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This 'Old Timer' asks: Why THE HATE for "FT8?"







"You have to grow with the times or the times will outgrow you." 

That is how my Music Director would sign off from his afternoon radio show back in the early 70's when I was Program Director at an AM radio station.

I never would have imagined in 1956 when I was introduced to Amateur Radio that one day as I left a doctor's appointment in 2024, I could carry a Ham Radio station in a small backpack and ride my bicycle less than a mile to a Parks on the Air site and communicate to other operators around the world. The only way I would have believed that back in 1956; is if I were sitting with Marty McFly in a Delorean and a plutonium-powered nuclear fission reactor with a Flex Capacitor traveling ay 88 MPH and set the date for March 14, 2024. 


March 14, 2024


You might wonder as why I mentioned my introduction to Ham Radio in 1956 and FT8 today. Well, in the early 1950's I remember Ice Boxes, not refrigerators. Ice Boxes. Several times a week The Ice Man riding in his mule drawn cart would stop by my neighbor and drop off a large cube of ice for their Ice Box to keep their perishables fresh.  It wasn't too long in the mid 1950's my neighbor purchased a refrigerator made at GE's Louisville's Appliance Park.




In the 1950's this "OLD FART"  remembers when telephones looked like this.


I even remember my phone number fro m the 50's, SPring7-8292.  There was no such time as an AREA CODE. You had to dial "0" in order to make a Long Distance Call.  There was such a time as a "Collect Call" and Person-to-Person Call". Also you could have a lowered monthly phone bill if you SHARED a phone line with another customer. These were know as PARTY LINES. Sometimes you might pick up the phone to place a cold and the other customer would be using it and you could listen to their conversation (NO PRIVACY). You had to wait until they finished to make you call. It wasn't until the early 60's, my parents changed over the more modern rotary phone, the mid 60's for the Princess and Trimline phones, mid 70's for the Push Button style phone and in the 1980's I found out my parents were sill leasing phones from AT&T. They were not pleased, I re-wired the three story home and installed cordless phone system throughout their house and cancelled their phone lease agreement with AT&T.




And finally I remember in early July of 1962 while spending my usual summer at my grandparents; my cousin and I sat in front of a Black and White TV and watched the launch of Telstar 1 Communications Satellite and a couple of weeks later watch the first international  satellite TV "LIVE" broadcast between the U.S. and Europe with Walter Cronkite, Chet Huntley and Howard Smith  U.S. newscasters.  

I do understand how some have a LOVE / HATE relationship with NEW technology and how it might infringe on them personally and individually. I guess you could blame a lot of this NEW technology on the Industrial Revolution. Maybe that's something to look at in a future blog. However when it comes to Amateur Radio I think I read somewhere about CONTINUATION and EXTENSION of the amateur's proven ability to contribute to the ADVENCEMENT of the radio art. Oh Yes, that's from FCC Rules and Regulations:      


PART 97—AMATEUR RADIO SERVICE

Subpart A—General Provisions

§97.1   Basis and purpose.

The rules and regulations in this part are designed to provide an amateur radio service having a fundamental purpose as expressed in the following principles:

(a) Recognition and enhancement of the value of the amateur service to the public as a voluntary noncommercial communication service, particularly with respect to providing emergency communications.

(b) Continuation and extension of the amateur's proven ability to contribute to the advancement of the radio art.

(c) Encouragement and improvement of the amateur service through rules which provide for advancing skills in both the communication and technical phases of the art.

(d) Expansion of the existing reservoir within the amateur radio service of trained operators, technicians, and electronics experts.

(e) Continuation and extension of the amateur's unique ability to enhance international goodwill.


My fellow FT8, CW, SSB, POTA colleague Robbie W1RCP goes a little more in depth in his YouTube Video: "Why the HATE for FT8?"


  

I remember the years I would lug my Ten Tec Omni along with a manual tuner along with a heavy marine battery and throw a wire into a tree for some portable operating in a park.  Today in 2024, I'm unwilling to go back in time on Marty McFLy's Delorean and operate in that manner

NOW, I can pack my entire digital station (QRP Labs QDX, Tufteln Linked EFHW antenna, battery, SotaBeams 10m Travel Mast, Bluetooth Keyboard, GPS Dongle USB cable and Panasonic FZ-G1 Toughpad into a standard school backpack and off I go to a POTA site which is less than a mile from my doctor's office.






              


For me the successful launch and operation of Telestar 1 in 1962 was an event more far reaching than Sputnik.  As a pre-teen, I felt I  understood the role satellites would have on communications in the future. I now can say my understanding was minuscule.  I could never imagine in 1956 or 1962 the HUGE role technology plays in our everyday lives.

