Wednesday, December 28, 2011

160m small receiving loop antenna

I found this small loop antenna diagram from an old magazine. It looks to be a reproduction of the 1938 QST drawings of the W6GPY receiving loop antenna for 160 meters. If the 4-turn is reduced to 3-turn, then it will cover 80 meters. One separate turn is used for coupling.

Then the following is another version of the W1FB loop as discussed in July, 1977, QST magazine.
Alright, the picture is upside-down.

Wednesday, December 14, 2011

50Mhz band plan

I copied the 6m band plan for my future reference. As a non-frequent 6m Ham radio operator, I do not bother to memorize this complicated band plan.

Thursday, December 8, 2011

LF local oscillator idea

I found this schematic. What I am interested in is the circuit portion of using the schmitt trigger nand gate IC - CD4093. This can generate a frequency somewhere between 70Khz to 1Mhz or it is what I read. I bought the IC while I was visiting a store in case I need a low frequency local oscillator.

Sunday, December 4, 2011

Intersting links for Android audio interface

I found a couple of interesting web links this morning. I have been thinking about developing Ham radio applications on Android. The major part that I have not figured out yet is how to sample audio data from Andriod audio input. It would need more digging for available APIs.

This gentleman (or company) must already figure that out and developed a hardware interface to be used with his applications including DroidPSK. The link is:

He references another interface link upon which his design is based:

The above shows how to enable PTT using the audio input from a receiver.