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Re: #FedEx Deliveries into Germany via Hannover Airport #fedex

Martin DK3UW
 

Hello Reinhard,

when I had to deal with customs they requested the invoice and a proof of payment so I supplied the invoice and my bank receipt.
So by presenting these 2 documents you or TNT as the agent making the declaration should be paying the right sum.
TNT will charge you for the paperwork so a total of € 20,00 may even be realistic.

Did you get the invoice before or after delivery ?
73's
Martin


Re: Cheap oscilloscope for QCX building

Evan Hand
 

Dan,

I do enjoy the open discussion that occurs in this group.  It helps me understand the RF aspects that my industrial electrical and automation control background did not cover.

I do own a TinySA, as well as an RSP1a, an RSP2, an Antuino from HFSystems, RFExplorer, and a Siglent 100MHz scope.  I do not have a lab-grade spectrum analyzer, so I can not do the verification tests myself other than the ones that can be done with just a single piece of equipment.  I have compared all of the SAs that I have, and the two that I use each has strengths and weaknesses.  The two that I use are the TinySA and the RSP1a with the Spectrum Analyzer software.  I have found this combination to provide repeatable results that I trust.

The TinySA has a limited resolution bandwidth (RBW) of 3kHz, making it impossible to do two-tone tests at audio frequencies that you need when testing an SSB transmitter linearity.  That is where the RSP1a comes in.  The RSP1a can not do a frequency span of more than 20MHz with confidence, so checking for 3rd order harmonics above 30 meters is questionable.  For both, I am using reference values like DBc, and am not worried about the absolute accuracy of a DBm measure.

To support my trust in the TinySA, I would suggest reviewing the TinySA.org Wiki and the YouTube videos that have compared it to more expensive spectrum analyzers.  The Tiny SA does well as long as the input level is kept below -30DBm, as stated in the video:
https://www.youtube.com/watch?v=VjqbMDNlCBs&t=0s

The initial video was not as favorable because the tester was not aware of the input level limitation:
https://www.youtube.com/watch?v=xFtF2AYT0iQ

As to your last statement on not trusting the TinySA, the alternative is purchasing a Rigol or Siglent SA for over $800 to test kits that cost less than $100.  Some day I may bite the bullet and buy a Siglent SA, but for now, the combination of the two I already have fits the bill for me.

As always, any feedback is always welcome as long as provided in a supportive manner.  That is how I learn.
73
Evan
AC9TU

PS:
The reason that I own so many pieces of low-cost equipment to do the same thing is that I tried to avoid the larger purchase of Siglent SA.  In the long run, I would have been better off having purchased the Siglent SA in the beginning as I have almost that amount invested in the other pieces of equipment.


Re: Static pops crackle in audio #20m #problem #qsx

Bryan Curl
 

Julian,
I apologize for any confusion.
The noise is NOT dependent on volume control. It can be heard with volume turned all the way down. With volume all the way up I can hear the receiver and the noise superimposed.
Antenna or dummy load does not matter.
When in Alignment mode the noise can be heard.
As I mentioned the noise can be heard in any condition.

But have a look at my previous post about using the powered speaker for tracing and finding some noise clear back at IC6 pins 1 & 7
Bryan, N0luf


Re: Cheap oscilloscope for QCX building

Dan W6AZI
 

Evan AC9TU, Gary K3WK, and Dave W6OG,

Thank you for engaging in discussion of this subject. It is a bit off-topic for this thread, but it illustrates the importance of understanding both the capabilities and limitations of our test equipment. I'd like to enumerate a few points made so far and add a few more observations concerning using any type of FFT-based (ie digital) spectrum analyzer.

8-bit ADC conversion is adequate for measuring -40dB spurious emissions, but only just so. This is borne out of the math (see above). I was skeptical when I first started using this feature on my Siglent scope, so I performed a series of careful measurements using a dual-output DDS signal generator and fixed attenuators. I discovered that indeed the Siglent can measure SEs down to -40dB within a few dB. However, at lower level SEs, everything falls apart rapidly as would be expected. Fortunately, the measurements "flatten out" at lower levels, meaning that the scope will indicate an artificially high SE level. That is, the measurement will be conservative at SE levels below -40dB.

Time-averaging the signal helps with the accuracy of the spectral measurements, as confirmed by my own experiments. Of course, the measured signal must be stable for this technique to work.

