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I have been a EDM transmitter fan for almost 4 years.This company makes the very best sounding fm stereo transmitter second to none.After 4 years of almost constant use I started to get some distortion on the audio.I sent it in for repair and they sent me there $175.00 audiophile LCD unit free of charge.I do not know of any other company that would send you a brand new unit for “free” after you have used one for 4 years.The sound of this unit is so incredible I cant tell the difference between the commercial 100 kw out there.I run a professional recording studio for over 40 years and have recorded over 1,000 albums.I do know what sounds good.The EDM is the Rolls Royce of small transmitters.
Total posts : 45366Well,the EDM is a good little transmitter,but unfortunately it is not FCC certified as your posted title might suggest. I have a dozen different FM transmitters including the EDM and I prefer the C.Crane . Its sound is equal to the EDM with the added ability to filter better around the pilot frequency and it is FCC certified. Also you dont need to fiddle with the MPX pot to make it sound right. The EDM would crash the pilot unless preceeded with a 15khz filter. It also easily overshoots the 75khz deviation especially on the high end of the audio spectrum. I would like to test their new one,maybe you can give us a review? I will agree that EDM stands behind their product and will help any way they can,C.Crane will also do the same having replaced my defective unit shipped for free and didnt want the old one back. All the other popular brands I have tested were inferior to these two units. Some were terrible sounding junk!
I suggest anyone who is going high profile to stick to certified transmitters to avoid the wrath of the FCC.Regards,Lee
http://www.freewebs.com/wilcomlabs/index.htm
Total posts : 45366Hi Lee & Others
Well the Crane might be FCC cerified but I would call it a toy compared to the EDM unit.I did buy a Crane unit several years ago and was very,very disapointed in its performance. The only thing I liked about the Crane over the EDM unit was the Crane did have a led light for setting the modulation level.Even after increasing its RF output it was not enough to cover my rather large house. Because I use a huge variety of audio sources (6 devices) I have a 10K or 20 K stereo pot feeding the EDM audio input.The new EDM LCD unit is incredible sounding.Absolutly no RF hum at 10 mw or 100 mw. using there recommended power supply Also what I understand there is a small audio limiter built in which keeps the audio almost sounding like the big 100 KW jobs.The new EDM LCD transmitter has fully adjustable RF output from 0 to 100 milliwatts which I think is great to keep its output legal.All in all I think the new EDM LCD model is very best.
Total posts : 45366If the C Crane FM unit is Part 15 compliant and still did not cover your rather large house and your EDM system does — that is rather strong evidence that the EDM system does not comply with Part 15 FM.
The FCC limits the field strength produced by a Part 15 FM system to 250 µV/m as measured 3 meters in any direction from the transmit antenna. Of note here is that this maximum free-space field strength is produced by a 1/2-wave dipole antenna when radiating about 11.4 nanowatts.
A 10 milliwatt transmitter or greater is massively overpowered to be compliant with Part 15 FM, unless the antenna radiates almost none of it.
Of course everyone is free to operate whatever they wish, but hopefully this information will be useful in such decisions.
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Total posts : 45366You will probably not cover a “rather large house” with any legal Part 15 certified FM transmitter. It has been my experience that FM is just a waste of time and money if you want to a) operate legally and b) have any kind of useful range. If you just want it to go across the room, you’re probably OK, but that’s about it.
A lot of people have the mistaken impression that you can operate on FM with 10 or even 100 mW of power, as you can on AM. Nothing could be further from the truth! If you feed that 100 mW into a quarter wave wire (about 30″), it will vastly exceed the FCC limits.
The best way to legally cover your rather large house with high quality sound would be to purchase one of the 900 MHz or 2.4 GHz audio links that are on the market. You can very easily get the coverage you want, without having to fear the wrath of the FCC. The only downside is that you need a special receiver; you cannot tune it in on a regular radio.
Or, you could use AM. I am very pleased with the quality of the signal as received on a GE Superadio or any of several other high quality AM radios that I have on hand.
