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74ACT08 vs 74ACT08SC

 

Trying to find a supplier in Europe for the QDX - IC5

The IC onboard have only the letters?74ACT08 on it and only manufacture I find is FAIRCHILD in USA
But I find 74ACT08SC in stock in Europe?
From the specs I see no difference on this to versions ?

Maybe Hans could pop in here and verify that the SC version is ok for the QDX ?

73 - Knut??

?


QDX: DC in vs. RF out

 

I made a few comparisons with my QDX on 40m in order to learn what input voltage is required to produced a desired output. I was surprised at how low of an input voltage the QDX would continue operating:



--
John AE5X


Re: Toroid Winding #qcxp40

 

The proper way to count turns of a toroid is the number of times the wire passes through the center of the core.? DO NOT count the turns on the outside of a core!? I also count 37 turns on the photo.

Mark, NK8Q

On Tue, Nov 9, 2021 at 8:21 AM ohwenzelph via <Ohwenzelph=[email protected]> wrote:
Looks like 37 (in the picture) to me.


Re: QDX - notes after day 1

 

Hi Steve,

You could use JS8 this is give you plenty of room to exchange more the just a report of locator and signal strength
Maybe we could arrange some Sunday evening net for QDX users

73 Frans PE0F


Re: QDX arrived

 

¿ªÔÆÌåÓý

That's why Linux is so much better than Windows...it will run reasonably well on old hardware, and superbly well on new hardware. If Linux boots quickly from the same drive that Windows takes 15 minutes to boot from, the hardware and in particular the hard drive is common: it's Windows that is at fault.


Hard hat firmly on!


73

Roger

8P6RX

---
**
Roger Hill
**


On 2021-11-09 10:39, Shirley Dulcey KE1L wrote:

15 minutes?? Windows 10 shouldn't even take 15 seconds to boot. If it takes 15 minutes on your system you are doing something horribly wrong. Trying to run it from a spinning hard drive qualifies as horribly wrong :)

On Tue, Nov 9, 2021 at 5:39 AM Hans Summers <hans.summers@...> wrote:
?
I do wonder if some people having non-transmit issues have a windows audio set up issue. If the windows audio mixer applies some kind of scaling, for example. I normally use Linux but I didn't have any problems when I tested on Win10 (my PC can boot into Win10 if I insist and if I'm prepared to wait 15 minutes).?
?




Re: QDX arrived

 

15 minutes?? Windows 10 shouldn't even take 15 seconds to boot. If it takes 15 minutes on your system you are doing something horribly wrong. Trying to run it from a spinning hard drive qualifies as horribly wrong :)


On Tue, Nov 9, 2021 at 5:39 AM Hans Summers <hans.summers@...> wrote:
?
I do wonder if some people having non-transmit issues have a windows audio set up issue. If the windows audio mixer applies some kind of scaling, for example. I normally use Linux but I didn't have any problems when I tested on Win10 (my PC can boot into Win10 if I insist and if I'm prepared to wait 15 minutes).?


Re: QDX arrived

 

I think that Windows sound card issues can be one of the primary reasons things don¡¯t work or stop working.?


Don
W6CZ


Re: Toroid Winding #qcxp40

 

Looks like 37 (in the picture) to me.


Re: QRPp with the QDX #20m #antenna

 

I've used mine for WSPR as well but am not comfortable running the full 5W output for two minutes. Turning the supply voltage down to 9.2V on 40m produces 2 watts out and the QDX runs cooler.
--
John AE5X


Re: QDX shipping update

 

Mine shipped from US warehouse on 11/5 arrived on 11/8? USPS.


Re: Toroid Winding #qcxp40

 

You counted correct. It may have had 1 taken off because to get the bandpass to peak properly. Same for L3 and L1, I think they are 1 or 2 less than the text, if the QCX+ pictures are the same as QCX mini pictures.

Mike/w1mt


On Tue, Nov 9, 2021 at 5:01 AM <kc2wan@...> wrote:
Perhaps this is a silly question.? Why does the image of the transformer toroid in the QCX+ assembly manual show 5/5/5/37 windings when the manual indicates it should be 5/5/5/38? Am I misunderstanding how to count windings?


Re: QDX Surface Mount inductors

 

Thank Hans,

Kit now built worked first time and software updated, however, I need to learn how to fly WSJT-X , I get a full 5 Watts on TX with 2:2 as suggested for 12V operation, I will plot the harmonics, and send you, I will try adding some caps across the inductors to bring them self resonance to 1MHz and see what happens first then replace them with your wired inductors, if unsuccessful.

PS windows 10 was tiresome with the com port, first it work then it lost it, and took awhile to get back.

What is the duty cycle at 5 Watts?


73

Andrew


Re: QDX arrived

 

Also with fldigi, be sure to check the TX level attenuator in the lower right corner. Mine was set to -3 dB, had to set it to 0 to get it to work.


Re: QDX arrived

 

Hi Phil

The default "rising edge threshold" setting in the QDX configuration screen is set to 80%. That's why it only seems to work when the WSJT-X slider is set to maximum. I believe the WSJT-X slider is logarithmic so the effect of reducing it is disproportionate, I mean 80% WSJT-X slider would correspond to much less than 80% amplitude in voltage terms. Anyway there's no point anything other than 100% because it doesn't alter the transmit output power at all, as it would on a conventional SSB transceiver.?

I do wonder if some people having non-transmit issues have a windows audio set up issue. If the windows audio mixer applies some kind of scaling, for example. I normally use Linux but I didn't have any problems when I tested on Win10 (my PC can boot into Win10 if I insist and if I'm prepared to wait 15 minutes).?

