Signal Propagation

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Stanley
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Re: Signal Propagation

Post by Stanley » 12 Aug 2015, 03:45

What a splendidly esoteric post! Well up to OG standards. (I think I understood some parts of it.....)
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Re: Signal Propagation

Post by Tizer » 12 Aug 2015, 09:12

Fascinating stuff...I can hear Michael Caine's voice saying `not many people know that'.

There was some news in the last week or so about a British radio enthusiast managing to communicate with the International Space Station. Is it really something knew? I thought it had been done before.

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Re: Signal Propagation

Post by PanBiker » 12 Aug 2015, 11:18

Thanks for your comment Stanley, lots of ways to communicate using the various natural occurrences, aurora, meteor scatter, moon bounce, (yes some actually do that), not forgetting of course some man made methods, the OSCARS, Orbital Satellite Carrying Amateur Radio. Radio amatuers have built dozens of satellites over the years and had them deployed as secondary payloads on commercial launches. The Russians actually deployed six amateur robot satellites by opening the door of an orbiting Soyuz and chucking them out at predetermined deployment points around the earth. This ensured that one or more were always accessible from anywhere on earth at any given time. That was back in the 1980's, amateurs now have digital "funcube" satellites deployed to play with along with the more conventional orbiting repeater talk through types.

To answer Tizers question, yes it has, many times before. From the ISS point of view it can only be done if there is a crew member onboard who is a licenced radio amateur. They will schedule contacts or call during their rest periods.

I had the pleasure of contacting Dr Owen Garriott who was the first American to operate amateur radio from space during his 1983 STS-9 Space shuttle mission. He was a seasoned astronaut by then having crewed Skylab 3 back in the 70's followed by a spell on Spacelab 1. I heard him calling on my 2m mobile transceiver I had in the car just as I parked up on the Main Street in Portpatrick. I had nipped down into town to get some bread, we were camping up on the hill at Dunskey Castle. STS-9 was on an overhead pass 250 miles straight above me, we exchanged signal reports and pleasantries, I have the confirmation (QSL) card somewhere.

Owen K. Garriott
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Re: Signal Propagation

Post by Stanley » 13 Aug 2015, 03:07

That figures.... pop out for some bread, have a chat with a man in a space vehicle, go back for breakfast....I told you it was esoteric....
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Re: Signal Propagation

Post by Tizer » 13 Aug 2015, 16:10

Well done with the Garriott contact Ian. It's amazing what you radio buffs can do!

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Re: Signal Propagation

Post by PanBiker » 17 Feb 2019, 10:06

Strangely enough, following on from my last post in here. My friend Kevin (M0XLT) sent me an image he had downloaded from The International Space Station celebrating the anniversary of the first NASA astronauts transmissions from the STS9 Space Shuttle, Dr Owen Garriott.

The ISS is currently conducting a series of SSTV (Slow Scan Television) experiments by transmitting a different image on each orbital pas of the station. I captured these two yesterday as the ISS made a couple of medium azimuth passes. The green noise bands are caused by fading on the signal. You can copy about 6 minutes of data on a fairly low azimuth path which equates to about 2.5 data streams of the same image. You can hear it transmitting as it comes over the horizon and the first image may be only partial. There is about a one minute pause and then the transmission starts again. It takes about 90 seconds to transmit the full image. The Space Station transmits on 145.800MHz. SSTV is transmitted as a stream of audio tones and I use an application on my mobile phone to capture and resolve the image. You can get similar applications for the computer if you have your transceivers audio output interfaced as I do. I have downloaded a program for the PC and will give that a go at some point.

The first one celebrates the Curiosity Rover on Mars:

Image

The next pass sent this one featuring the Hubble Space Telescope:

Image

Not bad reception for only a medium azimuth pass from 250 miles altitude.
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Re: Signal Propagation

Post by Stanley » 18 Feb 2019, 03:46

I can remember when having a telephone was the peak of home technology..... I can see the attraction though but too late for me!
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Re: Signal Propagation

Post by PanBiker » 02 Apr 2020, 15:10

Stanley wrote:
18 Feb 2019, 03:46
I can see the attraction though but too late for me!
I will put this here, not beyond the capabilities of anyone that has an interest. Particularly with the structured licencing schemes that are in effect now.

