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Re: Difficulty during alignment - RF output #20m #qcx #problem

W5EGA@...
 

Thank you sir!


Re: 0.03w RF output, 1w at transistor drains, Help? #qcx

 

The odd thing is, that, There still IS some form of rf output, because I'm picking up an (admittedly 300hz off) signal with an SDR reciever


Re: Difficulty during alignment - RF output #20m #qcx #problem

Ronald Taylor
 

The top pads don't connect to anything, so if you are careful not to damage the bottom ones putting Q6 back in, it should be OK..

Ron

On Thu, Aug 20, 2020 at 2:51 PM <W5EGA@...> wrote:
Well I finally got my new parts in. Everything went fine removing the BS170's - but I made a mistake unsoldering the MPS751. I accidentally pulled the top pads off two of the 3 pads for Q6 on the circuit board. Is there a fix for this or is it a lost cause? The bottom pads look fine, but I'm not sure if the top pads will be an issue.


Re: Newly built QCX+ processor works intermittently #qcx

Arv Evans <arvid.evans@...>
 

Rahul

Congratulations on your success.  Usually it is something simple that takes enormous amounts of time to troubleshoot.  

Arv
_._


On Thu, Aug 20, 2020 at 3:24 PM <rahul@...> wrote:
THANK YOU ALL!
It was a bad LCD header that I mangled. Got a new one and she works like a charm


Re: Can I use the nanoVNA 50 Ohm dummy load for alignment? #qcx

mike.carden
 



If I keep the key disconnected, is that alright? Sorry I just want to get up and running with this thing ASAP

This forum is full of posts from people who *accidentally* transmit from their QCX while setting up, and fry a handful of transistors.

The advice repeated over and over is to never apply power to the radio unless a dummy load or a known resonant antenna is connected.

-- 
MC



Re: Difficulty during alignment - RF output #20m #qcx #problem

W5EGA@...
 

Well I finally got my new parts in. Everything went fine removing the BS170's - but I made a mistake unsoldering the MPS751. I accidentally pulled the top pads off two of the 3 pads for Q6 on the circuit board. Is there a fix for this or is it a lost cause? The bottom pads look fine, but I'm not sure if the top pads will be an issue.


Re: 0.03w RF output, 1w at transistor drains, Help? #qcx

 

I measured those voltages with an external DMM, against ground.


Re: Newly built QCX+ processor works intermittently #qcx

rahul@...
 

THANK YOU ALL!
It was a bad LCD header that I mangled. Got a new one and she works like a charm


Re: Can I use the nanoVNA 50 Ohm dummy load for alignment? #qcx

rahul@...
 

so if I don't hit TX, I don't need a dummy load?

If I keep the key disconnected, is that alright? Sorry I just want to get up and running with this thing ASAP
:D


Re: Can I use the nanoVNA 50 Ohm dummy load for alignment? #qcx

DL2ARL
 

... or take a light bulb. Or whatever else you happen upon, a pair of wet shoelaces if it has to be and if two 100 Ohm 1/4W resistors are nowhere to be found. But leave that poor calibration resistor be an institution of precision and not a victim of raw power.

As KE1L clearly states above, no need for a dummy load for the calibration of the QCX+, but we understand your need of some steady load to transmit into after the calibration has been acheived. The nature of the load used is of lesser importance. Start with power levels as low as possible, use  a low suppy voltage, as low as can be depending on the function of the 5V voltage regulator. Maybe 7,5V would be too close to the spec of the voltage regulator, but you should not go beyond 9V for the first test. KD1JV suggests for the first "smoke test" a 9V block cell, even a "used one". This one will definitively not supply enough current to spoil things, if you do not have a smart power supply that can be set not to deliver too much current.

yours friendly, Razvan DL2ARL 


QRP-Labs Rx & U3S #u3s #rcvr

DL2ARL
 

Hello,
the QRP-Labs Rx is such a gem and Hans spoils us with a price tag as close to a give-away as goes, that I built several of them. Several for several purposes. Yes, I know who'se idea this is (thanks Rick kk7b), yes I am the happy owner of a R2 I bought from KangaUS a century ago. But Hans's approach is something I would badly miss, if it would not exist.

As long as used mono-band, as long as used as a stand alone build (i.e. without a TX on it's side) things remain tidy. But as soon as you attach it to a U3S and as soon as you think of multi-banding the joint, things get complicated. Not very complicated, everything has been nicely taken care of and all information is widely available at the qrp-labs site. But it is still of a rather complicated sort and trying to work trough a spaghetti ball of wires, I remembered KISS and that QRP is a state of the mind, obviously applying to the Rx path too.

So, I tried to make thing simple. NOT BETTER: there is no way of making things better than they are described on the qrp-labs site. But simple, simpler and better suited for my own purpose.

It concerns an U3S &  Rx Combo intended to work on 40m and above. The U3S has an Ultimate LowPass Switching Relay board.

