It's the one thing that spoils my enjoyment of my many gadgets - data transmission.
The DAB mini-system in the caravan began playing up this morning - poor signal.
My television is capable of reproducing a lovely picture, except it doesn't half the time because neither the Freeview or analogue signal is consistently strong.
I have to juggle mobile phones and providers to get coverage in the places I need it - signal issues again.
Winter is approaching, so it will soon be time to kiss goodbye to 5Live in the car as soon as the sun goes down.
Sky TV in Iffy Towers breaks up occasionally, more so in bad weather.
My computers are capable of doing lots of things, except they can't because the internet connection is not fast enough, or is prone to breaking up.
It seems to me the gadgets I buy are very capable, but their connections to the outside world are very poor.
A lot needs to be done to improve data transmission, doesn't it?
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I've been trying since 4pm yesterday to download a 1.2gb file to the ftp site of a repro house in singapore. At 9pm it just gave up so I decided to split it into 6 sections and do it piece be piece which meant setting the alarm clock for two hour intervals during the night.
I'm extremely naffed off to say the least.
"A lot needs to be done to improve data transmission, doesn't it?"
Damned right.
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Makes me realise how lucky I am - a consistent 10mb download speed and last down time was 3 years ago.
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In Zero Place I have
Freesat, 100% signal 100% quality, never breaks up in rain. Put dish up myself, a size larger than needed.
Freeview 80% signal strength, 100% quality, put up aerial myself, bigger than required.
DAB, 100% signal, 100% quality, Multiplexed to Aerial points, guess what, Put the aerial up myself.
FM, yes you guessed it.
Internet, signed up for 8 meg, get 7meg, 6 on a bad day. I wired all the internal telephone lines and sockets myself,
Been in the computer game for 36 years, you want data you gotta invest in your infrastructure,.
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Yes, there is a big gap between the reality & the hype. I get 2.9Mbps here at home. Mobile broadband rarely reaches dial up speeds (except in London my wife tells me). We'll all just have to round to Tigger's.
John
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...In Zero Place I have...100 per cent everything...
If there's a gap in the signal, it doesn't matter how good your infrastructure is, there will be a gap in what you see or hear.
Your good reception of everything is assisted by you being in the South East.
Things are a great deal different in the more sparsely populated areas of the country.
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The only thing I couldn't fix for you, (given sufficient budget) is the Internet.
Last edited by: Zero on Wed 29 Sep 10 at 10:22
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...The only thing I couldn't fix for you, (given sufficient budget) is the Internet...
Pity, because that is one of the more frustrating of my difficulties.
I have a roof-mounted FM and DAB aerial at Iffy Towers, but many users are not prepared to go that far.
I know of several people who have bought a DAB portable, plonked it on the kitchen bench, found it will only receive a handful of stations, and taken it back.
How would you fix 5Live in the CC3 after dark?
A DAB head unit?
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>> How would you fix 5Live in the CC3 after dark?
>>
>> A DAB head unit?
Probably, - what aerial do you have in the CC3?
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...what aerial do you have in the CC3?...
Standard screw in jobbie mounted on the bit of the roof that doesn't fold near the windscreen.
On Focus hatchbacks, there was some talk of a bad earth on the Ford brand sets causing poor AM reception.
The factory fit on the CC3 is a slightly more up-market Sony CD/radio.
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Ah those stubby aerials are a compromise for AM. One and a bit metres of chrome aerial, like the old days, works much better.
Few cars have space for them now, alas.
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...One and a bit metres of chrome aerial, like the old days, works much better...
That's a thought.
It might be possible to get one which would screw into the existing base.
Wouldn't interfere with the roof which goes back at that point as much as it goes up.
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>> ...One and a bit metres of chrome aerial, like the old days, works much better...
>>
If I can still remember how this works - it's been a couple of years since I cut any radio pack aerials to size - Zero's aerial length is a bit over optimum:
1/4 wave for that aerial type.
wavelength = v/f
say mid band 95 mhz, and v = 30,000,000 m/s
gives full wavelength about 3.16 metres. Quarterwave is 79 cm.
A bit more manageable 31 inches, in English.
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>> gives full wavelength about 3.16 metres. Quarterwave is 79 cm.
>>
>> A bit more manageable 31 inches, in English.
