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Re: QMX inductor winding
#qmx
Thank you.? The picture shows the windings going through the core, out the back (or bottom) and being wound on the core in an anti-clockwise direction.
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Re: QCX 50W Amp attenuator
#20m
#amplifier
#qcx
Hi Fernando,
I support Bojan's comment that the attenuator helps in the SWR match for the input.? Jim's suggestions can work, though I would use a QRP SWR meter like this one to verify that it is below 2:1: It has a 10 watt dummy load included. The safe bet would be to Find out why the QCX is not putting out full power: The power amp tweaking starts around 7 minutes into the video.? It is done with a QCX+, but the same technique works with any QCX, QDX, or QMX model.? The QDX and QMX are class D amps, so there is no need to tweak the L4 equivalent.? There is a need to balance between two bands that share a low pass filter on the multiband QDX and QMX models.? 73 Evan AC9TU |
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QMX
开云体育Hello Hans, After extensive testing of the QMX, I noticed a few things that I would like to mention here: 1.?????? In the logbook, CW is entered as the SSB mode (I already reported on this) 2.?????? Although S-Meter RX is on, no S-Meter is displayed. 3.?????? The volume of the sitetone depends on the volume coder. If the signals in the 40m band are very loud in the evening and you have to turn down the audio coder, the sidetone will also be very quiet. The setting in the menu to 099 has no effect. The volume of the sidetone should be independent of the audio coder and can only be changed through the setting in the menu. 4.?????? Despite setting the audio source and the transceiver at WSJT-x in the Raspberry and under Debian 12 in my laptop, it shows that the program does not recognize the TS-440 (hamlib error) 5.?????? It would still be a wish if the SWR could be shown on the display. We already have an SWR sensor on board and it just does its job quietly. ? 73 Reinhard DL3AS ? ? |
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Re: QDX - protection of BS17O PA
Hello,
toggle quoted message
Show quoted text
I see many post that will put diode or zener. But what do you think about putting a capacitor at the midpoint of T1? (or the opposite pin of L14, the one not plugged into C37). Maybe a 2x1uF ceramic. 73 Nicolas F4EGX Le mar. 5 sept. 2023 à 00:25, Gary W9TD <w9td@...> a écrit :
--
------------------------------------- Nicolas CHATELAIN F4EGX.67@... |
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Re: QMX inductor winding
#qmx
Alan, You are absolutely right that when toroids are wound wrong-handedly, they often won't fit nicely on the PCB.? And I haven't tried winding a toroid lately -- I always look at the PCB?and see which way the wires should go on a toroid -- but it just might be possible to add half a turn to one end, take half a turn off the other end, and flip the toroid?over to get the wires to match the PCB. You all know the chopstick trick and the crochet hook trick, right? ? 73 Jim N6OTQ On Tue, Sep 5, 2023 at 2:47?AM Alan G4ZFQ <alan4alan@...> wrote: On 05/09/2023 07:11, Jim Strohm wrote: |
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Re: QMX inductor winding
#qmx
On 05/09/2023 07:11, Jim Strohm wrote:
I ended up rewinding it in the other “handedness” direction.Jim, Not sure why. They are all wound the same. Wrong way makes no difference to operation provided all windings on that core are the same (wrong) way. However the wires will not go neatly into the correct holes. 73 Alan G4ZFQ |
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Re: Dire need for a part!
It was $4.99 for years (USPS) but that option seems gone recently so the new minimum is $6.99.? Over here where I live the shipping costs only about $0.75. And takes 2 days on average. But, the range of parts held by the component distributors is much less than Digikey! I'd take Digikey and $6.99 postage, being able to buy whatever I need from a stock of millions of different parts, any day! 73 Hans G0UPL On Tue, Sep 5, 2023, 9:42 AM Jim Strohm <jim.strohm@...> wrote:
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Re: QMX inductor winding
#qmx
Leighton, You're fine, by design. Handedness on toroidal windings only matters on the individual toroid core in question.? As long as the turns all go the same way, you're good.? On a non-tapped inductor like all the toroids in the low-pass filters, you can't change the handedness in mid-winding.? On a tapped inductor you can change, but most people notice this right away. The self-shielding properties of toroidal inductors means that two toroids side-by-side with different handedness will still work fine, and their crosstalk is nearly zero by design -- self-shielding. 73 Jim N6OTQ On Tue, Sep 5, 2023 at 2:05?AM Leighton <leighton.judd@...> wrote:
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QMX inductor winding
#qmx
Hi All, |
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Re: Dire need for a part!
