What are the basics for regular aerial installation? Might replace my dipole.

[danny_galaga]

So when I built my plane I used a dipole because it was neat and I didn't have to put a hole in my fuselage. But the radio hasn't been great. In desperation I ended up putting a hole in the fuselage anyway to make the dipole more upright. 

 

So two questions I guess. Would a regular aerial normally work better than a dipole? And what area do I make the ground plane? 

[skippydiesel]

I am not an electronics person:

 

In my limited experince, an aircraft grade (need not be certified) antena give far better transmit/receive performance than a dipole.

 

You can mount under or top of fuselage - If you go under (ventral), between or close to main undercarriage, often selected for ground clearance and an antenna with a "crick" in the end, usually selected.

 

Its good idea to mount the antenna, as far as practical from engine, to minimise the chance of electrical interference.

 

Ground plane not required if fuselage metal.

 

If fuselage composite or fabric over frame - Ground plane can be made of any metal. In aircraft weight & space considerations may dictate material. Copper foil, aluminium most commonly used. A cross pattern works just as well as a solid sheet .

 

Size of ground plane dicted by frequency (I think) and internal space in aircraft - this can be easily researched or someone on the Forum will recomende..

 

In my last (composite) aircraft I used:

• Ordinary aluminium "Flat Bar" 20 x 1.6 mm as the longitudinal strip (screwed down) 
• Builder ductile aluminium flashing for the cross fuselage strip.  The flashing is easy to smooth to the shape of the hull.  I glassed the flashing to the  hull,  going slightly vertical on each tip.
• Where the two aluminium strips crossed, I made a "sandwich" from aluminium sheet (probably 2mm thick) with locating holes for the (ventral) antenna base.
• I did use dielectric grease between the connecting surfaces for good conduction & inhibit corrosion.
• Electrical connection to "ground" return very important - make sure its excellent.
• Can't recall the dimension - do remeber that the flat bar was the correct length but the flashing was a bit short, due to fuselage shape & dimensions.
• After installation I did SWR the antenna for best performance.

The radios transmit/receive was terrific.😈