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zBitx power draw

 

Hi,
?
If I am running at 9V, and I am transmitting FT8 at 100%, what output power are you expecting and how much power is the device consuming?
?
Cheers,
Ben
 

At 8.4v(Batts) i'm seeing about 5w on tx

On Wed, May 7, 2025 at 6:41?PM Ben Sanders via <sandersbenjamin=[email protected]> wrote:

Hi,
?
If I am running at 9V, and I am transmitting FT8 at 100%, what output power are you expecting and how much power is the device consuming?
?
Cheers,
Ben
 

Do you happen to know how much power it is drawing then?
 

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At 9v and 100% I was showing 5 watts out with a current draw of around 3.8 amps on FT-8.

Cheers

Jim



On May 8, 2025, at 4:31?PM, Ben Sanders via groups.io <sandersbenjamin@...> wrote:

Do you happen to know how much power it is drawing then?
 

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Of course, the output power measurement is just probably by measuring voltage and assuming a resistance, but that’s a pretty low overall calculated efficiency, 15% or so. ? And of course part of that is that it’s having to run the other circuits but they aren’t that high power hogging! Perhaps other than the display? ? wide band transformer systems aren’t anywhere close to as good as the tuned networks we use decades ago. ? At least it seems that way.!!

Gordon kx4z?



On May 8, 2025, at 17:04, JAMES LEWIS JR via groups.io <jtlewis@...> wrote:

?At 9v and 100% I was showing 5 watts out with a current draw of around 3.8 amps on FT-8.

Cheers

Jim



On May 8, 2025, at 4:31?PM, Ben Sanders via groups.io <sandersbenjamin@...> wrote:

Do you happen to know how much power it is drawing then?
 

Thanks!? Just wanted to double check - that's what I was seeing, but seemed high.
 

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When you talk about efficiency, what are you actually talking about?

When I discuss efficiency I'm talking about a power source - 120 v, 3 amps in, 12 v, 23 amps out, for example.

I've never seen anyone compare radio efficiency - 13.8v at 21 amps in(290 watts) and comparing that to RF output (100 watt), about 34% efficency.

The Ft-818 needed 2.4 amps at 9.6v (23 watts) to generate 6 watts RF, that's about 25% efficiency, based on your model...

Ken, N2VIP

On May 8, 2025, at 17:38, Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> wrote:

?Of course, the output power measurement is just probably by measuring voltage and assuming a resistance, but that’s a pretty low overall calculated efficiency, 15% or so. ? And of course part of that is that it’s having to run the other circuits but they aren’t that high power hogging! Perhaps other than the display? ? wide band transformer systems aren’t anywhere close to as good as the tuned networks we use decades ago. ? At least it seems that way.!!

Gordon kx4z?



On May 8, 2025, at 17:04, JAMES LEWIS JR via groups.io <jtlewis@...> wrote:

?At 9v and 100% I was showing 5 watts out with a current draw of around 3.8 amps on FT-8.

Cheers

Jim



On May 8, 2025, at 4:31?PM, Ben Sanders via groups.io <sandersbenjamin@...> wrote:

Do you happen to know how much power it is drawing then?

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