Those 2.4 GHz videosender thingies

Mike 1972

With Videosenders, bluetooth and now wireless networking (802.11b WiFi and Hiperlan) using the 2.4-2.5 Ghz band (along with "leaky" microwave ovens) surely theres lots of interference problems ?

Ok I know that the Bluetooth and networking stuff can hop frequency but the videosenders are hardly that "smart" yet are they ?

Do the videosenders use AM FM or Digital for the video signal ?

Pat Gleeson

The videosenders are handy, but are prone to interference.

The videosender itself is a cause of interference on my Pace Digibox, blocking all channels on 11.681 Ghz V completely.

Turn the thing off, and voila, the channels come back.

sirlinux

They use FM, the only problem i have with mine is the microwave (also in 2.4ghz) sometimes interferes, ive heard they can jam 802.11b on some channels, ive had no problem with my mine though (or bluetooth).

watty

* Amateur 13cm band overlaps with 2 of the 4 Video Sender Video channels (2400MHz = 2.4GHz = 13 cm).

* Amatuer 70cm band overlaps with the Video Sender reverse Remote control channel on 430MHz

* Video sender is almost identical to Analog Satelite, i.e. FM video with two FM subcariers. Only difference is that for Stereo on Analog Satellite, the audio channels are spaced 180Khz apart and for Video Sender they are 6.0 and 6.5MHz, 500KHz spacing, so with analog Satreciever you can get L or R but not both.
Satellite IF signal from LNB to Receiver socket is 700MHz to 21500 MHz, The Video Sender is 2400Mhz approx.

* Both Digital and Analog Satellite Receiver inputs maximum are 300MHz less than Videosender band. If there is interference there is a fault.

* If your microwave is interfering get it checked!!!! Do you want to go blind!!!!!

* If the videosender interfers with Digital Satellite Receiver you may have a faulty coax or wrong kind of coax on LNB cable or aerial cables

* MMDS is AM analog and also Digital on 2.5GHz, just outside videosender band.

* Wifi 2.4GHz uses frequency chipped spread spectrum. I have tested Laptop/PC close to videosender TX and WiFi point in top of attic, no slowdown. Both 2M and 11 tested. The faster than 22Mbit Wifi uses different band. Wifi won't be affected.

* Most Wireless security cameras are Analog FM 2.4GHz, receivable with video sender. A WiFi (Wireless LAN) 2.4GHz camera is about 10 times price (1000 Euro not 100 Euro) and can only be received on a Wireless LAN, and gives a much worse picture

* All Analog TV and RF outlets are AM Video with FM mono sound. Any "Off Air Stereo" on Analog TV is a Digital subcarrier (Nicam) and is never generated by Digibox, VHS etc.

A VHS never records Nicam. Its tuner decodes it and the recording is FM video and FM audio on slanty tracks from drum and mono along edge of tape. The colour on VHS is recorded separately below the Video FM carrier in frequency.


Conclusion:
The only thing video senders can interfer with are wireless baby alarms, some cheap analog wireless security systems and some Amatuer Radio / TV activities which may use 430MHz or 2.4Ghz.

The 430Mhz signal is only active when the Video Sender Receiver part picks up an IR remote signal on its "eye".

The Digisender, Philips and Thomson seem OK.
Any video sender should have a CE mark label and also a CEPT number (the licence for 2.4GHz/430MHz). If it hasn't these two items on its label underneath, it is illegal and may interfer.

watty

I'll comment on "bluetooth" if I ever have it to test and they ever stop re-writing the spec.

phoenix2181

yep i've got one of digisender jobbies,

it works a treat except for some odd reason if there is a lot of pale colours on the scrren the picture starts to roll??? i've had it for amount 8 months & are well worth it , very for watching digital in other parts of the house.

one problem though...if you watching some thing a bit saucy on the old digital in your room everyone else can see what your watching downstaires but thats a sky digital prob in all fairness

parasite

it works a treat except for some odd reason if there is a lot of pale colours on the scrren the picture starts to roll???

off topic but i get this 'effect' on chorus, what causes it ??

pbirney

Originally posted by watty
The only thing video senders can interfer with are wireless baby alarms

Actually, they are unlikely to interfere with baby alarms/monitors as these operate in the 49MHz band.

BTW, what has any of this got to do with satellite?

Mike 1972

BTW, what has any of this got to do with satellite ?