WEAK-AM
Classical Music and More
Total posts : 45366I dont see any logic of using AM instead of FM.I mean here I have been using the same microphones that are used at Capitol Records $3,000 to $5,000 each and now I am going to broadcast those ultra high fidelity recordings in mono with very limited frequency response on AM so I dont get the rath of the FCC.I mean we might as well, since in the last few years the sub normal is now the norm.Mp3,s Ipods,and all that low quality stuff.I remember listening to recordings made 50 years ago that would simply blow my mind compared to the stuff thats out there now.I guess you could say that I have been broadcasting illegally for almost 4 years.As far as I know none of my neighbors have ever mentioned hearing my radio station and if they did Iam sure that it would be a kind comment since its usually easy listening type music.I dont think the FCC is interested in busting 10 milliwatt stations.
Total posts : 45366Custom Recordiin… wrote I dont think the FCC is interested in busting 10 milliwatt stations..
One would think and hope not but it apparently does happen. A while back I (http://www.part15.us/node/716#comment-1578) and Ermi Roos (http://part15.us/node/1375#comment-4249) sampled the FCC NOUOs reported on their site and from the field strengths reported calculated back to what effective radiated power was likely involved and found that, indeed, milliwatt levels could have produced the fields reported in some cases.
While we don’t know the circumstances regarding what prompted the FCC actions, we can presume that low powers were involved in some cases. Will everyone who exceeds the limits get caught? No, but apparently it does happen.
Neil
Total posts : 45366they hammered me with an EDM and a Comet 5/8 wave. got all of 2 blocks radius on a frequency that according to radio locator was clear.
so they are interested in busting what ever they can.
Thank You,
Rev. Robert P. Chrysafis
Universal Life Ministries
http://www.ulc.orgModerator Hunterdonfree
http://groups.yahoo.com/group/hunterdonfree
Total posts : 45366I think 2.4 GHz wi-casting under the more liberal ISM rules will be the new frontier for community broadcasting. maybe teaming it up with a Part 15 AM/FM combo and streaming over the wifi system.
with the availability of self contained WiFi radio receivers, this is looking like more and more of a possibility.
especially now with the industrial grade wifi stuff hitting ebay dirt cheap from defunct wisp’s.
Thank You,
Rev. Robert P. Chrysafis
Universal Life Ministries
http://www.ulc.orgModerator Hunterdonfree
http://groups.yahoo.com/group/hunterdonfree
Total posts : 45366Having been a broadcast engineer for the past 28 years, knowing the technical capabilities of AM and FM broadcast audio may be instructive.
Years ago, AM broadcasters did not have audio spectrum limitations put on the transmitted signal. Many times audio frequencies would be transmitted in excess of 12 KHz; that is if the transmitter audio section was capable of working at that level without going into meltdown. Modulation percentage was limited to 100 percent, both positive and negative. Today with NRSC audio standards, both for transmitters and receivers, 10 KHz audio is the highest audio frequency to be transmitted. This is done to limit the sideband interference so that more stations can operate peaceably side by side on the band. Modulation limits have changed however from 100 percent negative peaks and positive peaks to the contemporary positive peak standard not to exceed 125 percent “occasionally”. The new standards were also implemented to improve signal to noise ratio of the received audio and to more closely duplicate real-world transmitter and receiver audio. Most cheap AM receivers have never performed beyond 7 to 8 KHz in audio frequency with nearly no low end audio at all. AM with the proper pre-emphasis of audio and wave amplitude control processing can be made to sound nearly FM in mono. And finally, AM stereo transmitters do exist and work well. However, the diminishing supply of AM stereo receivers makes broadcasting in the mode purely audiophile experimentation.
The FCC considers the AM band utilitarian in nature and uses its “custodial” powers to keep the operators on the band legal and in check. Part 15 certified AM transmitters are considered intentional radiators and noise makers. As a micro-broadcaster, the more professional the operation, the less trouble the operator will have with inspectors and regulators.
FM broadcasting started as strictly monaural. The antenna systems were very narrow in bandwidth and caused the FM signal to not be of constant amplitude. The signal was prone to “AM-ing” causing received signal problems. This problem persisted until about 10 years ago when broadcasters began developing test equipment to measure the AM component of the FM carrier. FM stereo brought its own set of issues. The maximum modulation for program audio was about 85% of the mono signal (not as loud) and was limited in maximum frequency to less than 15 KHz so that the program audio wouldn’t interfere with the stereo pilot signal (19 KHz) and to limit the total channel bandwidth. So audio response suffered due to the stereo technology. The original stereo signal process exists today in a single chip. Plus, multi-band audio processors are used today, even on classical music radio stations, to permit the received audio to be heard over the ambient room or vehicular noise. Not exactly the “purist” approach.