 
I can see how some may depict FT8 as pictured in the image below.


If you're one of those who operated WSJT-x in auto-sequence, then I will agree it is like "Watching Paint Dry".  There are times when I feel like Luke Skywalker telling R2D2 I'm taking over control of my X-wing Starfighter.  I'll move out of Auto-sequence often to complete a QSO especially since I operate a lot of QRP. I try to use the same sense of operating like I SSB and CW. I'll move slightly off frequency to bee better heard, I'll move away for a few minutes to let the pileup subside, definitely find a clear frequency to transmit and move if necessary, send an occasional personal 73, tune up on an open frequency and send QRT when finished. 


There's so much hatred for FT8

 
Living in an apartment has its limitations as far as what type of antenna I can use along with high local noise levels.. Because of that, (and before I discovered POTA) FT8 was my primary mode of operation. In 2019 when band conditions were not all that GREAT as compared to now, I was able to enjoy our hobby immensely. Was it a mode I had been accustomed to? No! But it did allow me to operate. 

For me, FT8 open the door to another avenue of Amateur Radio.  As a result I've delved a little deeper in Weak Signal Propagation. I'm amazed how far a WSPR signal can reach with only 200 mW. 

So HATE FT8 if you like.  Like Telstar of 1962 , You never know what path FT8 (WSPR) may launch humans to in the next century.  Here's an example of what might be in store for WSPR. Read on .....
  
In May 2021, aerospace engineer Richard Godfrey suggested examining historical WSPR data as a way to define the flight path of Malaysia Airlines Flight 370 on 8 March 2014.[7] In November 2021, Godfrey stated his belief that his analysis indicates the aircraft flew in circles for around 22 minutes in an area 150 nautical miles (280 km; 170 mi) from the coast of Sumatra before vanishing, later proposing a search area centered around 33.177°S 95.3°E.[8][9][10][11]

As of March 2024, the validity of Godfrey's claim is yet to be established.[12] On 6 March 2024 the BBC documentary Why Planes Vanish: The Hunt for MH370 examined Godfrey's claim and reported that scientists at the University of Liverpool were undertaking an analytical study of the possibility of using WSPR technology to locate the missing aircraft. The University stated they would release their results within 6 months





                                                  


EA8/LA3ZA April 2023

21 May 2023 at 18:36

This was a fun holiday operation from the island of Tenerife with 2.5 - 4 Watts running digital modes, mostly FT8 and some FT4 using a low-band and a high-band QDX.

The best bands were 30 m (29%) and in particular 10 m (65%) with a lot of contacts across the Atlantic ocean as the picture shows. In total 62 different entities/countries were contacted. 

QSL via Logbook of the World.


3 tips for not blowing the finals of the QDX transceiver

28 April 2023 at 16:49

I have now used both the low- and the high-band QDXes daily as EA8/LA3ZA for a period of two weeks without destroying the four BS170 final transistors. Here are some procedures and tips.

But first, I do actually have experience in blowing the finals. That happended under testing prior to leaving, and all it took was 9.5 Volts for my 9 V build and what I thought was a dummy load, but which might have been an open circuit load. One BS170 developed a short between drain and gate with the result that 9.5 Volts was passed directly into the outputs of the driver IC5, 74ACT08, so IC5 blew as well.

My three tips for avoiding such failures are:

1. Use a reduced power supply voltage for tuning

I reduce the voltage from 9 to 7 Volts during tuning. as shown in the first image. That greatly reduces the risk of getting too high voltages over the BS170s.


2. Use a current limited power supply

The image shows a limit set at 1.3 Amperes. That reduces the risk of overheating, should the current for some reason rise more than expected.




3. Use Zener diodes to protect the final transistors

This tip comes from many of the transmitters designed by KD1JV over the years and consists in connecting Zener diodes from drain to source of each pair of PA transistors. The Zener diodes will conduct if the voltage exceeds a voltage somewhat less than what the transistor is rated for, 60 Volts, and protect the BS170s. 

I use 1N4756A, 47 V, 1W. I  measured power output before and after fitting them and could not detect any change from 80 m to 10 m. 

I have accidentally transmitted with full power into an open-circuit load after I fitted the diodes, and the QDX was just fine afterwards. I doubt that that would have been the case without the Zener diodes.

I cannot guarantee any adverse side effects of the Zener diodes, but my experience is that both the QDXes have worked flawlessly over the last few weeks, with plenty of contacts in South and North-America as well as in Europe. Those contacts have primarily been on 10 m (high-band QDX) and secondarily on 30 m (low-band QDX).

