The first thing to do is upload some log files from your flarm to their web site - it will give you a chart showing at what range it is working in all directions.
In many cases, the problem is not the antenna,but some shielding within the cockpit, etc. It can also be that the other units are in "stealth" mode, which dramatically reduces the usefulness of the system - detection is then based on alerting conflict instead of presence, If you are achieving 2.5km range in some directions, then work on antenna positioning before anything else. On 17/04/2011, at 12:31 , Paul Bart wrote: > Hi > > I have become concerned that the range at which my Flarm detects gliders is > not anywhere near specification. It often bypasses the green warning, going > straight to red. I understand that there are many factors in play, such as > shielding from the instrument panel, carbon etc., but I do not think that > this is the explanation in my case. So I thought I would invest in a better > antenna, but before I did that I had a look at the standard antenna provided. > When I removed the plastic covering I was surprised that the actual antenna > was only 48 mm long. Yet the manual states, that the antenna at 1/4 > wavelength should be 86 mm long. I also have the original Swiss Flarm > (inherited from a glider purchase from Europe) so I compared and its antenna > is approximately 80 mm, but as the cover is not removable, I cannot confirm > the length of the actual conductor. > > Anyway I had a look at a few wavelength calculators on the web and given the > average frequency the Oz Flarm operates on is about 921MHz, the 1/4 > wavelength should be approximately 77mm and not the 86 indicated in the > manual. I haste to add here that I know next to nothing about antenna design, > so a simple application of the formula might not be correct. > > In any case though, the length of the antenna on my Flarm is 48 mm, well > short of the manual stated 86 mm. > > So I would like to ask those that know more then I on this topic > 1) Is 48 mm the correct length (too long for 1/8 and too short for 1/4 > wavelength) > 2) If not, should it be 86mm as per manual, or 77mm as per calculated length > 3) If mine is NOT an isolated case and the 45 mm length is not correct, are > we having a fleet of Flarms out there with much poorer range and hence > effectiveness that we should have. > > Any help on the topic greatly appreciated > > Cheers > > Paul > _______________________________________________ > Aus-soaring mailing list > [email protected] > To check or change subscription details, visit: > http://lists.internode.on.net/mailman/listinfo/aus-soaring _______________________________________________ Aus-soaring mailing list [email protected] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring
