---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 01/31/11: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:05 AM - Re: Comm Antenna & SWR: Grounding Issue (Werner Schneider) 2. 08:48 AM - Re: Comm Antenna & SWR: Grounding Issue (kuffel@cyberport.net) 3. 09:48 AM - Shorai LiFePO4 (Jan de Jong) ________________________________ Message 1 _____________________________________ Time: 01:05:41 AM PST US From: Werner Schneider Subject: Re: AeroElectric-List: Comm Antenna & SWR: Grounding Issue Bob, I would pull the foam on a 1/2 radius out, fill them with resin/filler mix like the other cage holes, then drill them out to add a metal sleeve over the screws, that one would touch the base of your antenna and the groundplane (probably on two holes already enough), make sure the sleeves a re a tad longer then the fiber ull thickness. Then mount the antenna again (tarque screws)and use some rtv around the corner to seal. That is what I did with my belly antenna and it works fine. br Werner On 31.01.2011 03:58, Bob Falstad wrote: > > I'll probably just have to pull the ground plane and re-do the mechanical mounting again and hope I get a lower resistance. > > Would it make sense to get some conductive epoxy and bond a ground strap from the antenna base to the ground plane? I know soldering copper to aluminum doesn't work and corrodes almost immediately. I've seen some silver-filled epoxies rated as low as 0.001 Ohm-cm but that stuff is expensive. Could I solder a small ground strap to the antenna's metal base without damaging the antenna? I've got room in the hole for the BNC connector to run a small ground strap up from the antenna base to a ring terminal that I could clamp under one of the mounting screws. Would conductive gel under the hardware help? > > Since I've got a glass skin between the antenna base and the washer stack that leads to the ground plane, I didn't "brighten" the underside of the ground plane -- just the top under each of the four machine screws. I'm thinking if I brightened up both sides of the ground plane, there might be some improvement because of the additional contact between the hardware stack, the machine screws and the underside of the ground plane. > ________________________________ Message 2 _____________________________________ Time: 08:48:20 AM PST US From: "kuffel@cyberport.net" Subject: Re: AeroElectric-List: Comm Antenna & SWR: Grounding Issue Bob, Another issue you might want to keep in mind is the characteristics of the surface under a belly mounted antenna. Rebar in concrete or conductive soil near the tip (as opposed to the base) of a whip antenna can screw up performance until you are in the air. A reverse example of this is up in Alaska (again) the permafrost is very non-conductive. You could spread out an HF antenna on the ground, tune it exactly to frequency and raise it up 50 feet in the air with no change in performance. Or more related to your possible situation, Seattle's soggy soil is so conductive you can mount a vertical antenna in the ground and have it perform well without any of the normally required ground radial wires. Tom Kuffel ________________________________ Message 3 _____________________________________ Time: 09:48:32 AM PST US From: Jan de Jong Subject: AeroElectric-List: Shorai LiFePO4 Check out "Shorai". New light weight Japanese LiFePO4 battery with quite enthousiastic motorcyclist customers. Works well enough at low temperatures. Max. charging current 18A (no external shunts). Higher ratings coming. Has a 5 pin plug that I suspect may give access to the 4 cells. For our use I might want to monitor max. cell voltage to see <4V or interrupt charging. Cheers, Jan de Jong ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.