Hi Nigel
Thank you for this explanation. I have wondered if it was an 1/8, but I thought it was too long, as my (inexpert) calculation indicated 38mm as compare to the 45 I am getting on the standard antenna, but granted, it is difficult to know to which point measure on the elbow, so few mm can easily be lost / gained. When you say the 1/2 wavelength antenna sold by Mark has to be "submerged" for 1/4 of its length, are you talking simply in terms of available space or is it something to do with the performance? In any case, thank you for clarifying the issue. Cheers Paul On 18 April 2011 12:00, Nigel Andrews <[email protected]>wrote: > Hi all, > > > > As I was the original OEM of the OzFlarm some explanation for the antennas > is required. The original ozflarms used 1/8 wavelength stubs commonly used > on wireless modems in the 800 – 900 MHz band. We used them because the ¼ > wave would just not fit on most dashes if you used a true ground independent > type which added the extra height. So you could use out of the box the > supplied antenna and have reasonable coverage. We then offered a clear high > gain antenna which had excellent range but was difficult to locate in a > suitable position to take advantage of this. The final solution was a ½ wave > ground independent which Mark sells and works fine BUT you have to submerge > about ¼ of the length in the dash and poke the rest above. They work fine so > long as you don’t shield the radiating section. > > > > We also sold a stick on antenna that was a ½ wave dipole, those who have a > glass nosecone can use these, vertically polarised. Our club discus has one > and its working well. The ultimate solution is an external antenna with a > very short feed cable as you will lose most of the signal in the cable if > not careful. > > > > The new “powerflarm” has a better receive path and higher TX aimed at the > G.A market (sports aircraft, ultralights) but can be used in gliders, it > also receives mode A/C transmissions and issues “proximity” alarms, and if > equipped with ADS-B you will see their location and height, distance as > well. > > > > Choosing the correct antenna and providing the best location and > installation possible is imperative for maximum benefit of flarm, especially > early detection of a front on conflict so take the time to make it work, use > the antenna tool for ranging on the flarm site which looks at your IGC file > which has some information pertaining to the distance of other aircraft > received during the flight, best to use this at a comp where you have lots > of targets to provide the data. It will map your received profile, 2 or more > km’s is an acceptable result. > > > > Cheers > > > > Nigel > > > > > > > > *o** Nigel Andrews–* *Engineering / Sales* > > > > 1A/13 Steel Street (upstairs) > > Capalaba > > Queensland 4157 > > Australia > > > > - PO BOX 114, Capalaba, Queensland Australia 4157 > ( Mobile 0419989288 > > * [email protected] > > Skype - rv7pilot > > > > *Andrews Electronics Designs Pty Ltd* > > ABN - 921-33392140 > > Electronics engineering for the future > > > > **************DISCLAIMER************ > > > > The information contained in the above e-mail message or messages (which > includes any attachments) is confidential and may be legally privileged. It > is intended only for the use of the person or entity to which it is > addressed. If you are not the addressee any form of disclosure, copying, > modification, distribution or any action taken or omitted in reliance on the > information is unauthorised. If you received this communication in error, > please notify the sender immediately and delete it from your computer system > network. > > > > _______________________________________________ > 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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