On Sunday, July 22, 2012 7:32:39 PM UTC-7, Eric Greenwell wrote:
On 7/22/2012 7:13 PM, Darryl Ramm wrote:
> On Sunday, July 22, 2012 5:11:14 PM UTC-7, kirk.stant wrote:
>> I'm thinking of mounting a couple of "mouse" GPS
>> antennas on the inside of my fiberglass LS6 panel cover using
>> Dual-Lock on the TOP of the GPS antenna. Reason is to have more
>> real estate to place the antennas, and still provide a
>> "break-away" function if I have to jettison the canopy
>> (and cover, which goes with it). Any opinions about any effect the
>> plastic Dual-Lock would have on GPS reception?
>>
>> My gut feeling is "no effect", but I claim no deep
>> knowledge of the electromagnetic spectrum (other than how to run a
>> no-lock intercept using an APQ-120...).
>>
>> Comments?
>>
>> Kirk 66
>
> My concern is not RF absorbing (which will be minimal), but more the
> robustness of any adhesive tape on a too-hot-to touch black
> glareshield sitting on the ground on a 100F+ summer day. While 3M
> Dual-Lock is strong, and the adhesive on those strips typically much
> better/more stable at high temps, than any of the Velcro brand
> products I'd still be concerned about the adhesive
> "creeping"/"walking" or letting go on a really hot day. (but that is
> easy to test to see if its a problem)
>
> My facorite under-panel mounts are actually made of thin, one layer
> fiberglass moulded around a foam replica of the antenna that are
> potted under the glareshield and then the foam core is removed. Where
> you pry open a springy entry flap and push in the GPS "puck". I've
> got one made like this under my ASH-26E panel for the XM weather
> receiver puck for my Gamin 496, so not exactly a GPS antenna but it
> works great in this mount (in this case there is no break-away, as
> the 496 goes away with the canopy, but the DC power to the 496 has a
> break-away connector. You could look at GPS options that break away
> at a connector.
>
> Email me if you want and I'll try to find photos of the fiberglass
> mount for my XM antenna that Williams Soaring made.

I haven't seen Rex's solution, but maybe you can make a mount that
attaches to the instrument pod, holding the antenna up close to the
glare shield? That avoids the need for Dual-Lock or messing with
fiberglass. I used some 1/16" x1" x3" Lexan plastic to mount the
antenna, then bolted the end of the lexan to a convenient brace. The
flexible Lexan holds the antenna up to the inside of the glare shield.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what
you need to know tinyurl.com/yfs7tnz

I like that idea even more, easy to wire/check with the glareshield removed.

Darryl