A word of warning. Just because a radio is sensitive to FM signals doesn't necessarily mean that it will be as sensitive for AM ones. AM tuners are often compromised, particularly in newer radios.
Just look at the specs for a typical car radio. It may have a sensitivity of 1-2uv with 20db SNR for FM - AM is generally 25+uv or more. That relative deafness is offset somewhat by the increased field strength of a Part 15.219 signal.
I'm planning on doing some research on AM receivers much like the stuff I did for FM, so I should be able to give you the names of some good ones at some point.
Thanks Artisan Radio as this will help me tune in my Talking House or iAM transitter when I get it. I also hope I can find a Tecsun Radio good for both that would be really cool. If I didn't lose everything I had due to financial issues and still had a Stereo amp I could have got one of those Radio Shack AM Tuners that had AM Stereo on it. I heard the tuner was really good too so at least I could tell how things were doing. But a portable like the Tecsun with a meter is the best way to see how your AM transmitter does when your walk around outside. It does give you some meter readings.
RE: It may have a sensitivity of 1-2uv with 20db SNR for FM - AM is generally 25+uv or more.
Just to note that:
- the ambient r-f noise level normally is higher in the AM broadcast band than the FM broadcast band, and
- FM receivers are able to reject r-f noise to a greater extent than AM receivers, for the same received r-f voltage present across their input terminals
No mention of the transmitter....how do you know it was a talking house?
I thought that as long as the input to final is max 100mW and the antenna max is 3 meters there's no restriction on how far you can get the signal to go...in the USA?
Mark
... an FCC NOUO never reports the identity of the manufacturer/builder/distributor/installer of that transmitter -- only the user thereof.
Regardless of its certification status under FCC §15.209, §15.219 or §15.239, the operator of an unlicensed system is the only one legally responsible for its operation/performance.
Some have referred to website posts by the operator of the setup receiving the NOUO linked by http://transition.fcc.gov/eb/FieldNotices/2003/DOC-319568A1.html as using a transmitter supplied by "Talking House."
Whether or not that is true is unproven, AFAIK.
But this whole scenario should be of interest to those who wish to comply with "Part 15 AM."
Rich: True
One would think buying a certified AM Transmitter would be in the safe harbor if they keep the output to the final at 100mW, The antenna no longer than 102 inches or 3 meters and the ground at 3 meters. The Talking House AM Transmitter should be safe. Realtors use these to sell houses and have been doing this for decades. However one puts up a Radio station by using the input jack on the back of the transmitter and plugs it into a mixing board or computer and says over the air Your Rocking with the best neighborhood Album Rock station in this area at 1640 Khz and now your suddenly a Pirate? Wow what double standard the FCC has. You can't win. Run ¼ mile on FM well you are in a gray area. Think your safe and go AM nope not that either. It is clear that the FCC is cozening up with the NAB and they will do what the NAB wants them to do. I don't believe these transmitters cause any interference what so ever. The FCC should mention the make and model number of the transmitter in question so as others don't fall prey to this sort of treatment. And to have to cease and desist running a Talking House AM Transmitter? That agent should have been sued to non existence by the manufacturer of this transmitter if they could show full compliance. Then they should go after the NAB for conspiracy to commit a monopoly over the airwaves. The lies and the anti hobbyist attitude of these selfish folks trying to belittle anyone who wants to have a little fun and supply some entertainment in a small neighborhood often for non profit or just enough to cover the cost of the hobby. There are far more worse things that can happen. Granted one who goes ape and runs tuns of watts or even 10 watts going 15 miles should be dealt with, but we need to separate part 15 Radio from that other crowd of people who don't care rather or not they cause harm to the radio spectrum. Part 15 is getting more popular and there must be a reason for this. I didn't realize till I became an ALPB member how popular it was. I'd run into a few bedroom DJ's on my way to Florida years ago. But honestly I thought it was not as popular. Well it seems that there is an up rise in the hobby. So I guess we need to re educate the suit and tie folks who again have their tie way too tight and its choking the blood flow and oxygen to what little brain they may have. America needs to stand up and fight. Maybe a march with part 15 transmitters every ¼ to 1 mile apart is what it would take.
I think this was a Napolian Complex issue.
I've known many Napoleans.
There were some calculations published here a while ago which indicated the maximum field strength a legal Part 15 AM transmitter could achieve (i.e., 100 mw input to the final stage, 3 meter antenna + ground + feedline) - I can't remember what it was exactly.
The FCC obviously knows that as well. If they receive a complaint, and measure your field strength over that maximum, then you're inviting a site visit.
I seem to recall that the transmitter in question was a Talking House on an apartment balcony. If it was an unmodified certified transmitter, then there should have been no problem. We don't know the details of the installation so further speculation is not very useful.
But we do know that it was the same FCC inspector who was involved in the Kenc situation. And using the 209 section of Part 15 alone without referencing 219 (when you can be compliant with either) was incorrect. And we also know that the individual involved decided not to fight it, for whatever reason.
It just goes to show that whatever the rules are, the FCC has the final determination as to whether you're meeting those rules. Sometimes they give you the benefit of the doubt, sometimes not. At least on the AM band you have a much better chance of not interfering with any licensed stations and drawing a complaint.
I've been thinking on the same page with this AM VS FM deal. Right now being so close to businesses and where I can see a Radio tower I am not too sure if FM is a good idea or not. I know the range of my Transmitter goes dead before you get to the Radio tower that I see. And some nights I can operate without the inversion and some I can't. Going off air every hr or 1/2 hour has to annoy some of my listeners where as AM I could be transmitting 24/7 if I got the listeners. Don't get me wrong I love FM and I'm a pro FM person, but too I'm just trying to be realistic at the same time. I've still not had someone walk my street with different portable Radio's to see what would happen. Had a guy with a cell phone that has an FM Radio on it and I'm curious how far I can get to that receiver.