Idle current, QRPGuys DSB Digital Transceiver


sigcom1
 

Chuck,

After setting the Gate bias voltage according to the instructions, what is the resultant idle current on your DSB rig (jumpers set for bias setup)?

(I know it will vary somewhat from rig to rig)

73.......Steve Smith WB6TNL
"Snort Rosin"


chuck adams
 

It is going to depend on the supply voltage. A lot I think. Did
not run some tests.

Using a lab supply at 12.00V, I was getting an idle current of around
61-63mA if I remember correctly. Around 460mA on transmit, which I
thought was a bit high. All this on 20m with a 1:1SWR. I can't find
my notes, so a number of people need to set their P/S voltage at
12.00V exactly using a lab supply and post their readings. Safety
in numbers, hoping that people can do this accurately.

Sometime in the next week I'll try to set things up again and do double
check.

chuck, k7qo

On 10/4/19 8:37 PM, sigcom1 wrote:
Chuck,
After setting the Gate bias voltage according to the instructions, what is the resultant idle current on your DSB rig (jumpers set for bias setup)?
(I know it will vary somewhat from rig to rig)
73.......Steve Smith WB6TNL
"Snort Rosin"


Ken wa4mnt <wa4mnt@...>
 

Steve,

12.0 V on the lab supply, 50 ohm dummy load. With the berg connector in place , I get 53mA with the bias set full CW. I rotate CCW to 68mA, to set the bias. I then remove the berg connector for a receive current draw of 16mA.

ken


chuck adams
 

Ken gets the same values that I do for receive.
Question is going to be what do you get with
transmit with WSJT-X software on TUNE?

chuck, k7qo

On 10/5/19 1:42 AM, Ken wa4mnt wrote:
Steve,
12.0 V on the lab supply, 50 ohm dummy load. With the berg connector in place , I get 53mA with the bias set full CW. I rotate CCW to 68mA, to set the bias. I then remove the berg connector for a receive current draw of 16mA.
ken


sigcom1
 

Thanks, Ken.  That's very helpful information.
73.......Steve Smith WB6TNL


Ken wa4mnt <wa4mnt@...>
 

Chuck,

Here's what I got:

20m, 1.1w out @250mA
30m, 1.1w out @250mA
40m, 4.0w out @600mA

Those reading taken with Steve's instructions to advance the audio input until it reliably transmits, plus just a tad to insure it switches.

ken


Ken wa4mnt <wa4mnt@...>
 

Gang,

Looking at the figures I posted earlier for the 40m output, they looked high compared to some earlier figures, and I have been unable to match that output or to account for the discrepancy. A more recent measurement matches the 20m and 30m values but the revised 40m output to a 50 ohm load is 2.56W, using Steve's recommended setup procedure, with a 12.0v supply and transmit current of 590mA.

ken - wa4mnt