How to become a radio amateur in the UK
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Re: Signal Propagation

Post by Stanley » 03 Apr 2020, 03:09

I have to concentrate my energies simply on functioning normally Ian, no spare capacity for anything new!
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Re: Signal Propagation

Post by PanBiker » 03 Apr 2020, 09:16

It's there for anyone else that may drop by the thread. The Novice licence is relatively easy to pass for anyone of average intelligence and allows access to all the bands with low power (10w). You can communicate around the globe at that power level with simple wire antennas. Full access to the bands on low power is there to nurture advancement to the higher, (Intermediate and Advanced) categories of the licence which many do as their interest grows in the hobby. Moving to a staggered licencing system has increased the number of active radio amateurs with the easier access.

When I did my amateur radio exam (RAE), it was a City and Guilds technical exam taken at college which once passed gave you "Class B" access to frequencies above 144MHz. You then had to gain proficiency in Morse Code to progress to the "Class A" full licence which then allowed you on the HF bands with more power. The reason for retaining the Morse qualification was that we shared some bands with maritime services and if a ship was in distress it would call for help using Morse code. Amateur operators were expected to be able to recognise this and respond accordingly, contacting the coast guard and other emergency services. The Morse requirement was dropped in 2003 I think it was, as maritime traffic is now predominately via satellite and other modes.
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Re: Signal Propagation

Post by PanBiker » 06 Apr 2020, 20:13

Further to my posts above about obtaining an Amateur Radio licence. For the duration of the coronavirus pandemic, the practical component of the licence exam, (which is normally checked by qualified members of local radio clubs or societies) has been suspended.

The upshot of this is that an individual can now attain a Novice Licence with just an online multi-choice exam.

I think that in the long run this may well become the norm for any of the categories of licence.
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Re: Signal Propagation

Post by PanBiker » 24 Apr 2020, 22:54

Back to signal propagation and a new digital mode I have been playing with for a couple of days. WSPR, (pronounced whisper) and as the name suggests its a low powered mode that has been developed specifically for checking propagation paths and signal strengths. The acronym stands for Weak Signal Propagation Reporter. It is designed to work at extremely low power levels which if successful contact can be made proves the viability of the path if using more typical higher power levels.

The mode is controlled by a data control program on the computer. My transceiver is linked to the computer using what is called CAT control and that I have described in another thread. It basically allows the transceiver to be controlled by the data control programs on the computer and visa versa, changes on the transceiver will be echoed in the computer program.

This new mode is an extension of existing data modes but configured for a specific task. The mode works on spot frequencies allocated for data use within each amateur band. It operates automatically between transmit and receive in two minute slots controlled by the system clock of the computer. It will transmit a low power encoded data signal that contains basic contact details, effectively time of transmission, station callsign, location (maidenhead locator reference) and power level. So a data block may be: 14.20 - G4LWG - IO83VW - 5w/37dB. During the two minute transmission slot it repeats this sequence with an invitation to other WSPR stations to reply. After the transmission slot the system switches to receive and listens for stations that have received your transmission which then reply automatically, results are recorded in a viewing screen in the program window and in a program log. There is provision within the program to report the contacts to an online database website it then displays them on a global map to show where your transmissions have reached. You can configure the application for unattended operation and automatic frequency hopping so it can send transmissions on various different bands. As propagation alters according to day/night effects, tropospheric and solar effects. The online display of where your low powered signals have been heard based on each band can show you where the best propagation paths are and which bands are open. The results can also be used to show how efficient a particular antenna system is.

I have had it partially working up to now but run into a configuration problem with the received audio stream. I can transmit my data but not receive at the moment. I have uninstalled the program restarted and re-installed with the same result so I reckon I have missed something in the various bits of hardware that need to be configured. I am going round in circles at the moment so have decided to leave it for a while and do another clean start after reading all the notes again.
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Re: Signal Propagation

Post by Stanley » 25 Apr 2020, 02:07

Didn't understand it Ian but it still fascinates me. :biggrin2:
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Re: Signal Propagation

Post by PanBiker » 25 Apr 2020, 17:38

Here's a bit more fascination for you Stanley:

I was having problems with the receive side of the data program so I uninstalled the whole job lot did a restart and then re-installed the pckage. I think this is where I slipped up before. I didn't do a restart after uninstalling and I thing the application held on to some damaged files. Anyway after re-installing and reconfiguring the input and out audio channels, I noticed I now had activity in the logging window. The first image shows this after running for about an hour on three different bands, 20M, 30M and 40M that is 14Mhz, 10MHz and 7MHz respectively.

Image

You can see some of the stations that my low power (5w) transmissions have reached on each band. You can also see that i finished my session on the 40M band (7MHz)

Contacts are known as spots as that is a good description of the protocol of the mode. As I mentioned they can be automatically loaded to a number of online database sites that plot them on a global map. I took a few screen shots of my results from each of the three bands I operated on and from two different mapping sites.

