I've built a homemade 1.2ghz wireless video surveillance system and I came up about 30yrds
short on the range I needed
what or some option to increase the range
thanks
30 yards may be a good number. It depends on bandwidth, frequency and many other factors. Did you check what may be if your system will have more than 30 yards range?
Improving the antennas is probably the best thing to do, are you using proper antennas and use the correct cable, also can the antennas 'see each other' ie do you have line of sight transmission, this will make a great difference to the range
Yes, probably the easiest way to improve the range is to use a higher gain antenna on the transmit side. This will direct the power available from your transmitter to a smaller spatial angle, increasing the total received power at the other end. You probably have a single patch antenna that came with the unit, and its gain is probably around 6 dB. So if you found a 14 dB or so antenna somewhere, it will probably have the range you need.
On your picture RF connectors looks like F connectors from TV. If it so you may save some signal level by replacing them with high quality RF connectors. Even good 50 Ohm connector probably will be better. Using 50 Ohm instead of 75 will give -14 dB return loss, which is enough for CCTV. Corresponding insertion loss will be roughly 0.18 dB that is definitely less than losses into F connectors. You also may cut the cable shorter. But main improvement you can get from antenna. Remember it can be 50 Ohm too.
sorry RF-OM
this is the updated picture I had already replace the long coax with this one with screw connectors I'm not sure what ohm the coax is it's not marked (just a piece I found)
are you saying I need to use 75 ohm? and or this type connector ok are do I need something better.
thanks
Definitely on your picture there are F connectors. This connector was design for old analog TV systems for frequency band about 300 MHz. On 1.2 GHz it can easily introduced 1.5 dB of loss. This number is for soldered connector but you use crimped, so loss can be even more. You may buy inexpensive ham radio connectors and a small piece of good coaxial cable. Even if they will be 50 Ohm you will get improvement over the old F connectors. Try to ask manufacturer about better quality antenna. Even if they have no one, they probably will be able to tell where you can find it.