Fm 4W inductor?

[AmRadiant]

Hello all, about this project:

http://www.electronics-lab.com/projects/rf/021/index.html

can you explain how to build L2?

I read:

RFC (resistance 1MOhm with wrapped around her inductor of enough coils from fine isolated wire. Scratch of utmost inductor and you stick in utmost the resistance making thus a parallel L-r circuit.)

:-\

but can exist a simpler way to build this? how can I substitute this REALLY critical assembling with some more practical solution?

Thanks!

P.S. the first stage of this trasmitter alone works very good as 150 mW - 12V transmitter, very stable and not critical at all. I've replaced 0~45pF trimmer with a 5-20pf one, and L1 with 4 turns 1 cm diameter (very wide turns): it works ok at 88 Mhz

[sssaaa]

Hi AmRadiant

read this...

http://www.electronics-lab.com/forum/index.php?topic=3035.0

[AmRadiant]

many thanks ssa  :)

Maybe a simple VK200 can do the work I think... like this project:

http://www.electronics-lab.com/projects/rf/001/index.html

that is very similar (well... enhanced  ;D ) to the project above.. And I think I'll use a 2N3866 for T2. Maybe a madness, but I'll do some experiments (when I've a little free time) with a Peltier slab over heatsink for T2 and 28 Volts... I suppose that a simple fan isn't enough!

A little note about this project:

I don't think that is 'crappy' like someone said... remember that it can be made for about five-six euros and goes surely over 1 W rf power!

I've see (and assembled) project that use one only oscillator stage with a BC547 rated for 1 Watt at 15V  :o ... and that is very crappy, not this one  :D

Remember that, for irradiation, 2 watts or 3-4 watts is pratically the same...

So I must say that is the best projects with free oscillator, simple and cheap ever see. The first stage (that I've built) is fantastic, very versatile and incredibly stable.

But...

HOW ABOUT A LOWPASS FILTER?

maybe a lowpass 18 dB (PI) can be enough... but where can be put? above or below C7-L4-C8?