Forum Replies Created

Viewing 25 replies - 1 through 25 (of 74 total)
  • Author
    Replies
  • in reply to: Alexanderson Day 2024 #10642
    AlexanderSAQ
    Keymaster

    Hello!
    Great to hear that you are planning to come to World Heritage Grimeton Radio Station this summer.
    The 2024 Alexanderson Day will take place on Sunday, June 30th. The program for the day is not confirmed yet, but we will make sure to fill the whole day with interesting activities for all visitors. Please subscribe to our newsletter to stay updated: https://alexander.n.se/en/subscribe/

    Fredrik / Alexander association

    in reply to: Origin of SAQ Designation #10600
    AlexanderSAQ
    Keymaster

    Allen;
    The call sign SAQ was assigned in accordance with the 1912 International Radiotelegraph Convention. The 1906 Convention had specified that stations should be assigned call letters that “shall be distinguishable from one another and each must be formed of a group of three letters”, however no provisions were made for allocating call letter blocks among the various nations. Starting with the 1912 Convention, initial letters were allotted to the various signatories.

    Fredrik / Alexander association

    in reply to: Where were Morse code signals received? #10597
    AlexanderSAQ
    Keymaster

    Bill;
    From the antenna in Grimeton, the Morse code signals radiated in the form of electromagnetic waves, which followed the earth’s surface at the speed of light. A small portion reached Riverhead, a small village on Long Island outside New York, where receivers were housed in a small house. Here, the radio waves were converted into electric current, which was led into the RCA’s office on Broad Street in central New York.

    If the addressee was resident in New York, the message was printed out and the telegram was delivered to the addressee by telegram courier. If the telegram was to continue on the American continent, it would be further telegraphed, either by wire connection or by radio.

    You can read more here:
    https://earlyradiohistory.us/1922RCA.htm

    Fredrik / Alexander association

    in reply to: Who requested to transmit? #10596
    AlexanderSAQ
    Keymaster

    Bill;
    The SAQ transmitter was remotely controlled from the “Radio central” at the Swedish telecom office in Gothenburg, some 80km away from Grimeton.
    Telegrams arrived there from the government, from companies and from ordinary people. The messages was guaranteed to be conveyed to the US within 20 minutes, which was much faster than with a transatlantic cable, for example from Norway.
    There were four workplaces for transmission, where the contents of the telegrams were punched into perforated strips in special devices. The procedure was called punching and the devices were called perforators. In turn, the perforated strips were then fed into another device called a transmitter. In the transmitter, the information on the hole strips was converted into Morse signals, which were forwarded to Grimeton. There were two permanent telegraph lines which could be used for remote control of the SAQ transmitter and for service messages between the two stations. Typically, the transmitter was started very early in the morning at Grimeton and this was reported to Gothenburg, who then started the punched paper transmitter and directly controlled the telegraph relay on the SAQ transmitter, which sent out the messages into the ether. When there was no more messages, typically very late in the evening, the transmitter was shut down for a few hours until the next day’s telegrams.
    The signal between Gothenburg and Grimeton was driven by 48V batteries with the current limited to 30mA, which equals 1.5W. The current was permanent and the morse transmitter in Gothenburg reversed the polarity at “key down”, meaning that the signal relay at Grimeton was forced to open / close and was not depending on a spring. This allowed for very high speed communication, up to 450 characters per minute.

    Fredrik / Alexander assocation

    in reply to: 2024-12-24 Reception Reports #10594
    AlexanderSAQ
    Keymaster

    Gerhard;
    There is no exact transmission plan for SAQ but we always announce each transmission on our website and in our newsletter.
    You can sign up to the newsletter here: https://alexander.n.se/en/subscribe/

    Fredrik / Alexander assocation

    in reply to: Receive #10581
    AlexanderSAQ
    Keymaster

    Bill;
    The Alexanderson alternator was in fact designed to transmit both morse code and speech, however the unit at World Heritage Grimeton Radio Station in Sweden is able to send morse code only, this due to the antenna design. The energy in the antenna at resonance is much higher than the input from the transmitter. That means that there is a rise and decay time of some ten milliseconds on the antenna when keying down. This limitation in the antenna will allow only morse code to be sent.
    The Grimeton site did not have any means to receive the return signal from the transmission site at Rocky Point on Long Island, US. Instead a dedicated receiving station was located in the city of Kungsbacka, located some 50km north of Grimeton. This arrangement with two separate sites was made in order not to take any risks that the transmission should disturb the reception.