Well a lot of Satellite viewers use them
The subject line was pretty on topic and it got quite a few resposes so people must be vaugely interested

Lets not get TOO nit picky

watty

Originally posted by pbirney
Actually, they are unlikely to interfere with baby alarms/monitors as these operate in the 49MHz band.

BTW, what has any of this got to do with satellite?

Old or cheap baby alarms use 49MHz as do the "toy" walktalkies. There are better ones (that perhaps monitor room temperature too?), more expensive that are 2.4GHz FM.

The licence free (or near free) EU frequencies for approved equipment are:
1.x MHz old analog cordless phone receive
27MHz FM (AM and SSB are illegal) CB
49MHz low power very short range (50ft) Audio, old analog cordless phone send.
430MHz (Typically wireless remote or back channel on 2.4GHz, or wireless speakers / headphone, car alarm wireless key)
890MHz (Wireless terminals, barcode scanners)
2.4GHz FM analog Video, Frequency chipped WiFi Digital LAN, Alarm systems etc.

There are additional bands for Radio Microphones. Some need licence and some don't (Argos ones don't)


Video Senders are popular solution to Digibox, Digital Cable or DVD in another room.

Mobile Phones, Motor bike ignition and electrical motors (Washer, dryier, fridge, freezer) are more likely to create interference than any CE marked AND CEPT approved remote device to Satellite or TV watching.

I can actually "see" a local motorbike before I hear it go past!

DMC

Folks, its still on topic, more people with satellite TV use video senders to give multi-room viewing, which is not available with Sky Digital. And if it interferes with other equipment, then yes, raise it here.

Carry on.

ozpass

So do cordless 'phones not use 2.4 Ghz? I've been using it as an excuse whenever the digisender in our bedroom craps out.

Her: "Bloody picture's gone mad, get up and sort it will you."

Me: "It's just someone using their 'phone downstairs, it'll go away in a minute."

And by an odd stroke of luck it always does. The picture goes really bad when there's strong blue on the screen too, like the Chorus digital EPG. Very loud buzzing noise always accompanies it. Any ideas?

watty

I said OLD cordless phones use 1.6MHz / 49MHz analog.


Digital Cordless (DECT) are a different band. They very well could affect video senders. I think there are two different DECT bands, one about 890MHz and one in the microwaves. It is 1989 I last designed DECT equipment so I forget the details.

The DECT cordless standard allows for 64K data. In late 80s the idea was this would be in-office wireless networking. The 802 WiFi products at 2, 11, 22 and 56Mbit makes this idea and bluetooth for same a bit pointless.

Krusty_Clown

Watty: Just curious - How do you know so much on the subject?
Enthusiast or professional?

pbirney

Originally posted by watty
Old or cheap baby alarms use 49MHz as do the "toy" walktalkies. There are better ones (that perhaps monitor room temperature too?), more expensive that are 2.4GHz FM.

Actually, watty, the 49.82 to 49.98MHz band is the only official allocation in Ireland for the operation of baby monitors (10mw ERP). These devices are currently on sale in a number of outlets and are therefore not old devices. I'm not aware of the other systems on 2.4GHz that you mention but if they are in use in Ireland they are being used illegally. My work is connected with the radio comms. industry so I'm reasonably familiar with the frequency allocations for Ireland.

BTW, apologies for questioning whether this thread was off-topic. I can see the obvious relevance of video-senders to the satellite scene.

Paul.

watty

Used to be Comms Engineer, then Telecomms design. Now IT stuff.

Designed VHF stuff for Westing house in USA and a pocket information system with built in GSM and DECT in ME company just before the last Gulf war.

Perhaps the 2.4Ghz "baby" unit is either so fancy it isn't classified as a baby monitor or it is illegal. I only saw it in a window so didn't examine its stickers.

Are analog Cordless Phones still legal to sell?

pbirney

Originally posted by watty
Are analog Cordless Phones still legal to sell?

Yes, watty. There are still legal analog phones on sale (8 channels, I think) The base units transmit in the 31MHz band & the handsets transmit in the 39MHz band.

LFCFan

where's the best place to buy one of these digisenders? I saw one in Maplin for €85. Does this sound about right or should you be able to get them cheaper?

sirlinux

Maplins €85 price is very good, you usually dont see them for less than €100 here.