And now let the genius speak: instead of using 6 LowPasess for the need cleaning the Tx signal from the U3S and 6 BandPasses for the Rx....

I use one HIGH-Pass that sticks into the Rx  Daisy-Chained with the inevitable LowPass of the U3S. The High-Pass is calculated and stays put for the lowest frequency of interest.  The Low Pass frequency is automatically chosen by the Ultimate LowPass Switching Relay card depending of the band in use.

This is by no means a betterment of any sort. Just a KISS shortcut that fits my needs and my bill. Take a look at the snap-shot attached (credit given to the filter-calculator from RFsim99): it shows the Rx path trough the  Daisy-Chained combination of a 40m HighPass (stuck into the RX) and the 30m LowPass chosen by the  Relay card. If higher bands are chosen, the bandwidth of the filter-combo resulting increases accordingly, because the low corner of the 40m HighPass that sticks in the Rx stays put where it was originally calculated to be. 

It works for me. The nasty QRM at my location does not come from above but from below 5..6 MHz. And because a direct conversion receiver does not know what a mirror image frequency is, I have nothing to fear coming from above.

Hoping it helps,
yours friendly, Razvan DL2ARL


Re: WARNING--availability announcement

Gregg Myers
 

On my iPad, I use the Kindle App which you can download from the Apple Store. I assume it is the same as on a Mac - just get the Kindle app. It is free. Once a kindle book is purchased, it can be re-downloaded to any other device which also has the Kindle App in your name, or a stand-alone Kindle device. If you purchase it from within an app, it defaults to the device you are using (as Jack mentioned) but it can be re-downloaded to any other device you have Kindle for free. The current page being read on a particular book is synchronized on the app no matter where you are reading it.

It’s actually quite easy. I find it a lot harder to describe than actually doing it.

Good luck,
Gregg W7GRM

On Thu, Aug 20, 2020 at 2:38 PM jjpurdum via groups.io <jjpurdum=yahoo.com@groups.io> wrote:
John:

I'm told that your Kindle account has a record of what you've ordered and if it's on a Mac, that's what is sent.

Jack, W8TEE

On Thursday, August 20, 2020, 4:13:16 PM EDT, John Baines via groups.io <jbaines=mac.com@groups.io> wrote:


Hi Jack,

will the Kindle version be readable on macs and pcs?

73
John
M0JBA


On 20 Aug 2020, at 21:09, jjpurdum via groups.io <jjpurdum@...> wrote:

All:


<Cover002.jpg>
(You may recognize Hans' QCX in the upper-right corner.) The book is written for readers who have zero programming experience and uses the (free) Arduino Integrated Development Environment (IDE). The code can be used with the Arduino Uno, Nano, ATMega2560, STM32F103 ("Blue Pill"), ESP32, and Teensy T4. A printed PDF version will also be available in a few days. I don't know the discounted price of the printed version but my guess is around $30. The Kindle versions is $10. The PDF file is just over 350 pages, with over 850 index entries to help locating things for you. I will post the TOC for this book on the SoftwareControlledHamRadio group.

This is NOT the ARRL Projects book that Al (AC8GY) and I wrote. That should be out in about 3 weeks.



Jack, W8TEE


<Cover002.jpg>


Re: QCX+ Internal RF Power meter set up question.

AA6CK/4 - Jim <hgcreek1000@...>
 

Thank you, Ron.  This is exactly the answer I was looking for.  Rather than make an assumption, its better to seek clarification for the reasons you've given.  73 de Jim, AA6CK.


Re: WARNING--availability announcement

Paul AI4EE
 

I have an app on my pc that lets me read my kindle stuff. I think I got it from Amazon.



On 8/20/2020 4:13 PM, John Baines via groups.io wrote:

Hi Jack,

will the Kindle version be readable on macs and pcs?

73
John
M0JBA


On 20 Aug 2020, at 21:09, jjpurdum via groups.io <jjpurdum@...> wrote:

All:


<Cover002.jpg>
(You may recognize Hans' QCX in the upper-right corner.) The book is written for readers who have zero programming experience and uses the (free) Arduino Integrated Development Environment (IDE). The code can be used with the Arduino Uno, Nano, ATMega2560, STM32F103 ("Blue Pill"), ESP32, and Teensy T4. A printed PDF version will also be available in a few days. I don't know the discounted price of the printed version but my guess is around $30. The Kindle versions is $10. The PDF file is just over 350 pages, with over 850 index entries to help locating things for you. I will post the TOC for this book on the SoftwareControlledHamRadio group.

This is NOT the ARRL Projects book that Al (AC8GY) and I wrote. That should be out in about 3 weeks.



Jack, W8TEE

<Cover002.jpg>


Re: WARNING--availability announcement

jjpurdum
 

John:

I'm told that your Kindle account has a record of what you've ordered and if it's on a Mac, that's what is sent.

Jack, W8TEE

On Thursday, August 20, 2020, 4:13:16 PM EDT, John Baines via groups.io <jbaines@...> wrote:


Hi Jack,

will the Kindle version be readable on macs and pcs?