    Fredrik / Alexander association

    • This reply was modified 1 month, 3 weeks ago by AlexanderSAQ.
    AlexanderSAQ
    Keymaster

    Dear Ed,
    Thanks for your question.
    The Alexanderson alternator has a built-in automatic speed control system. From the high frequency generator, 64 individual tangles, each of them picking up the magnetic flux from the rotating disc, are each supplying 100V 30A to the magnetic amplifier, connected to the antenna. However, one of them is used as a feedback to a built-in resonance circuit, located behind the control panel. This circuit can control the feed current to a set of transductors, which each can adjust the supply voltage to the main drive motor. The speed of the drive motor is in direct relation to the generated magnetic flux, i.e. the transmission frequency. So the feedback signal from the Alexanderson alternator will allow for a very stable frequency, usually within +/- 10Hz.

    Fredrik / Alexander association

    AlexanderSAQ
    Keymaster

    Thanks Whitham for the link to the very interesting document by Elmer Eustice Bucher, describing the Alexanderson system.
    This document, together with many more rare and unique documents, can be found in our online library, available to our members.
    Link here: https://alexander.n.se/en/library/

    Fredrik / Alexander assocation

    in reply to: Why are the pump motors 3-phase? #10456
    AlexanderSAQ
    Keymaster

    Bob;
    Thanks for your question about the 3-phase motors.
    The 2-phase system was initially the most common power system in Schenectady NY, USA where Ernst FW Alexanderson worked and developed his alternator. When the 3-phase system later was taking over, General Electric and Alexanderson could not financially justify the redesign of the very complex speed control system from 2-phase to 3-phase and therefore kept it 2-phase for the main drive motor. However to change all the small drive motors for water cooling, rheostat circulation an so on, from 2-phase to 3-phase was an easy task.
    In the late 1890´s the Westinghouse engineer Charles Scott developed a three-phase transformer that allowed for easy conversion of 2-phase to 3-phase or the reverse.
    At Grimeton radio station we have a large 50kV – 2.3kV Scott-connected transformer in the external transformer building, which is supplying the drive motor with its 2-phase power. Inside the transmitter building there is a much smaller 2.3kV – 440V Scott connected transformer which will convert the 2-phase back to 3-phase for supply to all the small motors in the system.

    Fredrik / Alexander association

    in reply to: October 23rd test #10416
    AlexanderSAQ
    Keymaster

    Many thanks for your feedback on the today’s SAQ test transmission!
    Today was very special, as the transmitter has not been in operation for a few months, due to extended building maintenance.
    Additionally, during this period, we have made major service on the compensation liquid rheostat, cleaning it out and filling with new fresh water.

    There are two large liquid rheostats, filled with water and sodium carbonate, where the resistance can be adjusted by increasing or lowering the water level using a motor operated gate. The rotor of the main drive motor is wound three phase, and each lead goes to the start liquid rheostat, to three separate copper bars, from which a set of hollow tubes, with different lengths are mounted, hanging down towards the water level. When operating the gate from the control panel, the water level increases, more tubes will come into contact with the water, and the resistance between the three rotor phases will decrease, giving the motor more torque. At key down, a second compensation liquid rheostat is connected in parallel with the first, resulting in a lower resistance, giving the drive motor a good “torque boost” in order not to drop in speed when all the power shall go out to the antenna.

    As the compensation rheostat only is connected when the morse key is pressed down and as the actual load only can be determined when the alternator is connected to the antenna, we have been unable to refill the compensation rheostat with sodium carbonate until today. We use food grade sodium carbonate, with very low chloride levels.
    After some calculations, we filled 250g into the rheostat and started the alternator. We managed to get a good tuning of the drive motor speed but the compensation rheostat was at its upper max position, indicating that the sodium carbonate concentration was too low.
    So, we added another 50g, retuned the drive motor, added yet another 50g and made a final tuning of the drive motor.
    That was what you were hearing during those long tuning sessions today.
    After that we ran our “VVV VVV VVV de SAQ” message a couple of times to check that we got good speed stability and good power to the antenna.

    So, things look good for tomorrow’s transmission which we very much look forward to.

