That's a very good tip to remove the four inductors before starting construction.? It's a lot easier with no additional components on the board and the board able to lay flat on the desk.

Regarding the 0.6mm coil wires, I've always been able to burn off the enamel on every wire I've used before, even the 18swg (1.25mm) and 19swg (1.0mm) stuff used for winding big bandpass filters.? It just means changing the tip on the soldering iron to a larger one for that specific purpose and then changing it back again to solder them in.

73 Keith G6NHU

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QSO365 - My amateur radio blog:?

?

Can someone tell me the shipping point for US orders? I look at Informed Delivery but I suspect it won’t say the shipment is from QRPLabs. It seems that #163 should be in the mail, due to the reported delivery yesterday of #150 above. I haven’t received an Order Completed email and unfortunately I didn’t register with the store due to the wonkyness of it being overwhelmed.?

Don
W6CZ

Can someone tell me the shipping point for US orders? I look at Informed Delivery but I suspect it won’t say the shipment is from QRPLabs. It seems that #163 should be in the mail, due to the reported delivery yesterday of #150 above. I haven’t received an Order Completed email and unfortunately I didn’t register with the store due to the wonkyness of it being overwhelmed.?

Don
W6CZ

What kits are currently available at QRP Labs, kits that are not anticipated to have the same shipping and component delays that kits like the QDX are currently experiencing?? Much simpler kits are also on the table.? I would like to present such a list to our club for consideration as a group project, perhaps for some who have never before touched a soldering iron.

Thank you,
Karl
K4GMV

OH Yeah, with a vengeance!? Right now (13:30 UTC) the Kp Index is over 7!? I'm just now starting to hear signals weakly on 40 meters.? 20 is still dead as a hammer as is anything above there.

Jim, W0EB

------ Original Message ------

From: "Ron Carr" <rcarr@...>

To: [email protected]

Sent: 11/4/2021 8:26:38 AM

Subject: [QRPLabs] WSPR - Did the CME finally arrive

I am running a U3S on 40 meters and a band hopping receiver on the other HF bands and getting about 3 spots an hour.? I had thought the CME was supposed to affect this past weekend's signals.

Hi Wes

?

Syd, adding turns to a inductor used in a LPF will NEVER result in increased output. Take a look at the response curve for a LPF, there is a knee in the curve, below which there is full output, and above which the output reduces. All that happens when you add turns is the knee frequency decreases, when you remove turns the frequency increases.?

Respectfully I disagree... What?really happens in practice is that quite often you find that increasing the inductance does increase the output power. I see this all the time. *IF* an LPF is perfectly designed and perfectly?constructed with perfect components, and with perfect 50-ohm source and load, then yes the frequency response will be a flat line until there's a knee and at that point there will be an increasing attenuation with frequency; the 3dB point is called the cut-off frequency.?

If the inductances are anything off perfect, then you can easily end up with a response which has a peak in it, and a few dB insertion loss at lower frequencies. If that peak of the response is not aligned with the operating frequency then you see low power. If the inductances are too low for the design, then increasing them to the design value can definitely increase the output power.?

What happens in QCX is even more complex because there is normally not a perfect impedance match between the PA and the LPF input. When you tweak inductance values the output power can be increased if the impedance match is improved.?

Practically speaking, when tuning up QCX LPFs I have often found that increasing the inductance of L2 improves everything. I know it is slightly counter-intuitive but this is the reality.?

Generally I think the correct approach is to see what happens to the output power when you squeeze the turns and when you spread the turns. If the power increases as you squeeze the turns, this means that increasing inductance is increasing the output power. If the maximum output power occurs when you bunched together the turns as much as you could, then the tuning range available from turns squeezing is not enough; so in that case try adding on another turn or two, then try again. Conversely if the maximum power occurs when all the turns are spread out evenly around 100% of the toroid core, then this means that the adjustment range is not enough in the other direction - and in that case try removing a turn or two, then try again.?

73 Hans G0UPL