Stereo Micromitter needs a boost

[ritchie1]

Can anyone help me with a simple redisgn of the circuit in this link.

https://electronics-diy.com/schematics/BH1417_fm_transmitter.htm

I have built the unit as a inear monitor system for stage work, but have found it does not quite have the coverage needed to cover all members on the stage.

I am probably getting about 1/2 the coverage that I need.

Please help.

Ritchie

 

[Nigel Goodwin]

Can anyone help me with a simple redisgn of the circuit in this link.

https://electronics-diy.com/schematics/BH1417_fm_transmitter.htm

I have built the unit as a inear monitor system for stage work, but have found it does not quite have the coverage needed to cover all members on the stage.

I am probably getting about 1/2 the coverage that I need.

For a start have you removed the attenuator on the output?, it's designed to keep it legal in Australia - so removing it will make it illegal (it's already illegal in the UK!).

 

[ritchie1]

No I haven't, how much difference will this make.

 

[Nigel Goodwin]

No I haven't, how much difference will this make.

Quite a lot, and it's VERY easy to do, and costs nothing! - what are you using for an aerial?, that will have a huge effect as well.

 

[ritchie1]

have tried this

I just tried this and have found that this has helped but, on further checking and going over the setup proceedure I have found that the maximum I can get out of TP1 is 0.76 votls dc and not the stated 2 volt.

any ideas?

 

[ritchie1]

micromitter

length of tuned wire at present, this was supplied with the kit.

 

[ritchie1]

the other thing I am not sure of is the 68nh and 680nh coils, the ones supplied are surface mount, and bloody microscopic. but I don't think that would affect TP1 test.

 

[audioguru]

I just tried this and have found that this has helped but, on further checking and going over the setup proceedure I have found that the maximum I can get out of TP1 is 0.76 votls dc and not the stated 2 volt.

any ideas?

Does your voltmeter have a high input resistance?
Does the DC voltage at TP1 rise and fall as L1 is adjusted?
Are the switches set to a frequency in the chart?

 

[ritchie1]

micromitter

Multimeter has high input resistance, and by turning L1 adjusts from 0.43 to around 0.77 volts.