73
John
M0JBA


On 20 Aug 2020, at 21:09, jjpurdum via groups.io <jjpurdum@...> wrote:

All:


<Cover002.jpg>
(You may recognize Hans' QCX in the upper-right corner.) The book is written for readers who have zero programming experience and uses the (free) Arduino Integrated Development Environment (IDE). The code can be used with the Arduino Uno, Nano, ATMega2560, STM32F103 ("Blue Pill"), ESP32, and Teensy T4. A printed PDF version will also be available in a few days. I don't know the discounted price of the printed version but my guess is around $30. The Kindle versions is $10. The PDF file is just over 350 pages, with over 850 index entries to help locating things for you. I will post the TOC for this book on the SoftwareControlledHamRadio group.

This is NOT the ARRL Projects book that Al (AC8GY) and I wrote. That should be out in about 3 weeks.



Jack, W8TEE


<Cover002.jpg>


Re: QCX+ Internal RF Power meter set up question.

Ronald Taylor
 

Jim, pin 2 of JP17 is the input to the RF power meter function. Pin 3 is the DVM input. You only use one at a time. If you are asking where the other end of the wire goes, it goes to whatever test point you are trying to measure. In the case of the RF power meter, the ONLY spot you should check with this is the RF output connector of the radio. All other points will give meaningless information. AND you must have a 50 ohm dummy load on the output at the time, both to make 50 ohm measurements (which are what it is calibrated to read) and to keep from destroying the finals. It isn't even a great idea to use the power meter to check output into an antenna because they are rarely close to 50 ohms resistive. Hope that helps ... Ron


On Thu, Aug 20, 2020 at 1:22 PM AA6CK/4 - Jim <hgcreek1000@...> wrote:
I did, but where on the circuit board does pin 3 connect to?


Re: WARNING--availability announcement

jjpurdum
 

John:

I'm new to this Kindle stuff, but it appears that it is readable on the Mac. I'll check on that and get back with the answer.

Jack, W8TEE

On Thursday, August 20, 2020, 4:13:16 PM EDT, John Baines via groups.io <jbaines@...> wrote:


Hi Jack,

will the Kindle version be readable on macs and pcs?

73
John
M0JBA


On 20 Aug 2020, at 21:09, jjpurdum via groups.io <jjpurdum@...> wrote:

All:


<Cover002.jpg>
(You may recognize Hans' QCX in the upper-right corner.) The book is written for readers who have zero programming experience and uses the (free) Arduino Integrated Development Environment (IDE). The code can be used with the Arduino Uno, Nano, ATMega2560, STM32F103 ("Blue Pill"), ESP32, and Teensy T4. A printed PDF version will also be available in a few days. I don't know the discounted price of the printed version but my guess is around $30. The Kindle versions is $10. The PDF file is just over 350 pages, with over 850 index entries to help locating things for you. I will post the TOC for this book on the SoftwareControlledHamRadio group.

This is NOT the ARRL Projects book that Al (AC8GY) and I wrote. That should be out in about 3 weeks.



Jack, W8TEE


<Cover002.jpg>


Re: QCX+ Internal RF Power meter set up question.

AA6CK/4 - Jim <hgcreek1000@...>
 

I did, but where on the circuit board does pin 3 connect to?


Re: 10W HF Linear Amp Troubleshooting

ajparent1/kb1gmx
 

If your using the nanoVNA you have at least a 30DB (40 or more maybe needed)
Power attenuator on the amp output as the power will fry the NanoVNA.

Also if the nanoVNA is overdriven the gain reported (s21) will be
in error (compressed).

It's possible the BS170s are not being biased correctly.  The sources are 2.2 ohms
above ground so TX no signal you should see 8-15millivolts there.

For testing, the plots are on QRPlabs site to see.

The IRF510s should like they are being biased correctly.

I've built 4 so far for projects and as block amp on the bench.  
So I'm hard pressed to explain your problems.

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Re: WARNING--availability announcement

John Baines
 

Hi Jack,

will the Kindle version be readable on macs and pcs?

73
John
M0JBA


On 20 Aug 2020, at 21:09, jjpurdum via groups.io <jjpurdum@...> wrote:

All:


<Cover002.jpg>
(You may recognize Hans' QCX in the upper-right corner.) The book is written for readers who have zero programming experience and uses the (free) Arduino Integrated Development Environment (IDE). The code can be used with the Arduino Uno, Nano, ATMega2560, STM32F103 ("Blue Pill"), ESP32, and Teensy T4. A printed PDF version will also be available in a few days. I don't know the discounted price of the printed version but my guess is around $30. The Kindle versions is $10. The PDF file is just over 350 pages, with over 850 index entries to help locating things for you. I will post the TOC for this book on the SoftwareControlledHamRadio group.

This is NOT the ARRL Projects book that Al (AC8GY) and I wrote. That should be out in about 3 weeks.



Jack, W8TEE

<Cover002.jpg>