Re: Advise / Help with FCC Part 15 AM/FM installation
Kirt White / K7KDW
I used to have a part 15 FM transmitter but I got rid of it a while ago. Hopefully some of my experience with using them can help
Some brands may give a discount for a church if you order direct. I'm pretty sure Decade used to. Their transmitters are expensive but are rock solid. This may vary and, depending on your budget, some of these may be out of the question. I also assume most of these companies have back orders now.
Some churches are using non certified transmitters. I assume mostly because it's cheaper and they aren't aware of the regulations. Some will get away with using 1/2 watt or one that has adjustable power levels but some of these transmitters can be 5-25 watts. I think I still have a higher power one laying around and I would definitely not recommend using something like that, even aside from the legailty.
Some transmitters have built in antennas and some have external connectors. I haven't used one with a built in antenna but I doubt it would matter much for a parking lot. Having an external antenna gives you the added benefit of moving the antenna closer and higher up but is an added cost as well as an additional piece of equipment to deal with. A simple telescoping antenna gives you the ability to tune it (somewhat) and has worked well for me in the past.
Depending on the size of your parking area (and how noisy the band is in that area), a decent bluetooth FM transmitter may give you enough coverage. I wouldn't expect these to get much past 50 feet but it may be worth a try since I'm sure these are still readily available. Whichever one you choose, you would want one that could be frequency tuned. One like this (https://www.amazon.com/AUKEY-Transmitter-Bluetooth-Wireless-Handsfree/dp/B07F5H84HT) that doesn't have the cigarette lighter attachment built in would help in powering it without resorting to a creative solution. You would also need a bluetooth transmitter that could be paired with it to transmit out of your mixer. As a side note, you wouldn't want the pastor or whoever is speaking to be able to hear the output audio as the delay would be distracting. This is a few moving parts and I don't know how successful it would be but the parts are fairly inexpensive.
Our broadcast FM spectrum around here is pretty congested. Finding a good "open" frequency takes some trial and error. Distant FM signals (that still sound like white noise on your radio) still raise the noise floor so not only finding where there is an open frequency but finding the quietest can take some time. If you have an SDR that you can use to see the spectrum this can be beneficial. You may find some of the quietest spots to be on the edge of the digital sidebands of FM stations that come in pretty clear to that area.
Don't use a portable radio to test with. The sensitivity differences between car and portable receivers vary too much.
If your transmitter has the ability to transmit in mono, doing so may give you better results.
I hope some of these tips help and hopefully you can find the right solution.
From: email@example.com <firstname.lastname@example.org> on behalf of Lou Giliberto (KD7HCW) via groups.io <louis.giliberto@...>
Sent: Thursday, May 7, 2020 1:13 AM
To: email@example.com <firstname.lastname@example.org>
Subject: Re: [SnoVARC] Advise / Help with FCC Part 15 AM/FM installation
Sorry for the multiple responses. I was digging through some notes of mine.
For wifi the easiest solution is Zello. A broadcast room can be made. People would also be able to listen from home that way. If the service provides free wifi no cell data needs to be used.
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On May 7, 2020, 1:09 AM, Lou Giliberto (KD7HCW) via groups.io < louis.giliberto@...> wrote: