CW receiver

[Vaibhav Birit]

Any body has a simple circuit for a CW receiver. I am in search of a CW receiver circuit which is sensitive enough, yet simple to build. Also if PCB layout is available, then it would be great.

 

[Nigel Goodwin]

Any body has a simple circuit for a CW receiver. I am in search of a CW receiver circuit which is sensitive enough, yet simple to build. Also if PCB layout is available, then it would be great.

You don't give any suggestion of what band you want to cover?. But assuming it's an amateur band?, try googling for "direct conversion receiver".

 

[Vaibhav Birit]

I forgot to mention the band. i want it for the 20m (14 Mhz) band.

 

[Nigel Goodwin]

As I suggested, a simple google provides over 10,000 hits, adding '20m' reduces this to 176 hits - you might try https://www.qsl.net/vu2upx/Projects/dc_rx.htm which look fairly representative of a DC receiver.

 

[Vaibhav Birit]

Can a shortwave receiver be used to receive CW, if a BFO is kept in it's vicinity & attaching a long wire antenna to it.
If yes, How effective will be the sensitivity of the CW receiver so formed.

 

[JimB]

If by "shortwave receiver" you mean the average broadcast receiver with a shortwave band, the quick answer is, yes. It will work but probably very badly.

Problems:
The tuning rate will be too high.
The front end of the receiver will overload due to poor design and lack of signal frequency selectivity.
The IF bandwidth will be way too wide, you will receive many adjacent channel signals all at the same time.
The BFO will be detected as a signal and act on the AGC, reducing the sensitivity.

If you have such a receiver, try it, the exprience will be worth while. It will drive you on to make something better.

JimB

 

[Vaibhav Birit]

Thanks Jim for highlighting the drawbacks of the shortwave receiver as a CW receiver. As nigel suggested, it will be better to make a Direct Conversion recceiver.