new 100mw station opening in south philly

[FrankB-town]

There is a Black pirate on 99.7 booming in south philly just came on the air.

do they air the black computer show?

 

[BRUSSTAR]

Also, BMI is known to go after part 15 stations for about $200 licensing fee!

Didn't I just say that? (Minus the $200 part, which, I'm told, is usually more like $60 and still outrageous!)

 

[hipporadio]

If you’re serious about doing this doowop, make your first MANDITORY pit stop at the Hamilton website...

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

Beyond offering you a VERY GOOD “legal” transmitter for purchase, these folks have A LOT of info and real-world user feedback and links. The Rangemaster TX is exceptional [given the application] – don’t even consider any alternative. Many times, once Mr. Inspector visits and notices your use of that product—he’ll just take a hike... In fact, you may want to actually notify “Charlie” and request an inspection!

The “trick” is in the antenna – and there are MANY tricks that dramatically enhance range and pass FCC muster. Remember [unlike Part 15 operation on the FM band], there IS NO field strength/distance limitation when operating on the AM band. So if you “get a nice bump” from a well-thought and constructed system on AM, the FCC has little choice than to remain copasetic and allow you to continue.

This topic begs the question, "How far can one transmit with 100 MW on a high end frequency such as 1600-1720?"

Actually, the “X-band” provides two benefits for low-power AM broadcasting. Forget the full-power paradigm that “high is bad”. The FCC limit on antenna length [3 meters] is a constant [regardless of frequency], and is electrically-taller and more efficient at the upper-end of the band. The 1620-1700kHz spectrum has fewer stations and is much lower in the RFI that could easily clobber a 100mW signal – especially at night.

Coverage will depend on your antenna system/placement, the physical environment around your TX site, and the ground conductivity within the desired coverage area. A couple miles or range is a fairly-conservative bet, but I know of a few awesome exceptions that are FULLY LEGAL. One on Hilton Head winds its way through nearly a dozen miles of inter-coastal salt marsh, and can be heard 16 air-miles away on the south shore of Parris Island. It covers ALL of HHI – even at night! This station has an ingenious antenna design [in salt water] and sophisticated commercial audio processing [Aphex/TCElectronic multi-band digital/Inovonics]. Salt water and Part 15 AM are “best buds”, and you won’t be able to “shake that friendly hand” in high/dry/concrete South Philly.

I know of “ION Radio” well. I live nearby, and have a relative who owns a home in that development. They solidly cover the 1.5 x 2-mile neighborhood and much of Mount Pleasant and Sullivan’s Island. They have exceptional sound and an appreciative audience.

http://www.ionradio1640.com/

Here a couple other well-executed examples:

http://www.toddjenkins.com/radio17/

http://www.wtyb.com/

While Part 15 radio for many, is little more than a futile and expensive hobby – there are exceptions... GOOD LUCK! No "local voice" these days is a bad thing... Well MAYBE ;D

 

[Play Freebird]

If you install it properly, you can get anywhere from 1-2 miles coverage.

The station mentioned in Lansdale, WNAR-AM, is actually operating 3 transmitters in parallel for 300mW. Perfectly legal according to the Langhorner office. He can often be heard 3-4 miles away.

Although I'm located over 15 air miles from "WNAR", I receive enough signal that I can measure the carrier frequency on my HP 3586C selective level meter. However, the audio is buried pretty far down in the noise, I wouldn't call it "listenable".

Dave's parallel transmitter idea is a clever loophole. I can't find anything in the Part 15 rules that would prohibit this, so if you can afford to buy or build multiple transmitters, it's an easy way to boost coverage legally. WNAR's three transmitters are within 25 feet of one another and fed in phase from a common oscillator for an omnidirectional pattern, but if you have enough land separate them to the distances typically found in a directional array, I would expect impressive results. Here's why:

Consider a typical licensed AM two-tower array with the towers spaced 90 degrees and fed 90 degrees out of phase with 50/50 power division. This will produce the familiar "cardioid" pattern with about 3 dB of gain in the main lobe. If the TPO is 1 kW, each tower gets 500 watts, but the ERP will be 2 kW.