Alas we were talking about radio 5 live. Broadcasts on 909 or 693 Kilohertz, gives it a wavelength of about 435 metres, a 1/4wave being 110 metres.
Iffy cant fit 110 metres of whip to his Focus cc.
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Only problem with your working I think is that DAB is broadcast in what used to be Band III (old ITV 405) mid f about 200Mhz.
I cannot remember the effect of having a simple dipole aerial too long!
Should have read hthe whole thread! For MW the optimum length is is a straightened clothes hanger :)
Last edited by: pmh on Wed 29 Sep 10 at 14:01
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217-235Mhz, full wave 1.3 metres, 1/4 wave 30cm.
I built a Dab dipole aerial out of coathanger, choc block connector, and coax.
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>>
>> I know of several people who have bought a DAB portable, plonked it on the
>> kitchen bench, found it will only receive a handful of stations, and taken it back.
>>
Yes they really need to sort DAB coverage out so that it matches FM, I have the same issue with the portable in the kitchen. Slightly hissy mono FM I can live with, random boiling mud every few minutes drives me mad.
With an installed base in millions then I really don't think dumping DAB is an option, so they might as well make it work properly.
Freeview and Sky 99%+ reliable here in Spamcan towers on the Hants - Dorset border. Had to have a tree pruned back as it started shadowing the dish a couple of years back.
ADSL typically 4meg down 350K up, which is more than I need, also 99%+ reliable.
Cellular was fine until Vodafone rolled out 3G a couple of years back, now pretty iffy. Maybe RAN sharing will resolve this, we shall see.
I think the trouble with most digital transmission technologies is that most have the capability to offer a variety of compromises between cost, capacity and speed; unsurprisingly suppliers try and minimise cost for a given capacity and / or speed.
Last edited by: spamcan61 on Wed 29 Sep 10 at 11:12
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You may not adam & eve this, but if I shove my finger (wait for it, wait for it,) in the aeriel socket of my Panasonic LCDTV, I get an excellent piccie, and that's digital as well, none of that blimmin analog stuff left in the SW,
Same with my 'Pure' DAB wireless ~ 100% reception todo dia.
I put it down to the apparatus - buy Sony or Panasonic next time!
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>> You may not adam & eve this, but if I shove my finger (wait for
>> it, wait for it,) in the aeriel socket of my Panasonic LCDTV, I get an
>> excellent piccie,
And I bet you have a good line of sight to the mast. From my place the TV mast @ Sandy Heath is almost below the horizon. Digital reception just about OK with a multi element wideband aerial (multiplexes span a wide range of channels) and the shortest possible high quality downlead.
DAB is broadcast from down the road in Daventry but even that goes all burbly under some conditions.
Good old AM 5live mostly ok on 693 except for a few hours before dawn in winter when some Russian station breaks in.
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>>And I bet you have a good line of sight to the mast<<
That's quite correct, I can see the mast from my lounge,
When we lived in a south Cornish coastal village about 7 years ago, we were told "you won't get digital TV down there mate",
So I called in an Aeriel man from mevagissey and he was up & down his ladder with all manner of aerials til he found the right one, then he stuck an amplifier in the loft and the picture was nigh on purrfect,
until next doors conifers moved about in the wind!
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>> place the TV mast @ Sandy Heath is almost below the horizon. Digital reception just
>> about OK with a multi element wideband aerial (multiplexes span a wide range of channels)
>> and the shortest possible high quality downlead.
Almost is good enough. Aerial installers have lost the art of pulling signals in.
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>> Almost is good enough. Aerial installers have lost the art of pulling signals in.
That's a pretty accurate summary.
To be fair to the guy he really needed a cherry picker to get at my chimney. Doing it from a ladder then getting onto the ridge is, in climbers terms a bit exposed. He was definitely worried about having a Rod Hull moment.
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>> my chimney. Doing it from a ladder then getting onto the ridge is, in climbers
>> terms a bit exposed. He was definitely worried about having a Rod Hull moment.
>>
This is the way to it
www.youtube.com/v/uhtgsAXmz7U?fs=1&hl=en_US&color1=0x5d1719&color2=0xcd311b
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Too much iron in your diet.
