How to Build L2 RFC for 4 Watt FM Transmitter: Parallel L-R Circuit Explanation

hi i cant get ahold of the designer of the 4 watt fm transmitter on this site. if someone would check it out for me i dont understand the component L2 this is how he explains it ( L2 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 i dont understand could someone help me.
thank you
Randy

This device is referred to as a RF choke. Which is short for radio frequency choke. Basically it looks like a short for the dc power but an open for AC. This tries to prevent the AC signal from feeding back into the power supply, thus the word CHOKE. Chokes off the AC.

And the 1Mohm resistor is simply being used as a coil form (i.e. just something to wrap the wire around).

Re-reading your question, I'm wondering if "isolated" is really "insulated" and seeing the word "scratch" I suspect the instructions are telling you to use fine magnet wire and to scratch the [enamel] insulation off the ends and solder those ends to the leads on the resistor.

So, basically, solder one end of the wire to one of the leads on the resistor, then wrap the wire around the resistor body until there are the specified number of turns (or you use up the specified length -- not sure what the instructions say about that), then solder the remaining end of the wire to the other resistor lead.

That would be my guess.

Could you please send the website location URL please.

hi this should take you to the site
http://www.diy-electronic-projects.com/p121-4W-FM-Transmitter
thank you
Randy

thank you
Randy

thank you
Randy

Before you start building 4watt transmitters Would there be any point to this topic since all transmission is now digital Fm analogue transmission will be effectivley outed soon as will analogue Fm recievers

Not forgetting the damage that this is going to bring to the amateur radio societies where nearly all recievers and transmitters will now become obsolete particularly within the Fm broadcast bands Most amateur radio operators will be looking at massive changes to the methods that were once used for communications with a strong emphasis on digital rigs and data transmission this would also include the way that morse is sent

Do you not think that possibly we should be looking at how we create digital phase lock loops and digital transmission theory Perhaps im incorrect in saying this but since we are seeing all the old equipment being sold off Wouldnt this be enough to illustrate that analogue transmission is now becoming a subject of the past another door that is no closing bringing yet another end to the radio era of the last century Not that we should ever forget this but more importantly should introduce topics surrounding digital transmission and various protocols within this topic

Quite sad many respects

Hello im making a few of these transmitters to be used only if something happens on12/21/12. Im going to these on dead channels to comunicate with local friends and family.I had some troubles with the design but ironed them out. I would like to find some digital Fm analogue transmitter designs.
Thank you
Randy

Hello Steve that worked perfect i even guessed the number of turns on L2 i soldered both ends of the wire to the leads of the 1M Resistor. It turned out to be a very powerfull transmitter but i had to put a heatsink and mount a fan on T2. Ill send you a picture when im finished mounting everything into the enclosure.
Thank you
Randy

Hi try these designs

Best of luck with this

Mark