My conclusion after years of efforts and innumerable failed coco antennas is that one of the main factors in failure is using a coax with FPE (Foamed PolyEthylene) Insulation. I always made coco using TV cable RG6 which has FPE (Foamed) insulation because it was cheap and readily available. At that time I did not realize that the culprit is Foamed insulation.
The FPE (Foamed PolyEthylene) insulation has a wide range of V.F depending upon degree of foaming. Variation of degree of foaming from manufacturer to manufacturer, and even with same manufacturer and same model, reel to reel and even within the same reel, due to poor quality control. Although manufacturers / sellers do provide V.F, figure, but you cannot be sure that the coil / reel of coax you got has exactly the specified V.F.
On the other hand the solid PE (PolyEthylene) insulation has a fixed VF of 0.66 and does not depend on manufacturer or quality control.
As far as I remember, @triggers made his and his brother’s successful coco using a solid PE insulated coax. I request @triggers to tell if what I have said about his coax insulation is correct or not.
Yes I used PE insulation but only because I had some. I originally cut the segment lengths to suit FPE as I had no idea about VF at that time and the antennas were rubbish! Eventually worked out that the VF was 0.66 and built several antennas which were OK.
Thanks Toronto for the valuable technical insight on the performance of the foam base coax insulation that provides great direction for planning and implementing system components.
The FPE (Foamed PolyEthylene) insulated coax is in no way bad for transferring RF signals as Velocity Factor has almost negligible influence on efficiency of transferring RF signals. In fact it is the most common type of coax used for connecting Satellite Dish to TV receivers, and also to connect the on-the-air TV antenna on roof-top to a TV receiver.
However, due to variation of it’s Velocity Factor from manufacturer to manufacturer, and model to model and even from coil to coil, it is disastrous to use it for building a CoCo antenna.
The CoCo antenna requires a coax with accurately known Velocity Factor, and it’s element length is calculated according to this Velocity Factor. The CoCo antenna is very sensitive to dimensions, and gives poor performance if it’s element length do not match it’s actual Velocity Factor.
My main 1090 feeder has been trucking along pretty well, with only a few gray hairs along its 2278 days of continuous feeding. Power and internet outages have made the streak touch and go at times.
I also have a 978 FlightFeeder. That one, in addition to the perils noted above, has to cope with a precipitous drop in GA traffic when the weather turns exceptionally bad. Sometimes there just aren’t any planes to track. During the winter months I typically see 10 - 30 planes per day, but 11 days ago there were only 3, and a few days before that, only one!
My best streak on that one has been 330 days, and I can match that tomorrow if nothing goes wrong….
I have been babying the FlightFeeder along and patiently waiting, to finally get to a full-year streak. I did beat my previous record, but now I have this:
978 results around here are heavily dependent on weather, and we have had a very mild winter this year so I thought I had it in the bag. Unless a police helicopter pops up for a quick lookaround this evening, my streak on this one stands to end at 364 days!
On a happier note, my 1090 site has been rocking along for 2312 consecutive days
No basement floods. No moves, 5 miles nor 500. No multi-day power outages. No problems with my ISP thinking my feeder is trying to steal people’s credit cards (yes, that actually happened).
Maybe I’m about to jinx myself, but so far, so good since I set up my current PiAware feeder.
I think there’s a difference between “nothing received” and “not connecting.” That is to say, it’s not your fault that no UAT978 aircraft have passed by you. You have the feeder up and running.
I also saw 365 days for a while. Hence my comment earlier.
At first I thought it seemed silly to penalize a receiver for not having anything active in the area, but then I realized you could have someone keep their streak “alive” by simply having the box running even though it has no antenna connected. Since we get a higher level of access by feeding, I guess that makes sense, then.