The image shows how the Zener diodes are fitted on the underside of the printed circuit board of the Rev 4 PCB of the QDX.

QDX Twins 80-10 m

18 February 2023 at 22:15
My QDX twins from QRPLabs: 

  1. On top, the high-band version, 20-10 m, with a revision 4 PCB
  2. In the bottom, the original 80-20 m version with a revision 3a PCB
Both have been assembled for 9 Volts operation nominally.

My wife and I have identical twins in real life and at times one of the ways to distinguish between them was by different colors. Here it is the same, so the high-band QDX has a yellow LED and the low-band one has a green LED.

QDX with voltage regulator

31 December 2022 at 16:02

Here's my low-band (80m - 20 m) 9 Volt QDX with a voltage regulator. Its only modification is a green rather than a red LED, as I don't like red LEDs to indicate anything but error conditions. 

The power amplifier of the QDX has hardly any built-in protection and can be ruined if run at full power into a poorly matched antenna. It will also easily be ruined if run at a higher voltage than the 9 or 12 Volts one may choose for at build-time.

A recurring theme on the QRPLabs discussion list is how to feed it with the right supply voltage. My solution is an "ZK-4KX CNC DC DC Buck Boost Converter CC CV 0.5-30V 4A Power Module Adjustable Regulated power supply" from AliExpress as shown in the image. It can take any DC voltage between 4.8 and 30 Volts and convert it up or down to the desired value.

I turn it down to 7 Volts for manual tuning of the antenna and up to 9-9.5 Volts in order to achieve near 5 Watts output. If I exceed 10 Volts, the power module is set to turn itself off.

QDX on 17 and 15 m: Receiver

26 August 2022 at 11:46

I got myself one of the marvellous digital transceivers from QRPLabs recently: The QDX - QRPLabs Digital Transceiver. It is set up with receiver bandpass filters and transmitter lowpass filters for 80, 40, 30, and 20 m. It has also been found that the 40 m filters work well for 60 m. 

The latest firmware, version 1_04, has a new "Band Configuration" screen where one may configure the list of supported bands. It is the intention that higher bands will eventually be supported.

I am not so interested in 80 m, so I wanted to see if I already now could get the receiver to work on 17 m and 15 m. With reference to the schematics, I modified the input filter's inductor, L12. 

It is tapped at 19, 30, 36, and 41 turns for 20, 30, 40, and 80 m respectively. It resonates with input capacitors C28-C31, with 22, 30, 56, and 220 pF respectively. 

I gave the inductor 36 turns, omitting the extra turns for 80 m, and then tapped L12 after 13 turns. I also also changed C30 to 15 pF. That give me the  bandpass characteristics shown below, as analyzed with the built-in analysis function of the QDX:


The filter peaks at about 19.5 MHz and is about 2 dB down at 18.1 MHz and about 7 dB down at 21 MHz. It seems to work well, and in my first tests, it receives FT8 well on both bands. 

Here's a new sweep with firmware 1_05_002 (beta) which uses colors which are easier to read:




And now the next thing to do is the transmitter's lowpass filter for 17/15m, which is a bit harder.

QDX Revision 3 Build Begins in REAL TIME

1 July 2022 at 02:16

Hey everyone- been a busy few months lately. Between bad health, travelling, and then working hard just take care of Live Stuff, I’ve hardly had time for the Ye Olde Blog! I’ll try to write more regularly. A lot of my attention has been going to YouTube and in this series, starting with the video …

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The post QDX Revision 3 Build Begins in REAL TIME appeared first on MiscDotGeek.

QDX Down! Understanding and Preventing QDX Revision 1 Failure

19 March 2022 at 21:16

The QRP Labs QDX is an incredible piece of radio engineering, but the first revision had a flaw that ultimately destroyed a some of the Revision 1 radios. To be clear: Unless you bought out of the first batch of 500, this does not apply to you. The second and upcoming third batches do not …

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The post QDX Down! Understanding and Preventing QDX Revision 1 Failure appeared first on MiscDotGeek.

FT8CN and the QDX

 

 

It is being reported on the QRP Labs forum, that some have got the little smart QDX digital transceiver communicating with the FT8CN app.

The rig is noticed straight away by FT8CN using an OTG USB lead and a minimum of configuring. 

The QDX and a small phone or tablet, allow true FT8 portable operating with minimum hardware to cart around.

Pick up the thread here

Details about the QDX https://qrp-labs.com/qdx.html

   

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