AM 1000 Range Master

You have stressed your requirement for a "100% legal" transmitter. On FM this practically means about 200 foot range.

On AM, many report greater range. Since you mentioned the Range Master, I will confine my comments to this device.

The Range Master is FCC certified which gives some assurance of assembling a legal AM part 15 station in terms of the transmitter. The device itself is certified but it could be installed in such a manner as to be out of compliance with the rules. Here is the section of part 15 which applies (out of order on purpose):

Section 15.219 Operation in the band 510 - 1705 kHz.
(a) The total input power to the final radio frequency stage (exclusive of filament or heater
power) shall not exceed 100 milliwatts.

(c) All emissions below 510 kHz or above 1705 kHz shall be attenuated at least 20 dB below the
level of the unmodulated carrier. Determination of compliance with the 20 dB attenuation specification
may be based on measurements at the intentional radiator's antenna output terminal unless the intentional
radiator uses a permanently attached antenna, in which case compliance shall be demonstrated by
measuring the radiated emissions.

These two requirements (para a and c) are met by a certified transmitter such as the Range Master.

(b) The total length of the transmission line, antenna and ground lead (if used) shall not exceed 3
meters.

This is where there is some problem with interpretation. A literal reading of para b would require that the unit be placed at ground level so the ground lead length is minimized to comply with the length requirements. Others will say that the length of the metal mast or the protective ground wire for an elevated installation is not counted in this length. You will have to carefully read para b and decide which is the correct "100% legal" interpretation.

Neil

Even by the most optimistic figuring, there's simply no way a legal part15 FM can get anywhere near that sort of range. 200 ft or thereabouts is about the best you can do to portable or inexpensive receivers, and sticking to mono would help even with getting that.. *Maybe* as much as 1/4 mile (400 meters) if it's a good stereo with an external gain antenna on the listener's end. *Maybe* a little more with a really good car radio. But not much more. That'd be assuming about perfect conditions and terrain, which just isn't going to happen anyplace where you have enough people to make up a listening audience. Even at one mile with an excellent car radio, if it was anything even remotely like a clear signal it'd simply have to be running too much power.

At a 4-6 mile range with the kind of reliability an advertiser would probably want to see, you'd need to go with a licensed station. And even LPFM wouldn't work for that, since they have to be noncommercial as I understand it.

The Rangemaster is reputed to be a nice piece of gear by people who use it, and they're the ones that would know. But considering even the 'sales pitch' only claims 1-2 miles possible (and that'd probably be to a good car radio and not a strong signal at that), I'd say 4-6 miles radius for your range is probably beyond what part15 can do within a reasonable amount of practicality and expense. I don't mean to sound discouraging, but part15 (FM or AM) is a very limited amount of power and it can only manage so much. Even with the very best equipment on both ends, it will only get a usable signal so far.

Sure, maybe if you had several Rangemasters (or whatever) around that 4-6 mile distance and used some means of keeping them sychronized or at least no "lag" in the audio, it might be possible, it's been done a few places so far as I understand. But for most people that'd be a pretty expensive prospect to dive into.

Say that each transmitter has a "rock solid signal" range of a one mile radius.. I'm not saying they do, but just hypothetically speaking for the sake of discussion. So it'd take 2 of them to cover a 4 mile stretch of road.. 4 to cover a 4 mile by 4 mile square.. To cover a 6 mile by 6 mile square, that'd be *9* of them. Add in whatever you're using to get a synchonized signal to each of those, plus even a small studio, and even assuming you know enough people in the right locations that would let you set up transmitters on their property you can see what I mean about it being pretty expensive? Maybe you have deep enough pockets for it, but for most people that'd be a much bigger chunk of change than one would want to shell out for a hobby that *might* make enough in ad revenues to pay for itself somewhat. How many ad spots at what you feel you could charge would it take to pay even what you laid out for equipment in a year or even 5 yrs?

Don't get me wrong, part15 is great fun, and it's possible to have listeners even in the 200 or so ft range allowed for part15 FM. I manage to have a few. But 4-6 miles? Seeking a commercial license and funding/resources to build a commercial station would probably be your best bet to cover an area that size, and that's probably not what you're wanting to hear.

Daniel

Hi kudiaradio,

There is a station in the Carolinas that is doing exactly what you describe, although I don't know how many Rangemasters they are using. They do use several, creating a network, and they also stream.

http://www.surfside1640.com

You might want to contact Dave Solomon to get more details. I have relatives in S.C. not far from Greenville..next time we go up there I'd like to make it a point to check them out in person.
Dave and I have corresponded before and he is very helpful.

WJJD Country Giant:
http://www.live365.com/stations/alanmccall

NEW STATION: Musicbox 1610 (building in 2007)
http://www.musicbox1610.com

My Space:
http://www.myspace.com/radioboyalan

Hi, kudiaradio -

Lots of claims are made about "Part 15" AM systems with a coverage range of 4-6 miles. But here are some calculations showing about what to expect for an absolutely legal Part 15 AM system (as in Neil's comments), based on the measured performance of commercial AM broadcast systems.

If an AM transmitter such as a Rangemaster has 80 milliwatts of output power on 1600 kHz, is installed outdoors with its ground terminal connection within 6" of the physical earth and with its ground lead connected to a typical r-f ground (25 ohms), it should produce a clear-path field strength of about 2 mV/m at a distance of 80 meters (262 feet) -- which is about the minimum needed for relatively noise-free reception on a cheap radio inside a home in an urban area.

