Category Archives: CW and QRP

Information related to CW and/or low-power or QRP operating and equipment

The Secrets of CW

This is a summary of an interesting take on Morse Code. The author has some interesting takes on learning cw! I never thought about ‘Sleep Learning’ CW. Also I agree: one should become proficient at the straight key before moving on. Also the comparison of how typists learn is good…

CW-HELLO-WORLD

THE SECRETS OF CW by Frank Merritt, VE7FPM

Many CW Amateur Radio operators never get beyond the very elementary mode of operation. In dealing with this fascinating situation it is necessary to go right back to the beginning with operating CW. In the beginning many operators just don’t like CW. We humans are individually programmed. The CW operators in-training used the punching bag to relieve the tensions of learning CW all day. Experimentally it was found that if a radio receiver was tuned to an RTTY signal the CW trainees would be gone in less than two minutes. The CW trainees were used to the random rhythm of CW and found the repetitive nature of RTTY to be very disturbing. The very nature of the CW signal was incompatible with the RTTY signal.

The very interesting feature of this tale of subliminal conflict is that the sound of RTTY was familiar and acceptable to me but not those students of CW. Years later when I was studying CW to prepare for my Amateur Radio examination I found that as I accepted the rhythm of CW I no longer had any difficulty in learning CW. Those trying to learn CW virtually always have a mental block or pre-conditioning that causes a conflict when learning it. How many times have we heard prospective Hams say that “learning CW is just too hard”.

The manner of dealing with this deep-seated emotional feeling is amazingly easy. When learning CW it is necessary to condition the mind to accept the rhythm of CW. A source of random CW is required that can be varied in both speed and volume.

What is new is the way that the CW practice unit is used. By playing the random CW at a low audio level it is just barely perceived by the brain. Periodically change the selection of the random CW text. Make no attempt to recognize the CW characters. Sleep teaching? If using the unit for sleep teaching be sure that if you use a pillow speaker the level is very low. Years ago I jammed an old record player to continuously repeat a record and then used a record with random CW characters. The second problem was found to be that eventually the brain has the capability of memorizing an amazing length of random CW. Hence it is desirable to be able to select one of a number of random CW offerings.

morse_code_poster-Small

It will take time and perseverance. Little by little you will be able to notice an improvement with the ease that you hear and remember CW. Along with this practice it is wise to use a newspaper as a source and gain practice sending CW. In sending code the greatest emphasis should be placed on sending PERFECT code. Use a straight key for this practice. Learn to send perfect characters and words using the proper spacing of one space between characters and three spaces between words. This term goes back to the early years of CW sending in which the short muscles of the wrist get tired and the operator just has to stop sending. Just keep the wrist muscles taut without strain and do no pivot at the wrist. In a matter of time borrow a Ham receiver and tune in to the CW portion of the band that seems to work the best for you.

First learn to send perfect CW with the hand key. It is a good training for learning to converse in CW with other noises within and without the car. Yes, there is still more to the mystery of operating CW. We now delve into the innermost byways of this interesting facet of Amateur Radio. The earliest forms of communicating intelligence by radio were by CW. The CW that we now use is a derivative of the land-line Morse communications. From CW the state-of-the-art progressed (?) to voice as with Amplitude Modulation (AM). There remained many operators who did not abandon CW in preference to voice communications. Many CW operators realized that there was something more to the International Morse Code than just memorizing the representations of the letters, numbers and punctuation.

Typists find that there are different levels of typing. As proficiency increases it is found that the typist can read a bit faster than the actual typing. As time goes by the typist notices that there is a mental translation that permits the eyes to provide the input to the brain resulting in typing without any conscious action. Again, as time goes by the typist finds that he/she is able to read the typed text and edit it for typing errors. This diversion has nothing directly to do with our premise of CW operation but indicates the power of the brain.

As time goes by in the practice of CW the operator becomes aware of small words at first that just “pop out” of the audio. The eventuality of this characteristic is that in a matter of time the operator finds that he/she is copying two to three words behind and that the word/words are mentally checked and corrected for errors.

morse

Each operator has what is called a FIST. In WWII this meant that radio intercept operators knew the fists of many of the enemy operators which provided a clue when the enemy moved units to a new location. It was quite common for the intercept operators to provide names for the enemy operators which sometimes were quite humorous.

Perfect hand key sending is beautiful to hear. Also, it is easy to copy! This leads us into the problems that arise in copying CW. It is not uncommon that under some conditions a relatively good code operator may not be able to copy well if at all. It is obvious that the goal of every operator should be to send perfect code.

To be sure there are countries that have developed somewhat unusual forms of CW but for the most part Amateur Radio CW operation is in English. The first contact of any operator is very challenging to deal with this new language of CW.

The other side of the coin of CW operations is that for most operators WORK is required to master the art of CW.   In all CW operations there is a desire for brevity. This is why a number of codes have been developed to express more complicated statements or questions in the form of three letters of the code in question. The Q-code designation of QTH stands for the geographical location of the sender or QTH? Efficiency of transmission is a consideration of CW operators. CW may be sent and received with a bandwidth of 500 Hz or less! Of course, the other side of this equation is that a good stable and selective receiver is a great advantage in operating with CW.