John
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>>Too much iron in your diet.<<
Well ole Son, you could be correct there, joking or not, I'll tell y'all another thing, I can actually 'feel' the signal when holding the business end of the co ax, I'm not clued up on all this electrickery,
but I know that the TV signal is probably just milliamp stuff so perhaps its ME that's live!
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>> >>Too much iron in your diet.<<
>>
>> Well ole Son, you could be correct there, joking or not, I'll tell y'all another
>> thing, I can actually 'feel' the signal when holding the business end of the co
>> ax, I'm not clued up on all this electrickery,
>> but I know that the TV signal is probably just milliamp stuff so perhaps its
>> ME that's live!
Nope, that will be voltage leakage from your aerial amplifier.
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>>Nope, that will be voltage leakage from your aerial amplifier<<.
Eh, I haven't got an aerial amplifier, its not a particularly good aerial either,
when I was living with my German byrd, such was the electricity between us - bulbs used to blow!
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>The only thing I couldn't fix for you, (given sufficient budget) is the Internet.
I think we could do that for him too.
Multiple phone lines, multiple adsl connections and a cheapo pc running Linux for link aggregation.
Messy to setup but it'd work.
Kevin...
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I cant go to the exchange and connect him, dig the holes in the road, climb the poles.
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>I cant go to the exchange and connect him, dig the holes in the road, climb the poles.
Why not? Pensioners usually have plenty of free time don't they ;-0
Anyway, Iffy has loads of money so he can just get BT to run him a couple of dozen new connections to his nearest junction box. Failing that I'm sure he could afford a stack of these:
tinyurl.com/2w6kvfn
Kevin...
Last edited by: Kevin on Wed 29 Sep 10 at 20:24
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...Failing that I'm sure he could afford a stack of these:
A WAN load balancer and VPN contractor?
I know I often say this about computer equipment, but I really have no idea what this might do.
We are talking hypothetically, but would I really need a dozen or more lines to get a faster speed?
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yes
Last edited by: Zero on Wed 29 Sep 10 at 21:25
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OpenBSD excels at this kind of thing. It's trivial to setup either multilink (aggregated bandwidth, provided your ISP supports MLPPP) or multipath (horrible, horrible). I.e. 5 mins after installing you could have it running.
Then you could get really fancy and use ifstated to transparently handle a link or remote side failure. Then you could get carried away and use CARP (cue the jokes, it's like VRRP) with a second box to transparently handle subscriber-side hardware failure...
I still support a ~100 user site i setup a few years ago with carp & equal cost multi-pathing, it works well in a business environment with many users but would be crap for a single user (really needs a proxy to ensure connections are "sticky" to each path, otherwise user complains t'internet channel on the telly's playing up.
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>A WAN load balancer and VPN contractor?
It's a fancy router that can also take a 3G dongle for connection via cellular.
>We are talking hypothetically, but would I really need a dozen or more lines to get a faster speed?
Link aggregation at Megabit speeds typically has a one-to-one link to throughput ratio. Two links, twice the throughput. You only start to get problems if you have multiple 10GigE links. In that case you can pretty much work on the assumption that each link will require full use of a cpu core, especially if you aren't using jumbo frames.
Kevin...
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"Anyway, Iffy has loads of money"
He lives in a caravan...
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I stopped short of using that phrase myself, but...
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you were going to accuse him of having a transit with a towball and a beacon on top.
I was much kinder.
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"I was much kinder"
I'm sure he'll appreciate that
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You know, I get the feeling my empathy will be misunderstood.
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He has to tell me he is ignoring me, otherwise I wont know.
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...He has to tell me he is ignoring me, otherwise I wont know...
Zilcho,
To have one member ignoring you is unfortunate, but to have two would almost be an epidemic.
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...He lives in a caravan...
Better that than a cardboard box.
Actually, the 'van is my weekend/holiday residence.
It has central heating, double glazing, en-suite facilities.
And painfully slow broadband.
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"en-suite facilities." - a gazunder.
John
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..."en-suite facilities." - a gazunder...
Not heard that term since my grandmother was alive.
Typically Victorian, they didn't like to refer directly to anything remotely connected to rude bits.
"Sit upon" or "btm" for bottom is another example.
Going back to the 'van, it wouldn't go under because I have a divan.
A memory foam divan, no less.
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>Actually, the 'van is my weekend/holiday residence.
