Distance from roof-mounted dis-cone antennae to box

[CoastGuardJon]

Hi Dud, thanks for the tips above, 1090Mhz is around 27-28cm?  have you tried a full wave skin back as per your description, your 6-7cm makes a half-wave dipole?

[bratters]

Totally agree about lofts Dudley - mine acts as a black hole for radio signals and produces interesting polar diagrams with totally signal-free areas. Also true about discones - no good at all for 1090.

After a lot of playing about I'm back to RB supplied twig on a suction-mounted soapdish at the highest point on a upstairs window with a clear view - south in my case. No extended leads or feeds and it works well.

I'll have to try the coax stick sometime though - does the length need to be more specific than 6 or 7 cms. or is this approximation OK?

[nortonbeak]

I'll have to try the coax stick sometime though - does the length need to be more specific than 6 or 7 cms. or is this approximation OK?

According to my sums, the length should be 68.7597 mm :-)

You might need a very sharp knife :-0

[bratters]

Only four decimal places? Call that accurate? Oh, the standards these days!  :-)

[dudbaker]

pjwood123

You would expect the RB attenna to work better than my homebrew attempt.  The RB attenna has a loading coil so is longer.  My attenna works well because of the height.  3 feet gives 10db. 

CoastGuardjon.

I would call my attenna a 1/4 wave refering to the lenght of the radiating element.  I would have thought any other multiple, such as full wave, would need some loading.

To get extra gain I will put up a Professional attenna sometime.  My experment has shown a blind spot to the west.  Chimney I think.

To see the result look at Stansted.  You will see myflights landing 5 miles from my house.

dudbaker

[CoastGuardJon]

Hi Dud, thanks for the info..