The FM band is the “money” band to the FCC. And as such, they guard it like the crown jewels. Hence, the more narrow field strength rules for Part 15. Mess with the signal of an FM broadcast station and the full weight of the FCC will be on its way. To prove a point, it took an act of Congress, literally, to cause the FCC to create the Low Power FM (LPFM) service. It took years for the feds to finally put the service together. It took congressional arm twisting to finally get the service implemented just a few years ago. Many of the modern day Part 15 rules have been driven by agency compromises with the National Association of Broadcasters and broadcasting lobbyists in Washington, D.C.
As a final note, the better quality the audio supplied to the transmitting system and the better the receiver design, the better the over all quality of the listened to radio product. So, when you use a blanket criticism of FM over AM based on audio quality, consider there are caveats. Neither are capable of broadcasting “studio quality” audio. I have designed and built recording studios with equipment much more expensive than you mention here. Remember, even a Stradavarius in the hands of anyone but a master still produces, at best, so-so music.
Rev. Marshall Johnson, Sr.
President & General Manger
Rhema Radio – The Word In Worship
The Dalles, Oregon, USA
http://www.freewebs.com/rhemaradio
Total posts : 45366Just curious what they did.Were you fined?Did they take your transmitter away?Were you running 10 Mills or 100mills? Did the FCC say you were causing interferece.Did the FCC receive complaints about your transmissions etc.?
Total posts : 45366Just curious what they did.Were you fined?Did they take your transmitter away?Were you running 10 Mills or 100mills? Did the FCC say you were causing interference.Did the FCC receive complaints about your transmissions etc.?
Pardon the obvious here… but why should anyone using unlicensed and unmodified transmitter+antenna systems such as have been legally certified and used as given in FCC Part 15 FM be inspired to ask the questions quoted above?
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Total posts : 45366they received a complaint from aPD of another station not even local to me that was driving thru town and happened on my signal.
I had 200mW EiRP and Covered all of 2-3 city blocks due to local terrain and antenna height.
it was an informal visit. no paperwork.
Thank You,
Rev. Robert P. Chrysafis
Universal Life Ministries
http://www.ulc.orgModerator Hunterdonfree
http://groups.yahoo.com/group/hunterdonfree
Total posts : 45366A quick check of the FCC Enforcement Bureau Web Site will give some info on that
FCC Enforcement actions in the FM band
AM Band Enforcement Actions
AM Band Action
AM Band Action
AM Band Action
AM Band Action
AM Band Action
AM Band ActionExperimental broadcasting for a better tomorrow!
Total posts : 45366SCWIS,
I thought the 990 kHz NOV was particularly interesting. With 650 uV at 38M, this poor fellow was not exactly setting the world on fire! I wonder if perhaps one of his neighbors turned him in, since that signal level really does not produce much usable coverage on the AM band, especially considering electrical and atmospheric noise.
I also thought it was interesting that this particular notice did not include any details about the antenna and ground lead. Chances are the transmitter was home built, since I don’t think any of the currently available certified transmitters operate that low in the band. I should calculate how far this is above the field strength that could be achieved with a legal Part 15 AM installation. I am sure it is, but perhaps not all that much, relatively speaking.
This serves to reinforce the fact that although people can and do ignore the rules, they should not be surprised when they get caught. For some of these incidents, the inspectors traveled quite a long distance, and I can imagine that they probably did not enjoy wasting all that time and effort.
Personally, I don’t think it is worth taking a chance, especially with FM band operation. Legal FM working range is practically useless. And even on AM, it’s better to be safe than sorry and comply fully with the rules unless you’ve got a big bank account. It would be interesting, however, to see how an agent would react if they came out and measured a Part 15 installation that was particularly efficient, yet compliant with the rules as far as power, antenna, and ground lead requirements. I wonder if that has ever happened, because I am sure you can easily exceed the AM band field strength limits with a good setup.
WEAK-AM
Classical Music and More!
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