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zbitx Power

 

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What are other seeing with the power levels? I have a QRP Labs dummy load that I connect my volt meter to get a peak voltage reading.?
The voltage on the radio is 7.7v, drops down to about 6.8-6.9v when tx. The Driver is set to 100 on all of the tests, and the mode was 2TONE.
When I tx into the dummy load. Based on the calculation its showing I'm outputting about:
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Band? |? DummyLoad? |? Radio
80m? ? ? ? ? ? 2.5w? ? ? ? ? ? ? ? ? ?3w
40m? ? ? ? ? ? 2.8w? ? ? ? ? ? ? ? ? ?3w
20m? ? ? ? ? ? 2.4w? ? ? ? ? ? ? ? ? ?3w
17m? ? ? ? ? ? 2.8w? ? ? ? ? ? ? ? ? ?3w
15m? ? ? ? ? ? 2.2w? ? ? ? ? ? ? ? ? ?3w
10m? ? ? ? ? ? 1.25w? ? ? ? ? ? ? ? ?2w
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I'm thinking that's on the lower power levels than I would have expected. Are others seeing the same thing ??
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https://qrp-labs.com/images/dummyload/dummyload.pdf
 

You will get 5w if your power supply holds to 8.4 volts o transmit? i can see from your readings that the dc supply is dipping to 6.8v on transmit. This indicates that the power supply is current starved


On Tue, Apr 1, 2025, 8:08 AM David T-- VE3TOS via <digiital=gmail.com@groups.io> wrote:
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What are other seeing with the power levels? I have a QRP Labs dummy load that I connect my volt meter to get a peak voltage reading.?
The voltage on the radio is 7.7v, drops down to about 6.8-6.9v when tx. The Driver is set to 100 on all of the tests, and the mode was 2TONE.
When I tx into the dummy load. Based on the calculation its showing I'm outputting about:
?
Band? |? DummyLoad? |? Radio
80m? ? ? ? ? ? 2.5w? ? ? ? ? ? ? ? ? ?3w
40m? ? ? ? ? ? 2.8w? ? ? ? ? ? ? ? ? ?3w
20m? ? ? ? ? ? 2.4w? ? ? ? ? ? ? ? ? ?3w
17m? ? ? ? ? ? 2.8w? ? ? ? ? ? ? ? ? ?3w
15m? ? ? ? ? ? 2.2w? ? ? ? ? ? ? ? ? ?3w
10m? ? ? ? ? ? 1.25w? ? ? ? ? ? ? ? ?2w
?
I'm thinking that's on the lower power levels than I would have expected. Are others seeing the same thing ??
?
 

I'm using the batteries.? They are older(recovered from Laptops) batteries. So that could be the case why it's dipping.?
 

When you buy NEW 18650 batteries, they have max current draw ratings. ?Check that before you buy. ?
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I purchased these:
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They appear to have the right curves. ?8A continuous draw. ?High Capacity.
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We will see how they work when my radio arrives.
 

These are the set? I was using at the time of testing.? ?Looks?like they aren't really designed for a?constant high current?discharge,?

I have a number of other batteries which I will have to dig up the specs to see if I have any set of batts that will handle the current?needed on tx.?

On Mon, Mar 31, 2025 at 11:37?PM Robert Fairbairn via <bobfa=pm.me@groups.io> wrote:
When you buy NEW 18650 batteries, they have max current draw ratings.? Check that before you buy. ?
?
I purchased these:
?
?
They appear to have the right curves. ?8A continuous draw.? High Capacity.
?
We will see how they work when my radio arrives.

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