GPS anetenna location OK in baggage area of a fiblerglass glider?

maanantai 26. helmikuuta 2018 19.49.54 UTC+2 Darryl Ramm kirjoitti:
On Monday, February 26, 2018 at 6:40:27 AM UTC-8, krasw wrote:

I'm not sure which cereal box you are reading to get all your knowledge, but you might want to consider switching brands.

Please refer to make and model of glider where the fuselage is carbon with glass turtle deck?

Name one where it is not. Go do the light test Jon discussed. Every Schleicher fueslage I have looked at is this way. Pretty sure the DG1000 is, ...

You were claiming no glider fuselages have this, having used GPS antennas mounted under the turtleneck in several otherwise carbon fiber glider fuselages I know you are wrong about that.

Here is a game for the upcoming SSA convention... folks there can ask or look to check if the turtledecks in all the gliders on display are RF transparent or not.

Oh the anticipation for the advancement of human (well r.a.s.) knowledge is killing me.... :-)

Dude, please don't die.......

While I hope you have some replies copied to a text file so you can, "copy paste" to cover things that have been asked many times (yes, on some car forums I have "canned replies" in a text file, just copy paste as an answer), I hope you stay around.

Maybe that is a kiss of death.......;-)

maanantai 26. helmikuuta 2018 21.12.23 UTC+2 Darryl Ramm kirjoitti:
Name one where it is not.

Sorry but with "light test" you have no clue of the turtle deck material. Why an earth would factories go trough massive pain and expense of laying up turtledeck using different material instead of just rolling up carbon/kevlar? Instruments and their antennas tend to reside in the instrument panel. Routing GPS antennas to behind pilots back, who does this, and why would factories be interested in this? Please give some reference to glass turtledeck in carbon fuselage, anything will do. RF transparence is different thing, antenna on the hat shelf sees sky trough canopy as I stated earlier.

If you are fortunate enough to own an SZD 55-1, mount the FLARM in the tail battery box. Bond the FLARM antenna to the vertical stab just below the metal parts of the horizontal stab. Bond the ADS-B antenna to the vertical stab just above the rudder counter weight. Makes for very short antenna leads. Use the existing battery cables to power the FLARM from a new battery box mounted to the stbd side of the main gear box. Now for the hard part, fish a data cable forward to the FLARM display of your choice.

On Monday, February 26, 2018 at 6:40:27 AM UTC-8, krasw wrote:

Well there is not, this is simply not true.

Read The Fine Manual... From the ASW-27 flight manual:

"Since the whole airframe ex cept for the fin and a small area above the baggage compartment contains carbon fibre which screens electromagnetic radiation, the ELT's antenna must be fitted in the top of the baggage compartment and extend into the canopy area."

On a sunny day, have a friend place their hand on the outside of the fuselage and look inside. If you can see the hand's shadow, it's not carbon.

5Z

On Monday, February 26, 2018 at 12:07:49 PM UTC-8, krasw wrote:

Sorry but with "light test" you have no clue of the turtle deck material.

Dude, chill. They're trying to talk sense for ya.

* Radio waves and light are both electromagnetic radiation; the only difference between them is frequency. If light goes in through the turtledeck structure, then radio waves will almost certainly to in and out as well.

* It doesn't matter if the turtledeck is fiberglass or Kevlar (aramid) or basalt fiber. If light goes through it, so will radio waves. Light doesn't go through carbon or aluminum, and neither does radio waves. BTW that's one of the reasons UV-curing vinylester resins are kind of a dead-end, they won't play nice with carbon. Someday there might be x-ray-curing vinynlesters, though, so hang on to your lead apron.

* When I designed the HP-24 fuselage, I surveyed the field and found that many if not most manufacturers were using radio transparent fiberglass for the portion over the wing, and I did the same. I also made the rudder out of Kevlar, and developed a tuned dipole com antenna that is a standard part of the rudder kit.

* I specifically decided not to develop an internal transponder antenna for the rudder or fuselage; for that I recommend an external blade antenna. I have on my to-do list the development of a flush 1090 mHz slot antenna, but it's pretty far down the list.

--Bob K.

On Monday, February 26, 2018 at 6:28:31 AM UTC-8, Dan Marotta wrote:
This may or may not be related, but...

I mentioned GPS dropouts to my avionics technician since I had several
GPS pucks under the fiberglass glare shield on my Stemme. They were
mounted directly under my Flarm antennae so I moved them to the top of
the glare shied and to the canopy frame up front. This took care of most
of the dropouts but there is still an occasional dropout.

The tech said he's seen this on power planes as well and he thinks it's
a failing GPS antenna.Â* He said that one antenna failing could
(apparently) transmit interference which could take out others.Â* He
suggested disconnecting my antennae one at a time and flying with that
system down and see if there are problems with the others.Â* It might be
less painful simply to get another GPS antenna (they're cheap) and swap
it around the cockpit from system to system and see if that fixes the
problem.Â* ...Or maybe an antenna combiner...

OBTW, there should be no problem with mounting an antenna underneath a
fiberglass cover.

On 2/25/2018 7:44 PM, Dirk_PW wrote:
I'm doing a little housekeeping with instrument panel this winter with the intent to eventually install an ADS-B solution (whatever that may be). The panel is quite cluttered right now. I'm considering one option of moving the FLARM GPS antenna (and eventually a ADS-B GPS antenna) back behind my head somewhere in the baggage area. I'm curious if anyone has done this and has had any problem acquiring a GPS signal (on a fiberglass glider). I'm currently having no problems acquiring a signal with the GPS antenna under the fiberglass front panel. Thanks.

--
Dan, 5J

Check for electrical noise on your mains. In my case it was caused by switching power supplies for the Oudie and Colibri II. I was seeing occasional dropouts in my IGC traces. Liberal use of ferrites stopped the problem cold.

I fly out west with a Powerflarm and a garmin 196 with remote antennae.The antennae are seperated by at least a foot or so under the glare sheild. At first and for years I had the 196 feeding my SN10B and without fail at exactly 00:00 UTC, I was usually on final glide or a long way from home, I would get about minute or three of dropouts. These would last for 5 to 30 seconds but very annoying. They would not show up on the 196, but I would get the warning on the SN10.If looking at the signal on the 196 it was always good and it would be updating its position constantly. After switching to the powerflarm as a gps source it has stopped. Still dont know why it was happening.

CH

On Monday, February 26, 2018 at 12:07:49 PM UTC-8, krasw wrote:
maanantai 26. helmikuuta 2018 21.12.23 UTC+2 Darryl Ramm kirjoitti:
Name one where it is not.

Sorry but with "light test" you have no clue of the turtle deck material. Why an earth would factories go trough massive pain and expense of laying up turtledeck using different material instead of just rolling up carbon/kevlar? Instruments and their antennas tend to reside in the instrument panel.. Routing GPS antennas to behind pilots back, who does this, and why would factories be interested in this? Please give some reference to glass turtledeck in carbon fuselage, anything will do. RF transparence is different thing, antenna on the hat shelf sees sky trough canopy as I stated earlier.

An ASH26E has an all carbon fuselage but a fiberglass turtle deck. As does every other AS glider I have ever seen (20, 24, 25, 29, 31, etc.). Every Ventus and Discus I have ever seen has a fiberglass turtle deck. Ditto every DG and Lak. Rather, please point to a composite glider that does not. In a Pilatus, Schweizer, or Blanik you will have some trouble as they are aluminum.