A very important but often overlooked aspect of any sampled system is the shape of the digital sampling window. The window shape must be chosen according to the nature of the measured waveform (pulse, sine wave, etc.) Choosing the wrong window can lead to very significant measurement errors, which I have also confirmed experimentally. In the case of the Siglent scope, the Blackman window is the appropriate choice for measuring spurious emissions of a transmitter, as this window is best suited for sinusoidal waveforms. I have been unable to find a specification for the digital sampling window used in the TinySA.

I do not own a TinySA, but I would like to see experimental evidence that it will accurately measure spurious emissions down to -40dB. Talking about its specifications (16 bit ADC, etc.) is all well and good, but the rubber hits the road with a real physical measurement.

I would not trust either the TinySA or an 8-bit digital scope with a spurious emission measurement if real accuracy was required. These devices are great for getting a ballpark figure as a reality check, but a true measurement within a dB or so requires a much more sophisticated and expensive instrument. As a side note, we have seen how the Baofeng debacle illustrates that spurious emissions are now an unenforced requirement. But as a matter of basic courtesy, it is still important for us to measure SEs to avoid being received on higher bands. This is particularly important for those of us who build kits or homegrown designs who may have inadvertently added harmonic-inducing "features". Therefore, even approximate measurements of spurious emissions are valuable.

An aspect of the rig to consider is the filtering action of the antenna matching device being used. For example, I use an L-network which provides approximately 20dB of attenuation at the second harmonic. Therefore, I'm considerably less concerned about the accuracy of my spurious emission measurements at a 50 ohm dummy load.

--
73,  Dan - W6AZI


Re: Static pops crackle in audio #20m #problem #qsx

Bryan Curl
 

This was very interesting. I can find this noise (more like a similar noise) in several places going all the way back to pin 1 and 7 IC5. The only place that the noise matched exactly to the headset, though, was on IC10 pin 1&2.. At c4 and c10 the noise presents as a very soft rumbling or rushing noise which I presume gets amplified into what I hear down the line.


Re: Static pops crackle in audio #20m #problem #qsx

 

Yes, I've had that experience too, but a) Bryan said that the noise is dependent on the volume control position, which would suggest C21 - before the volume control, and b) usually there is an obvious DC offset at the volume control with C21 or C22 failures, and Bryan didn't see that.
--
Julian, N4JO.


Sig Gen/VFO IF Offset question

stephen white
 

I am trying to use this VFO as the basis of a 80-10 Mhz transceiver.   I don't seem to be able to set the offset value for different presets.  Once the offset is set it for 80 meters with a 9.000mhz IF it needs to be a minus offset and what I need for 20 meters is a positive offset.  Can I set the offset as + or - per preset??  I don't see how to do this..

Steve  NU0P


Re: Static pops crackle in audio #20m #problem #qsx

nz0tham@...
 

I had this same issue with my QCX+ after I built it.  Replacing C22 resolved the problem.

73, Bill NZ0T


Re: QDX Terminal Emulator Setting-up PuTTY #qdx

Mark N8MH
 

Hi Mike, since you're using Windows, you can forget about the references to Linux ports, such as this "/dev/ttyACM1" or similar.  It's going to be COMx, where x is specific to the QDX in your system.

What is the COM port that shows up when you plug in the QDX and disappears when you unplug it? (and use the power to do this, not the USB cable...).

All you really need is to figure out what is the COM port number for the QDX, select that in Putty, leave baud at 9600, and then click "open".  That should give you a terminal window to the QDX.  It's actually simpler than the directions appear...

Mark N8MH


Re: Static pops crackle in audio #20m #problem #qsx

Bryan Curl
 

Julian,
All the test points on all other ICs were at 000.2 mVac. Then IC10 Pins 1 and 2 were at a baseline of 10-15 mVac with crashes going up to the 35 mVac range. Like you said the reaction time of the Fluke 83 was noticeable but it was a good indication that something is amiss around IC10.
If you think its a good next step, Im looking at the schematic and working a plan to poke around in the vicinity of IC 8-10 with a small powered speaker. 
Bryan


Re: QDX Terminal Emulator Setting-up PuTTY #qdx

Mike Easterbrook
 

OS is W10

COM is (I think) what it defaulted to at startup.

/dev/ttyACM etc is per instructions in manual

Mike

On Fri, 18 Mar 2022, 21:59 Julian N4JO, <n4jo@...> wrote:
Mike,

"COM1" is a Windows serial port, while "/dev/ttyACM1" is a Linux serial port.
Let's start here: what OS are you using ?

--
Julian, N4JO.