Operating with CW with a narrow bandpass receiver means that much undesired noise and the effects of other signals is just lost. This is a very great enhancement and makes CW operating much more pleasurable.

Operating CW is an art as much as anything else. Some think that CW will just fade away. It is somewhat unfortunate that effort is required to become a CW operator. As operators in general realize that there is something more than voice or digital communications they become candidates for the art of CW. Time will tell.

First Homebrew Contact on my Scratch Built BitX 20 SSB Transceiver

About a year ago I decided to build a SSB transceiver for making contacts with other amature radio operators on the HF bands.  I was given good advice from both Bill and Pete from the SolderSmoke Podcast  to start out with a direct conversion receiver then go with the BitX as a fist SSB rig.  I am very happy that they gave me that advice and I would agree that the BitX is not a good first project.

After getting all the proper adjustments made and confirming proper operation with a dummy load it was time to put this rig on the air (I don’t need a case)!   I tried calling CQ using SSB voice but no one came back.  I then decided to add some relays and other modifications to allow digital modes.

On January 15, 2017 at 21:46z I answered a psk31 CQ from Josh K1JOG in Kissimmee, FL.  Little did he know that he would be making history (maybe just for me) in my first home brew QSO.  Below is his eQSL card to me.

Thank you Josh K1JOG for the contact!

If you are interested in scratch building this rig you can follow the photo link  below:

BitX by Ashhar Farhan, VU2ESE

Ashhar Farhan also sells a BitX-40 at http://www.hfsigs.com/

The units he has built in India are almost ready to put on the air.  You build the case / box or just go open board style!  You can’t beat the $59 price for a rig!

Below are some photos of my project:

Mic amp on the left LM386 audio amp on the right

A good place to start is the Audio “end”.  I built mine using perf prototype board.  FYI the 10k ohm resistor on the mic amp needs to be 39k ohm for proper bias.

Balanced Modulator
Balanced Modulator

On the balanced modulator, I used a mystery toroid core because I have a bunch of them and they did not cost much!

10 MHz crystal filter

In this photo you can see some transmit and receive amplifiers and the crystal filter.  I built some test equipment and used a frequency counter to make a matched set of crystals.

Mixer circuit

The mixer circuit is shown here with some coax to the left that is from the VFO.

Original VFO design on the left. Filtered SI5351 clock generator on the right

You can see the benefit of building small modules.  With SMA connectors, I can quickly swap out the VFO “soul” of this rig!  No more drift with the SI5351 chip! I ordered mine from Adafruit. I added a small LC filter to the output to make a nice sine wave.  I am not sure it is needed.

Band Pass Filter by Pete N6QW

Now I had trouble with the original band pass filter.  I’m not sure why but a quick google search on 20m band pass filter and I found a replacement circuit on his website.  When I told Pete about this he sent me a new updated design to try.  My PTT relays are 5v so the small heatsink is for a voltage regulator.  I also included diode protection for the replays.

Irf510 power amplifier

The IRF510 is more of a switch and not designed for linear RF amplification but it is cheap and works great for QRP.  They have different bias requirements from one unit to the next.  That is why you carefully set the bias level with a trim pot.  The large heat sink was part of an old high power LED driver that died.  I used T37-6 toroid cores for the low pass filter on the right. The 2nd relay was needed to prevent the output of the IRF510 feeding back into the original PTT switch and back into a nasty loop.

I am not sure if this rig will ever get a case or future modifications but I do know that I would like to see if I can make more contacts with it.

I would like to end this article with a quote I very much like from a video with Rev. George Dobbs, G3RJV

“Radio construction is rather like a pilgrimage where the journey is often more important than the destination”.

73,

Mike,  AB1YK

Lawn Chairs on the Air!

When Nashua Area Radio Club President Emeritus Ed Deichler, K2TE, wrote an article about his attic antennas last year, he included photos of this Attic antenna layout. I spotted some folded lawn chairs stored up there and suggested he just open them up and load them as radiators. Evidently everyone just laughed it off.  Over the years I have experimentally loaded many items from wire hangars to entire automobiles as antennas and fed them. After all, a tuner will load your rig to practically anything!

Who does not have a couple of lawn chairs? Well, I assure you that the Lawn Chair antenna does exist! This is for the “I don’t have room for an antenna” challenged!

The K2MIJ (Shirley, NY) Lawn Chair Antenna – What started out as a lark has now turned into a serious endeavour. I am trying to Work All States running 5 Watts into a pair of folding aluminum lawn chairs as my antenna. Seeing how well things have gone so far, I am also going make a serious attempt at working DXCC! If you would like to help me reach my goal, check out http://www.qrpspots.com/   I will be self spotting when and where the “Lawn Chairs” will be!-  Modes: Phone (SSB) and CW – The Lawn Chair antenna is fed with a Yaesu FT-817nd @ 5 Watts, A 4:1 Balun, 6 Feet of RG8X Coax into an LDG Z11 Autotuner.

