Hi all!
someone on another forum posted a link to an interesting ebay auction for a radio range calculator. i bid on it as it was cheap, and ended up winning it!
this is a fun toy!
its an analog meter with different pots on it that you can set to see how far your radio is "getting out".
the meter scale reads out in miles and km X 10.
Who wants to post some numbers and see how this thing works?
i put this in the antenna category because i figured thats where most people would have fun with it.
here is the post i made on the other forum so you will know how it works:
So, after removing it from its box (it was packed really well too!) the first thing that struck me was the size of the meter movement.
its about 3" by 4" which as we all know instantly makes something cooler!
After that, before i even put a battery in it (it runs off of a 9 volt battery) i took the cover off and looked at the circuitry.
this thing is about as simple as it gets. (no pics yet, but i will take some)
its not point to point wired like you'd think, it has a PC board mounted over the pots and switch.
four 2SC1815 transistors in a row, followed by seven trimmer pots, a couple of resistors and a couple of diodes, and thats it.
obviously the "magic" comes from the proper adjustment of these internal pots, and who knows what they used to set them!
since i had it open, i cleaned all the pots and the switch. i must say that this looks like a high quality piece of gear judging from the quality of the potentiometers used in it.
here are the different controls for everyone so they can tell me what they want me to set them to:
RX SENSITIVITY MICROVOLTS: 0.1 TO 12
TX POWER WATTS: 1 TO 640
TOWER HEIGHT FEET: 15 TO 1000
ANTENNA GAIN OR CABLE LOSS Db: -4 TO 30
FREQUENCY MHz: 30, 160, or 450
The meter will read out in miles and kilometers x10 (10 Km equals about 6 miles)
for my first test, i set it at what my station currently does:
the RX sensitivity will be for the average receiver that will be hearing you so i set it at about .5 microvolts, i put the RF power at 5 watts, my antenna is about 25 feet off the ground,
my antenna gain is just above 0 (antron 99), and of course the only freq setting will be 30mhz.
the meter says that i get out about 8 miles!
so i increased the TX power to simulate my modulated wattage (about 200 watts) and it increased to about 22 miles.
this actually seems about right!!!
i think the "funnest" part of the toy is trying to see how much a change in your station will increase your effective distance.
so i tried increasing the height of my antenna tower. so now im putting out 200 watts on a regular vertical antenna that is about 25 feet off of the ground, and im getting about 22 miles out of it.
increase the tower height to 60 feet, and i get out 40 miles. double the height gave me about double the distance.
increase the tower height to 120 feet, and i get out 60 miles. seems like there is a point of diminishing returns here!
increase the tower height to 1000 feet, well, the meter pegs on the right end of the scale (i figure that equals about 100 miles as the markings stop at 80 miles) so i decrease the tower height just until i can see the needle back off a bit, and it looks as though if i had a 300 foot tower i would get out about 100 miles.
this is FUN!!!!!!
with everything the same i decided to see what being on VHF or UHF would be like:
160mhz: down from 100 miles to 40 miles.
450mhz: down to 32 miles.
ok, i could keep doing this, but i will take a break and see who wants to jump in with some figures for me to try out.
when you give me the figures you want me to plug in, be sure to mention some parameter that you want me to mess with and note the changes.
its more fun that way!
this thing is so cool. i will be on the forum off and on for the next 8 hours, and ill keep checking back. so responses shouldnt take too long.
back to you forum!
LC
someone on another forum posted a link to an interesting ebay auction for a radio range calculator. i bid on it as it was cheap, and ended up winning it!
this is a fun toy!
its an analog meter with different pots on it that you can set to see how far your radio is "getting out".
the meter scale reads out in miles and km X 10.
Who wants to post some numbers and see how this thing works?
i put this in the antenna category because i figured thats where most people would have fun with it.
here is the post i made on the other forum so you will know how it works:
So, after removing it from its box (it was packed really well too!) the first thing that struck me was the size of the meter movement.
its about 3" by 4" which as we all know instantly makes something cooler!
After that, before i even put a battery in it (it runs off of a 9 volt battery) i took the cover off and looked at the circuitry.
this thing is about as simple as it gets. (no pics yet, but i will take some)
its not point to point wired like you'd think, it has a PC board mounted over the pots and switch.
four 2SC1815 transistors in a row, followed by seven trimmer pots, a couple of resistors and a couple of diodes, and thats it.
obviously the "magic" comes from the proper adjustment of these internal pots, and who knows what they used to set them!
since i had it open, i cleaned all the pots and the switch. i must say that this looks like a high quality piece of gear judging from the quality of the potentiometers used in it.
here are the different controls for everyone so they can tell me what they want me to set them to:
RX SENSITIVITY MICROVOLTS: 0.1 TO 12
TX POWER WATTS: 1 TO 640
TOWER HEIGHT FEET: 15 TO 1000
ANTENNA GAIN OR CABLE LOSS Db: -4 TO 30
FREQUENCY MHz: 30, 160, or 450
The meter will read out in miles and kilometers x10 (10 Km equals about 6 miles)
for my first test, i set it at what my station currently does:
the RX sensitivity will be for the average receiver that will be hearing you so i set it at about .5 microvolts, i put the RF power at 5 watts, my antenna is about 25 feet off the ground,
my antenna gain is just above 0 (antron 99), and of course the only freq setting will be 30mhz.
the meter says that i get out about 8 miles!
so i increased the TX power to simulate my modulated wattage (about 200 watts) and it increased to about 22 miles.
this actually seems about right!!!
i think the "funnest" part of the toy is trying to see how much a change in your station will increase your effective distance.
so i tried increasing the height of my antenna tower. so now im putting out 200 watts on a regular vertical antenna that is about 25 feet off of the ground, and im getting about 22 miles out of it.
increase the tower height to 60 feet, and i get out 40 miles. double the height gave me about double the distance.
increase the tower height to 120 feet, and i get out 60 miles. seems like there is a point of diminishing returns here!
increase the tower height to 1000 feet, well, the meter pegs on the right end of the scale (i figure that equals about 100 miles as the markings stop at 80 miles) so i decrease the tower height just until i can see the needle back off a bit, and it looks as though if i had a 300 foot tower i would get out about 100 miles.
this is FUN!!!!!!
with everything the same i decided to see what being on VHF or UHF would be like:
160mhz: down from 100 miles to 40 miles.
450mhz: down to 32 miles.
ok, i could keep doing this, but i will take a break and see who wants to jump in with some figures for me to try out.
when you give me the figures you want me to plug in, be sure to mention some parameter that you want me to mess with and note the changes.
its more fun that way!
this thing is so cool. i will be on the forum off and on for the next 8 hours, and ill keep checking back. so responses shouldnt take too long.
back to you forum!
LC