    Fredrik / Alexander association

    in reply to: CW or MCW? #10289
    AlexanderSAQ
    Keymaster

    Dear Jörg,
    Here’s a simplified description of how the morse code is created when transmitting with SAQ:
    The Alexanderson alternator is supplying a magnetic flux with the frequency 17,200 Hz, or 17.2 kHz via 64 separate windings, each delivering 100V and 30A, which is led to two separate transformers in the high frequency amplifier. 32 leads are going to the first transformer and another 32 leads are going to the second transformer.
    Each transformer then has 32 individual primary windings, each of them electrically insulated from each other.
    2000V is generated in the secondary winding of each transformer. The secondary windings from both transformers are connected in parallel and further connected to the antenna.
    However, there is also a third winding in each transformer, located between the primary and secondary winding. This winding can be supplied with 250V DC, 12A current (3kW), controlled by the morse key. When the morse key is up (no signal) the DC current is flowing through the third middle winding, reducing the amount of energy being induced from the primary to the secondary winding.
    At key-down, the current in the middle winding is blocked, and full power is induced into the secondary winding.
    So, at key-up there will be a very limited amount of energy going out into the antenna. The magnetic amplifier is simply “leaking” a little carrier wave, which can be detected if you have a sensitive receiver.

    In addition to the two transformers, there is a second system, also operated by the morse key, to alter the antenna resonance frequency.
    In the lower part of the “magnetic amplifier” two “transductors” are located. A transductor is a variable inductance, consisting of a primary winding for the AC and a secondary winding for DC, both placed around an iron core. The iron core works as an inductance for the AC winding, however when 250V 30A current is flowing in the DC winding, the iron core is magnetically saturated and thus reduces its inductance.
    The antenna is a resonant circuit with its resonance frequency set to 17.2kHz and the two transductors are connected inline with the antenna.
    This means that by key-up, the antenna is not tuned to the resonance frequency, due to the changed inductance in the two transductors.
    At key-down, the 250V 12A DC current is blocked, the inductance will be altered and the antenna will be in tune.

    Ernst Alexanderson invented this system, with all its components, to allow a relatively small DC current of 3kW to control a very large power of 200kW.

    Wikipedia is not reflecting the correct function and should be updated.
    The speed of the drive motor is very constant. The speed control system is very sophisticated and can be explained in a separate reply, if required.
    I hope this explanation will give you a basic understandning of how the morse code is created.

    Fredrik / Alexander association

    • This reply was modified 4 months, 4 weeks ago by AlexanderSAQ.
    • This reply was modified 4 months, 4 weeks ago by AlexanderSAQ.
    • This reply was modified 4 months, 4 weeks ago by AlexanderSAQ.
    in reply to: Question Antenna-Ammeter-Current at about 13:28 CET #10067
    AlexanderSAQ
    Keymaster

    Dear Jens,
    Sorry for late reply.
    The antenna current meter, located in the upper right corner of the control panel is an important tool in the process of tuning SAQ.
    The scale is between 0 – 200A, however it is logarithmic and really hard to read at 50-70A where we are today.
    We always try to get as much amperage out into the antenna as possible. On World Radio Day, Feb 13th 2023 we had about 60A on the meter which is just below our target 65A.
    The reasons to that could be many, weather, humidity, temperature, and of course, our own skills.

    Tuning SAQ is a matter of keeping the main drive motor at a very constant speed, both at key-up and at key-down. The speed of the drive motor will directly determine the transmission frequency. There are two large liquid rheostats, filled with water and sodium carbonate, where the resistance can be adjusted by increasing or lowering the water level using a motor operated gate. The rotor of the main drive motor is wound three phase, and each lead goes to one of the liquid rheostats, to three separate copper bars, from which a set of hollow tubes, with different lengths are mounted, hanging down towards the water level. When operating the gate from the control panel, the water level increases, more tubes will come into contact with the water, and the resistance between the three rotor phases will decrease, giving the motor more torque. At key down, a second liquid rheostat will be connected in parallel with the first one, giving a good “torque boost” to the drive motor.

    Another aspect of tuning SAQ is to adjust the tuning frequency of the antenna, to exactly match the alternator frequency. This is done by operating an adjustable inductor coil at key-down and observing the meter for outgoing power to the antenna. Turn the inductor coil until maximum power has been reached. Don’t forget to keep an eye on the speed of the drive motor, so that tuning is done at the correct frequency.

