HFU HF Underground
General Category => General Radio Discussion => Topic started by: Beerus Maximus on July 13, 2020, 1437 UTC
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Might we see a new shortwave station in Illinois? Chris will be thrilled to learn it plans to broadcast in DRM!
http://www.radioworld.com/news-and-business/headlines/proposed-shortwave-station-in-illinois-prompts-an-objection
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Yippee! Only about 10 miles from me, so I doubt I will need to put up an end fed dipole to hear this.
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Really??? In Illinois? You'd think that to better cover Europe that they would want to be located in the East Coast, and not in the Mid-West. Still, interesting, if the station is allowed to come on-air for DRM.
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Really??? In Illinois? You'd think that to better cover Europe that they would want to be located in the East Coast, and not in the Mid-West. Still, interesting, if the station is allowed to come on-air for DRM.
The whole point here is minimizing total transmission delay time. They want to be as close to the Chicago Mercantile Exchange as possible.
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Just what the World needs - another megawatt Bible-thumper.
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Just what the World needs - another megawatt Bible-thumper.
Right, my thoughts exactly. Oh goodie for us.
Mike
N0TLD
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15 KW seems low for a serious SW broadcaster. But maybe not inappropriate for a HFT data broadcast using log periodic beams for a point to point circuit.
Are DRM transmissions low enough latency to be consistent with high frequency trading requirements?
I’ve wondered what part of the FCC rules they were going to apply for a license under. They certainly aren’t aeronautical or maritime and an experimental license no longer worked once they became operational. Maybe this is their path.
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15 KW seems low for a serious SW broadcaster. But maybe not inappropriate for a HFT data broadcast using log periodic beams for a point to point circuit.
Are DRM transmissions low enough latency to be consistent with high frequency trading requirements?
I’ve wondered what part of the FCC rules they were going to apply for a license under. They certainly aren’t aeronautical or maritime and an experimental license no longer worked once they became operational. Maybe this is their path.
I suspect 15 kW is enough with directional antennas on each end of the circuit. I suspect they should be able to transmit their data payload over DRM without too much of an additional delay, they probably have figured that part out already.
There used to be allocations for fixed services like the old point to point telephone services, but perhaps licensing for that no longer exists? You'd think if there was something else they could use, they would have done that, before going down the SWBC/DRM route.
Honestly, if this keeps them out of the 43m/utility/other fun bands, fine with me.
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Not only does propagation delay make an impact but interleaving and/or fec in the signal will also add delays, however minor they may be. S4285, what drm is based on as I recall, has some interleave/fec modes that can cause several seconds of delay.
https://www.etsi.org/deliver/etsi_es/201900_201999/201980/03.02.01_60/es_201980v030201p.pdf.
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I suspect it will be something that looks like DRM but isn't. In that regard, any sort of COFDM modulation could be used, most likely with LDPC or similar error correction to keep the delays down.
+-RH
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I can't see how this is going to be fast enough for trades. Most Data Center locations are based on fiber latency and it used to be in Milliseconds Now It's in Microseconds. it won't be long until it's in Nanoseconds. Even Microwave would be faster for trading.. So there must be something more to it.
tAC
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I'd like to see a microwave shot across the Atlantic... My guess is that the accrued latency in passing through the various networks is longer than a direct HF circuit. If they were smart, they would just run their own fiber across the pond and be done with it.
To me its all a reminder that the game is rigged, and those with deep pockets will find ways to screw the little guy.
+-RH
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The whole point here is minimizing total transmission delay time. They want to be as close to the Chicago Mercantile Exchange as possible.
That's exactly it. There was a story, not sure if it was posted here or if I read it elsewhere, where some guy discovered someone that purchased an old cell tower in Chicago and attached a SW antenna to it and were using it for this purpose. They weren't a licensed SW broadcast station, but rather a ham guy or maybe even a pirate - can't remember.
In addition, I wonder how they got the approval for less than 50kW. That is the minimum power for SW broadcasting in the US. I actually looked into starting a SW station once and was turned off by the high minimum power requirement.
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...In addition, I wonder how they got the approval for less than 50kW. That is the minimum power for SW broadcasting in the US. I actually looked into starting a SW station once and was turned off by the high minimum power requirement.
CFR 47 part 73.751;
§ 73.751 Operating power.
No international broadcast station shall be authorized to install, or be licensed for operation of, transmitter equipment with:
(a) A rated carrier power of less than 50 kilowatts (kW) if double-sideband (DSB) modulation is used,
(b) A peak envelope power of less than 50 kW if single-sideband (SSB) modulation is used, or
(c) A mean power of less than 10 kW if digital modulation is used.
[70 FR 46676, Aug. 10, 2005]
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I can't see how this is going to be fast enough for trades. Most Data Center locations are based on fiber latency and it used to be in Milliseconds Now It's in Microseconds. it won't be long until it's in Nanoseconds. Even Microwave would be faster for trading.. So there must be something more to it.
tAC
Raft Technologies claims “milliseconds of advantage between exchanges oceans apart”. Signals that travels through a medium like fiber or processing equipment will do so at “slower than the speed of light in a vacuum”. The radiowave path is traversed at the speed of light. Latency accumulates, so the more equipment and fiber they can cut out of the path by going direct, the greater the possible advantage.
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This discussion on latency is interesting. It claims that Starlink could beat the latency of terrestrial fiber. I wonder how these numbers compare to the use of HF? If Starlink does implement the laser satellite linking, could this kill the use of HF for HFT?
https://youtu.be/m05abdGSOxY
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Yes, and no... HF still has the feature of being anonymous. You don't know who is listening, unless they tell you. However, it could put a bigger clinch on terrestrial broadcasting, unless you use this system as a network linking. Lots of possibilities here, but which way they will actually go is anyone's guess.
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I see it as a non-starter, aside from the mercantile data transmissions.
Who are they going to broadcast to that isn't already served by present day broadcasters? It doesn't make sense. 20 years ago, it would still have made sense. Not in 2021. I mean, how many DRM receivers are there worldwide, really?
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Where would be the other end of the data link ? Wall Street ? or in Europe? or elsewhere ?
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Where would be the other end of the data link ? Wall Street ? or in Europe? or elsewhere ?
The PDF of the application (linked on the Radio World page) says the station is to 'specifically serve the areas of Europe that may be authorized by the Commission". The PDF also has info on the type of log-periodic that the station plans to use. It looks like it's beam / azimuth is 47 degrees from true north -- aiming the signal NE towards EU.