Video Senders

There is great variation in quality of transmitter, receiver (for 2.4GHz and FM bandwidth used, should be < 15MHz) and the 433MHz reverse link. If the FM video TX and RX are properly designed then the WiFi and Video will co-exist

WiFi channels are 5MHz each and typical 802.11g uses 3 channels completely and a bit on each side. (22MHz)

Properly designed Video Senders use 15MHz wide channel 

Comreg since 2009 have now approved 5.8Ghz for Video Senders and other SRD (short range devices)

Quote:
1. Radio Frequency Plan for Ireland (Revision 1) (ComReg Document 08/90R1) http://www.comreg.ie/_fileupload/pu...<
2. Permitted Short Range Devices in Ireland (Revision 4) (ComReg Document 02/71R4)
http://www.comreg.ie/_fileupload/pu...<
Date of Entry into force 22/12/2009

2.4GHz Video Sender Video/Audio Channel

  • Channel A: 2.411 GHz
  • Channel B: 2.434 GHz
  • Channel C: 2.453 GHz
  • Channel D: 2.473 GHz

The Return IR remote signal is sent "as is" over a 433.92MHz (typical) link with no channel selection. If the remote doesn't use ASK/OOK with manchester type encoding with a 32Khz to 44kHz carrier, the return "remote control" channel will not operate well or at all. Fortunately most Remotes use Philips RC5 or RC6 or similar, which does work. Some UPC set-box for cable TV use IRDA which is a high speed serial protocol. It won't work with most Video Senders. Philips has a model which supports this, but we haven't tested it.

The "Digisender" brand are overpriced.  The name even is misleading snake oil. They are FM analogue, like all the others. We have not tested Philips models yet.

Many Video senders are poorly made, exceeding either the 15MHz bandwidth on transmitter (thus interfering with WiFi) or having poor receivers (thus interfered by WiFi).  Often the Remote "back channel" receiver on the video transmitter is poor and generates 433MHz interference if it's a Super Regenerative type. The better units.use a Superhet radio and don't create interference.

Many makes and type have been tested. Some big brand name expensive ones are the worst. The Lidl model was really poor. One of best so far tested is at Maplin (link may go dead)<

The 5.8GHz may work fine but have poorer range.

All video Senders use 15MHz deviation FM composite video. The audio is true stereo on separate 6.0 and 6.5MHz FM subcarriers added to the video, so the video is higher quality than any Domestic RF modulator and the audio better than FM radio Stereo (which doesn't have completely separate channels)

You can use IP video (MPEG or MJPEG) over 5.8GHz or 2.4GHz WiFi also. The 5.8GHz video senders are same as 2.4GHz, Analogue FM, even if "digi" is in name. Actual IP/MPEG/MJPEG "Wifi" based "video senders" are characterised by generally being a transmitter half only and x10 price compared to analogue video sender, the "receiver" is your PC or laptop or Internet client.

WiFi (802.11 b/g/n, not a and not full n) is
CH 1 = 2.412
CH 13 = 2.472 

Channels are spaced at 5MHz, Channel 12 & 13 not permitted in USA.

But the spectrum extends about 11MHz either side of a nominal channel (this is why with 802.11g you can only have 3 or 4 wifi points in same area 1, 6 and 11 in USA or 1, 5, 9 and 13 here and rest of Europe if receiver design is good, not 11 or 13. For full speed 802.11n mimo you can only have ONE WiFi point. It uses entire band.

So A and 11 or 13 does work and D and 1 better, as some devices can't select channel 12 or 13. If it doesn't then the video sender is really poor design

The best solution is a pair of Cat5e cables. Can be used with SCART via baluns (up to 400m) or even with HDMI via adaptors (up to 100m).