short range radio audio transmitter am or fm?("bug")

Jul 13, 2004 0 Replies

I tried posting this on the sci. and alt. electronics newsgroups, but I didn't get any response, and roboticists are generally electronic-wizish (if you see what I mean) so I thought I'd post here. Maybe I have misworded my post in such a manner that it drives respondents away, that seems to happen to me.


I am looking for a sort of wireless mi rophone that's really small to use on stage(we want the actor to wear it). I looked at commercial ones, but they're way too expensive. I was hoping to make a simple one myself(it doesn't have to be great sound quality) and, after looking at some kits I came to the conclusion that the simple fm transmitters were unsuitable because their broadcast frequency probably shifts too much and too easily since none of them are crystal controlled.



Could I use a VXCO somehow to transmit FM? (maybe with a frequency doubler or something)



Does anyone have any good designs for stable FM transmitters? (I found out there's 2 nice single chip transmitters, the BH1417 and BH1416 by rohm but the design in the datasheet is for line input only. I guess I just add an amp and a mic? are there any components I could leave out from the datasheet design to simplify it?) also, the single chip designs have AGC, so that would be a plus.



Could I just use a 1 MHz oscillator (like a can type) and some discretes(including a mic) for a transmitter?



I found a good looking design at

formatting link
for an am transmitter, but again it's for line level input, and adding an amp would make it larger still.



Thanks for any suggestions, all are appreciated.


Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required