I’m in the process of selecting locations for one or more “MOAN” relay nodes in Sacramento, CA.
I have used the engine at “Radio Mobile Online” to produce coverage plots for a couple of our possible sites, and have gotten some awesome results - but I want to make sure I’ve done it correctly.
Specifically, the engine asks for certain parameters of the receiver and transmitter that I’ve just guessed at so far, including:
- Tx power. I have this at 1 Watt.
- Tx line loss. I have this at .1 dB, to be on the conservative side.
- Rx line loss. Again, I have set this at .1 dB.
- Rx threshold in uV. I have this at .25 microvolts.
- Required reliability. Totally guessing here. I put it at 60%.
I’m also working with an assumption that narrowband data is more robust and reliable than voice transmission. This based on experience with HAM radio, where data transmission is able to “get through,” even at relatively lower power levels, under atmospheric conditions that render voice communications literally impossible. Don’t know if the same applies to the mode of data transmission utilized by goTenna operating at UHF. Hence the “reliability” at 60% (the default for voice in this program is 70%).
Any help here would be greatly appreciated. Thanks!
I haven’t used Radio Mobile Online for this purpose, but have made extensive use of http://heywhatsthat.com/ for coverage maps. It doesn’t require anything but location and height above ground level (AGL).
I’ve used the results for plotting potential coverage and found it to be quite adequate. It seems to take into account both terrain and the buildings that could potentially screen signals, an important factor when things are pretty flat as they are here.
It delivers output that sometimes predicts signals in relatively small areas at greater distances than you’d expect. These are verifiable and accurate in my experience. Since power is apparently assumed (and not inputted) at greater distances it’s somewhat optimistic, but given line of sight connections of more than 50 miles have been verified with goTenna Mesh devices, they may still prove accurate on a good day (when the leaves are off, for instance.)
I’d suggest giving it a try, then comparing the results with the program you’re currently using.
As for the “Required Reliability” I’d suggest trying some plots that use the default 70% reliability and comparing the results with both itself at 60% and with http://heywhatsthat.com/ results. While it’s true data may not need as high a number to be successful, the need for LOS connections with GTM suggests to me not to go lower with that number in order to increase the likelihood of new or inexperienced users getting a good connection.