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Airbender

Splitter for two RX ant's on a 900 Mhz system

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Friends,

I am using a range-video 900 mhz rx for my video downlink. My TX is a 500mw using a 5 db omni oriented horizontally. Currently, I have a 12 db panel antenna on the rx, but due to the inherent nature of the panel this limits me to a specific direction on the field I fly.

So, what if I could combine another omni with the panel antenna using a splitter? Therefore I could have the best of both worlds, right? or would this insert too much loss? Or, I could have two omni's on my rx, one vertical and the other horizontal.

I have attached the type of splitter I would like to use.

Please reply with your comments.

TIA to all in advance.

Edited by Airbender

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The way aerials work with each other is complex and the results can not be forseen. The proper way to use 2 aerials is with 2 rx's feeding their video into a diversity switcher. Try searching the subject here as it has come up many times, try a search for 'diversity'.

Terry

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Also orient your Tx antenna in a vertical plane and you'll probably double your range. And search the forum. You'll find out this subject and a possible solution has been brought up in the last two or three months.

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mmm ron did quick search, either search function isn't working or something else. Anyways just quickly what was the best antenna orientation. vertical down, horizontal back vertical up for tx?

Thanks in advance.

Ivan.

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Vertical down for airborne Rx or Tx and vertical for ground Tx Ivan. But not always practical to hold your Tx with the antenna vertical though. Some Tx makers in another lifetime used to have their Tx antennas canted a few degrees towards vertical on the Tx case.

Never hurts though, if you're near the end of the Tx, Rx range to make the effort to hold the Tx antenna vertical. Might possibly save a plane in a lot of cases. Cross polarization of the signal between the Tx and the Rx is the culprit here as well as minimum radiation off of the end of the Tx antenna.

Edited by W3FJW-Ron

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Hmmm thanks for that timbit. I had read that jetpilot actually suggests having the tx shoot out the back horizontally so when the signal degrades, he turns the plane and is ok again. That a bad idea?

I guess one more quick question... I have dx7 and some of the recievers have satillites, putting one horizontal is not worth the effort? Putting them all vertical is the way to go?

Ivan.

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I should back up a bit Ivan. I was speaking of 2.4ghz radios. Common useage for 72mhz & below radios is wih the Rx antenna in a horizontal plane due to the length and as the Tx antenna is usually held more or less horizontaly. Tx antenna should always be held broadside to the aircraft antenna and never pointed at it.

As far as the diversity Rx (2 antennas & 2 Rx, 2.4ghz) one antenna should be mounted vertically, preferably out the bottom of the fuselage and one horizontaly. This gives you best reception when aircraft changes attitude as the Rx with the best received signal controls the plane.

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