Home |
Search |
Today's Posts |
#22
![]() |
|||
|
|||
![]() "Joe" wrote in message k.net... Hi John, That's what I have been doing. Just using a piece of 20 ga wire for an antenna, it is about 15cm in length (a vertical antenna). On the transmitter, I was using a loop, a piece of 20 ga wire with a 1 pf cap between the hot end of the antenna and the transmitter pin, other end grounded. Last nite after I read all the responses, I went to the Handbook and looked at page 10.10. There is a graph at the bottom of the page that shows inductances of a straight piece of wire at that frequency. Anyway, I rigged up a 0.9" piece of 20ga wire between two 8pf ( I did not have 8.2pf) caps and the reception increased dramatically. My test method was: Receiver in my house on a bench. TX outside about 80 feet away. In the old configuration, the receiver would sometimes receive the TX pulses. Once I put the TX inside my tool shed (about) the same distance away, the receiver would not pick up the signal. So after I rigged up my "almost" 18nH inductor and the 2 8pf caps, I repeated the experiment and the receiver was able to reliably receive the transmissions in both places. So I definitely saw an improvement. As far as FCC goes, this frequency is supposed to be for ISM, and you can use it unlicensed subject to part 15, that's why my first attempt was to work on the receiver, not the TX, but I may experiment on the TX now also. Joe KB1KVI Good work, Joe. Keep experimenting. It pays off. John |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
shunt inductor for 1/4 wave ground plane | Antenna | |||
Current in antenna loading coils controversy | Antenna | |||
Current in antenna loading coils controversy - new measurement | Antenna | |||
Clean Roller Inductor | Antenna |