Today's Message Index:
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1. 09:05 AM - Re: Antenna Grounding (Eric Page)
2. 10:03 AM - Re: Kitfox vertical fin antenna opportunities (Eric Page)
3. 10:15 AM - Re: Some Thoughts on Z101 (Eric Page)
4. 02:51 PM - Re: Kitfox vertical fin antenna opportunities (user9253)
5. 05:43 PM - I forgot how to list on the list (Janet Amtmann)
Message 1
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| Subject: | Re: Antenna Grounding |
nuckolls.bob(at)aeroelect wrote:
> ...RADIUS is equal to the seated height of the
> antenna so closer to 6" diameter for ADSB and
> 5.75" for the xponder antenna
Yeah, the 3" diameter was a brain fart on my part. I meant radius.
> ...I'd really like to see a sweep of the
> antenna mounted in the vertical fin. At the least,
> proximity of metal to the antenna might well
> call for physical 'shortening' of the antenna.
I have a poor-man's VNA, so I'll see what I can do. I ordered some RG-400 last
night, so it'll be a week or two before I can mock up a test. If I can make
the VNA show something that looks sensible, I'll post it here.
According to the manufacturer's data, this antenna cannot be shortened.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=500643#500643
Message 2
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| Subject: | Re: Kitfox vertical fin antenna opportunities |
nuckolls.bob(at)aeroelect wrote:
> Would you folks with access to a 'naked'
> structure tell me what dimensions apply to
> the items labeled in the attached photograph?
A couple of notes... This installation would only be possible in a Kitfox with
the optional airfoiled tail, which adds wood ribs to the steel structure. Otherwise
the vertical stab and rudder are flat sided and there is no room to pass
an antenna vertically within the stab. When installed, the ribs are only there
to shape the fabric and are not structural.
I bought my project from its first builder, and the tail ribs were already installed.
It was very messily done, but the ribs are firmly attached so I did not
remove/replace them. Their location is specified in the build manual, but accuracy
obviously depends on the builder. These measurements are from my example:
A: 6-1/2"
B: 6-3/8"
C: 6-1/8"
D: 6-3/8"
E: 19" (sits on 3/8" dia steel tube)
F: 22-1/2"
G: 27" (widest rib; sits on 7/8" dia steel tube)
H: 6-1/4"
The ribs taper from 3-3/4" wide at the bottom of "A" to 1-7/8" wide at the top
of "H".
I'm attaching some photos of how I did my installation. I fabricated a wood block
with an angled end that would direct the antenna with equal spacing between
the forward and aft tubes in the stab. The wood block has a slot in the bottom
end to receive the antenna, which is secured with a fillet of caulk.
Each rib has a 1" slot, through which the antenna elements pass, again secured
with a small dab of caulk to prevent chafing. The center feed point falls in
the space labeled "B" in your photo, so the coax will be supported by Adel clamps
on diagonal steel member "F". The feed point is secured against vibration
by a vertical strip of wood bonded to the ribs above and below, and attached
to the feed point with a dab of caulk.
The bottom element of the antenna will be secured by pinching between two small
wood blocks, with their inner surfaces lined with a thin rubber sheet for grip.
This will be done after the horizontal stab is installed, as the antenna passes
through the open center section of the stab.
> Names and email addresses of individuals
> flying Kitfox, embedded off-the-shelf antennas for VHF
> comm would be useful too.
I can't help with that, unfortunately. I roughly copied the installation done
by another builder who used this antenna. He reported on the TeamKitfox forum
that he hears aircraft in the pattern at an airport 70 miles away from his, has
good comms with ATC and has had no complaints about his transmissions.
As I posted in the other thread, I'll try to get a VNA sweep once I have the coax
installed and the weather improves so I can roll the fuselage outside. It's
snowing sideways for the next several days.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=500644#500644
Attachments:
http://forums.matronics.com//files/img_1267_125.jpg
http://forums.matronics.com//files/img_1099_561.jpg
http://forums.matronics.com//files/img_0966_272.jpg
http://forums.matronics.com//files/img_0965_118.jpg
http://forums.matronics.com//files/img_0963_207.jpg
Message 3
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| Subject: | Re: Some Thoughts on Z101 |
Bob -- was there more to be said on this topic? I answered your questions above,
but the thread wandered then slipped below the noise floor...
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=500645#500645
Message 4
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| Subject: | Re: Kitfox vertical fin antenna opportunities |
It took me awhile to realize that the vertical black object going through the
middle of the ribs is actually the com antenna and not structural steel. Is that
a black plastic box at the bottom? What is inside of it? And what is the
purpose of the triangular part that you are holding? Thanks
Theoretically the steel tubes will block radio waves fore and aft. But one can
not argue with the success of others. The installation looks good and I think
that you will be happy with the antenna.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=500649#500649
Message 5
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| Subject: | I forgot how to list on the list |
How do I list on the list. I do get the list in my emails.
Jurgen Amtmann
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