Transatlantic Ham Radio question

[ADSWNJ]

Anyone out there into Ham Radio?

I'm curious if you can routinely get a transatlantic US <> UK/EU radio signal from normal (non-exotic) equipment, presumably bouncing the signal off the ionosphere. Is it a stable signal?

Theoretically - what would the optimal frequency be for this, if you could stomp on any radio channel you wanted

 

[Notebook]

Asked an old friend who has an amateur licence about this. Here is his reply

Interesting question, I never really got into 'spheric bouncing of signals although from memory it was always a 'hit and mis' business.
As far as reliable comms over long distances, using non exotic equipment, I would say short wave SSB for speech, using something like the amateur 20m band (14 MHz). I still have my Yaesu FT101B which can pump out 250W PEP on the HF bands, it's about the size of a small desktop computer. Given a reasonable aerial, I would say that I could get pretty much get 100% reliable comms with the USA at any time. Although under certain propagation conditions this can change, 'sun spots' for example. CW can give an even more reliable path, if anyone can still read it that is? You could always generate and decode it by machine, now there's a good project.
As to the optimum frequency there was a web site which gave this info on a daily basis.
I know some amateurs experimented with 'moon bounce' using gig frequencies, there is probably info on the web.

SSB is "single-side band" a modulation method. CW is "Continuous Wave, or Morse Code in old money.

N.

 

[ADSWNJ]

Asked an old friend who has an amateur licence about this. Here is his reply

[...]

SSB is "single-side band" a modulation method. CW is "Continuous Wave, or Morse Code in old money.

N.

Thanks N - that's fascinating. Did not realize that it was that solid a transmission path over such distances.

 

[Notebook]

No probs, I'll pass on your thanks too.

I don't think he is on the air much now, but I'll check. He had to learn Morse as part of his
licence(I think Marconi was on the test). Says he can still read Morse, but sending is another thing!

N.

 

[kuddel]

Hey ADSWNJ,

while also remotely interested in Ham radio (my farther also has a amateur radio license) I can say it's very interesting to listen to transmissions from all over the world.
Nowadays, due to the internet and SDR, it is quite easy for you to do such things.
Look at http://websdr.org where you can choose several locations which have installed web-based receiver setups which you can listen to.
For example you might try to listen at a station located near Enschede (Netherland)
http://websdr.ewi.utwente.nl:8901/ to see whatever transmissions you can pick up some transmissions. The antenna however is not "tuned" to be used for your special transatlantic case. It's generally just a "broadband" antenna to get "as much as possible".
There you can "tune" through the long-wave medium-wave or short-wave bands and listen to transmissions that are received life.

 

[dseagrav]

I am an Extra-class ham radio operator located in central Illinois. My personal bests are New Zealand and Poland using 50 watts power in the 10 MHz band, and central Russia using 80 watts power on the 14 MHz band (the signal went over the north pole rather than east or west). I forget what my southernmost contact is because there's so many of them - paths to South America are very reliable.

I have very modest equipment - My normal antenna is a basically just a long wire strung between two 16-foot 2x4s and a tree, and my backup antenna is a portable antenna raised on demand using a long aluminum pole. My entire station can be packed up for portable operation in one hour, takes about another hour to set up once at its destination, and I can operate for several days using what I have on hand at any given point. No special preparation is made or required. In fact, if there was a real emergency the equipment will outlast me - I will require dialysis long before I run out of communications capability.

 

[Notebook]

After chatting about the above posts, got a bit more from Les.

What-ho George,
 
RF is a funny old thing, very unpredictable, I used to use an old Pye 'Cambridge' when I first started going mobile on the 2mtr band. It ran 10 watts FM was crystal controlled on TX, but I had modified the receiver to be tuneable over the whole band (2 MHz). Most times I could chat to people up to 20 or 30 miles away, however one day during a 'lift' I put out a CQ call, and a bloke up in Leicestershire came back. We had unbroken comms for my entire journey from Teddington to Merstham, (my old gaff).
 