    //Fredrik

    in reply to: Could not receive at 17.3 kHz #10019
    AlexanderSAQ
    Keymaster

    Sorry, you could not hear SAQ in WRD 2023.
    We do receive positive reports from New England, this time we have a positive report from NH.
    You can check out all received reports here:
    https://drive.google.com/open?id=18nSI0tfCQsxGJo9x7YA7tqBSHYopmGpU&usp=sharing

    Fredrik / Alexander association

    in reply to: “Rectifiers” at SAQ #10018
    AlexanderSAQ
    Keymaster

    Bob;
    The two DC generator sets for 125/250 V DC consist of two 125 V DC generators each and between these is an induction motor as the drive motor. These DC generators are self-magnetizing, that means they initially build up a voltage by means of remanent magnetism, and then the field winding receives its current from the armature winding. Some consumers need 125 V DC, e.g. relays for speed control and keying as well as the control motors for the antenna connecting switch and the variometer, and receives voltage from one generator. For objects that need 250 V DC, the two generators are connected in series. The magnetic amplifier, the field winding of the high frequency generator and the field windings of the 500 V DC generators use 250 V DC.
    Only one of these DC generators is in operation, the other is redundancy.

    The 500 V DC generator sets consist each of a 500 V DC generator powered by an induction motor. The only function of these DC power supplies is to supply control current to the four transductors that are included in the speed control and are connected in the drive motor supply lines. These DC generators receive their field current from the 250 V DC generators.
    Only one of these DC generators is in operation.Only one of these DC generators is in operation, the other is redundancy.

    Fredrik / Alexander association

    in reply to: Christmas 2022 Covid problem #9951
    AlexanderSAQ
    Keymaster

    Correct.
    Please see our homepage.

    Covid-19 stops SAQ on Christmas Eve morning

    Fredrik/AlexanderSAQ

    in reply to: Christmas 2022 Covid problem #9944
    AlexanderSAQ
    Keymaster

    Dear Keith,
    Sorry, but Covid-19 will prevent any activity on the Grimeton radio station.
    It is such a great disappointment but we have no other options.
    Kind regards,
    Fredrik/AlexanderSAQ

    in reply to: SAQ 16 november 2022 #9788
    AlexanderSAQ
    Keymaster

    Dear Jochen,
    We made some tests yesterday and everything went well.
    Information about today’s schedule you will find here:

    SAQ scheduled to air on November 16th, 2022.

    Fredrik/AlexanderSAQ

    in reply to: SAQ 16 november 2022 #9787
    AlexanderSAQ
    Keymaster

    Dear Jochen,
    We made some tests yesterday and everything went well.
    Information about today’s schedule you will find here:

    SAQ scheduled to air on November 16th, 2022.

    Fredrik/AlexanderSAQ

    in reply to: Supporting Masts Ground Grid Connection #9769
    AlexanderSAQ
    Keymaster

    Dear Marcus,
    Here are some details of the antenna:

    The top lines
    The antenna current is distributed over the antenna via eight top lines. These go from the tuning coil at the station building up to the cross arm of the first tower, then under the cross arms of the other towers, and finally down to the tuning coil at the last tower. The material in the top lines is phosphor bronze, which is sufficiently tensile to withstand spans as long as 380 meters. The top lines are suspended in 2.9 m long insulators.
    (Originally there were twelve top lines. These were equipped with so-called break couplings, which had a dual purpose. They would break and let the lines fall down in the event of a large ice load or strong winds, partly to protect the lines from breakage, but also to protect the towers from extreme loads. However, the breakage couplings broke awkwardly often, and after a major cable race in the late 1960’s it was decided to remove four of the top lines, thus reducing the load on the towers so that the breakage couplings were not needed to protect them, and the breakage couplings could be replaced with fixed suspension. the problems with the top lines have been greatly reduced since then.)

    Radiant parts of the antenna
    Only vertical polarization works for long-distance connections. Therefore, useful radiation occurs only from elements that have a vertical component. From each of the intermediate towers, a conductor goes down to the ground almost vertically, and it is from these conductors that the radio radiation takes place. In addition, the ups and downs at the end towers are radiating. Between the towers, the top lines have no radiant function. On the other hand, the top lines act as capacitances in the oscillation circuits of the antenna.

    The oscillation circuit
    A capacitance and an inductance together form an oscillation circuit with a resonant frequency which is determined by the magnitude of the capacitance and the inductance. The capacitance in Grimeton’s antenna is formed by the top lines that make up one “plate” in the capacitance and the ground plane that make up the other “plate”. The capacitance of the antenna is about 47 nF. The inductance is mainly formed by the six tuning coils. The resonant frequency, i.e. the desired transmission frequency 17,200 Hz, is affected by adding on more or fewer turns on one or more of the tuning coils. Fine adjustment takes place with the variometer (variable inductance) inside the station building.