However, a Part 15 station with two parallel transmitters would be allowed to feed each antenna with a full 100 mW; there's no need to split the power of a single transmitter in half. This should yield 6 dB gain over a single nondirectional transmitter/antenna. Arrays with greater numbers of towers should have an even greater advantage! So with 4 in line, or in a rectangle, you should be able to get well over 10 dB of gain in one particular direction, if phased correctly.

 

[rtetro]

Perhaps Rene can explain the whole "higher end of the dial being better" thing, as unusual as it sounds, that is, if it's even true

Quite simple, really. Because the wavelength is shorter at the upper end of the band, a 3 meter long antenna (just over nine feet), which is the maximum allowed under part 15, is going to be more efficient at higher frequencies. At the low end of the dial the wavelength is just too darn long to make such a short antenna of any real value.

 

[Those RRRRs]

Quite simple, really. Because the wavelength is shorter at the upper end of the band, a 3 meter long antenna (just over nine feet), which is the maximum allowed under part 15, is going to be more efficient at higher frequencies. At the low end of the dial the wavelength is just too darn long to make such a short antenna of any real value.

Supposedly 1540's tower is on top of a hill. If this is true, considering that 1540 is rather high on the dial, could Rene's explanation be the reason that 1540's signal doesn't get out like other 50,000 watters such as KYW?

In other words, too much height for such a short wavelength?

 

[Tom Wells]

Elevation is of no help for MW. You just can't hook into good ground conductivity from up on a hill.

Take this analogy. Forget looking up. Your vertical antenna fires its RF into the ground, straight down.
The further away from true RF ground your antenna is, resistance-wise or distance, the less groundwave propogation occurs.

The ground plane is the point of reference your signal must have good current into, it is like a strong stable foundation.
Your signal needs to referenced against 0 volts at all times. Real world losses always mean we don't have 0volts at
the ground point...unless we are on a...salt marsh, or its electrical equivalent.

The salt marsh is the ideal. Those without should really weave multi-multi-multi radial spokes to get the best from pt 15 AM.
Getting "your" ground plane then down as close as possible to the true RF ground is the next improvement, which is why those with
the salt marsh have the Ace of Spades.

The oldest trick in the world to help a poor location is to dump a LOT of salt around your ground rod.

Using other "convenient" grounds will get you some kind of signal out, but to the extent they do not lead quite directly to
earth itself they will have some funny lobes due to the ground/stick cancellations.
These other grounds often carry noise and hum into an otherwise fine signal.

 

[amfmsw]

Tom is on the money.

1540's signal suffers from several points.

First, the number of powerful co-channels and its' tight pattern. Like WNTP, it uses multiple towers (WNWR 3 sticks in a dogleg, sending 150000 equivilent watts to the Jersey Pine Barrens and 500 watts to nearby Norristown.

Second, the ground conductivity at the Roxborough site is pretty bed. A lot of shale and clay-like dirt.

Third, the tower height (length) is 3/8 wave. That length send the signal out to the freakin' sky from the tippy-top of the tower instead of along the ground. There was talk of extending the lenght of the towers to 1/2 or 5/8th wavelength, but $$ was short.

 

[RadioStationDudeUSA]

id reccomend a Hamilton AM 1000 Rangmaster too..

As long as the ERP at the antenna for each unit doesnt exceed 100milliwatts, you can synch many of them together.

it's been done and keith's website (www.am1000rangemaster.com) tells you how to do it.

for a stronger signal, slave 4 or 5 of them together at one location
for a wider, bigger coverage, spread them out 2 miles apart on the same channel.

an the innovonics 222 is a good processor, new they run about $800 IO think.. used.. $300 to $400 and well worth it..