HAM’S LIFE

The rapid developing electronics field has a very close association with ham radio and I refer to other technologies to illustrate that the expediential advance in technology covers much more then just electronics.  It may be a stretch in the mind of some to link this with ham radio but in my thinking there is a connection.  

Saturday night I heard the last part of a radio talk show that apparently had a guest earlier in the show.  The guest, it would seem as I followed the call in discussion, believed that modern electronic technology came as result of a UFO crash in Roswell, New Mexico in July of 1947.  Now I can not prove nor disprove if a UFO crashed in Roswell or if any technology was learned from that craft if it did crash but I do not believe we need UFO conspiracy theories to understand modern technology advancements.

The Industrial Revolution is considered to have started around 1760.  Up to that time things did not change much.  When people wanted to go somewhere by land they walked, rode a beast of burden, or rode in some kind of wagon or cart drawn by such animals.  If they wanted to go by water they had to row or be wind driven.   Harnessed steam power change that.

The world started changing.  The change, sense that time, has continued to change at an accelerated rate.  Swifter means of transportation and greater productivity of factories prompted the need for faster and more efficient communications.

The word telegraph comes from Greek and means distant writing.  Though a few telegraph devices using electricity were developed prior to Samuel Morse’s telegraph but they died while Mr. Morse’s telegraph took root and grew.  The telegraph started the age of electronic communications in 1837. 

Just 40 years after Mr. Morse showed the world how to put messages on wire and send them long distances in a flash Alexander Graham Bell showed the world how to put the human voice on wire and send it over long distances. 

While the world of electronic communication was growing during 1800’s and early 1900’s other fields of technology also grew.  Accelerated development was happening in all fields Firearms, Electric lights, Internal Combustion engines, photography, and the list could go on. 

Nikola Tesla demonstrated a wireless telegraph in St. Louis, MO in 1893 but Guglielmo (Italian for William) Marconi made it to the patent office first with an economical and effective system that communicated more then just a few meters away.  It was 60 years (1837 to 1897) from when the first effective wire telegraph was patented until the first effective wireless telegraph was patented and it was 40 years from when the telegraph was invented until the telephone was invented but it was only 2 years from when the wireless telegraph was demonstrated until the wireless telephone was demonstrated.  1899 A. Fredrick Collins successfully made a voice transmission.

In 1906 Lee De Forest placed a grid in the vacuum diode and made it a triode he called an Audion.  The Audion had a little gain but it was not until about 1912   triodes with sufficient gain make an oscillator was able to be produced.  The vacuum tube was further developed.  It had more grids added and it was reduced in size.  Using the vacuum tube allowed transmitters to operate with a continuous wave (CW) on a specified frequency rather then the parasitic signal spread over a band.  Receivers could then use active devices rather then the passive units of prior days.    The little glowing marvel made it so that almost every home in the United States had at least one radio receiver in it by 1930.

In 1939 RCA released the AC/DC radio using the All American Five vacuum tubes and radios started appearing in several rooms in the home.  They could fit in packages small enough to sit on a book shelf, kitchen counter, or bed side night stand.  Soon many companies started selling these efficient, attractive, small, inexpensive, and very dangerous radios.  Compact battery operated vacuum tube radios were also being produced.  Automobiles with radios started showing up just after 1930.

By 1947 Television antennas were sprouting on the roofs of houses all across the United States. 

In 1925 Julius Edgar Liliendfield filed the first patent for a transistor in Canada.  The new transistor was very similar in operation to a Field Effect Transistor.  Because Mr. Liliendfield did not publish any research and his patent did not cite any examples of the device being constructed Oskar Heil was able to patent a similar device in 1934.

Though Bell Laboratories was not able to patent a working bipolar transistor prior to December of 1947 they had been working on the concept of a solid state replacement for the vacuum tube for several years before 1947.

Now all of this was prior to the events that happened in Roswell in July of 1947.

Looking at the technological developments that took place from the beginning of the Industrial Revelation until 1947 and noticing the accelerating advances in that technology and comparing it to the rate of acceleration sense 1947 personally I would say we are just about on target where we should be without the need of some extra-terrestrials technology input.     

