area the better. maybe enough to broad cast for the town, the town is only .5 Square mile. What would you recommend.



like Steve said, how far would you like to reach out far. how much money you want to put into it, how much would you want do you sound like pros

Share this post


Link to post
Share on other sites

I will offer some information and you can take it for what it is worth. I debated on posting this as I am sure it might cause some argument with some that might disagree. But I thought it might be useful and put some peoples minds at ease.

I am a HAM radio operator that does Skywarn nets for my city and was in radio for a few years. At our last skywarn training class last spring I got to talking to an official that is with the FCC and we got to talking about about these transmitters. My weather site and weather severs host the offical weather stream for the NWS service NOAA radio for my NWS transmitter KEC56 for my area. I was telling him about how I use my transmitter during the offseason from Christmas to broadcast my weather radio through the tranismitter in my neighborhood as a service to those not equppied with weather radios and was asking him if this was a problem doing so. To make a long story short, we got to talking about range of these low power transmitters and what is legal to do and what is not. He said that even though the guidelines say you can't do this or that. They are not going to come after someone that is only using there transmitter a couple hours a day or even for a single month like for Christmas Displays going just over 1/2 mile range. A mile range or more and if it causes problems, yes they will give you warnings or tell you to terminate the transmission. He said mostly what these rules were written for were those trying to run pirate radio stations that run on a 365 day a year schedule. They are not worried about the amature citizens broadcasting 1/2 mile to a mile a few hrs a night for a month.

Now with that said, don't take this as an invitation to do it just because you can get away with it. Try to follow the guidelines at all cost because it will make you look better in the long run if something becomes in question. If your transmission just so happens to go just over 1/2 a mile don't sweat it. You are not going to have FCC beating on your door. As he said, there resources are tied up with more important things then worrying about something this petty.

Share this post


Link to post
Share on other sites

Texan is right, it is a well known fact that the FCC does not have the man power that it once did and it can no longer afford to operate most of their monitoring stations anymore. There used to be one in Va Beach that we as CB operators back in the day used to see driving around in a white van with antennas all over it trying to track down those suspected of using over 4 watts. That building is still there, but it is just a simple field office now.

If you are going to try and run a higher power station, you really need to make sure that you are not interfering with anyone. It's an out of site, out of mind thing. The most important thing to check is that you are not interfering with the air band at all. If the FCC receives a complaint, they are obligated to check it out.

I use a spectrum analyzer when checking for unwanted emissions coming from my transmitters because I don't like surprises. It's also important to me because i live 4 miles away from a USCG base which has it's own airport and a separate regional airport right beside it. If you don't have access to a spectrum analyzer, there are some decent police scanners out there that have them built in.

Like Texan, I am also a licensed amateur radio operator and have been for over 12 years. The ramifications would be a lot more serious on our part for operating anything against FCC guidelines than anyone else which is why it makes sense to take a little extra precaution when dealing with the feds.:D

Steve

Share this post


Link to post
Share on other sites

One more caution though.. Some of these transmitters throw a lot of harmonic energy out, even the Ramsey units, though not as bad as some of the chinese ones. Some police/fire, and aircraft radio may be subject to interference from the harmonics if they line up in the wrong place. I would recommend that if you are pushing the envelope, look into something like the Ramsey LPFM filter, to filter out RF energy above the FM band before it makes it to your antenna. You don't want police or fire to be impacted, or to be pushing the FCC to find you.. If you are near an aircraft approach path, the FAA might even find you before the FCC...

Share this post


Link to post
Share on other sites

Some very good points, you don't want to interfere with any police, fire, air traffic and that was one of the things he listed not to interfere with and things would be ok. I live 3 blocks from the Fire Station so I kindly let them know what was up ahead of time and said hey I have this and this is what it is used for and if it becomes a problem let me know. No complaints yet so it is a good thing. I still wouldn't knowingly push the envelope just because you can though. If your transmission just so happens to clip the FCC specs a bit, no reason to freak out ether unless you are just really breaking them and interfering with offical governement air traffic (police, fire, planes, etc.).

Share this post


Link to post
Share on other sites

I figured I'd add one more thing, just because you are running legally, doesn't mean that you are safe from the feds either. You can run within the legal limits and still cause interference locally like with your neighbors or in Texan's case even a fire house 3 blocks away so it is always best to be proactive instead of reactive when working with transmitters.

Steve

Share this post


Link to post
Share on other sites

I did a little searching and found this transmitter and i am thinking about buying it since i am on a budget.

http://www.electronickits.com/kit/complete/radi/ck301.htm

don't forget that you can get more gain with the right fm transmit antenna. you can even set up director/reflector to consentrate the signal as well.

google yagi antenna

Share this post


Link to post
Share on other sites

And the two worst things you can do are

- broadcast over a nearby FM station, especially one that has a listening audience in your area ... if those listeners are affected, you can get reported

- run the station 24x7 and even when not needed ... it's easy to explain the light show, but if your doing the radio station thing, then your essentially doing pirate radio - christmas style. This is made worse if your also over-broadcasting (#1 above). I know lots of members that DO run Christmas tunes for the month and don't have problems.

For what your wanting to do, its the FCC Part 15 regulations that come into play.

You get a free license to broadcast, but there are a lot of stipulations as mentioned above. In general, your legal to 200' ... but its actually an obscure power measurement that defines the legal transmit distance. (so its 100 to 300'). Your allow to run either an FCC-certified transmitter (capped at 10mW) or a kit-built transmitter of unspecified power. So the higher powered units must originate from a kit. So those selling non-FCC certified transmitter that do not originate as a kit ... are in violation. But since so many are from China ... they just ignore our laws and fairly immune from prosecution ... but as operators of these units, you are not exempt.

But that said, I'd just use a good quality transmitter and good antenna ... and operate it responsibly.

Either a Ramsey or EDM paired with a decent antenna and using good low-loss antenna cable (keeping it as short in distance as possible and mounting it as high as possible) ... should get you 1/2 mile to 1 mile ... but be responsible in your operation.

I would recommend a quality transmitter with lower power instead of a grossly over-powered unit of poor quality. The one you linked to might be good based on the price-tag. I've been told by NUMEROUS pirate radio folks that the EDM is best unit under $1000 ... and it's only 1 to 100mW (1/100 to 1/10 of 1 watt). You don't need lots of watts to go 1/2 mile to 1 mile ... you need a good quality unit that sounds good and has low unintended emissions (low interference to others).

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.
Sign in to follow this  

×
×
  • Create New...