LOL, it isn't USD$15 today.? Wait a week or so, and it'll change.? On Mon, Sep 4, 2023 at 11:38?PM Hans Summers <hans.summers@...> wrote:
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Re: QCX 50W Amp attenuator
#20m
#amplifier
#qcx
A caution -- verify the finals' maximum voltage from the device datasheet and don't get too close to this.? The magic smoke in RF finals can be expensive, even if they're IRF510s, which have to be hand-selected and hand-matched from one of the few known-good manufacturers. ? 73 Jim N6OTQ On Tue, Sep 5, 2023 at 1:22?AM Bojan Naglic <bojan.naglic@...> wrote: Hi Fernando, |
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Re: QCX 50W Amp attenuator
#20m
#amplifier
#qcx
Fernando,? Don't remove the attenuator.? Wire around?it,?or if you have an unbuilt kit, leave out the resistors for now.? For this wire, solder to the traces.? Don't use the through-hole vias in the traces.? Why?? You may want or need to have an attenuator at some time in the future. ?? If the amp can safely take 3W (the 2.5W from the QCX, plus a little bit more) for an extended period, you should be good. ? You may want to test, and not trust what the manual says.? To test, you should have a stiff power supply for the amp (a variable supply is strongly?preferred), a 100 watt continuous-duty dummy load for the output, and a power meter between the amp output?and the dummy load.? The power meter need not be calibrated -- you just want it to read 3/4 scale on initial key-down.? This is to look for a CHANGE?in power output, not to measure individual watts,?although?$5000 worth of HP/Agilent/Keysight* digital RF wattmeter is nice to have.? Actually, a $5 SWR meter for 27 MHz CB will substitute for an actual power meter -- just dial the sensitivity for 3/4 scale on forward power. ? ? ? Monitor the temperature?of the heatsink AND the dummy load.? If either goes over 150F or 50C (too hot to hold your finger on it), shut things down and note how long it took to get too hot.? If it's the amp heatsink that gets too hot, try adding a fan, perhaps making a shroud out of cardboard to channel the fan's output through the fins.? If it's the dummy?load that gets too hot, you need a bigger dummy load. ? You should see some decrease in power as the finals get hot, but if the decrease is only a little and the heatsink stays cool enough to touch, then you're good to go.? On the other hand, if you see what seems to be too much?power?out, you can turn down the voltage on the PS,?but not below 8V. ? "12 volts" nominal is often much closer to 14 V?actual. ? 73 Jim N6OTQ * Are we going to start abbreviating HP/Agilent/Keysight as HAK? On Tue, Sep 5, 2023 at 12:16?AM Fernando TUSELL <qrplabs@...> wrote: I have a QCX which is turning a bit more than 2.5W. I have been unsuccessful in obtaining a substantial increase in output. I have recently bought a 50W amp and I see that there is an attenuator (made of R2-R3-R4) to protect against excessive input. Am I right to think that I can ommit R2 and R4 and bridge R3, as the input power anyway is low enough? |
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Re: QCX 50W Amp attenuator
#20m
#amplifier
#qcx
Hi Fernando,
this attenuator serves also as a matching network for the PA input so I do not recomend to omit it. To gain more power you need to increase the PA supply voltage. 73 Bojan S53DZ |
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Easy Linux access to QMX via PuTTY
I've not seen this mentioned in the documentation but when working under Linux the entire command to connect to the QMX can be entered in one go. And as it's remembered by the terminal 'history' it's then available for repeat use via the F3 key.
On my system I just typed: sudo putty -serial /dev/serial/by-id/usb-QRP_Labs_QMX_Transceiver-if00 From then on it's just F3 as required. |
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QCX 50W Amp attenuator
#20m
#amplifier
#qcx
I have a QCX which is turning a bit more than 2.5W. I have been unsuccessful in obtaining a substantial increase in output. I have recently bought a 50W amp and I see that there is an attenuator (made of R2-R3-R4) to protect against excessive input. Am I right to think that I can ommit R2 and R4 and bridge R3, as the input power anyway is low enough?
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Re: Ideas please
Hello Cliff,
I suggest you take a look at the clearance between the lower case lid edge that? is used for the threads of the blacks screws for the cabinet and the BS170:s soldered close to the edge of the board. To do this you need to remove both side panels. Now put the bottom lid back. Now look at something moderately bright (computer screen?) through the QMX. You will se very little, if any, clearance between the soldering and the above mentioned edge of the lower case lid. I used a sharp chisel to remove some material from the lid, and covered the now exposed aluminium with kapton tape. I hope my explanation is understandable... 73 de SM5EIE /Gunnar |
Reinhard Gr?nz
Iro
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