There have been many changes in ham radio procedure over the years. I am not talking about law, though that too has changed, I am talking about operating practices. Establishing initial contact after a station has called CQ is one of changes.

When I got my license in 1960 calling CQ on 2 meters was standard practice but today CQ is rarely heard on 2 meters.

My first license was a novice class and the requirements by the FCC were that all novice class operators were to use crystal controlled transmitters with no more then 75 watts final DC input power. Being crystal controlled meant operators could not move the frequency of the transmitter to zero beat with the signal being received. A station may call CQ on 7173 KHz and another station with a 7170 crystal might answer. If the calling station just listened on frequency used to call CQ the answering station would not be heard by the 7173 station. After calling CQ the transmitting station operator would tune the receiver above and below the crystal frequency to see an answer was being given on a near by frequency. Even general class operators using VFOs would tune to listen for crystal controlled stations.

Today operating crystal controlled transmitters almost eliminates answering a station not transmitting close to the crystal frequency. This has produced a change in the process of answering a CQ. The recommended way of answering a CQ in 1960 was to send the call sign of the station that gave the CQ three times and then send the call sign of the station answering the CQ three times.

Making a contact might sound something like this in 1960: First the CQ was given, “CQ CQ CQ DE WA6OHP WA6OHP WA6OHP” which was repeated 2 times followed by “K”. The station answering would send, “WA6OHP WA6OHP WA6OHP DE K6KRL K6KRL K6KRL K” (K6KRL was my mentor Jim who is now silent key – this call has not been reissued).

Today calling CQ has not changed but when answering the CQ it is recommended the answering station give the call sign of the station being called only once followed by the sending stations call given three times followed by K. So it now would sound like this, “WA6OHP DE K6KRL K6KRL K6KRL K”.

I do not know when, how, or why KN became standard practice for turning the QSO back to the other station but after contact is established the ARRL recommends using KN in place of K. KN means “only the station being called should answer” and it is a way of saying “we do not want anyone else joining into our QSO.” Round tables QSO’s can be a lot of fun. I would like to see the KN eliminated except where special circumstances would warrant its use. It serves no purpose except where the stations do not want another person joining in and when used to replace K it eliminates stations the ability to indicate they do not want break-in.

When using voice replies to CQ the procedure is, for the most part, the same. The DE is replaced with “this is” and K is replaced with “over”. The phonetic alphabet to identify the answering stations call sign.

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“KN” is a single character and should be over-scored but I do not know how to do that on this computer.

Ramsey Electronics has several inexpensive easy to assemble electronic kits. Some are specifically amateur radio related and others are not. The QAMP20 is a 20 meter 20 watt linear amplifier. Being linear it will run CW, SSB, or AM. It can be driven with ½ to 2 watts with a power requirement of 12 VDC at 4 Amps.

Ramsey’s estimated assembly time is 4 hours for beginner, 2 hours for intermediate, and 1.5 hours for advanced builders. I did not time myself but I would say that their timing estimate is fairly accurate.

The instruction booklet, as with all their kits I have assembled so far, is very well done and can be followed by anyone even with no electronic knowledge.

Alignment is very easy. Basically it is just a matter of setting the bias.

The work horses of the amplifier are two P16NF06 MOSFET transistors. They are run in Push-Pull format so as to reduce potential second harmonic output. It has a 3 stage pi network low pass filter output to further reduce the harmonic output. The input and output to the transistor are both through ferrite wideband transformers.

The exciter input uses a T-R relay circuit which is operated by a simple diode detector to sense when RF is applied and a two transistors amplifier circuit to drive the relay. If the power switch is not on the relay will not actuate and thus the exciter can be run “bare foot” but when the power is on it will switch on as soon as the exciter is keyed.

When testing the QAMP20 I found that ½ watts in gave 5 watts out and 1 watt in gave 10 watts output. An IFR service monitor’s power meter was used for the test. The efficiency is about 30 to 35% which is about where a class AB amplifier should run.

Over all, with the exception of the plastic box to house the unit, I would give this unit a very high rating considering the cost.