Re: Static pops crackle in audio #20m #problem #qsx

 

BT speaker: yep, we can certainly talk more about that.
Scope: absolutely, you'll be glad you did. My first was a "USB oscilloscope", an Owon VDS1022I, which uses a Windows app for the user interface & display. It's a 20MHz device which, while not the best, is still very useful up to 20m/14MHz band. The "I" means it has opto-isolation, which is REALLY important, because your computer and your radio won't be running from the same power supply, and you definitely don't want ground loops.

Whatever you do, get something with either a good sized screen, or the ability to stream to an external display; again, you'll be glad you did.
--
Julian, N4JO.


Re: Static pops crackle in audio #20m #problem #qsx

Bryan Curl
 

This looks like an interesting possibility as I do have Bluetooth seekers lying around. 
I might need some details about where to use this, and more importantly where NOT to.
I might just pop for a cheapo Oscope. ($50 variety) if this Bluetooth method becomes unhelpful.


Re: QDX Terminal Emulator Setting-up PuTTY #qdx

Alan G4ZFQ
 

On 18/03/2022 13:59, Julian N4JO wrote:
Mike,
"COM1" is a Windows serial port, while "/dev/ttyACM1" is a Linux serial port.
Yes, as far as I recall and that is about the only difference. Hans' instructions work in Windows.

73 Alan G4ZFQ


Re: LightAPRS-W Programming Error #kph #lightaprs

BrianB
 

Andrew,

I don’t see where you state the issue/error you are trying to resolve. Let us know and maybe someone can help.

73,
BrianB
N6CVO


Re: Static pops crackle in audio #20m #problem #qsx

tony.volpe.1951@...
 

I bought a ready built QCX+ a few months back and after a few days of faultless operation it developed a weird fault involving very strange noises - digital pulses audible and horrifically loud sidetone. I spent quite a bit of time inspecting the circuit board for unsoldered joints, shorts caused by tiny flakes of solder and wire left after cutting soldered leads and all looked perfect. 

My fault also involved microphony and I eventually tracked the issue down to the location around C24, an electrolytic capacitor. I found that by very gently tapping that perfect looking capacitor the fault would come and go. On inspecting the connections at the back of the board to C24, I could see that one lead had a fraction of a mm of wire poking out of the joint and the other was just flat solder - without a wire. I wobbled the part and one wire was simply sitting in the hole unsoldered, even though the builder had attempted to solder the lead and had simply covered the hole with solder. The lead was making intermittent contact in my case.

The OP's fault might be something like that. I assume that in my case the builder had snipped the surplus leads off, placed the component and one lead was a bit too short to get right through to the track and thus did not get hot enough to complete the soldering job when the iron was applied.

I had checked that board many times and every component looked like it was soldered properly. The microphonic effect might indicate something like that is the cause here. 

It is worth checking anyway perhaps.


Re: QDX Terminal Emulator Setting-up PuTTY #qdx

 

Mike,

"COM1" is a Windows serial port, while "/dev/ttyACM1" is a Linux serial port.
Let's start here: what OS are you using ?

--
Julian, N4JO.


Re: QCX Build Timelapse

tony.volpe.1951@...
 

Very nice. Reminded me of Christmas Eve 2020 when I built mine. Sadly, that particular radio is presently broken after a short circuit was created between the drain and gate of one of the PA fets.... this blew up IC3 and possibly other parts on the 5v rail by leaking a near 12v onto the five volt components. 


Re: QCX Build Timelapse

Keith "Al" AG5GW
 

On the little Settings gear you can slow down the video.  Look on the bottom edge of the window, near the right hand side.  


QDX Terminal Emulator Setting-up PuTTY #qdx

Mike Easterbrook
 

QDX is built. Rx /Tx working. RF output slightly low:

9V supply, no reverse polarity protection diode (yet):
20m 4.5W Est. Efficiency 66%
30m 4.5W Est. Efficiency 54%
40m 4.4W Est. Efficiency 63%
80m 4.4W Est. Efficiency 64%

Original QDX - Firmware 1.03 - only mod is feeding 3.3v regulator from the 5v line

Trying to look at the filter performance but have had no success in getting PuTTY started, let alone working.  I have been following Hans' instructions in the QDX manual but always get stuck at "serial line .... /dev/ttyACM1"  point. 

I note that my Putty config screen differs bit from the one in the manual is this relevant?




I am in need of a point-by-point instruction list for PuTTY like Hans' construction instructions for the kit build itself.  I reckon I understand less than 10 % of the PuTTY instructions I have been able to find so far. Anyone out there got the patience to do this or point me to where I can find this.

Thanks Mike 9V1LX

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