Hi Matthew Thanks for your reply. I am aware of the ability to upload the log files. That being said, I would still like to resolve the antenna issue. As I have said I am not an expert, but as far as I know it is important to achieve the appropriate resonance in the antenna and that will only happen with it being of correct length.
Cheers Paul On 17 April 2011 13:08, Matthew Gage <[email protected]> wrote: > 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 >
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