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This amplifier is for sale on eBay: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=190189665379&ssPageName=STRK:MESE:IT&ih=009

The albatross is a large seabird which ranges widely over the Southern Ocean and in the North Pacific. They are among the largest of the world’s flying birds and when in flight they are as graceful as any bird can be but their take off and landings are a sight to behold. To get off into the wild blue yonder they run down the beach and flap their wings but because of nose dives resulting in feet over beak it frequently takes several attempts to succeed. Landings can also result in similar summersault type of maneuver. Thus they earned the name “gooney bird.”

The military transport plane C-47 which was the same as the civilian DC-3 also acquired the name “gooney bird.” The DC-3 was a very fine aircraft and many are still flying today so I do not know why they were call “gooney birds” but it was a name attached and used by those serving in the military at that time.

The yellow gooney bird was neither a bird nor an airplane. It was not able to fly at all under its own power. The yellow gooney bird was a ham radio transceiver produced by the Gonset Company in Burbank, CA. Gonset produced some of the Communicator II in yellow cabinets exclusively for the United States Civil Defense program. The Gonset Communicator II, like the albatross and the C-47, became known as a “gooney bird.” They were a very good AM 2 and 6 meter transceiver which was able to be operated on 6 and 12 VDC as well as 120 VAC. The transmitter portion was crystal controlled but the receiver was tunable across the whole band.

Though I speak of the radio’s operation in past tense there are many, as the one in the photo, still operating. Mine, as you can see, is not yellow but it is exactly like the yellow version with the only differences being it is gray and it does not have the red triangle with the letters CD inside.

Last year there was a television program called “Jericho.” . In an early program there was a gray Gonset Communicator II with the actors trying to figure out why it did not work. The answer was obvious to all who know this radio. Unlike most radios with the antenna port on the back this unit has its antenna connector on the top and the unit in “Jericho” there was no antenna plugged into it. So it is no wonder it did not work. A 19 inch whip on a PL-259 works very well on these units.

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Note: If you do not know code and you watched Jericho the code sent at the beginning of each program was real. It told the name of that evenings program title.

(Single sideband is superior to conventional AM for communications purpose; see this site post on 12/03/2007. Those who were trying to prove this said the carrier just went along for the ride and added nothing to the demodulation process but to provide a reference for the detector. The purpose of this post is not to bash the ARRL or any other group or individual but merely to question the accuracy of that statement.)

Going back to part one of this series when describing AM signal detection it was noted that there appeared to be a problem and in part two the problem with DSB being detected revealed more to the underlying question.

Consider the 4 MHz signal being modulated by a 1 KHz signal producing the two additional frequencies of 3.999 MHz and 4.001 MHz. When demodulated in a standard AM detector it will produce a 1 KHz output. As mentioned yesterday if the carrier is removed and just the two sideband frequencies are transmitted the receiver will have to remove one sideband and reinsert the carrier or distortion will be produced.

There is a frequency separation of 2 KHz between 3.999 and 4.001 MHz. If these two signals fed into a standard AM detector they would mix and produce a 2 KHz tone. If a 4 MHz signal is inserted the output will be 4 minus 3.999 and 4.001 minus 4 each equaling 1 KHz but there will still be the 4.001 and 3.999 MHz signals producing the 2 KHz signal so the output of the receiver will be a 1 KHz output plus a 2 KHz output.

An AM receiver does not require a lot of selectivity to detect a high quality audio signal. A crystal detector can be built with no front end separation and a strong AM signal can be received with pure clarity. The two sidebands do not interfere by beating against each other yet both are there at equal levels.

When an AM signal is produced care must be taken not to over modulate the modulated stage. Over modulation occurs when the modulated stage output is shutoff by the audio signal level. The carrier power is being increased and decreased at the rate of the modulating frequency which produces a modulation envelope at the output. When a carrier is reinserted in the receiver it is at a constant level and there is no modulation envelope there are just two signals one at a constant level and the other varying producing that unmistakable SSB sound excellent for communications but not something one would want to listen to music on.

While we are not allowed to transmit music many hams took pride in the broadcast like quality of their AM transmissions which is not possible with SSB.

