Rangemaster - Part 15

[KDus]

That map on my facebook is old and from a previous location.
I'll work on a new one. Currently, I'm at about 4 watts with a slightly directional antenna.
As I get better at it, I could make one for all affiliates.
I'd really like to know how they compare to real world performance.

Edit: Just updated map on my facebook, made adjustments that more accurately depict the real world.

[KDus]

Marc Stevens often pimps the part15, liberty1640.com stations that he's on. I'll bet you could talk with the guys that are actually using the equipment and hear what they have to say.

[RFBurns]

Well I do have to admit that the Rangemaster has it hands down when combining the units for extending range. The thing that bothers me about these units is the non-regulating power output.

With a properly built and matched antenna system conforming to the Part 15 219 rules, there should not be any reason for adjustment of power.

But the things are certified so thats a good thing.

I have devoted a lot of time to Part 15 219 intentional radiator "tinkering", sometimes getting results far exceeding the design specs, and other times results that were less than favorable. This is why I have shifted my operations on my AM side over to Carrier Current.

But I still have the good ol 3 meter setup (home made) out there on the 3 foot pole and fire that up once in a while. Using a CCUFF C-QUAM board w/o the added final (aprox 45mw max) the whole thing covers about 3/4 mile on dry days, and about 1.7 miles when it rains.

Still that does not come close to my CC setup....neutral loading, with 5 watts my station covers the entire city. Just added a recently ebay purchase of an LPB TX-25 25th anniversary special with its companion TCU-30 coupler. Whats cool is the thing is simply plugged into a wall socket close to the power panel in my home feeding the neutral line and is covering the entire city with a clean signal.

Here is a neat little CC transmitter constructed around tubes. I have built one of these and it has a very warm and smooth sound. Parts are easily to obtain and it has its own coupler system and designed to couple to the neutral line, bypassing those pesky road blocking transformers.

http://k6prk.org/CARRIER%20CURRENT%20AM%20TRANSMITTER.HTM

RFB

[MidAtlanticEngineer]

Perhaps to clarify part 15 FM and "power levels". Part 15 FM isn't restricted by RF power output, it is limited by field strength.  250 uv at 10 meters from the antenna.

There are no restrictions on how high you can mount an FM transmitter/antenna. So yes, mount everything high up for an FM operation and you'll have great coverage.


So don't get FM confused with the power input limits that are set for part 15 AM which is 100 milliwatts into the final stage.

You could run a 20kw FM transmitter and not be in violation, just as long as you do not exceed the field strength limit. You could be your towns most powerful FM station with the smallest coverage     

[RFBurns]

You could run a 20kw FM transmitter and not be in violation, just as long as you do not exceed the field strength limit. You could be your towns most powerful FM station with the smallest coverage     

Well...yes you could....if you had a proper dummy load to handle that power as well as a 3 phase 220vac utility drop. Not exactly common in the A-typical residential home. Oh dear lets not forget about the ventilation/heat exchange requirements too for such a transmitter!

A dummy load could be constructed from the suggestions found in any ARRL handbook. However I would also add a closed system of forced pumped coolant for the dummy load resistors. At 20Kw, even 1kw, will make those dummy loads heat up like a fireplace in no time.

Yep...one might want to put such a setup in a small storage building away from living space and studio as the transmitter ventilation system and dummy load coolant system will produce quite a bit of noise.

They dont seem so loud when out there at those remote tower sites but put one inside a residential setting and they are incredibly loud! Got good earplugs? 


RFB