HLLY Professional 30W FM transmitter Will be available soon!!

[Max-Paul]

We use a 35w transmitter with our GPS surveying equipment and we've gone a good 4+ miles way and received a good signal. If I remember right its rated at like 7-10 miles depending on environment.

Chris, I would think that your GPS unit is not in the 100Mhz band? And I would happen to think that maybe, then too maybe not, but are your antennas omni or directional? And with 35 watts and 7-10 miles I am going to guess you might be in the 400Mhz band or as we hams would call the 70cm range. I know with 35 watts I could get better than 7-10 miles in the 2mtr or 144Mhz band. But as with all radios things like vegetation and terrain will have a factor in propagation.

[ChrisL1976]

Chris, I would think that your GPS unit is not in the 100Mhz band? And I would happen to think that maybe, then too maybe not, but are your antennas omni or directional? And with 35 watts and 7-10 miles I am going to guess you might be in the 400Mhz band or as we hams would call the 70cm range. I know with 35 watts I could get better than 7-10 miles in the 2mtr or 144Mhz band. But as with all radios things like vegetation and terrain will have a factor in propagation.

I'm not sure what the specifics are on the radio. It may go further, although the accuracy of the measurement method drops over really long distances, so that may be the reason for the short range in the Equip. documentation. I know we've done 4 miles in central Illinois which for the most part of pretty flat. The radio is the old Pacific Crest blue brick as they call it at our service people.

This is the transmitter and reciever.

[Max-Paul]

Wow Chris,

Them blue brick people are not forth coming about what freqs they use. I see that the data is either 4800 or 9600. I know from my Ham days that we could not transmit Packet signals at 9600 below 440 Mhz. So I am going to take an educated guess and say if you are using 9600 baud that your radio more than likely is in the 400 Mhz range. And I also did packet on 144 Mhz with 1200 baud as max speed. So, I am going to guess that the 4800 might be in the high 200 or low 300 Mhz range. Interesting RF modem.

I suppose with the use of the 2 units that you get better resolution. Kind of like the WAS with a hand held or car GPS units get when they can receive a WAS station. But in your case (And I am asking) the non-gps unit is at a known location and then the GPS unit goes to an un-know spot and the new location info is displayed?

[ChrisL1976]

Here's the spec sheet on the specific radio set.

Actually you run 2 complete GPS units. The base unit is a fixed station and transmits the base station GPS information it receiving. The rover unit takes that GPS information and along with the GPS its receiving lands you with and accuracy less than 2 cm. Our average resolution is around 0.03-0.05'. Your typical handheld/car GPS systems will get you not much better than around 5' plus. Without the 2 units working together, you cant get the accuracy required for accurate measurements.

[VO1HAX]

Chris, I would think that your GPS unit is not in the 100Mhz band? And I would happen to think that maybe, then too maybe not, but are your antennas omni or directional? And with 35 watts and 7-10 miles I am going to guess you might be in the 400Mhz band or as we hams would call the 70cm range. I know with 35 watts I could get better than 7-10 miles in the 2mtr or 144Mhz band. But as with all radios things like vegetation and terrain will have a factor in propagation.

Oh no, another ham!!!

The FM broadcast band is pretty close to the 2m band, so I would expect similar characteristics. I have gotten 25 miles on 5W on 2m (with a 5/8 wave vertical), talking to a guy with a glassmount 1/4 running 5 Watts.

Yeah, anyone running that much power on the FM broadcast band better hope they are ready for when the FCC or IC/CRTC (in Canada) knock on their door, those transmitters aren't even approved by either of them, so even with a license, those things would be illegal!

[csmith]

Danger Will Robinson!

PlanetChristmas does not endorse anything illegal.

Building an unlicensed radio stations using a transmitter that exceeds what is allowed by the FCC here in the USA is definitely illegal and a recipe to get men in black knocking at your door.

Let's move on to another subject.