Poynting antennae and sat dish?

[acidrain]

I have a poynting DIPL A0042-04 antennae ( small P.O.S that you slot into a 3G card... only 2dbi ) and a DSTV dish lying around.

Now excuse my idiotic question if it is, but would i get more gain if i place the antenna in the middle of the dish?

 

[JJF]

Hi Acidrain,

It is a bit diffucult to say, of course you must mount the antenna at exactly the right position, where the LNB used to be.

The problems that you may find :
1. DIPL-A0042-04 is an omni antenna, so only the energy that is radiated towards the dish will be reflected. Most of the energy from the dipole will be radiated all over the place. So if you do manage to get it to work, you will probably not see a huge amount of gain from it.

2. The distance from the feed to the dish may be wrong. Remember that you are also radiating energy forward (away from the dish). If your distance is wrong, then the energy relflected from the dish may actually subtract (destructive interference) from the energy that is radiated forward directly from the antenna, ending up with a lower gain than without the dish.

3. Mechanically it is going to be difficult to mount at the correct spot. But with enough duct-tape, cable ties and double sided tape you may get it right.

Normally a dish antenna is made out of a directional antenna (like an LPDA or yagi) firing directly into the dish. All (or most) of the energy is then reflected back from the dish towards your target.

Regards,

JJF.

 

[Poynting1]

Would work fine. You have to position the antenna at the point just in front of the feed ring (where the lna would normal go). You then must be careful in "aiming" the dish. A DSTV dish points in the direction (roughly) of the feed arm so that when you want to have a beam to the horizon it looks like the dish is pointing about 20 degrees down (into the ground). You will notice that the feed arm is then about horizontal. In cape town many dishes appear to be pointing at buildings etc but the beam is offset to the dish "face" by about 20 degrees upwards.

 

[acidrain]

Thanks for the advice guys. Did try it and found that i went from 2 bars to full signal but then found out it was just a good day for signal and went back to normal a couple of days later

Long story short, just bought a medium gain yagi. Bit pricy but beats having a black "stick" lying on my desk.