Dual Yagi setup advice.

[Ronnierozier2]

Hello all,

I need to see if someone could suggest a proper setup for what im trying to accomplish. Please be gental cause all this is new to me.

I live in a small delta town in the Middle of Mississippi. I recently purchased a SDS100 and after programming I did not hear a thing. Come to find out I have no signal on my front porch or anywhere in my yard. After some research I found there are 2 towers one South West and one East of my location somewhere around 17-20 miles away. What I did was gather some equipment from my work and started testing. ?What i did was take a 5' Yagi turned to somewhere in the 900mhz spectrum and some LMR400 cable and set this up pointing East towards one of the sites and now able to get 5 bars on my sds100. I turned the antenna towards the other tower with the same result.

I tried this same test with a 9dbi gain omni directional antenna with results that were not optimal. The Yagi is clearly the winner in this situation. So now to my question. What do I need to take 2 of the exactly same Yagi antennas and point one south west and one east to pickup both antenna sites and bring them down on a single coax?

I would like to know what i need to take the two yagi's and bring them down on a single coax. I know just enough that I need some type of combiner or something like that so the signal wont come in on one antenna and go out of the other.

Any suggestions? please advise

 

[Ubbe]

If you use a combiner, and you can use a $5 CATV splitter, you will loose a little bit more than 3dB from the antennas. If you have 5 bars it would probably still work. You can look at the RSSI signal strength in dBm to see how much 3dB are. Being a 75 ohm CATV splitter it will add an additional 0,5dB loss, if the antenna are 50 ohm, plus 0,5dB internal losses. If you now have -85dBm or stronger signal then no problem.

/Ubbe

 

[prcguy]

If you take two identical Yagi's and point them the same direction and put them the perfect spacing apart and with a proper phasing harness or power divider you can get up to 3dB more gain and a slightly narrower radiation pattern. Point the same two Yagi's different directions where a signal cant be received equally on both Yagi's and you will loose at least 3dB or 50% signal level into each Yagi due to splitter or power divider loss.

A 5ft long Yagi at 900MHz is a lot of gain and I have a 6ft version with 17dBi gain so a 5ft would be close like 15-16dBi. I suspect the advertised gain on your omni might be misleading and it takes a vertical a good 8 to 9ft tall to get 9-10dBi gain. How tall is yours? I would think an 8-9ft vertical might pick up both directions you need.

 

[Ronnierozier2]

If you take two identical Yagi's and point them the same direction and put them the perfect spacing apart and with a proper phasing harness or power divider you can get up to 3dB more gain and a slightly narrower radiation pattern. Point the same two Yagi's different directions where a signal cant be received equally on both Yagi's and you will loose at least 3dB or 50% signal level into each Yagi due to splitter or power divider loss.

A 5ft long Yagi at 900MHz is a lot of gain and I have a 6ft version with 17dBi gain so a 5ft would be close like 15-16dBi. I suspect the advertised gain on your omni might be misleading and it takes a vertical a good 8 to 9ft tall to get 9-10dBi gain. How tall is yours? I would think an 8-9ft vertical might pick up both directions you need.

right now I have the temporary setup and it’s about 12’ off the ground. Once I figure out what I need I will be able to get it about 40’ from the ground