Dear friends pleases see attached file. It has a detailed description of my problem and photos.
Thanks.

 

hi bi,
Welcome to AAC.
You will get a better response if you post the text and images directly to the thread instead of a docx file.

Moderation.

 

Can you see my .docx file, or I have to re-post my question.

 

hi bi,
The file is viewable, but some members are reluctant to open certain types of files.

E

 

I have successfully used a high performance , 100MHZ lab scope to adjust the harmonic traps on a CB radio. With a proper load resistance connected to the output, I adjusted for the best sine wave. with three cycles displayed it was not difficult. The good advice is to not be near the scope's performance limits.

 

Thanks, next time I will now better.

 

I am using a scope with 200MHz bandwidth and 200MHz passive 10 to 1 probe.

 

Hello,

If you want to measure the rf output of a transmitter, use a dummyload with an measure output.
This one is capable of handling 100 watts with a 40 dB attenuated output:
https://www.box73.de/product_info.php?products_id=4787

Bertus

 

My just taring to build a voltage amplifier not a power amplifier. A scope is what is usually used for this purpose.

 

Usually a description of a problem, or of a requirement, is a good starting point for a thread.
And I am wondering if you are working towards converting a CB radio to the nearby "ten meter" HAM bands.
I had been considering the possibility of doing that with a MUCH OLDER CB transceiver that I was given.
My target was 29.5+ MHZ FM communications. But then I realized I have no clue as to how much activity is
going on in hat sector. So the project is paused.

 

That's why people work with 50 ohm systems and some sort of ground plane , I never had any luck with rf until I at least used Manhattan style on a pc board base. Then I started to make my own pc boards when i was using SMD . you could build a really high impedance buffer amp.

 

For MasterBill2: No, I am not doing anything with CB conversion. What I am doing is for the remote control.
For jaclement: I know about Manhattan style, I have tried it for a different circuit.
Yes, I already build a high impedance amplifier. Both, my high impedance amplifier and passive probe with the 5pF series capacitor show similar results, i.e. greater measured that simulated drop at 27MHz! I would like to confirm that my considerations and calculations are all correct and I did not miss anything important that may explain my results. If this is the case, then I have stop baying transistors from amazon or e-bay. I do not know yet where to buy them. Where do you buy yours?
Concerning the 50 ohms systems, it is my understanding that it is used for 50 ohms transmission lines. The load for my single stage amplifier is not a transmission line but another transistor.
Regarding the ground plain, it shields from EMI, but it also increasing the parasitic capacitance.
Thanks guys, keep in touch.

 

I am using a scope with 200MHz bandwidth and 200MHz passive 10 to 1 probe.

THAT scope should work quite wellfor adjusting the harmonic traps for the best sine wave at the desired frequency. What makes it difficult is that the harmonics just show up as a small amount of distortion in the wave form.