The first two show the 20M band (14MHz)

Image


Image


These two show the 30M band (10MHz)

Image


Image


The last pair are the 40M band (7Mhz)

Image


Image


You can see the difference in the propagation paths on the different frequencies. In the hour or so I was operation 20M gave the best results for distance where I reached Sao Paulo in South America and out to the West Coast of the USA. The bulk of reception in mainland Europe.

30M and the propagation paths alter slightly to the North and South. I have reached up into Iceland and down to the West Coast of Africa. The contacts to mainland Europe increase at the slightly lower frequency and extend further to the East just into Russia.

40M and lower frequency still and you can see many more shorter paths, some just in the UK and more to the nearer countries on the continent with better paths to the Southern Europe. I have clicked some of the contacts to show identification information. You can see that my signals were heard by a Short Wave Listener in Ireland (Eire).

All of these transmissions were at a power output level of 5W erp from my transceiver which is as low as it will go. Many operators use considerably lower power in this mode. My normal transmission power is 100W erp. Many others on the bands will use 400W (max for a UK Radio Amateur) and above for some of the continental stations.
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Re: Signal Propagation

Post by Tripps » 25 Apr 2020, 22:48

Nice mixture of the modern with the almost antique. Automatic QSL with none of that tedious CQ DX stuff - and all results logged and mapped. I'm impressed. Just think - contacting America from your back yard, with about the same power as an energy saving light bulb. :smile:

Wasn't there a vicar from Rochdale who used to do a column in Radcom on QRP, a long time ago?
Born to be mild. . .

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Re: Signal Propagation

Post by Stanley » 26 Apr 2020, 02:16

Morning David, I'm impressed. All I can do is note West coast USA and mutter "But not so much in the South I think....".
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Re: Signal Propagation

Post by PanBiker » 26 Apr 2020, 08:34

Tripps wrote:
25 Apr 2020, 22:48
Wasn't there a vicar from Rochdale who used to do a column in Radcom on QRP, a long time ago?
Indeed there was he died last year. He founded the GQRP Club and was a pioneer of low power communication.

Reverend George Dobbs G3RJV

RSGB Tribute

I met him at various Radio Rallies. I bet Sue's husband Bob would have known him.
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Re: Signal Propagation

Post by PanBiker » 26 Apr 2020, 19:40

Tripps wrote:
25 Apr 2020, 22:48
Just think - contacting America from your back yard, with about the same power as an energy saving light bulb.
With 5W erp and only 20m of wire. No multi element beams here. My chimney stack to a neighbours gable. :smile:

As an aside, I have the transceiver working via CAT control now so I can setup a schedule to operate for set periods on the bands I want to check and switch automatically between them. All good fun and a useful tool as we head up the slope to solar maximum when band conditions should improve across the spectrum. This will show the bands and paths that are open and should be workable for more conventional modes and contacts.
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Re: Signal Propagation

Post by Stanley » 27 Apr 2020, 02:51

The Rev. Dobbs..... Rochdale must have been where they sent the more eccentric clergy. I met one there who was a leading authority on orchids. He gave a talk one night at the Milnrow Lit and Sci. Fascinating man.
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Re: Signal Propagation

Post by PanBiker » 28 Apr 2020, 10:34

Most academics who study solar activity and space weather agree that Solar Cycle 25 will be starting about now or could be a little later in 2020 and should reach maximum between 2023 and 2026. Signs of increasing sunspot activity over some months in 2019 and earlier this year have been indicators that the new upward slope has begun. Increasing numbers of sunspots will have a direct effect on our ionosphere and will have increased propagation effects on the HF bands enhancing skip distances for radio transmissions.
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Re: Signal Propagation

Post by Stanley » 29 Apr 2020, 02:57

Will it affect Covid19?
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Re: Signal Propagation

Post by plaques » 29 Apr 2020, 07:46

Knowing nothing about radio signals but Tesla's free energy has always been at the back of my mind.

A couple of internet comments here.

From 1891 to 1898 he experimented with the transmission of electrical energy using a radio frequency resonant transformer of the Tesla coil, which produces high voltage, high frequency alternating currents. With that he was able to transfer power over short distances without connecting wires.

Since Tesla's day, we've known that it's possible to wirelessly send electricity through magnetic induction. ... And Tesla's dream of worldwide wireless energy is still alive. Japan's space agency is developing a solar-satellite that would beam power back to earth with microwaves.

Along with 'Earth Batteries' is free energy something we don't want to talk about?

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Re: Signal Propagation

Post by Stanley » 30 Apr 2020, 03:28

Certainly not by the energy companies P!
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