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Showing posts with label The last laugh.SMPS Supply. Show all posts
Showing posts with label The last laugh.SMPS Supply. Show all posts

Friday, January 30, 2009

The last laugh

After introducing the toroid kit for Bitx Version 3 I also felt the need to try out how the Bitx Version 3 performed with the toroid cores as mentioned by Leonard and as a part of the new Bitx kit.

So I began with a new set of boards and in a few days I was able to complete all the stages and the time had come to test the rx section of my Bitx.

I had the FLL Counter connected for checking the drift in the Bitx and making my vfo stable with its enhanced stability feature.

As I had checked the BFO and VFO frequencies, I had not checked the audio quality of rx only the voltages that were on the I.C pins. I had assumed the rx would be ok,
as I switched the rx I was welcomed by a strong audio which made me pleased that the rx had started well, but my excitement did not last for long, what followed was a motorboating type of noise and hum, which the rx was picking up.
My first doubt was on the FLL, so I removed and disconnected it from the Bitx,
but this did not cure the problem.
After looking around I decided to only connect the audio amp and see the results, and yes the noise was still there.This confirmed that the audio amp was picking up some hum from a source.

It was my last laugh when I came to know the problem.The culprit was the SMPS
12V adopter supply I have for checking some projects. It did not occur to me that I should not use it.

I connected my small 12v 7ah battery and was greeted with a cool audio and a very good RF signals. I connected the FLL back which did not emit any hum and which is also working real cool, it is giving a pleasing readout, and making the vfo stable at the same time.

I heard a few strong VU stations on the Bitx and the quality is some what better then with binocular cores.

I will put up some pics soon with the FLL in operation with the Bitx, both are doing a very good job.

This post is just been written to be careful in not connecting an SMPS supply , that would make you go in looking for the problem like me, as we age we loose the sharpness of the mind and perform dumb mistakes like I did. Hi. Hi

Best 73's

Sunil VU3SUA

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