Subject: Re: BA1404 TXes Saga Continues.. From: mweiss7401@aol.com (MWeiss7401) Date: 1997/06/21 Message-ID: <19970621070901.DAA17984@ladder01.news.aol.com> Newsgroups: alt.radio.pirate Well the little FMST100 transmitter shipped to the customer today and heavily-modified at that. There ARE some things one can do to increase the output of the BA1404: This kit had a 330-ohm resistor feeding DC power to the RF output pin (I think that was pin 7, but diagram is not with me now). Normally, one would think that to increase power, one only need put a lower resistor value. --Not! The lower value also "shorts" out the RF signal. So here's what I did to circumvent: Wind #26 kinar wire around a 1/8" rod as a form, about 6 turns. Take out the 330-ohm resistor and put the coil, and a 47-ohm resistor, in series with eachother, in place of where the 330-ohm was. This DOUBLED the RF voltage output of the chip. Another quick mod was to replace the 3.3 volt zener with a 5 volt zener. This increased the RF output another 35%. There you have it. The BA1404 is now putting out 10 times legal power (and it's still piss weak.) For this particular application, I also added two cheap 2n2222 transistor stages, as raw, simple amplifiers. Basically, a collector choke to B+, a 39-ohm resistor to ground from emitter and a 47 k pullup with 82k pull down on the base biasing. 15 pF caps into the the 2n2222 and interstage between 2n2222s. Each stage tripled the voltage output across 50 ohms resistive load. Out of the box, unmodified, this thing has a range of 25' max. We now have it covering 40-acre campsite, with the mods. Now if I can convince them they need a limiter. :-) Mark The "Peg-legged" Bass Pig