AGC Pictures

To help in construction the AGC circuit used in Bitx3B or if used in any other receiver , some pictures are being published here. One resistance that was sitting between preset and lm324 is 10K , the value is now shown in the AGC pcb image file

ADE-1 Mixer for Bitx Version 3

Information is being provided as how to connect the ADE-1 Mixer for the older version of Bitx3 And also for Bitx Version 3B. The Bitx Version 3 C has already been updated with ADE-1 Mixers.

BITX VERSION 3 B WITH ADE-1

Bitx Version 3C

For those of you wishing to build the Bitx 3 with ADE-1 Mixers the good news is that the PCB's are ready for the Bitx Version 3C.   There have been no other changes in Bitx 3C

The Bitx3C has been tested and performance is good. I shall publish a video soon of a working set.
 Published below are two pictures of Bitx3C.

Bitx Version 3C Solder Side with ADE-1 Mixers

                                        

Bitx Version 3C Components Side 

      The Bitx Version 3C PCB And kit will be available by next week onwards.

Bitx3B VFO complete band coverage with zero drift

A new video of Bitx3B is being shown here, which has the following improvement:

1. Full coverage of 20Mt band from 14.000MHZ to 14.350MHZ
2. Zero drift with varicap tuning diode.

The varicap is 1SV149  .   They work up to a maximum of 10V biasing and capable of a C max of 500pF at 1V bias. so we can manage from 8V regulator easily.

This device was suggested to me by my good friend MVS  Sarma from Hyderabad. India.
After trying this device i did not think twice by replacing it with MV209.

So now we have a very stable VFO with BITX3B giving a complete band coverage, who wants a DDS anyway for a mono  band tcvr ........

      VIDEO OF BITX 3B  FULL COVERAGE WITH STABLE VFO  WITH NO DRIFT

Missing ground track in exciter, band pass filter stage.

Kindly correct the band pass filter stage in the Bitx3B pcb which has a missing track that should be connected between 39PF and ground for L1 and L2

How to connect Bitx VFO with Ik3OIL FLL

Many friends had requested me to  show how the Bitx VFO could be connected to the Ik3OIl FLL counter to stop the drift in the Bitx VFO.

Presented here is a video and details as how to connect the Bitx VFO with the Ik3OIL freq counter.


First we present the video with the Bitx VFO that is connected with the Ik3OIL Freq counter.
The FLL control circuit works with combination of some components and software on the counter and some parts are on the IK3OIL VFO pcb. The main part being the BB204 varactor diode. A buffer stage has been taken from the Ik3OIL VFO pcb.

In this demo we powered the bitx VFO and the Ik3OIL Counter . You may observe that after the red led stops to blink the FLL takes control and stabilizes the VFO.
In the demo i have also rotated the main tune and fine tune capacitor which gives complete coverage for the 20mt band. There is no drift as the tuning is stopped and the FLL control takes the new readout and starts to control the VFO.

This demo has been done on the Bitx version 3 exciter.

I would welcome any one who wants any more help.

                                                     

BITX VER 3 WITH Ik3OIL FLL CONNECTED

                                              

               IK3 OIL VFO PCB USED WITH THE SET UP

                        BITX VERSION 3 EXCITER PCB

                           FLL FREQUENCY COUNTER

 

1. Some important points to be noted: 
2.  In VFO use Polystyrene Or NPO capacitors
3. Use RG174u for all RF connections
4. 12 Volts can be taken to the FLL VFO pcb from the bitx power supply 

Stacked VFO coil for bitx3b vfo

Bitx3B VFO stage picture has been posted here. The Bitx3B VFO is made with two number's of
T37-6 stacked together and quick fix applied on it.

The trimmer at control of FLL will need to be engaged at such a point as to observe the least drift .
The VFO is rock solid and i did not find any drift .

The FLL menu switch has been soldered on the solder side of PCB, so that it could be easier pressing the switch while adjusting the BFO or VFO to set their frequencies.