Re: QCX and peaking BPF


Denis F6GKQ
 

Hi Daniel,

First, you don't tell us which band is your QCX... Please, confirm : 40, 20, other ?

Look at Alan messageĀ https://groups.io/g/QRPLabs/message/23136, he gave you valuable informations.

I had the missing peak problem on my QCX 40m. I solved it two ways :
1) putting a 50 ohms (my dummy load but you can take any 47, 51, 56 ohms resistor you have in your junk box) across the antenna input. At this stage, I started getting a peak that I couldn't get with the antenna plug leaved open.
2) I improved the level at the peak by removing 3 turns on my T1 longest winding. Now, the peak is at scale x7 and quite all segments lighted.

It is difficult to tell you where the problem is, you should try to follow the troubleshooting procedure that Hans wrote. Low signal when looking for the BPF peak can be with a problem on the LPF (double check turns number, solder joints, etc.) also on T1 and, then, more difficult to find... on any place else after T1.

Hope you will find...

--
73 from Denis, F6GKQ
QCX 40m nr 3082

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