Update PCB for sdr

After revised circuit of SDR. Circuit idea from YU1LM and I improve a oscillator for using AD9850 module. Side of PCB applied for aluminum case 100 x120 mm.

And idea for Font-end may I separated box for control

73

E22ICQ

DDS with AD9850 and Basic Stamp microcontroller..(part 1)

I and my friend in group "Thailand Amateur Radio Group" will dicuss at RAST meeting in May. We talk about make DDS project. After we buy a DDS AD9850 module. We go back to a workbeanch for starting our jobs. Somebody used RasberryPi foe control, somebody use adurino and I select Basic Stamp. This for start to re-learning a basic language again (I lean at grade 1 in High school). So shall be lean step by step.

The Basic Stamp 2p24 has feature for I2C communicate to module ,16 I/O ports for connect Encoder, Buzzer etc. and include feature for LCD command.

Now I can write a program for up and down a data and output to screen. Next step make a program for control DDS.

Balun 1:1

Dipole antenna made by wire or pipe what I cut to quarter-wavelength for each side or measure a impedance at center to 50 ohm. Actual at center of antenna (Center fed) has impedance 50 ohm balanced. I must adding a Balun to convert unbalanced signal from transceiver to balanced signal to antenna.

I selected a balun 1:1 for my antenna. Balun 1:1 is suppressing current unbalance signal better than a Balun choke coil. My Balun used 14 turns of 3 wire on AM ferrite rod. Next to 6 meters each side of wire for dipole antenna.

Thank you @vk2zay for advice for selection a Balun.

Welcome to HF bands

Long waiting in a intermediate license. Now I upgraded a license from beginner to intermediate class in Thailand.
Difference for beginner class and Intermediate class are extended for using in HF bands and at HF bands I does a transmitting at 200W power.

It's OK. Let's see my callsign in the air.

Check Daily HAP Charts

When we need to check what High frequency for Dxing at hourly. We can check data on Hourly Area Prediction or HAP. This data made by Australian Government in IPS radio and Space Services. example I need check in Bangkok to communication and see the color chart to see a recommended frequency for communication.

See at below for what Frequency for communicate.
http://www.ips.gov.au/Images/HF%20Systems/Global%20HF/HAP%20Charts/Bangkok.gif

Antenna 3E for DXing 11meters

The first Project for me before I start to beginner Amateur Radio. This Project I make for using on CB-radio. This project has not pefect curse I don't know about the rf design. Manager of my group(153RT007 op;Ken) helpful for some design (you can see in http://153rt.com/webboard/index.php?topic=49.msg369#msg369 ) for used in this antenna.
I hope friend can hear me on Dxing.