Any suggestions for a decent low-power (i.e., LEGAL) FM transmitter?

mhardy6647

Remember in the old days, we had little FM transmitter gizmos that plugged into our cigarette lighter accessory power port and allowed one to get output from a portable CD player (or the prehistoric versions of the iPod, hewn from stone using crude tools by ancient Neanderthal geeks) to listen to on one's car radio?

Here's the thing. Our church's pastor is thinking seriously of doing "drive in church" as a bridge from our current service paradigm (via Zoom) and the still somewhat distant goal of meeting again in person. His thesis is that the easiest way to get information ("content") from the church to a collection of cars (literally) in the parking lot would be via the cars' FM radios (as opposed to a more sophisticated "digital solution").

I know there's a market for pirate FM radio and transmitters that are not legal to use unlicensed -- but I was wondering if there are (still) legally low powered transmitters with a range of -- I dunno -- a couple of hundred feet, and, if so, if any of them are any good?

Cost isn't really a factor.

Anyone with any fairly recent experience/suggestions in that arena?
Figured it wouldn't hurt to ask!

Thanks!

Clipdat

Just daisy chain together 100 of the little ones!

Jstas

Cheapest one I've found that isn't from a sketchy site is this Rolls HR70 but everyone has them backordered until June.

https://www.bswusa.com/Tuners-and-Receivers-Rolls-HR70-P14872.aspx?gclid=CjwKCAjwte71BRBCEiwAU_V9h0FJcjWlUvgUGi0rOqjodigYg33Q1hcPvgOCB18MB1WUqWfNM5oFqhoCrboQAvD_BwE

Jstas

If you go to Google and search for "fm transmitter for churches" many links pop up. Anything under $200 is sold out, though. If you can swing $250-$300, there's a number of them in stock in places, though.

mhardy6647

Yeah, I did find that Rolls; Markertek is coy about lead time but all such gizmos do seem to be sold out. Imagine that?! I mean, maybe people are using them for toilet paper?

What a weird time we're living in.

Thanks, @Jstas (oh, and @Clipdat, too, for the outside the box thinking )

Mikey081057

Why do drive in where you could broadcast the service on ZOOM?

mhardy6647

We do that now -- it's a physical closeness thing -- actually, it turns out, many churches are doing, or thinking about, drive in services. Folks would like to be at church. We're also thinking that some folks may not want to come into church even after we've got the go-ahead to have folks inside (perhaps at lower density) for an in-person service.

In the former case, I picture the pastor standing on the front steps delivering the message (sermon). FM radio would work better than any digital/streaming option; latency would be a big problem with digital.

The other problem with streaming could be copyright issues with music. There are, of course, generalized licensing options for churches that are inexpensive (e.g., CCLI), but not all copyrighted music is covered, and streaming may not be permitted.
Now, admittedly, the same restrictions would apply to analog broadcasting, but they'd be much less visible, so to speak, to the ambulance-chaser litigation-happy types.

mlistens03

Doc, why don't ya bring the FrankenAltecs. They could probably be heard for miles on 10 watts. (Just kidding)

But seriously, a pair or two of some big and efficient PA loudspeakers, strategically placed around the parking lot, would do the trick methinks. Although the FM transmitter might be the cheaper option if your church doesn't have big monitors already.

Mikey081057

So you could zoom to your mobile device and connect it to your car audio on bluetooth..

No static at all!

https://www.youtube.com/watch?v=HV3zWSawJiw

But I guess you are hung up on frequency modulation.

mhardy6647

mlistens03 wrote: »

Doc, why don't ya bring the FrankenAltecs. They could probably be heard for miles on 10 watts. (Just kidding)

But seriously, a pair or two of some big and efficient PA loudspeakers, strategically placed around the parking lot, would do the trick methinks. Although the FM transmitter might be the cheaper option if your church doesn't have big monitors already.

I think the idea is not to rouse the ire of any heathen neighbors

mhardy6647

Mikey081057 wrote: »

So you could zoom to your mobile device and connect it to your car audio on bluetooth..

No static at all!

https://www.youtube.com/watch?v=HV3zWSawJiw

But I guess you are hung up on frequency modulation.

The hybrid option will work fine as long as no one can see the 'live' action -- there'll be a delay for anything being streamed, whereas with good ol' analog, everything happens at the speed of light

No static at all was the subject line to one of the zillions of e-mails I've sent out in the last couple of days on this topic since I was asked about it. :P

Believe me, if I didn't think the local constabulary would intervene, I'd roll a coupla big ol' PA speakers out and we'd do it Woodstock style (sans mud and brown acid... at least ideally).

Mikey081057

I could imagine the outrage some would put forth if they heard a religious event rattling their storm windows

aprazer402

Several years ago, ~15-25? Real estate agents occasionally placed a transmitter in the house and placed the radio frequency on the for sale sign for prospective buyers that were driving by to tune to to get the skinny on the house; size, BR's, price... There must still be something similar available.

Mikey081057

aprazer402 wrote: »

Several years ago, ~15-25? Real estate agents occasionally placed a transmitter in the house and placed the radio frequency on the for sale sign for prospective buyers that were driving by to tune to to get the skinny on the house; size, BR's, price... There must still be something similar available.

Zillow

aprazer402

...

