My attempt to go Green!
Posted on July 2, 2009
With all the talk lately about saving the enviroment, solar power, recycling and hybrid cars it might make sense to try our hand at alternative power sources for part 15 radio stations.
Some full time FM radio stations are thinking about making the move to alternative power sources. One station has been “Green” for years, K-Taos or KTAO 101.9 fm New Mexico. KTAO transmits with 50.000 watts and feeding power to the station is solar arrays and banks of batteries that generate as much as 32 kilowatts per day.
While my setup isn’t as elaborate as KTAO by any stretch of the imagination we are after all experimental so I started small. I have installed a small solar cell on the back of the Scoche FMT 4 and loaded the battery compartment with two fully charged AAA Nimh rechargeable batteries.
I measured close to 2 volts coming from the solar cell and the (2) AAA batteries are slightly over 3 volts. This might be just enough to keep the batteries charge for more than three days. The batteries alone offer 3 1/2 days of juice for the FMT 4 by themselves. (i got the solar cell from a small dual powered calculator for a $1.00)
The FMT 4 does not offer a way to power it from AC but even if it did, that would defeat the purpose of this experiment.
I plugged the transmitter into a portable am/fm radio set to am 1680 and the transmitter is set to transmit on 87.9 fm. Then I placed the transmitter/radio in a kitchen window that gets exposure to the sun for most of the day. (there are no mods to the antenna)
One thing i did notice was even though the little radio i am using is mono, when i was feeding the audio of 106.7 fm into the fmt 4 there was the effect of a overly sensitive AGC. The sound was rising and dropping as if i was overdriving the audio or riding the controls.
I couldn’t stand that so i turned down the volume on the radio wich seemed to limit this problem but after listening to it more it was still there just not as bad. After messing with the Ramsey 25b i decided to change the small radio to am 1680 and the trouble cleared up.
It might be the FMT was trying to process the stereo information taken from 106.7 fm but didnt have all the information and it responded to it the best way it could. The constant up and down levels were the result of stereo being fed into a mono radio then attempting to make it stereo again. ( that was my best guess anyways)
Basically i want to see how long the Nimh battery’s will last before they would actually need to be placed back in the charger.
Now time will tell if this little mod will fail or not. I’ll offer pictures later.
Im pleased to see that this little transmitter has offered us something to work with for so little and from the looks of it, this has to be the longest running thread ive seen for awhile.
As always, keep rockin!