>It has central heating, double glazing, en-suite facilities.
You're lucky. Our "weekend/holiday residence" is a paper bag in a septic tank.
Must be nice to be wealthy.
Kevin...
Last edited by: Kevin on Wed 29 Sep 10 at 22:22
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...Must be nice to be wealthy...
I was.
Until I bought the 'van.
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Never on W.H. Smith's best-seller list, but:
"Communication in the Presence of Noise" by Claude E. Shannon, January 1949
tells you all you need to know.......
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>> Never on W.H. Smith's best-seller list, but:
>>
>> "Communication in the Presence of Noise" by Claude E. Shannon, January 1949
>>
>> tells you all you need to know.......
>>
Oh yes, I had to dig that seminal paper out at work a few weeks back when a colleague claimed that multiple antenna systems broke Shannon's law.
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I have a digital amplifier in the loft and it all works perfectly despite being in a hollow and the nearest transmitter several miles away.
The roof is, however, rather high due to the age of the house but not that high as only 2 stories. 10metres ish...+ chimney = 12 metres I guess...
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:
>>
>> "Communication in the Presence of Noise" by Claude E. Shannon, January 1949
>>
..and whilst we're in the 'nothing new under the sun' mode, the majority of cellular base station RF amplifiers I've come across over the last few years use a Doherty configuration, first described in 1936:-
www.mpdigest.com/issue/Articles/2007/aug/freescale/Default2.asp
Caution - link contains extreme RF geek content.
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>> Caution - link contains extreme RF geek content.
>>
He's still a geek but we don't call him RF any more, he's Zero now
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If you really want the geek content try -
www.postech.ac.kr/ee/mmic/poweramp/doherty_amplifier_modified.html
and to think that once upon a time I probably understood it all!
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>> >>Nope, that will be voltage leakage from your aerial amplifier<<.
>> Eh, I haven't got an aerial amplifier, its not a particularly good aerial either,
I think the tingly finger when touching the connector thing is probably _another_ impromptu battery, this time comprising:
and a big sweaty (and acidic) digit across the inner and outer of the Belling_lee connector as the electrolyte and detector of the voltage.
the alloy outer casing of the Belling-Lee connector
the copper inner on the coax
the inner and outer of the connector are effectively looped together by the folded di-pole at the far end.
Your mileage and sensitivity to voltage may vary.
As for internet at any price - get a fibre to home (or cabinet, if it's not too far away).
That'll get over the local loop problem.
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..or you can get a gigabit ethernet microwave link for about 20K USD per pair....
I've often had mild shocks when touching an earthed appliance (generally a PC these days) with one hand and the outer screen of an aerial downlead with the other. Does the outer naturally float at half mains voltage or something?
I should be able to work that out for myself really but my head's full of blocked drains at the moment.
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Dog's sorted on his internet connection - www.bbc.co.uk/news/technology-11435640
John
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>>Dog's sorted on his internet connection - www.bbc.co.uk/news/technology-11435640<<
I notice its the fibre-to-the-cabinet technology (FTTC) in Cornwall and not the faster fibre-to-the-home technology,
Good news for the many areas in Cornwall that can only access the ww via dial up though,
When we first came to the duchy 15 years ago, there were still many homesteads without mains leccie,
got their water from a bore hole which ideally wasn't anywhere near their cesspit.
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Caught you! You're an expert in this IT stuff aren't you?
John
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>>Caught you! You're an expert in this IT stuff aren't you?<<
Aye, an expert in cut & paste :)
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>> Does the outer naturally float at half mains voltage or something?
AFAIR
There was a time when TV sets used to work live chassis at "half mains" and you relied on the isolating RF socket to avoid getting a tickle..
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>> >> Does the outer naturally float at half mains voltage or something?
>>
>> AFAIR
>>
>> There was a time when TV sets used to work live chassis at "half mains"
>> and you relied on the isolating RF socket to avoid getting a tickle..
>>
The other thing that occurs to me (at least in Spamcan towers) is that the mains PSU for the masthead preamp only has a two wire power connection, so maybe that floats. Presumably nobody bothers earthing the outer braid of your average domestic aerial installation, so there has to be some potential for it to float.
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Data transmission - the great unsolved problem - BiggerBadderDave