So the ones who are saying that the carrier just goes along for the ride and is of no use may need to rethink their position

In part 1 of SSB VERSUS AM the fact that “All the necessary intelligence for communications is contained in just one sideband” of an AM signal was addressed. SSB is one sideband of an AM signal being transmitted with the carrier and other sideband removed.

The process of producing a SSB signal begins with a balanced modulator which allows the carrier to be eliminated by splitting the carrier signal into two equal parts 180 degrees apart. When the two parts are applied to the modulator’ because they are 180 degrees out of phase, one will be going positive while the other is going negative at the same level and the two carrier phases cancel each other out. When the modulating signal is applied it will not be balanced out so the two sidebands produced will be present while the carrier will not.

The resulting output of a balanced modulator is a double sideband signal with suppressed carrier. Each sideband will be a mirror image of the other. Double sideband is legal to transmit on the amateur radio bands and a few hams have experimented with it. When DSB is being received the receiver must remove the unwanted sideband thus creating a SSB signal and insert the carrier. If the receiver does not remove the unwanted sideband distortion will result. (The plot thickens.) By removing the unwanted sideband at the transmitter means that one half the power is transmitted and the bandwidth is reduced to a little less then one half that needed to transmit both sidebands.

Sometimes the undesired sideband is removed by a phasing method (see diagram above). That is the audio is fed into a 90 degree phase shift network so two equal signal with a 90 degree phase difference is produced each of which are fed to a separate balanced modulator. The RF oscillator frequency is fed to one balanced modulator directly and to the other balanced modulator via a 90 degree phase shift network. This process is a little difficult to visualize but it was used by the Johnson Viking people in the 1960s to produce a SSB conversion unit that could be used with the Viking Ranger, an AM transmitter, to produce SSB output. The phasing method allows the oscillator frequency to be used directly without mixers between the modulator and the output.

The second method is easier to understand because it uses a sharp cutoff filter following the balanced modulator (diagram above). The filter allows only one sideband to pass but if the transmitter is to be used on more then one frequency it must be passed through at least one mixer stage to produce the desired output frequency. Usually two mixers are used, one to change bands and the other to vary the frequency within the band.

During the days of transition from standard AM as the most popular means of transmitting voice communications on the ham bands to SSB replacing standard AM as the preferred method of modulation the argument was frequently heard that the carrier was just excess weight and just went along for the ride. There were cartoon illustrations one which showed three hams on their way to a ham picnic; two were much smaller then the third that was walking between the two and carrying nothing while the other two had all the food. The point of the cartoon was the largest of the three, the carrier, carried nothing.

Repeating for the third time “All the necessary intelligence for communications is contained in just one sideband” but does carrier just go along for the ride as still claimed by some today? That is a question which will have to wait until tomorrow.

Reginald Aubrey Fessenden is believed to be the first person to make a wireless voice transmission. Fessenden demonstrated the possibility of transmitting voice on December 23, 1900 by the process, which at that time was only a theory, known as heterodyne principle, the combining of two signals to form a third signal; he did that by using a spark-gap transmitter modulated by a carbon microphone, amplifiers had not yet been invented. His voice was heard over a distance of about 1.6 kilometers (one mile).

1907 Lee De Forest’s added the grid to the already existing diode vacuum tube to produced the triode tube he called an “audion”. The audion allowed for amplification. By the use of positive feedback in an amplifier the triode can be used as an oscillator. The oscillator made a single frequency continuous wave transmission possible. Amplitude Modulating the continuous wave signal with voice produced a far superior quality voice transmission to that provided by Fessenden’s spark-gap transmitter. FM did not come into existence until 1933.

The AM signal was and still is produced by the same principle Fessenden used in 1900, the heterodyne principle. A modulator is an audio amplifier which is connected in such a way as to control the output of a Radio Frequency amplifier. This will cause the two frequencies to be mixed together and produce not a third and a fourth frequency. When two frequencies are mixed together in a non linear circuit they will produce an output which will include the sum and the difference of the two frequencies. If a 4 MHz signal is Amplitude Modulated with a 1 KHz signal there will be a 4.001 MHz signal and a 3.999 MHz signal added to the already existing 1 KHz and 4 MHz signals. Because frequency difference between 4 MHz and 1 KHz is relatively large the 1 KHz signal is easily eliminated but 4 MHz and the two new frequencies, known as sidebands, are too close to be separated by conventional L/C circuits so there is a carrier of 4 MHz transmitted along with the two sidebands.