Uncle_Art

I have a clever little transmitter in front of me that fits what you need. It's made by EDM Electronics (https://www.edmdesign.com/index.html) and they claim it is Part 15 legal. It does not wear an FCC Type Acceptance number, as there is no FCC in it's country of origin. I paid $249 for mine, with the enclosure and power brick. That may have changed due to increased demand.

Here in the US, you are limited by Part 15 of the FCC rules. This unit is as "clean" as possible, so even if you exceed the limit for power or field strength, accidentally or otherwise, none of the neighbors will complain, as the digital tuning and good design keep it from throwing crap all over adjacent channels. It is WAY more stable and clean (emission wise) than the cheap Oriental competitors. They spew crap across the FM band regardless of power level. Plus, You WILL need to provide some degree of safety limiting between the Church PA and the transmitter, as any overmodulation in any FM transmitter will splash you into adjacent channels.and that makes for complaints, and eventually, a visit from the dreaded black sedan with gov't plates.

It ships as a joke of a Kit, to comply with other regulations... in the sense that the power input jack, for a plain old 12v wall wart, is shipped loose. Someone needs to solder it to the pcb to make it work. I recall having to put in the case as well, using 8 philips screws (included)

Mounted at a decent height, even a simple FM receiver antenna, or old analog tv rabbit ears can make it legally audible for blocks. (you adjust the length to match it to your chosen frequency, which ideally will have nobody broadcasting adjacent to it, never mind ON it.) Minimal effort can lead to a nice, tuned antenna that will easily service a large parking lot.

The box is about the size of a stack of 3x5 index cards, and can easily be installed near the antenna, in an appropriate enclosure to minimize transmission cable loss. Audio will travel miles over wire; RF, not so much.

Should you need further assistance, feel free to hit me up at art@broadcasttek.com After 20 years with every one of the Megamergeropoly Radio groups, and 15 years as a contractor profiting from their mistakes, anything I can do to help "the little guy" is an opportunity I cannot pass up.

Regards
=art

Uncle_Art

Not used to doing this, but as a disclaimer, I have no involvement with EDM other than as a happy customer of several of their LCD Series units in the last 10 years or so. I have no ties to the supplier, only what I know from deploying several of their products.

mhardy6647

Uncle_Art wrote: »

Not used to doing this, but as a disclaimer, I have no involvement with EDM other than as a happy customer of several of their LCD Series units in the last 10 years or so. I have no ties to the supplier, only what I know from deploying several of their products.

Probably a good idea that you did so, since we do tend to get spammers 'round here pushing stuff via blind links.

So, as it happens, I took a chance and invested in one of these (speaking of blind links )

https://rolls.com/product/HR70



The FCC regs for legal micropower FM are based on field strength not transmitter power, so they're actually a little murky for anyone who isn't equipped to do measurements in the field. Since the above gizmo is US made and sold by US vendors (I purchased from Markertek, whom I like very much for pro/semi-pro A/V stuff), I assume it's OK.

The good news: with the supplied antenna (basically a hank of coax with a piece of wire cut to about midband 1/4 wavelength for broadcast FM), good quality signal covers our church's small-ish (but not tiny) parking lot. We have actually used it once for a memorial service, which we conducted as a hybrid (with tents and carefully spaced chairs, plus the 'drive-in' coverage) and reports were that it worked pretty darned well.

The only problem was a fairly long lead time when I ordered it (ca. 6 wks); all such gizmos are in short supply due to so many folks wanting to do drive-in this or that!

I'd recommend it to anyone who needed such a thing. Heck, I am thinking about buying myself one -- even though I have no earthly realistic use for it!

Uncle_Art

That;s a really nice piece of kit. As usual Rolls cranked out a really nice, quality product.
Sorry for not moticing the thread was stale, and you already did just fine.

Fortunate to own a Potomac Field intensity meter, so I always run the property with that, and adjust power as needed, My antenna Theory gets kinda fuzzy

I know everything zrolls sell is great, to a point, and that bugger looks cool. I may need to try one myself

Again, sorry for my stale and crusty reply.
-art

mhardy6647

Antennae are -- kinda magical.
Well... to a biochemist, at any rate.

dcmeigs

I had to google Duck Sensitivity. The mind boggles with possibilities.

Uncle_Art

"Antennae are -- kinda magical."

Indeed, they are. Fot to go too far off topic, but that's why we call FM "F'in Magic" and AM "Ancient Magic"

I recently worked for an AM station who, if their 50Kw Array became unusable (painting, tower lamp replacement, ATU failure, etc) would go to 5kW on a live TV antenna using a "Bazooka" configuration. Look that up, and you'll find Hams use it all the time, but at 5Kw AM, with a full power Digital TV station and half dozen other antennae on it... Wow, what fun to tune!

My understanding is now that vehicles are abandoning Tuners left and right, or confining the AM/FM antenna to that little "Shark Fin" on the roof, not only is receive efficiency murdered, but you really don't know if the rcv stick is horizontal or vertical. (Since most commercial FMs use "circular" polarization. ) So Ironically, a homemade whip antenna sticking straight up may or may not be picked up by a car with the antenna sandwiched in the glass across the window, running horizontally.

Ain't physics a b*tch?

Uncle_Art

And just to be ironic, for those who truly care about Radio, isn't it odd that we may soon be buying the same type of "FM Tuner Add On" units like they offered in the late 70's, when cars didn't have FM tuners?!?

What do we do when they throw out AM? Drive around with a restored 5 Stage transistor radio on the passenger seat, plugged into the Aux In?