RF Amplifier

[Hero999]

No, do your own work!

 

[muki55]

Hello!

I've tried to design a high-frequncy antenna amplifier that only amplifies frequenzies around 392MHz. I've browsed through Harry's pages and various other sites and found information on basic transistor amplifier design and so on. And here I have the fruits of my efforts

I must point out that this is my first self designed transistor amplifier. I have the schematic and some of my calculations attached. Will this amplifier work? I'm trying to receive an ASK-modulated signal (yes my rfPIC).

Thanks for your time, I'm looking forward to any responce I might get. :wink:

I'm a bit unsure about the currents in the circuit, is 10mA collector current too much for a preamp?

The preamplifier that i propose offers 20dB in all the region of VHF or FM and it still can also reach in 500MHZ. Enough aid for a lot of applications.
Note: Place the PCB in metal box of suitable dimensions.

Hope that it will help you.

 

[audioguru]

Hi Muki,
Remove the 120pF capacitors. Their reactance at 433MHz is only 3 ohms and they are shorting the transistors collector to base so they don't have any gain.

 

[muki55]

hello audioguru,
thanks for the advice but its working properly in my uncle's tv antenna without this the reception is very poor.
Anyway thanks a lot

 

[Hero999]

Only because the capacitors probably aren't capacitors at that frequency, remove them and the performance should improve.