LFCFan

Originally posted by sirlinux
Maplins €85 price is very good, you usually dont see them for less than €100 here.

me think's me be buying it so! Ta!.....hold on, do you work for Maplin? mmmm, very dodgy!

sirlinux

Nope, dont work there, just spend to much money there.

watty

Videosenders typically €100 here.

Maplin special offer today is £49.95 add post etc propabily

Genghis

I can recommend Maplin's. I have that digisender for over a year now, and after the digibox itself, it was the best piece of equipment I have bought. No complaints, crystal clear sound and vision, and an 'eye' to add remote signals (which works, but is awkward for me personally with the way our main TV stand is set up, so we don't use it, and actually by using autoview you can get away without it).

Does anyone know if they sell additional receivers and how much in-store (not £STG via web).

LFCFan

just bought one from Maplin. €84.99. Cheapest I could find anywhere.

LFCFan

hooked it up last night and it's a great wee yoke. The picture and sound are perfect even when sending the DVD picture. Remote eye works great too. Well pleased with it.

yankinlk

hey watty, is there any reason that a videosender bought from the states would not work here?

iam thinking of ordering this and bringing it back with me next month: http://www.x10.com/products/x10_vk57a.htm#

I figure the only problem will be power, but cant i buy two irish ac adapters over here for like a tenner each and use them to power them?

I really like the idea of being able to use the software and remote to control the dvd and mp3 player on my pc upstairs - downstairs in front of my tv.

LFCFan

can you get an adaptor to hook up the digisender to your PC?

watty

That product is misleading USA advert. It only work with a PC that has a TV out.

It is is only a regular videosender.

It would be illegal in EU unless it has a CE mark. May not use same band.

The PC does NOT control it, it has a free universal remote, also nothing to do with PC.

Don't waste your money Yankinlk, as by time you add PSU it is lmost same price as here and almost certinally not approved.

Also the Video bandwidth may be poorer as USA TV does not typically have as much bandwidth. (It should not care if fed with 60 or 50 frame video with NTSC /Secam or PAL.).

In general it is a bad idea to bring USA electronic gadgets here as they are often:
1) Poorer quality
2) Incompatible
3) Unapproved or even dangerous / interfering (110V insulation vs 220V, different radio bands etc, different standards.

Things to especially avoid:
Record players (esp with mains motor, spin wrong speed)
DVD (even if it region free, it will convert PAL to NTSC badly compared with PAL on PAL or a European model playing NTSC in NTSC or PAL)
VHS
TV (No PAL USA TVs, but PAL EU TVs that do NTSC are common)
FM Radio (Different equalisation)
Digital Radio (incompatible with UK)
Terrestrial Digital TV / receiver incompatible with UK
Digital Satellite (EU ones will do NTSC, but US rarely do PAL..!)
Camcorders (any type)
Etc...

watty

Originally posted by LFCFan
can you get an adaptor to hook up the digisender to your PC?

You can have:
Graphics card with TV out
External VGA to Video convertor (cheap ones rubbish)
Video Edit card on PC with TV out
Satellite Card on PC with TV out.

Any of these will drive a video sender.

I have connected to video senders:
Inspiron Notebook TV out
Cougar Video card TV out
Hauppauge DVBs Satellite Card TV out
Samsung 8mm analog PAL video camera

yankinlk

fair enuff, but what about controlling my pc upstairs with the tv as a monitor. the dvds, mpegs, mp3s etc sitting on pc upstatirs, and the cool gadegty thingy (remote, whatever) controlling the whole show downstairs.

can i do that with anything i can buy here? i thought thats what the thing from the us was gonna do for me.

option2: i dont necessarily want to go down this road but to build a really tiny pc that i can stick in the place of the current dvd under the telly and network to the file storage pc / broadband / dvd player upstairs.

yankinlk

Ok, that maplins one looks the job. it looks like it will send the remote signal back to the pc....now all i have to do is get the pc to accept the remote signal to control dvd mp3 playback etc...

any ideas?

watty

You won't control the DVD playback unless you got a HW MPEG2 decoder card with a IR remote.

In theory there are several routes, none of which are likely to be very good with existing non-remote program:

1) Buy a IR remote PC interface for PC about 100 Euro

2) Simply connect an IR receiver module (about 3 Euro + 5V Power needed) to a Serial port handshake line and read and interpret IR commands in VB6 (Done this, it works). Then use "Sendkeys" or similar to control another window from your custom program by simulated keyboard commands depending on which IR command is received.