73 Hans G0UPL
http://qrp-labs.com


-------- Original message --------
From: "Phil Hazelton via groups.io" <philhazelton@...>
Date: Tue, Nov 9, 2021, 1:04 PM
To: [email protected]
Subject: Re: [QRPLabs] QDX arrived
Hi all,
Just finished mine between 3.7 and 4.5 W with 12 V depending on band. FWIW, I¡¯m running Windows 10, and WSJTX 2.4.0. I set the Rig to Kenwood TS440S as recommended, but was having trouble band switching and there was no Tx, I changed to TS480 and everything worked perfectly. Also, the wsjtx power slider MUST be set to 100%, other wise you will not get any output power at all.
PSK reporter spots all over Europe, furthest so far 3385 Km into Russia from UK.
73
Phil?
G8PJH?



On 9 Nov 2021, at 05:21, Don Melcher <don@...> wrote:

?

And it¡¯s the perfect size!! Nearly identical to a RaspberryPi. This os going to be fun.?


Don
W6CZ
DM07bk


Re: QDX arrived

 

¿ªÔÆÌåÓý

Hi all,
Just finished mine between 3.7 and 4.5 W with 12 V depending on band. FWIW, I¡¯m running Windows 10, and WSJTX 2.4.0. I set the Rig to Kenwood TS440S as recommended, but was having trouble band switching and there was no Tx, I changed to TS480 and everything worked perfectly. Also, the wsjtx power slider MUST be set to 100%, other wise you will not get any output power at all.
PSK reporter spots all over Europe, furthest so far 3385 Km into Russia from UK.
73
Phil?
G8PJH?



On 9 Nov 2021, at 05:21, Don Melcher <don@...> wrote:

?

And it¡¯s the perfect size!! Nearly identical to a RaspberryPi. This os going to be fun.?


Don
W6CZ
DM07bk


QDX - notes after day 1

 

My QDX has been on the air for a day, so far on 40m only.
Receiver performance has exceeded my expectations.
I have built it for 12V operation and am running with 11V at the moment - lots of QSOs with signals heard in 3 continents. Attached image is from PSKReporter.
?
I am using the?same computers and?USB leads as my main rig which?runs up to 100W, but I have found that RF feedback is a problem with?the?QDX even at 2W.
The symptoms are dropping the USB CAT control and QDX going into oscillation. This self-oscillation continues when WSJT is closed. I would recommend that output is monitored with a power meter or receiver. Without monitoring it is difficult to spot and could lead to overheating - I wonder if that may be the cause of some transistor failures.
The feedback problem has been resolved with ferrites on all leads :-)
?
I managed to break one of the axial inductors. My fault - I just didn't realise how brittle and fragile they could be. Easily fixed for 5p, but take care when bending the leads.

On my QDX one of the ICs did just foul the case by a fraction of a mm. I quick scrape with a scalpel fixed it, but it would have been enough to drag the IC off the PCB if any force had been used.
?
It would be nice to be able to identify other stations as QDX users. Calling 'CQ QDX' would just confuse all other stations. Any ideas ?

73
Steve, G4GXL


Toroid Winding #qcxp40

 

Perhaps this is a silly question.? Why does the image of the transformer toroid in the QCX+ assembly manual show 5/5/5/37 windings when the manual indicates it should be 5/5/5/38? Am I misunderstanding how to count windings?


Re: QDX shipping update

John Myers, KD8MQ
 

¿ªÔÆÌåÓý

Thank you Mike, I was not aware of that.

John Myers, WG8X

On Oct 28, 2021, at 11:01 AM, Hans Summers <hans.summers@...> wrote:

?
Hi Fred

More likely, you should have it by Monday. Trust in USPS! I expect you will let us know on Monday :-)?

73 Hans G0UPL

On Thu, Oct 28, 2021 at 5:44 PM Fred Spinner <fred.spinner@...> wrote:
I received my shipping notice email (from US stock) for order 50001 this morning.? So in a week or so I should get the QDX.? Maybe I will be able to build over Thanksgiving... We will see.??

Fred W0FMS/7

On Wed, Oct 27, 2021, 7:26 AM Pat <pat.ring1@...> wrote:
On Wed, Oct 27, 2021 at 09:07 AM, Mike KK7ER wrote:
the USPS will notify you of ANY package on its way to you if you sign up for an account
I have been using this service for years.? It not only tells you about packages you are receiving, but provides an image of all normal-sized mail, like mail in the regular-sized envelopes and postcards.? I get an email every morning with these details, so I get to see the junk mail before it hits my mail box!? When there is a foot or two of snow outside, I know in advance if I need to make the trek out to the mail box.? I see I have a USPS package shipped by pirateship and coming from Sedalia, MO.? I have received QRP Labs kits from Sedalia before, so likely have the kit by the weekend.??


QRPp with the QDX #20m #antenna

 

I added a 20 dB, 5 W attenuator in series with the antenna line and have been running 17 dBm = 50 mW on 20m and 40m WSPR.?

Quite amazing how well the receiver works, even with the attenuation and also a large number of stations spotting my micro signal; however I should?not have found this too surprising as I have been regularly been spotting 5 and 10 mW WSPR signals from Europe [without the attenuator].??

Definitely having a lot of fun on digital modes with the QDX -- and it is saving me from having to listen to all the [switching power supply] noise here in the city.?

73


Re: QDX - rig control error

 

Ken, Bob
Thank you for your thoughts.? I will try to find some time later today to try them out.? Mine doesn't pass the CAT test - the errors come up when the button is clicked and I'm pretty sure I've got 'Mode' set to none, but I'll check.

Chris