When received the signal is passed through a detector, a non linear circuit, which will allow the sideband frequency and the carrier frequency to mix thus producing a 1 KHz signal. (Do you see a problem? Stick with this series and see how the ARRL and other SSB advocates may not be telling the whole truth.)

When 100% modulation is achieved both sidebands combined equal one half the carrier’s power. So if a transmitter has 100 watts output un-modulated it will have 150 watts output when modulated at 100%. If the carrier and one sideband are removed the remaining sideband would be 25 watts. All the necessary intelligence for communications is contained in just one sideband. The audio is produced in the receiver as the sideband frequency is heterodyned against the carrier frequency or the reinserted carrier (BFO output).

Using the 4 MHz described above modulated at 1 KHz but filtering out all frequencies from 4 MHz and up only the 3.999 MHz, lower sideband, signal will be transmitted. Reinserting a 4 MHz signal at the receiver will produce a 1 KHz tone. If the carrier is modulated with a voice signal instead of a single frequency signal the principle will remain the same but multiple frequencies will be involved.

In AM if the operator speak softly so the carrier is only 50% modulated the power contained 1 one sideband will be 12.5 watts which means it will produce less output power in the detectors output and thus it is not as loud in the receiver’s speaker. It should also be noted that if the signal is reduced at the receiver either by reduction of transmitter power or by increasing distance the volume will be reduced.

How the carrier and undesired sideband are removed will be discussed tomorrow.

In 1960 Single Side Band (SSB) signals could be heard on the ham bands but standard Amplitude Modulation (AM) was still the most popular mode of voice transmission. There were arguments as to the value of SSB over AM (SSB is a modified standard AM signal). Quality of the sound was one major objection to SSB while cost and complexity of equipment for transmission and reception was another. But change was, and still is, inevitable thus SSB quickly grew to the point where it became the normal and AM (sometimes called Ancient Modulation) became the rare mode of communications.

SSB was first introduced by John Renshaw Carson when he applied for paten on 1 December 1915. The first recorded used of SSB was by the telephone companies starting in the 1930’s as a means of multiplexing (using a single carrier or in this case single pair of wires to carry multiple information channels simultaneously) telephone lines. Using a pilot frequency a carrier was established for each channel and the Upper Side Band was used to transmit the communications in one direction while the Lower Side Band was used to transmit the information in the other direction.

After WWII amateur radio operators began to experiment with SSB on the air.

Up to 1950 the United States Air Force bombers carried a radio operator to maintain communications. This meant an extra person, thus that much less payload could be carried and extra fuel was needed. It also required the operator to receive a message and passing that information on to the pilot or other crew member for whom it was intended. The reverse was also true; the radio operator took the message and passed it on to its intended recipient’s operator. With the advent of the B52 jet bomber communication speed needed to increase to accommodate the increased speed of the aircraft’s movement. The middle man, the radio operator, became the target for elimination.

Two Generals in the United States Air Force, General Curtis E. LeMay W6EZV and Lt. General Francis H. Griswold K0DWC, addressed this problem by placing SSB amateur radio stations in two B52 bombers. By this they were able to prove the improved quality of long-range voice communications. High quality long distance voice communications allowed the crew to communicate directly without a radioman.

For years after becoming a ham I asked why CW was called CW. The answer was always the same, “CW means continuous wave” but it is not continuous because by nature Morse code is made up of broken carrier or wave. When I continued with this line of thought again I would get a single answer, “I don’t know why.” Oh if I had just talked to a ham who had been one for long enough to have used a Spark Gap transmitter I would have received my answer.

The first wireless transmitters were basically nothing more then a voltage source, a coil, an arc or spark gap, a key, an antenna, and a ground. The coil was frequently a spark coil from a model T Ford. The transmitted signal was over the whole RF spectrum. Later tuned circuits were added which suppressed the RF signals generated above and below a given wave length but the output was still a very wide portion of the band.

