veronica fm transmitter

[tinubegood]

hello everybody
    i started building the following veronica 1W fm transmitter, but i'am not sure about its reliability plz tell me if its correct circuit or not, i've got this circuit from following link.

www.geocities.com/Area51/Nebula/3736/veronica.htm

also plz help me if anyone could provide some knowledge about this circuit with block diagram.

View attachment 38514

 

[audioguru2]

Hi Tinu,
Reliability? So it lasts without failing? Who knows?

The kit is fairly old so I don't think all its parts are still available. It RF transistors and varactor diodes must be very hard to find.

I don't think its performance would be good:
1) It is mono FM, not stereo like modern circuits.
2) It doesn't have pre-emphasis for its audio. So its reception on a radio will sound muffled without treble sounds.

 

[Platonas]

Hello people,
I would like to comment on the cct a little bit.
1.  Stereo can be added lated by the use of a sepparate stereo generator.
2.  The same can be done about pre-emphasis using a cct from another FM transmitter and adapt it accordingly.
3.  The thing I am worring about is the stability.  The oscilator part consists of a single stage, T2 and T3 (BF494), and produces high levels of power.  Around 100 to 200 mW.  This is somewhat high for an oscillator in order to have good frequency stability.  It could drift easyly (this is my opinion, I havent tested the cct at all) since I beleive at this power the transistors will heat a little bit.

Anyway appart from this, it looks to be a nice cct and I hope I am wrong about the stability.

Regards
P.

 

[audioguru2]

The frequency stability of the Veronca transmitter was tested in a review in Google's cache. It drifted very much when its supply voltage was changed and when something changed its antenna. Its frequency stability was said to be not good enough for it to be legally used in Britain.

 

[tinubegood]

hello audioguru,

  could u provide me  circuit  for a good stereo fm transmitter with partlist and necessary theory behind the circuit plz ... :-\

 

[audioguru2]

In Google, enter Silicon Chip Micromitter in the search bar. the 1st link will be their crystal-controlled stereo FM transmitter project that is modern and works very well.