Not sure what an 'extra class' licence is in the USA, I have a class A licence which means I can operate on any band in any mode. Although I haven't been on the air for years, I still keep my call sign G4AVE. Quite a few people didn't want to study for the full licence, and so had a class B. This meant you could only transmit speech on VHF. I really struggled to convince the GPO that I could pass the 12 WPM Morse test.
 
Toodle pip,
Les  

CQ is a code used by radio amateurs, not only though. I used QSY when changing frequencies when I was doing my flying, I think.

https://en.wikipedia.org/wiki/CQ_(call)

N.

 

[dseagrav]

Extra class is the maximum privileges license class in the US, so analogous to the UK Class A (now called "Full License").

Long-distance propagation above 50 MHz is completely different from below; Above 50 MHz, signals are not refracted enough by the ionosphere to return to Earth. (As frequency increases, refraction angle decreases, and the waves miss the Earth on the far side.) As you approach around 100 MHz the angle decreases to effectively nil, and signals pass straight through. This is why all except the first few space communications attempts are VHF or above.

The 2-meter band is around 145 MHz, so the propagation phenomena observed by your friend was likely a tropospheric duct rather than ionospheric bounce.

I had to pass the 5 WPM CW test when I first got my license, but I haven't used it in ages; I really need to "knock off the rust" and get back into it at some point. The FCC has since eliminated the requirement to learn CW, but it remains popular due to its extremely good weak-signal performance.

OF-related sidenote: I once got yelled at by another ham for "abusing" the ISS. It has a standard type of digital repeater system you can send messages to and have them relayed back to Earth. On the east coast there is another system that can receive these standard messages and resend them via the internet as email. A friend of mine has a brother in grade school who is obsessed with all things NASA and space. I decided to send him an email via the ISS. As the message length is very limited, I sent "LOL, SPACE". (think lolcats). Anyway, this was apparently very offensive to someone, who insisted that some unwritten rule stated that all messages sent must be absolutely 100% serious, no fun is allowed, and threatened to report me to "authorities" if I did not apologize in writing to him personally and promise to never contact the ISS again.

I ignored him - Some people think they own the world. Never heard another word about it.

 

[Notebook]

Thanks for that dseagrav, I'll pass your points on to Les.
I think he misses the radio-days, it does take a lot of time, and it seems people you were in contact with, sometimes just go off-air. Probably a generation thing too.

I sometimes buy one of the UK radio mags if they have something interesting, usually related to the ISS amateur station. Shame some folk get all possessive about it.
Got the impression half the fun of ham-radio was the sense of community.

N.

 

[dseagrav]

Shame some folk get all possessive about it.
Got the impression half the fun of ham-radio was the sense of community

It is, and by and large the community is great - it's just that technology allows the jerks to be disproportionately loud. Anyone with Google and my callsign has immediate access to my real name and mailing address. Anyone who knows about the ARRL's member services could email me without having to know my "real" email address. Callsign is used as username on the larger ham radio forums so they can find and harass me there too. Since radio is a public resource there is no expectation of privacy, the federal government is required to make this information public, and this plays heavily into the hands of authoritarians and malcontents. As long as they don't use the radio itself as a means of doing so they can freely harass any number of people for as long as they are physically able.

Thankfully, time and tide seem to be working in our favor. Amateur radio licensing is at an all-time high, and the population is growing beyond the ability of theirs to harass. Most of the objectionable types are dying out or leaving the hobby as they fail to get the authority and attention they crave. As long as we don't create any more of them, the problem stands to solve itself eventually.

 

[Notebook]

Glad to hear its mostly a happy community, Les hasn't mentioned any unpleasantness, though I will ask him more about it next time I see him.
He did say his call-sign is public domain, so I guess its international.

I have noticed in the amateur magazines, they are trying to get more interest from schools and colleges. Trying to get the average down, I presume?

some of the letters pages have complained about "bad-behaviour", especially using "repeaters". Don't know why these should attract it? I'm guessing they do what they say, extend the range of your transmission/receive?

N.

 

[thepenguin]

Chiming in here:

Transatlantic communication isn't that hard. I've seen people do it at frequencies as high as 50MHz(6 meters) across the earth (during a contest, no less). If you're willing to bounce off the moon to do it, there's not really a limit to how high you can go.

