At last I’ve got a “proper” 1090 aerial up on the roof. Until now I’ve been content with some goodish results from my supplied aerial high in the loft.
I tried to do some pre-purchase research however until someone comes up with a definitive side by side “Which Antenna” test, there are only our own personal evaluations and opinions to go on with few actual performance comparisons.
I finally opted for the “controversial” Radarmax X2 from Anchor Supplies in Nottingham. I say controversial because this aerial greatly disappointed our friend “Orkney” up north but on the other hand it highly delighted our friend “G0HWC” down south. So this is a third opinion from a man literally in the middle.
My choice was influenced by a sensible price, a local(ish) company who supplied my original RB (and gave good after-sale service in exchanging it when it died) plus the opportunity to deal directly with the experienced radio amateur who both designed & built the product. He also advised on the appropriate coax and connectors and made up the cable for me.
My house is 110 feet asl in a flattish area, with housing on three sides but open fields for 300m to the south. There are some trees around but the serious obstructions are mostly topographical, especially to the south west. The nearest airport is EGNX at 15nm but because of an intervening ridge, 3000 feet is the lowest I receive for landings/takeoffs.
The antenna was gable end mounted with 7m of RG213u coax feeding into and along the loft floor to where the box is sited. There is a 12m USB feed down from the box to the PC in a back bedroom - now converted into a study/studio.
A measure of the aerial’s performance can be judged from the “before and after” pic. below. This illustrates the much enhanced all-round coverage with even a range increase to the protected southwest. I now enjoy a near 360° field of view with ranges between 150-200nm.
It is worth noting that in spite of the increased height of the aerial (2 metres plus), my previous maximum range of 205nm has shown only a nominal increase. Nevertheless, overall there has been a dramatic improvement in the Polar Diagram with the new antenna.
What the pic. cannot show is the numbers and I have made a rough table.
My initial comparisons are:
MyFlights historically 50-100 standard; 100-140 busy; 140-160 peak.
MyFlights yesterday 110-160 standard; 160-210 busy; 210-240 peak.
NB my timeouts are set at 5secs.
MyLog Aircraft total (0700 - 2200) historically between 1500 - 1650
MyLog Aircraft total (0700 - 2200) yesterday 1965
Scrutiny of the map shows that the major increase in flight numbers does not come as a result of the expansion to the northeast on the polar diagram. The increase comes mainly from areas that were already covered by the old set-up. Therefore the new antenna is pulling in far more signals from pre-existing areas. I particularly note the disappearance of my “black holes” into which flights temporarily vanished before reappearing further on.
More analysis on the figures is needed and they could be misleading. I suspect that the skies have rarely been busier than they are right now as the airlines battle to overcome their backlogs. When things get back to normal, I’ll have a clearer idea of exactly what the numbers are and from where and how the increases have arisen.
So am I happy with my new antenna? With up to 240 in MyFlights and 150-200nm range in virtually every direction, you bet I am!
The product:
http://www.anchorsupplies.com/radarmax.htmDISCLAIMER
I have absolutely no connection whatsoever with the supplier beyond being an occasional customer. I would have had no reservations about slaughtering this product had it been a dud.
John.
