Now that is WAY cool! That's one of the neatest dipole arrangements I've ever seen. You even shrink tubed a couple of ferrite beads on it. Nice. I know you are involved with AMSAT. Ever go to Hamvention? This would make a great presentation in a forum.
Scotty -----Original Message----- From: Bdale Garbee [mailto:[email protected]] Sent: Friday, April 14, 2017 1:10 PM To: Scott Myers; 'Altus Metrum' Subject: Re: [altusmetrum] New Member Scott Myers <[email protected]> writes: > If I do an external antenna, I'll probably try a simple dipole > arrangement made of some fine 22 gauge wire fed by several inches of > RG316, assuming the board will allow for the balanced antenna set-up. > Otherwise, I'll just use the stripped back center conductor of the > RG316 that I tune with my antenna analyzer while installed in the > avionics bay. One of my larger airframes (a 10" Goblin) used an external dipole just inside the airframe tube, since the TeleMetrum was mounted in a side-access ebay close to the 98mm motor mount tube. I used a surplus RG-316 cable with SMAs that I cut one end off of to solder to the dipole feed point. That rocket never flew very high (always under 12k feet), and the signals were great. Probably my proudest rocketry antenna achievement to date, though, was the "fintenna" hack on YikStik3. I loaded two of the carbon fiber fins as "dipole elements", tuning with a piston trimmer cap at the feedpoint until I had a great match with the motor case in place. I'm fairly sure I was getting radiation from the case and the fins... the signals were *very* strong, and the one flight of that airframe before the fire went perfectly. Note that on this project I used edge-launched SMC connectors, because there wasn't enough room for an SMA in the fin-can aviation bay, built between the 75mm motor mount and 98mm airframe tube... ;-) Many photos taken... http://gag.com/rockets/airframes/YikStik3/ Linked from there is a large set of build photos from that project, this one shows the antenna in fairly good detail: http://gallery.gag.com/rockets/YikStik3/Build/cimg1944.jpg Bottom line is use the wire whip on the board unless you think you really need something else, then don't be afraid to experiment! The ground station software's display of received signal strength on each packet makes it easy to do your own RF ground testing. Bdale _______________________________________________ altusmetrum mailing list [email protected] http://lists.gag.com/mailman/listinfo/altusmetrum
