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hi all, ?just started to assemble the bitx40. ?new to kit building....confused on the e DC power connection instructions.

i route the two-wire connector from the PWR1 on the board to the power supply socket (brown wire to positive and black wire to grd).

now here where i am confused: ?am i supposed to run a wire from the power supply socket (positive connector where I just connected the brown wire of the two wire connector) to the Volume control (which connector on the volume control? ?would it be where the red wire is connected to the Volume control?)

next: ?it says to run a PA power line to the Power Amplifier. ?i don't understand from where to where I am suppose to connect this line.?

in the picture in the instructions it shows a brown and black wire from the two ?wire connector to the power supply socket. ?i get that. ?but then in the picture it shows a red wire attached to the power supply socket (positive) and a second black wire on the power supply socket (grd). ?but it does not show where this red wire goes nor where the second black wire goes?

sorry for the 'beginner' questions.

thanks for any help,

Paul

Paul (call sign?) wrote...

confused on the e DC power connection instructions...

The post at /g/BITX20/message/23973
that Jerry pointed out pretty much says it all.

Keep in mind that there are two places on the main
circuit board that need to get power. The Raduino
also needs power. The power connection at the back
right of the main board (if you have the PA at the
back) is power to everything else on the main board.
The power connection over near the IRF510 PA is for
the final and nothing else. This is so you can
optionally run the PA at a higher voltage... with a
larger heat sink. If you are going to run everything
on 12V, just connect the three places together
wherever you switch the power on and off and of
course tie all of the grounds together too, avoiding
ground loops.

--
73 Keith VE7GDH

No schematic Karl, but it's quite simple. A regulated 12 V supply for the BitX and prior to the regulator is the feed to the PA. Because of how I have it set up, when I turn it off I turn off power to the supply so the on-off switch on the volume control is rarely, if ever, used.

BTW, did you ever get your friend's BitX going? I'm not far from you and offered my bench but the email probably ended up in your spam box.

Vince.

--
Michigan VHF Corp.

I got mine to work with a DPDT switch.? I have the whole thing powered by a 3-cell li-po battery at 12.6V max, 11.1V nominal.

I found that there was a common ground on the input and output of the boost converter I had - There was no voltage potential across the in and out negative terminals, only the voltage of the positive terminal changed.? I don't know a lot about such converters - You may want to check yours.

All of the following are connected directly to ground on my power connector:
Raduino ground
Board ground
PA ground
Boost converter ground (both input and output)

The positive wire from my power connector went to the switch on the volume control knob, so devices were not powered unless I turned the radio on.

From the volume switch, positive connectors went to the:
Raduino
Board power
one of the center poles on the DPDT switch.

I don't know the numbering conventions for switches, but let's number the pins on the back of my DPDT switch like so:

1? ? ? ? 2
3? ? ? ? 4
5? ? ? ? 6

1 and 2 are shorted together.
3 goes to PA +
4 goes to battery +
5 goes to the +out on the boost converter
6 goes to +in on the boost converter.

In position one, the PA+ and battery+ are directly connected - PA gets 12V.? There is no power to the boost converter at all, so it cannot run and possibly produce RFI
In position 2, the + from the battery is routed through the boost converter, feeding 20V to the PA.

A cooler solution might be to power the PA only through the boost converter and have an external knob control the voltage of the booster - You could dial the power wherever you wanted.? You would probably want to make sure you couldn't turn it up past maybe 24V though - Wouldn't want to fry it!? You would also want to make sure your boost converter was RF quiet first, too.? Mine is pretty good, but does produce a quiet hiss over the speaker.

Hope this helps!
KE0GYC