Diff: NodeGMI

--- Version 12 

+++ Version 13 

@@ -6,7 +6,7 @@ 

 

 Using a DWL-650 card connected to a 18dBi ex Galaxy antenna on an antenna rotator.  Note that the antenna polarisation is __vertical__. 

 Is there anyone else active in the area? 

-(http://web.aanet.com.au/glenns/wireless/conifer_rotator.jpg GMI Antenna) 

+(http://web.aanet.com.au/glenns/images/conifer_rotator.jpg GMI Antenna) 

 

 !! DWL-650 Card 

 These are my mods to the DWL-650, I used a short length of RG188 coax from 

@@ -14,11 +14,11 @@ 

 An SMA connector is used on the tail.  These are heaps more rugged than the 

 MMCX connectors. 

 

-(http://web.aanet.com.au/glenns/wireless/dlink_mod1.jpg Dlink mods) 

+(http://web.aanet.com.au/glenns/images/dlink_mod1.jpg Dlink mods) 

 

 I was a bit worried about the strain that the coax tail placed on the card, so I made a little strain relief from plastic and bolted the SMA socket on the tail to the plastic.  The idea behind using plastic for the SMA socket mount was to protect the card from damage.  Should the plastic strain relief become caught on something solid, it will break, rather than break the PCMCIA card protrusion. 

 

-(http://web.aanet.com.au/glenns/wireless/dlink_sma2.jpg Card Strain Relief ) 

+(http://web.aanet.com.au/glenns/images/dlink_sma2.jpg Card Strain Relief ) 

 

 There are some details on the web showing how to add a tail to the DWL-650 and also stating that it does not matter which diversity antenna connection is re routed to the tail.  My experience shows it does matter.  When I re routed the antenna capacitor as shown in the earlier image, I found that although the card received signals well through the tail, I could not see any RF power on a power meter through the tail. 

 When I made an RF sniffer loop and placed it over the internal antenna, I noted RF only from the internal antenna. 

@@ -36,22 +36,22 @@ 

 The antenna matches and performs very well. 

 Here are some photos: 

 

-(http://web.aanet.com.au/glenns/wireless/biquad1.jpg Biquad pic 1) 

+(http://web.aanet.com.au/glenns/images/biquad1.jpg Biquad pic 1) 

 

-(http://web.aanet.com.au/glenns/wireless/biquad2.jpg Biquad pic 2) 

+(http://web.aanet.com.au/glenns/images/biquad2.jpg Biquad pic 2) 

 

-(http://web.aanet.com.au/glenns/wireless/biquad3.jpg Biquad pic 3) 

+(http://web.aanet.com.au/glenns/images/biquad3.jpg Biquad pic 3) 

 

 !! Helical Antenna 

 

 Put together a 12 turn helical antenna based on Remco den Besten's design from 

 http://helix.remco.tk/ and did some tests on air.  So far it doesn't perform so well taking in to account that its circular polarisation will be down 3dB from a linearly polarised antenna.  Will have to check it out on the network analyser. 

 

-(http://web.aanet.com.au/glenns/wireless/helix.jpg Helical pic) 

+(http://web.aanet.com.au/glenns/images/helix.jpg Helical pic) 

 

 Redesigned the match on the helical and now the thing seems to work as expected.  Not too sure on the basis for the design for the old match.  The match I used is based on a transmission line fabricated from a curved strip of copper foil running almost parallel to the reflector.  The theory and implementation is described in the ARRL handbook. 

 

-(http://web.aanet.com.au/glenns/wireless/new_helix_match.jpg Helical match) 

+(http://web.aanet.com.au/glenns/images/new_helix_match.jpg Helical match) 

 

 !! Aerosol Questions 

 

@@ -77,12 +77,12 @@ 

 Have managed to connect to [NodeACD] after a polarisation switch to vertical and a temporary relocation of the antenna.  The trunk of a big cypress tree was in the way.  Should be enough signal to use after some optimisation of feeder and antenna. 

 

 [NodeGSJ ] may be LOS.  Here is a photo in the direction of GSJ with 30x optical zoom at a distance of 5km. 

-(http://web.aanet.com.au/glenns/wireless/NodeGSJ_from_GMI.jpg View to GSJ) 

+(http://web.aanet.com.au/glenns/images/NodeGSJ_from_GMI.jpg View to GSJ) 

 

 Here are some path profiles done with Pathloss for the two nodes.  Note that the terrain data used by the package has a resolution of about 200 metres so it's probably not that accurate for the 1km path. 

 

-(http://web.aanet.com.au/glenns/wireless/path_acd_gmi.jpg Path to ACD) 

-(http://web.aanet.com.au/glenns/wireless/path_gsj_gmi.jpg Path to GSJ) 

+(http://web.aanet.com.au/glenns/images/path_acd_gmi.jpg Path to ACD) 

+(http://web.aanet.com.au/glenns/images/path_gsj_gmi.jpg Path to GSJ) 

 

 2003-07-13: Link to [NodeACD] has now been stable for 24hrs with -78dBm signals at NodeGMI.  Reported link speed of between 5.5 and 11Mbit/sec. 

 

@@ -93,7 +93,7 @@ 

 Power over Ethernet supplies 12VDC to the enclosure where it is converted to 5VDC by a switchmode DC converter.  A switching convertor was chosen so as to minimise heat build up within the enclosure.  Has been running for a couple of days with only slight temp increase inside although it will need some sort of sun screen to shade direct sunlight from the enclosure in the warmer months. 

 See picture: 

 

-(http://web.aanet.com.au/glenns/wireless/svecAP_in_a_box.jpg SVEC in box) 

+(http://web.aanet.com.au/glenns/images/svecAP_in_a_box.jpg SVEC in box) 

 

 Well it was 33 degrees today and the thermometer probe inside the box only reported a max of 40 degrees.  Guess it will survive the summer then.