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Power Output

 

Hi all

I have just built and finished my first QMX+ and it worked first time well impressed. Just one question on the power output which I am measuring into a dummy load.

On 160m I am getting 7.2w, 80m 7.3w, 60m 6.5w, 40m 5.6w, 30m 5.5w, 20m 5.2w, 17m 4w, 15m 4.7w, 12m 2.8, 10m 3.5w 6m 2.8w so dropping from 7.2w to 2.8w is there any way I can “smooth” this out a little, drop 160m down and increase 6m ???

Thanks

For any pointers

Paul

G0HEU
 

The extra high output at 160m is normal.? Hans previously said he will reduce it because associated with it are high peak voltages at the BS170's exceeding the manufacturer's rating.? You can remove a turn from the 6m LPF inductors.
Good luck - be very careful at 160m, particularly avoid high swr and definitely don't operate with more than 12v, use 10v if possible.
Chris
 

On Fri, Mar 28, 2025 at 06:19 PM, paul G0HEU wrote:
is there any way I can “smooth” this out a little, drop 160m down and increase 6m ???
You can only do this balancing act with bands which share a lowpass filter.? Otherwise, it is mostly the output transistors (and I suspect their drivers, which have to drive their gate capacitances) losing "oomph!" at the higher bands.? Component losses and parasitics are worse at low VHF as well.
73, Don N2VGU
 

Could the PA modulator be used to adjust the max power on a band by band basis?? This is something that Hans would have to implement but is there any technical reason such as overloading the PA modulator that would prevent this?
?
I think that power control would be nice anyway and doing this on a band? by band basis would be a minor addition.
?
Chris, G5CTH
 

Hi Chris

Already on my list, OM

73 Hans G0UPL


On Sat, Mar 29, 2025, 09:18 Chris via <chris.rowland=[email protected]> wrote:
Could the PA modulator be used to adjust the max power on a band by band basis?? This is something that Hans would have to implement but is there any technical reason such as overloading the PA modulator that would prevent this?
?
I think that power control would be nice anyway and doing this on a band? by band basis would be a minor addition.
?
Chris, G5CTH
 

开云体育

thanks for the information.

I don’t use 160m as i don’t have the space for a antenna but a increase on 6m would be useful

thanks for a cracking kit had a few 20m & 40m FT8 contacts yesterday

well impressed

Paul


On 29/03/2025 08:35, Hans Summers via groups.io wrote:

Hi Chris

Already on my list, OM

73 Hans G0UPL


On Sat, Mar 29, 2025, 09:18 Chris via <chris.rowland=[email protected]> wrote:
Could the PA modulator be used to adjust the max power on a band by band basis?? This is something that Hans would have to implement but is there any technical reason such as overloading the PA modulator that would prevent this?
?
I think that power control would be nice anyway and doing this on a band? by band basis would be a minor addition.
?
Chris, G5CTH
 

开云体育

Paul,

For years I would break something so I could learn about it by doing a repair. ?BUT over the years I have backed off on that idea and especially on the small hf rigs. ?If yours is working to your satisfaction on the bands you use just leave it alone. The tight placement of parts means being “perfect” in your removal and re-soldering the part back in. It’s so easy to damage other parts while doing that. Please enjoy the mini miracle you have on your bench.

Have fun.

Dave K8WPE


On Mar 29, 2025, at 5:35?AM, paul G0HEU via groups.io <g0heu70@...> wrote:

?

thanks for the information.

I don’t use 160m as i don’t have the space for a antenna but a increase on 6m would be useful

thanks for a cracking kit had a few 20m & 40m FT8 contacts yesterday

well impressed

Paul


On 29/03/2025 08:35, Hans Summers via groups.io wrote:
Hi Chris

Already on my list, OM

73 Hans G0UPL


On Sat, Mar 29, 2025, 09:18 Chris via <chris.rowland=[email protected]> wrote:
Could the PA modulator be used to adjust the max power on a band by band basis?? This is something that Hans would have to implement but is there any technical reason such as overloading the PA modulator that would prevent this?
?
I think that power control would be nice anyway and doing this on a band? by band basis would be a minor addition.
?
Chris, G5CTH
 

Hans aren't you on vacation!?
Your wife should take your phone/computer.
Enjoy
Chris

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