Another problem with the Spark Gap transmitter was the signal would dampen out. The signal could not be sustained for a long period and thus the spark must be continuously interrupted and restarted. This meant a lot of noise but that was good because the receivers were only passive devices. They had no amplification just a detector and those early detectors were not all that efficient. Certainly they did not have a bfo but with the white sound produced along with the interrupt/restart frequency there was a sufficient noise in the signal to copy.

After Lee de Forest added a grid to the Fleming valve, now called vacuum tube diode, in 1906 he found it could be used to amplify a signal. This allowed the construction of the regenerative receiver and soon the audion, the name de Forest gave his triode, was also used to as an oscillator to generate the transmitted signal. The first ham stations using this new form of generating and detecting an RF signal usually consisted of a single audion being used as both the transmitter and the regenerative receiver.

The definition for Continuous Wave is a single frequency sustained at a constant level. If a carrier is modulated it will contain sidebands and in the case of FM not only sidebands but also the frequency of the carrier itself changes. Thus to qualify as CW it must be unmodulated. CW was also known as “undamped waves”, to distinguish damped wave generated by the Spark Gap transmission.

There were a few hams that experimented with trying to modulate spark gap transmitters but for the most part all wireless communications were by Mores Code.

Now the continuous wave could be sent but it contained no intelligence. To use it for communications it had to be interrupted into dots and dashes thus the true name for this communications was actually Interrupted Continuous Wave or ICW but the I was dropped and it became just CW, the necessity for the keying was understood.

There was a period of time where there were both CW and Spark Gap signals on the air. Those using Spark Gap usually had passive detectors and thus were unable to read the CW signals so amplitude modulation was added making it Modulated Interrupted Continuous Wave or IMCW which was shortened to MCW.

Now if someone asks you why radio Morse code is called CW you can tell them it is short for ICW.

A ham radio club in New Jersey held a meeting one evening where they had a special speaker talking about distress communications. As I sat listening to the repeater and working one of the hams that had been at that meeting started calling “Mayday” just trying to be funny. Either the speaker missed a very important part of his subject or someone was not listening when he did. Others came on and they were all joking around about the whole thing when I broke in and told them the little story that was in last weeks article here on Ham’s Life.

Distress calls are serious business. In the United States of America a false distress call can result in 6 years in a federal prison (the time has been decreased sense 1965) plus $250,000 in fines. On top of that some states, if they render state assistance, can charge the person making such a call for the cost to the state for responding and that can add up to several thousands of dollars.

That is enough threats now for some information about distress.

After Marconi revealed his invention to the world the shipping industry was quick to employ it on board their ships. Ships could communicate with land stations giving and receiving various bits of necessary information to improve the efficiency in transporting their load. The radio operators came from the most likely source, the land telegraph operators.

The railroad telegraphers and the message wiring companies had adopted a special code which was used to notify that this message was for everyone listing. It was CQ so when they went aboard ships they carried the same code. When in distress most operators would add a D to the end of CQ making it CQD. But there was no standard so others used DDD. There was some confusion so at the second Berlin Radiotelegraphic Conference 1906 the subject was discussed at length. The conference finally accepted that SOS would be the acceptable international distress calling signal.

Some think SOS was chosen to mean Save Our Soles, and others argue that it means Save Our Ship but the truth is it doesn’t mean either. The Marconi Yearbook of Wireless Telegraphy and Telephony, 1918 made it very clear with these words, “This signal [SOS] was adopted simply on account of its easy radiation and its unmistakable character. There is no special signification in the letter themselves, and it is entirely incorrect to put full stops between them (the three letters).” SOS is a single character not three separate letters (not … — … but …—…).

Voice communications became possible and this required a voice equivalent to the SOS signal. The French expression “M’aidez” (which means “come help me” though apparently not grammatically correct) was considered. The word took on a more English sound and thus became Mayday (one word).

If you are discussing a holiday which comes on the first of May you do not call it “May Day”. Someone who does not speak English may have no idea what you are saying but hear and recognize that word “Mayday”. Just don’t use those two words together on the radio unless there is a real distress.

Distress means eminent danger to life. My car won’t start and I need a tow is not a distress. My car is hanging over a cliff and may plunge over the edge at any time and I can’t get out is a distress.