Lawn Chair DXCC Countries/Entities worked list – Hungary – Canary Islands – Germany – Sweden – Ireland – Poland – Czech Rep. – Russia – Wales – Spain – Trinidad & Tobago – Greece – Slovenia – Belgium – Cuba –  Puerto Rico – Canada – Bermuda – Croatia – Scotland – St. Lucia – England – Bonaire – Austria – Azores – Italy – Belarus – Jamaica – Martinique – Aruba – Slovak Republic – Isle of Man –  France -Antigua and Barbuda – Dominican Rep. – Turks and Caicos – Venezuela – US Virgin Islands -Netherlands – Ukraine – Lithuania – Sardinia – Serbia – Denmark – Portugal – Northern Ireland -Brazil – Morocco – Alaska – French Guiana – Grenada – Switzerland – Latvia.

A First Homebrewed Transceiver

I recently wrote an article about Nashua ARC’s 2017 Project Night (forgive my shameless self-promotion). In it, I expressed my awe of what our club members can do, and how it has inspired me to attempt my own first build.

The winter really is the best time to do this. And it’s time for me to embark on this journey of fun, learning, and frustration! So I turned to Mike (AB1YK) who knows about such things, since he and I are attempting to organize a future summer weekend Tech Build Event for the club. The Pixie and the DSO138 oscilloscope are the warm-ups for this main-event. One suggestion Mike threw out was a Direct-Conversion Receiver (DCR) as advertised in the January 2015 issue of QRP Quarterly which you can actually download here (and as far as the application to the Tech Build goes, perhaps we only build parts of the DCR given time constraints). This article is entitled Let’s Build Something: Part I by Ben Kuo (KK6FUT) and Pete Juliano (N6QW).

In it, they outline the main building blocks of the build. The nice thing about this build is once one is done, it is amenable to some modular alteration to turn it into a fully working QRP SSB transceiver! (Though I do not know how much wattage at this stage) The other nice thing about this build is all the parts are clearly labeled and Pete provides links at the end of the article for YouTube videos about the build. Maybe it’s just my noob eyes, but I find the videos moderately useful for someone starting from scratch, but I can see the utility for a more experience builder. Additionally, this build utilizes the Manhattan style of building. I find this optimal for someone just starting out because I can easily visualize all the connections between the components and have relatively easy access to make measurements and tests with probes.

Let’s go through parts and I’ll tell you what I know (at a cursory level) and what I don’t

  • 40m bandpass filter: Totally on this one. I’ve never built a filter before but looking forward to doing this. In fact I need to build one for my ADS-B antenna at 1090 MHz, but it doesn’t seem feasible to do from components at that frequency. Any ideas anyone? I’m kind of stumped.

  • RF amplifier: REALLY looking forward to tackling this one, but this won’t be the first thing I do. Makes sense to have for weak signals.

  • Double-balanced mixer: Now I know something has to knock the RF down to an intermediate frequency (IF) and when I see mixer, this is where my brain goes.  The double-balanced bit was foreign to me, but as advertised in the article (‘double balanced’ implies that the original signal and local oscillator frequencies are deliberately nulled out as part of the mixing process and do not appear at the output.)

  • Arduino Based Sample DDS: In order to even produce an IF, we need a local oscillator (LO). This is where the Arduino comes in. The authors argued they looked at a number of options for the LO including a VFO (variable frequency oscillator), varactor tuned oscillator (should know this from my Extra exam — but full disclosure — I can’t help you now), and a DDS (direct digital synthesizer). They felt the simplest option was the DDS (hence the Arduino).

  • Audio amplifier: We want to amplify the audio signal so we can hear it through our 8 Ohm speaker!

So now if you put all the components and modules together, you arrive at something which should look like:

I like this project for a few reasons.

  1. It’s a more interesting build and takes longer than 2 hours.
  2. It will have amateur radio applications in my shack. I do hope to work some pretty cool QRP with this rig (when I turn it into a full-on transceiver).
  3. I will learn A LOT about the electronic components integrated into the rig and be able to have an excuse to buy some test equipment.
  4. I get to work on my soldering skills.
  5. The modular design is attractive so that if I wish to make alterations in the future, it seems I will readily be able to do so without having to tear the entire rig apart.
  6. Understanding, at the end, how all of these parts function together to make my transceiver work. I look forward to sharing whatever knowledge I accrue during this build with future amateur radio hobbyists just breaking in.

I will certainly post articles as my progress commences. Currently, I am in the market to buy components and test equipment and will begin to build probably the simplest module first; currently that seems to be the filter. And I have learned a very valuable lesson from being in the club and participating in its activities that I am applying to this build. Initially do things to set yourself up for the highest probability of success so that you keep your morale, interest, and momentum high. Nothing is worse than diving head-first into the hardest part of a project and losing any and all ambition when things begin to not work (and they will…).

73,

Brian (AB1ZO)