Batboard

Hello I am new to doing Radio Coverage Maps I was wondering if some one could do a few for me.

This will be for a cross band repeater system

33.70 and 150s range

Antenna Location is
Lat 42.105
Long -78.39

Antenna Hight is 68 M above ground

Tranmit power will be 100 Watts both sides

5.5 DB gain Dipole antenna for 33.70

6 DB dain Omni antenna for 155 antenna

Hopefully someone can help I tried in radio mobile and had no luck.

ASWEEZY wrote:Hello I am new to doing Radio Coverage Maps I was wondering if some one could do a few for me.

This will be for a cross band repeater system

33.70 and 150s range

Antenna Location is
Lat 42.105
Long -78.39

Antenna Hight is 68 M above ground

Tranmit power will be 100 Watts both sides

5.5 DB gain Dipole antenna for 33.70

6 DB dain Omni antenna for 155 antenna

Hopefully someone can help I tried in radio mobile and had no luck.

What your asking for is where many companies make their living from. To run a plot like your asking for takes a
good investment on a software program. then you have to purchase the terrain data for the location or region
that your located in. Then the man hour time to sit down at the computer and run the program, not once, but
your asking it to be run 2 times. Once for each frequency band.

Maybe this is why you haven't had anyone step forward and offer to do it for nothing. There probably is some
where in the order of an investment of $8 K to $20 K just to have the software to do this. This is how these
companies make their income to survive. Your asking them to just give away some $500 to upwards of $3000
for providing the output plots.

Jim

Actually Jim, Radio Mobile is a free download and well supported. Astounding program. But, put your chaps on because there is a learning curve rodeo for it.

http://www.cplus.org/rmw/english1.html

Asweezy - I'll be glad to do it. Tell me what kind of line for both antennas, any losses you know about in each line, and the sensitivity of each receiver. I can knock it out tonight.

ps: tell me about your mobile for each band too - forward power, rcvr sense, desense, ant gain, line loss. Let me know if there is a specific location you want plotted. Otherwise I'll just plot a 75km radius around the site.

Ok it is going to be brand new units on an existing tower. I would guess maybe 1 DB loss for the cross. Mobiles will be CDM1250 Lowband at 60 Watts with the standard spectrum antenna. CDM1550 LS for VHF at 45 Watts with 3 DB Gain antennas. Hope that helps. Thanks for trying for me.

Here is 150mhz, highest confidence (best it can possibly get), 125km plot (75km wasn't big enough, hills are too low!)



Here is 33mhz, highest confidence, 125km plot



Assumptions -
33mhz base - 100w xmit, 1uv rcvr, 2db line and cavity loss, 68m elevation, 5.5db dipole omni, no special obstructions
33mhz mobile - 60w xmit, .7uv rcvr, .5db line loss, 2m elevation, unity gain omni
150mhz base - 100w xmit, .39uv rcvr, 2db line and cavity loss, 68m elevation, 6db omni, no special obstructions
150mhz mobile - 45w xmit, .31uv rcvr, .5db line loss, 2m elevation, 3db omni

Looks great thank you!! Now the Maps I have seen are one color I don’t want to sound like a total idiot but the Green Area is just about 100% coverage correct?

yep. Green is good, red is bad, and yellow is just so-so. Yellow is where you can expect chop, picket fencing, and increased noise. I hate the one color plots because they don't reflect real performance. They show coverage all the way out to the fringe where in reality it was noisy and almost unusable several miles back. Single color plots also average too much filling close in dead spots. Tri-color shows you where you can expect great coverage, poor coverage, and no coverage. Remember, these plots are high confidence and optimistic. Land cover is taken into account, but I do not have urban clutter data for your area. I also guessimated desense for your site since I have never been there and don't know how noisy or how quiet it is. This could be a walkin talkin monster radio system, or it could be deaf as a stone and not much better than dixie cups on a string.

YMMV. Let the famous unconditional 30/30 warranty period on this fine piece of engineering begin. (30 feet or 30 seconds whichever occurs first)

Just for s&g's, I plotted this again from 300km height because I knew the low band would talk further than shown above. I used the same parameters as before, and put both plots side by side for easy comparison. As you can see the primary green coverage is about the same for both. But, once terrain eats up line of sight and the sky wave, the ground wave pushes on for low band. Anyone who has worked there knows this, but it is fun to see it none the less. The depth of the yellow area increase greatly for the lower frequencies.