BitX -Completed......

BitX (G6LBQ) MK2  project is almost completed..(

I haven't started to build a PA stage. Not considering a high power PA stage for this transceiver. A PA with 10-20W output will be good enough for this.

Since the Tx stages are not functional, I haven't connected LPF and microphone at all.

I am operating ( receiving to be precise) the BitX using a PIC based DDS VFO. I am not happy with its performance. Since the BITX IF is set to 11.0592 Mhz , the VFO frequency should be rxFreq + 11.0592Mhz.  VFO is low in amplitude at the high end of HF. Redesigning the LPF at the VFO final stage can solve the this issue up to some extend. I don't want to do any changes this VFO.


Next task is to build a nice VFO based on the arduino, possibly use the Arduino Mega itself as it has lot of program memory and EEPROM to store user settings.
One option is to drive the locally available AD9850 DDS board from the Arduino, or it will be better to use the Si570. Si570 is bit costlier as compared to the AD9850 module , but the stability and frequency range of this little monster Si570 will override the cost factor.

Vinod.

PA0RDT Mini Whip....

    At the moment my BitX Tranceiver needs a good receiving antenna. Since the space to keep an antenna in my house is limited,  I think PA0RDT mini whip is a good option for me.

Today I built the PA0RDT in Manhattan style.

I have used experimental version of PA0RDT





Before connecting to BitX, I think it is a good idea to connect the PA0RDT to the  Club Transceiver (Yaesu FT 757) and test the performance.

Raspberry pi wobbulator

Tom Herbison has developed an excellent test equipment using the raspberry pi.

This can be used to  measure crystal frequencies, filter performance etc..

Tom's blog contains all details about this nice project.

Raspberry pi wobbulator needs 2 more plug in boards
    1) AD9850 DDS Module
    2) ADC PI Module
and an envelope detector (seems similar to the one used in the old AM broadcast receivers)
AD9850 module is available in e-bay.
ADC PI is a product of ab electronics.co.uk.

Since raspberry pi has GPIO pins,  it will be easy to interface a graphic lcd. Once the wobbulator program is modified to display the data in lcd, then the  raspberry pi wobbulator become a handheld device.

Nice idea uhhh??

This is time to take raspberry pi out of the shelf.  Or maybe it's a good idea to keep this project for next year. :)

I have tried couple of Linux distributions in raspberry pi.  Used my 32inch Samsung television as the monitor. Raspberry pi needs at least 700mA , 5V power supply.  I used my Samsung galaxy mobile charger to power the pi. This credit card sized computer is a good choice for people who want to try Linux.

Multiband exciter stages....

G6LBQ multiband exciter is almost finished.

Couple of things in the todo list including the LSB/USB crystals and crystal filter unit.
Certainty I have not tested any of the stages other than 1 & 2. I just measured the current consumption of both stages.  23-25 mA deflected in my multimeter.

MK2 exciter uses LM380 as the audio amplifier.LM380 (8 pin) version is not readily available in the market, I need to look for a good source.

Starter Post

Well , This is my first post about experiments in Amateur Radio....

Recently I started building one Transceiver based on the G6LBQ MK2 Exciter.

Couple of weeks back I received the Exciter board from DXKits

Exciter Stage - 1 is just finished :)...


I have built one Band Pass Filter which covers the entire HF Bands..

G4CFY kit(SPECTRUM COMMUNICATIONS) is used to build the BPF.

I will post test results of BPF, and new pictures of exciter stages in coming days..


Vinod