3) The Hauppauge / Technotrend DVBs PCI card has a IR eye (as does ordinary Win TV cards). There is a free SDK to do your own custom Satellite receive application with sample C++ program (I customised that a bit to see what I could do. I managed OSD and reading a TV remote control). Then you need the same piece of program you would have written for (2).

Unless you have a DVD player program that uses HW decoder card that has a remote "eye" for IR, the program will only accept mouse/keyboard and thus difficult to control from a remote even if you can receive the IR data on the PC.


The IRDA infra red ports on PC or Laptop are NOT AT ALL compatible with IR remote controller usage. Only exception seems to be a Palm Pilot IR port.


Note that even a 99 Euro standalone DVD player plays DVDs "better" than even a 2 GHz a PC in SW, and has IR remote control.

My supervision 2500 DVD player plays SVCD made at home from 8mm analog camcorder tapes far better than my 1.8GHz PC and comercial VCD better. I use a old PC with a HW MPEG1 player card to plya CDi format VCD, nothing else plays them.


The Satellite PCI Card will play MPEG2 files in HW to TV (no PC SW/ decoding needed), flawlessly, but can't play DVD VOB files :-( Also its IR remote does not control the Play/Record functions but only TV/Radio select, Channel, Teletext, Favorites, channel select and volume of the Satellite programs. So without writing your own program using the SDK it won't control even Hard Disk MPEG2 playback.

watty

The PC as a home media system is not quite a reality unl;ess you want a 17" screen, keyboard and mouse in Living room.

It is hype and a gleam in Bill Gates eye (X box unimpressive compared with PS2)

A PS3 or next version of XP on PC might do all you want via an IR remote.

Until then you need to be clever programmer with too much time on your hands.

watty

It is not common yet, but Windows Xp media Centre edition has a "built in" remote control and handset.

The remote may only be with OEM versions i.e. an HP or Dell PC with it pre-installed.

It can be bought for XP compatible PCs (Pentium, 500MHz or faster, 256M RAM, min 20G disk, min 16MRAM VGA, less than 2 years old DESIGN, not sale)

Pioneers get the arrows in the back.. I'd let someone else test it!

Doodah7

help wanted: I just purchased one of the Digisenders from Maplin, the 2020 version. Unfortunately I can't get it to work!

I plugged the transmitter unit via SCART into the Digibox and hooked receiver unit into the portable via SCART, fiddled wit the aerials on both and nothing.... I matched up the channel switches on the units as per the instructions.

Do I have to remove the aerial from portable which received the four Irish stations for the digisender to work??? Do I have to tune in a station on the poratble to view the transmitted signal???

What I did notice on the transmission unit was a red light contantly flicking as if a remote control was being used (when it wasn't).

Any ideas??? Was it a bad one out of the box???

LFCFan

Originally posted by tallpaul
Do I have to remove the aerial from portable which received the four Irish stations for the digisender to work??? Do I have to tune in a station on the poratble to view the transmitted signal???

You have to use the AV button to view the signal from the digisender. I've got that system from Maplin too and it works fine. Make sure the wee dish thingys are pointing at each other.

Doodah7

god but that's bloody obvious that. :rolleyes: I should really have thought of that...

Thanks for the quick response LFCFan, I will try it tonight....

dougal

Quick question on these senders.
I currently have a one for all digisender set up and working perfectly.

My question is can I add another receiver that will take the signal from the original transmitter.

If so are the receivers sold seperately?

watty

Yes.

and
Yes.
Doesn't even half to be same brand. They use the same frequecies / standards.

Try Argos, Maplin etc.

Failing getting a RX only buy a pair, then set TX1 to Ch C and TX2 to Ch C. Then either Receiver can get either TX (Save Digibox and DVD palyer) just by change the RX channel switch.

dougal

Excellent - Thanks watty.

Probably just get the pair - would be better than regretting not having the extra TX later.

ceejay

LFCFan,

Did you buy yours from Maplin's store here, or over the net from the UK?

Does anyone know if they are any better than the Philips VL1200? Are the little dishes better than the antennae that the Philips uses? Personally I prefer the look of the Philips ones. Anyone know where you can get them here (maybe Argos/Dixons)?

Do they all use some kind of cable to send the IR signals to the source boxes once it's been received back at the transmitter, i.e. you stick a IR transmitter to the receiver on the source device, if you know what I mean?