Or, if you'd prefer a more traditional route and use the ionosphere, it's pretty reliable on SSB, CW, or any one of the various digital modes (JT65 and RTTY being common examples).

 

[dseagrav]

He did say his call-sign is public domain, so I guess its international.

Correct - Callsigns are internationally federated. Each government is issued a number of prefixes, and then issues individual callsigns out of their prefixes. Tail numbers in aviation work the same way.

I have noticed in the amateur magazines, they are trying to get more interest from schools and colleges. Trying to get the average down, I presume?

I assume you meant "average age", in which case yes. There is a strong public perception that amateur radio is an old and outmoded hobby, and that radio as a medium is obsolete. It is essential to the survival of the hobby and medium that we combat this perception, and involving the younger public is the best way.

some of the letters pages have complained about "bad-behaviour", especially using "repeaters". Don't know why these should attract it? I'm guessing they do what they say, extend the range of your transmission/receive?

Repeaters are common in the VHF and above bands. Since propagation above 50 MHz is largely line-of-sight, range of mobile stations is limited. The low power of a typical mobile station further limits it. A repeater is a strong central station installed in a high place (or with a high tower) which simply repeats on its output what it hears on its input. Satellites are a type of repeater. Many repeaters also have internet connections, phone connections, voice messaging, and other features. A good VHF repeater will usually give you an effective range of 40-80 miles, compared to the 3-5 you would have on your own. (This is still peanuts compared to HF though, where paths greater than 1000 miles are common.)

As for why they accumulate so many problem users, it's not at all complicated. Access to VHF repeaters is easy and cheap, with the cheapest Chinese handheld radios now costing less than $50. This leads to a disproportionate percentage of the population congregating on their local VHF repeaters. The relatively short range of a repeater also gives the users a sense of anonymity. This plus the comparatively large audience tends to result as postulated in John Gabriel's "Greater Internet F*ckwad Theory": "Normal Person + Anonymity + Audience = Total F*ckwad".

 

[ADSWNJ]

The reason why I was asking was as a result of a discussion with a friend about lowest latency communications between trading markets in London and NY. This traffic runs at the speed of light through glass (plus the switching/boost delays), in transatlantic cables. For land-based communications e.g. Chicago to NY, the fastest path is microwaves and booster stations. We were musing about transfers from NY to London, either by repeater ships in the North Atlantic, or by bouncing a signal straight off the ionosphere. The question would be whether this is faster than going through glass. Probably not, right?

I guess there's always neutrino communication after that!

 

[dseagrav]

The reason why I was asking was as a result of a discussion with a friend about lowest latency communications between trading markets in London and NY. This traffic runs at the speed of light through glass (plus the switching/boost delays), in transatlantic cables. For land-based communications e.g. Chicago to NY, the fastest path is microwaves and booster stations. We were musing about transfers from NY to London, either by repeater ships in the North Atlantic, or by bouncing a signal straight off the ionosphere. The question would be whether this is faster than going through glass. Probably not, right?

I guess there's always neutrino communication after that!

Radio travels at C, so a long HF path would be much faster in terms of latency, but bandwidth is so limited at HF you wouldn't be able to do much with it. A network of low orbit satellites providing a constantly-available path might do the trick, with a much better bandwidth figure. It still wouldn't have the bandwidth of the fiber but you'd murder it on latency. (IIRC light in glass is .6C or something like that)

 

[Ravenous]

Yeah the neutrinos would be a "straight line" so slightly faster than reflected short wave. UK to New Zealand would be a considerable saving in fact...

 

[ADSWNJ]

Neutrino-comms is a pretty big investment though If ham radio can send a buy or sell signal in a very short burst, it could be interesting. If the path bouncing off the ionosphere is more than 1.0/0.6 longer, then the glass path is faster.

Eh, it was only a drinking discussion, nothing serious!

 

[dseagrav]

You wouldn't be able to do it in the real world anyway, for one insurmountable reason - Ham radio is strictly non-commercial. Sending messages from which you stand to make a profit or operate a business is generally illegal.

There are several commercial allocations in the same general neighborhood as most of the ham radio spectrum though - You could get a license for one of those.