This same Part 15 setup will produce about 0.167 mV/m of field strength at 1 kilometer (3,280 feet, 0.62 miles) to an outdoor radio over a clear path with no buildings, wires etc. This signal level should be usable on a good AM receiving system (including a good antenna) at that distance, and somewhat beyond. This field strength does not include earth losses along the propagation path, which accumulate over longer paths.

Producing a solid, competitive AM signal for a 4-6 mile radius from a single transmitter that a casual listener would notice when tuning around, and stay tuned to takes a lot more power than the FCC presently allows for unlicensed stations.

This probably doesn't sound too good to you, but maybe it is better to know it, anyway, at this stage in your thinking.

Rich
//

AM 1000/Rangmaster users report they are VERY happy with that transmitter but that's Part 15 happy, not 6 miles happy.

Rich makes an excellent point, kudiaradio, along with most of the other posts.

Most of us here love to broadcast, and love to see how far we can push out our signal, but with Part 15 appropriate expectations.

That means "how far past 200 feet" not "how close to 6 miles."

If you set up a Part 15 compliant system expecting anything measured in miles you will be very disappointed. I am one of the biggest proponents of experimentation here but even I have realistic goals for the service.

With FM, if anyone can hear you, you're using too much power 🙂 There are two 10 watt licensed LPFM stations in my community and we can't tune those in at the 4 to 6 mile range you're looking for either.

With AM, just test for yourself the next time you pass a traffic information station (TIS). Those are also licensed for 10 watts and very few attain 4 to 6 miles.

Thanks a lot for all of your replies. I have two other questions though. Do you have to pay royalties on copyrighted music you play if you are Part 15 or is this only for licensed stations? I currently have an internet radio station that I pay royalties for.

Also do you think that if I want decent range (2 miles or so) but don't want to rack up FCC fees, that using the range master and creating a network of them would be the best idea?

Thanks a whole lot everyone. You've been a lot of help so far.

Go For It. I just talked to Kieth Friday and purchased my first Rangemaster. After doing a lot of research I think it is one of the best made. The ground lead debate is the only thing. That can be solved by a choke which he included with my am1000. See this page from his site http://www.am1000rangemaster.com/groundxmit.html. As for range a AM Porcessor will be a must to get miles of range. Keep a check on ebay for one. An almost new 222 went for $475 a few days ago. Have fun I hope to!
RD

Previously on Part15.us:

part15.us/node/1350

part15.us/node/126

part15.us/node/1323

part15.us/node/1025

Experimental broadcasting for a better tomorrow!

Kudia,

About 2 weeks ago, I went to help a friend in a neighboring county put in a Part 15, and he had purchased a Rangemaster. He had it mounted
12 feet high, with a ground running to a ground rod driven in the ground. No processor. And he was getting about 3/4 mile with that limited setup.

I'm in the process of rebuilding my station after having the Florida climate create havoc with my previous station. I only have a Volumax but would like to get an Inovonics 222 processor.

After hearing my friend's Rangemaster, I would recommend it. And if you visit radio-info.com, under Community Radio near the bottom of the boards, Carl Van Orden (antenna guy) wrote about a ground system he built that he says works wonderfully with the Rangemaster. I've
recently been in touch with Carl. You might want to check that out.

Feel free to email me directly at [email protected] if you'd like.

I'm also a webcaster, on Live365.com with WJJD Country Giant Radio.
Just waiting to see if the royalty mess kills it off...sigh..

WJJD Country Giant:
http://www.live365.com/stations/alanmccall

NEW STATION: Musicbox 1610 (building in 2007)
http://www.musicbox1610.com

My Space:
http://www.myspace.com/radioboyalan

I use a Rangemaster here in Dade City, Fl with good results. The terrain is hilly, yes hilly so range around town varies. A good car radio can hear reliably about 1 mile. The transmitter is mounted on a 10 foot pipe with a few radials at the base of the pipe.

A second installation is at Saint Leo University 4 miles west of Dade City. operating on 1620 KHZ. The transmitter is mounted on the roof of the library building about 30 feet off the ground. The audio chain uses a 222 processor that is still in the tweaking process. The antenna is 3 meters and at the base of the transmitter is 30 ten foot radials fashioned 300 ohm TV twinlead. The twinlead is tied together at the transmitter end and open at the far end effectivly creating 60 conductors. The twinlead is tacked to the roof with silicon rubber. The range in this installation is much better than the Dade City station.

Since the FCC is a mere 30 minutes away, FCC Certification is a BIG issue. The rules are different for an AM station on campus, so we also run the power up a bit.

Hope this helps, John

WDCX AM1610 Part 15
http://home.earthlink.net/~wdcx
John
Owner-Operator-Chief Engineer-Program Manager

Check out the how to hints on the rangemaster website. Especially the following link:

http://www.am1000rangemaster.com/pro_am.html

I am using a Valor PRO-AM PHF-160 with my non FCC certified Part 15 transmitter and have been impressed with the results of the antenna. I think the antenna would work much better with a rangemaster.

I purchased the antenna from R&L Electronics. It cost $49.95.

Coming in late here, but here's my setup:

Rangemaster transmitter elevated 34 feet, 108" CB whip antenna, ten ground radials 19 feet long covering 180 degrees. Aphex Compellor compressor/limiter followed by the Innovonics 222. In a car radio, the reception at 1 mile is good to very good, 1.25 miles adequate, and by 1.5 miles the signal has considerable static. Range varies with conditions, and there are certain areas of town with electrical interference where the signal is greatly deteriorated.

Chuck

Chuck,

Thanks for sharing your experience with the Rangemaster.

Does anyone have any range data for a Rangemaster installed at ground level?

Neil