Thanks,

Ciarán.

watty

Soem have an IR LED built in "transmitter" for the received Remote Control signal. The thomson (excellent) has a cable with THREE separate LED modules on it (A good idea).

If you handy with soldering Iron and screwdriver it isn't hard to "convert" either kind to the other kind.

DaithiSurfer

I have the philips digisender thing and it seems that someone else (outside my house) is changing my channels with their remote. I've tried changing the channel switches on the digisender but this does not seem to effect the channel that the remote is on. Maybe these things are getting a bit too common and people are starting too interfere with each other. Another thing i noticed is that my wireless network is causing interference on the receiver tv.

watty

The channels (unfortunately) only apply to the TV transmiter / receiver on 2.4GHz not the IR Transmitter / receiver on 433MHz.

If it has a separate UHF whip from the 2.4GHz (some have and some not) try aluminium foil around part of it to make it less sensitive.

Someone nearby has same device, sadly.

I had a Philips VHS which had a choice of two command codes, a good idea...

ceejay

watty,

Some more questions, if you don't mind Which Thomson model do you have, where did you get it, and how much was it? Which of the others would you recommend, if any? Is it likely that my DECT phone will interfere?

Thanks,

Ciarán.

Doodah7

Further to my earlier post (which somewhat resurrected this thread), I got my digisender to work by pressing the AV button on the remote. Thanks again LFCFan.

Ceejay: with the ones from Maplins, I don't seem to have to use the antennae on either thingy. Whether in the kitchen or upstairs in one of the bedrooms, the signal comes across crystal clear, perfect sound and the Sky remote works perfectly. So i can store them neatly and unobtrusively:)

As for the price, with a rising euro, it is probably cheaper to buy online, even if there is a charge for P&P.

ShaneOC

Originally posted by tallpaul
As for the price, with a rising euro, it is probably cheaper to buy online, even if there is a charge for P&P.

From xe.com

Live mid-market rates as of 2003.05.12 15:18:19 GMT.
1.00 EUR= 0.717400 GBP

Still climbing...

ceejay

Originally posted by tallpaul
So i can store them neatly and unobtrusively.

See, this is important to me. That's why I was wondering about how the IR signal gets from the digisender to the source boxes, i.e. does it need to be placed somewhere so that it can transmit the IR signals to the boxes. The Thomson one that watty has seems to have (optic fibre?) cables that you can use to send the signal, so the digisender can go pretty much wherever you want - within reach of the cables anyway. Also, the dishes look kind of big, which is why I'm interested in the Philips ones, they look pretty compact. Though if they're omni-directional maybe they're not as good as the ones with the dishes.

As for the price, with a rising euro, it is probably cheaper to buy online, even if there is a charge for P&P.

That's a fair point, though it is quicker just to pop into Maplins store or Dixons or somewhere like that. I'm not sure how much can be saved by buying online, but that's what I will probably do. I just need to decide which one to get

Ciarán.

LFCFan

Originally posted by ceejay
That's why I was wondering about how the IR signal gets from the digisender to the source boxes

There's a wee little mouse (as in computer mouse but a lot smaller) shaped IR Transmitter that can be stuck somewhere that can 'see' the IR recievers on your equipment. You hardly notice it.

That's a fair point, though it is quicker just to pop into Maplins store or Dixons or somewhere like that. I'm not sure how much can be saved by buying online, but that's what I will probably do. I just need to decide which one to get

It's €85 in Maplins at the moment.

watty

The Thomson was bought in Savin's O'Connel st Limerick for 127 Euro (not cheapest place in Ireland).
It is a wire with 3 LEDs with a jack plug / socket on the transmitter (easier to add to any model if you handly soldering).

They are all very similar. I got one out of Argos for a frend (not the Philips) and similar idea but different brand.

kar999

I've just purchased the Maplins Gigaair 2020 (£50) and in addition to using it as a video sender I have hooked up a Wireless security cam (also from Maplins).

The reciever will pick up either the video signal from the transmiter at the digi/sat box end or the covert camera. You just have to have them on different channles (flicking the jumper switches). There's still scope for adding another two cameras (1 video + 3 cams) or other input sources. It can even switch between the 4 input channels at 4 or 8 sec intervals if you want to use it more as a security system.

I'm really pleased with the quality and for the price of a camera (£50) have got a fully functional security system as well as the video sender.