rf amplifier

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dipole
Posts: 2
Joined: Sun Apr 19, 2020 4:14 pm

rf amplifier

Unread post by dipole »

hello there i have abit of a problem im still learning ..if anyone could help that would be great.. ive got 2 amplifiers what i put togeather the first one has a 10 dbm drive and it gives out 14.6 dbm its a 2 stage transistor the transistor is a bc54b...the next amplifier is also being driven with a 10 dbm drive and the outout is 20 dbm thease transistors are 2n3904 this has 2 stages..now what im trying to do is join one amplifier up to the next so we have 4 transistors but what happens is it cancels out each other i have dc blockers in the correct places im abit like i said im still learning..i can upload pics if needed thanks...
M0XXQ
Posts: 484
Joined: Thu Sep 27, 2018 10:23 pm
Location: Newcastle upon Tyne
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Re: rf amplifier

Unread post by M0XXQ »

Hi dipole and welcome to the forum.
What sort of signal are you trying to amplify, e.g. TX RF or RX pre-amp?
If you can give us a better idea on what it is you're trying to achieve I am sure somebody can help :)

Cheers

Rob.
dipole
Posts: 2
Joined: Sun Apr 19, 2020 4:14 pm

Re: rf amplifier

Unread post by dipole »

hello rob thanks for replying its a tx amplifier ive managed to build 2 what im trying to do is join them togeather but like i said in my first post it cancels out when i connect the 4 transistors togeather im useing a 1 nano fad capacitor for the dc blocker..it be great if i could go forward in this project if u could it be great it takes alot of my time at the moment but not enough time in the day.. the first amplifier is a 2 stage transistor its a 10 dbm input and its a 15 dbm output.. the second is a 10 dbm input n we get a 20 dbm output when i join them togeather they cancel out on the multimetre when i check the biasing on the second stage of the amplifier we get a negative sign on the metre if u have any advice it would be great thanks..
VK5TM
Posts: 242
Joined: Sun Oct 28, 2018 11:40 pm
Location: South Australia
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Re: rf amplifier

Unread post by VK5TM »

Welcome Dipole.

Some pics and the schematics would be a great help so we can see what you are trying to accomplish.

Also what do you mean by "it cancels out" when you join them together?
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