BITX SSB QRP TCVR FOR HAM RADIO

Wednesday, April 22, 2015

Tunning Range For The Bitx3b/3c

Two pictures being published which show the tunning range with 1sv149 being used in our Bitx series.

From 13.994 TO 14.418. with the same schematic values for the VFO section.

Bitx3C With SBL-1 Mixer

Good News for people who are not being able to find ADE-1 ASK mixer and would still like to build the Bitx3C version. We now have a new pcb BITX 3C with SBL-1 Mixer.

The BITX3C with SBL-1 mixer has been tested completely and works great. we shall be providing the PCB soon on our website as well as on our ebay store.

Also is available the BITX3C SBL-1 AS A KIT or just a pcb to buy.
we shall provide the schematic but no manual, the same Bitx3B manual can be used as most stages are same, leaving the mixers.

Some pictures below of Bitx3C with SBL-1 mixer, i have also mounted the BC549 in the mic pre amp for Q15 as mentioned in the last post.

BITX3C SBL-1 VERSION BUILT UP FOR DEMO

BITX3C SBL-1 PCB

Dynamic Microphone For Bitx

Lately I have been using a Dynamic microphone for Bitx3B as shown in pictures below.The audio seems to be quite good with it.

One important part that has to be installed in line of microphone is a 3.3uf Tantalum capacitor, to block the positive 12 volts TX voltage.

Q15 which is 2n3904 in the mic pre amp stage can be changed to BC549 which is a low noise VERSION,
The gain seems to be better then 2n3904 and much better audio quality, it has to mounted in reverse.

Monday, April 13, 2015

New Pictures Bitx3B

For our Bitx3b builders my priority was to build another Bitx3b tcvr , this one with mods on the PA and Exciter Board. The building up of a new Bitx3b ssb tcvr for 20mt band has been greatly rewarding,

Recently i made many contacts on the air with DX and as well as Local stations in India. The stability of PA is excellent with the mod of cutting off the RX antenna on Transmit, so NO oscillation's from the PA now.

I have attached some pictures of the new build set.

The audio mute board tends to overlap the PA board a bit, this happened because of adding few extra
components to the PA board mod of antenna cut of to RX on transmit. The audio mute board can be mounted with some extra spacers so that the board sits a bit above the PA Board.

A few of you may have problem with the screws size for the case sent, if you have not been able to find screws locally then kindly send me an email for a set to be sent for your Bitx 3b case.

Some pictures which i took of a new Bitx3B build by me recently.

If any one has problem in building the Bitx3b he can be free to email me

best of 73s

Saturday, March 7, 2015

Bitx3B Modules Layout And Connections

Here is a complete layout of Bitx3B modules

Hope it helps all Bitx 3B Builders.

Tuesday, March 3, 2015

Bitx3B High Resolution Pictures

We are publishing some latest and very clear pictures of high resolution for Bitx3B Exciter-PA-AGC and Audio Mute modules.

Hope it helps the builders with location of part values etc.

Bitx3B Exciter-PA-AGC-Audio Mute

AGC

Audio Mute

VFO Stage Bitx3B

Bitx 3B PA

Bitx3B Exciter

Friday, February 27, 2015

New PCB Bitx3B 3C Exciter And PA

The new printed circuit boards for Bitx3B Bitx3C And PA are ready, these are the boards on which we have done the modifications for RX antenna cut off on transmit mode.

Good news the kits for Bitx3B and Bitx3C are ready and we shall start selling them from 1 March 2015 on wards. Keep a watch on our website and ebay shop if you would like to purchase the kit.

Published below are a few pictures of our new modified Bitx3B and PA built recently.

A brief summary of mods done for new boards are as given below.

1. Bitx3B Exciter,mod done to disconnect of Exciter RX Ant on Transmit.
2. Bitx3C Exciter, mod done to disconnect of Exciter RX Ant on Transmit.

New PA Board mod done:

1. Disconnection of RX Antenna on Transmit at P5.
2. Selection of 12 or 24 Volts for Final.
3. Capacitors 0.01 across all four IN4007. 4. IN4007 across both relays.
4. PC Fan 12 Volts for cooling transistors.