    Tuning coils
    The six tuning coils have a considerable format, about 1.8 m high and 2.7 m in diameter. They are set up on concrete foundations. The inductance of each coil is about 0.01 Henry.

    Ground line network
    An important part of the antenna is located below the earth’s surface. Along the entire length of the antenna, copper conductors are buried across the longitudinal direction of the antenna. These conductors reach about 250 m on each side of the antenna centerline. The distance between the copper conductors is normally about 6 m. Near the towers and the tuning coils they are denser. The copper conductors are interconnected about 100 meters from and on each side of the center line.

    Balance network
    To achieve good ground contact, each tuning coil is connected to the ground line network in 14 points. This is done via the so-called the balance network. This consists of conductors that are hung in wooden poles about 4 meters above the ground. The balance network branches out from the tuning coil to seven connection points on each side of resp. tower. The connection points are located 100 meters from the center line of the antenna and the distance between the connection points is approximately 54 meters. Thus, the ground current is evenly distributed to the ground line network along the entire length of the antenna.

    I hope this will give you an idea of how the antenna works.

    Fredrik/AlexanderSAQ

    in reply to: SAQ 16 november 2022 #9768
    AlexanderSAQ
    Keymaster

    Dear Job,
    Yes, we have finally got everything in place for a transmission on November 16th.
    Please read more here: https://alexander.n.se/saq-scheduled-to-air-on-november-16th-2022/

    Fredrik / AlexanderSAQ

    in reply to: Antenna Conductor Details #9702
    AlexanderSAQ
    Keymaster

    Dear Marcus,
    A phosphor bronze wire consists of 7 strands, each 2.5mm in diameter, twisted into a helix, forming a rope.
    The vertical radiator in tower 2-5 is made from six thinner phosphor bronze wires, see image https://commons.wikimedia.org/w/index.php?curid=1296820, separated by a metal ring, 250mm in diameter.

    Fredrik/AlexanderSAQ

    • This reply was modified 1 year, 4 months ago by AlexanderSAQ.
    in reply to: Antenna Conductor Details #9700
    AlexanderSAQ
    Keymaster

    Dear Marcus,
    The antenna top distribution net is made from 8 pcs 7×2.5mm phosphor bronze wires. The 8 wires are mounted on isolators, hanging down from the top support structure. The sag between each tower is approx. 17m, depending on the temperature.
    At each tower, there is a tuning coil, made from litz wire, 1.8m in height and 2.7m in diameter. On tower 1 and 6 the coil is located were the top network is going up/comming down. On tower 2-5 the tuning coil is connected to a near-vertical lead, connected to the top distribution net.

    Fredrik/AlexanderSAQ

    in reply to: Will there be a transmission on 24.December 2021? #9259
    AlexanderSAQ
    Keymaster

    Dear Alex,
    YES!! – we are planning for a transmission on Christmas Eve, Dec. 24th.
    A brand new post (https://alexander.n.se/saq-scheduled-for-a-transmission-on-christmas-eve-december-24th/) on our website alexander.n.se will reveal all details.
    Looking forward to your report!
    //Fredrik / AlexanderSAQ

    in reply to: SAQ transmission on UN Day Oct24th 2021 (NOT FOR QSL) #9232
    AlexanderSAQ
    Keymaster

    Hallo Hans-Peter,
    Bitte hier einen offiziellen Bericht hinterlassen:
    https://forms.gle/PiyVsFuNZY1junuk8
    MfG,
    Fredrik / AlexanderSAQ

    in reply to: SAQ transmission on July 4th 2021 (NOT FOR QSL) #9208
    AlexanderSAQ
    Keymaster

    Dear Ricardo,
    Yes, we are planning for a transmission on October 24th.
    Startup of the transmitter will begin at 16.30 CET (14.30 UTC) and a message will be sent out at 17.00 CET ( 15.00 UTC)
    The entire event can be followed live on our YouTube channel here: https://youtu.be/f6cEm9A71g8

    The text to be transmitted is not published in advance, but this year’s message is composed by the Swedish human rights lawyer and sustainability expert Ms. Parul Sharma.
    Transmitted speed is usually close to 15 WPM.
    You can read more about the entire event here: https://alexander.n.se/saq-grimeton-un-day-transmission-on-october-24th-2021/

    Best of luck!
    Regards,
    Fredrik/AlexanderSAQ

Viewing 25 replies - 1 through 25 (of 74 total)

Subscribe!

Be the first to know about upcoming SAQ transmissions by subscribing to our newsletter.

No, thanks!