Today's Message Index:
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1. 05:38 AM - Re: Headset to hand-held and panel radio at same time? (Robert L. Nuckolls, III)
2. 06:50 AM - Re: Headset to hand-held and panel radio at same time? (Alec Myers)
3. 08:49 AM - Re: EAA award and banquet (Robert L. Nuckolls, III)
4. 08:49 AM - Fw: Help with panel design? (Peter Feneht)
5. 08:52 AM - Glastar Dipole comm antennae behind doors (Robert L. Nuckolls, III)
6. 10:52 AM - Re: Re: EAA award and banquet (rd2)
7. 04:50 PM - Re: EAA award and banquet (johGrey)
Message 1
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| Subject: | Re: Headset to hand-held and panel radio at same |
time?
At 04:57 PM 10/27/2019, you wrote:
>
>Is is possible to utilize a Y cable to connect a headset to a
>hand-held and panel radio at the same time? The situation would be
>no intercom panel, Garmin GTR200, Yaesu FTA-550, and twin plugs on
>the panel for a headset. This topic link indicates OK
>http://forum.matronics.com/viewtopic.php?t=37809 but it refers to an
>intercom panel. However, the Audio Systems chapter seems to
>indicate that either radio would not sense an resistance in the
>other so the headset would not receive much useful output. My
>thought is the handheld could function as a back up to the GTR200
>and or second frequency monitor if the volume was turned up with out
>the need to change the headset plugs from one to the other.
You can try it . . . there's no risk
of damage . . . it simply would not
work as you expect.
Adding multiple audio sources together
is normally done with an audio
isolation amplifier as described
in the chapter. As to microphones,
the mic in your headset can be connected
to only ONE transmitter at a time.
You would need a XMTR1/XMTR2 microphone
transfer switch.
So if you're only needing the HT for
backup, you might as well transfer the
headphones audio with the same switch.
Bob . . .
Message 2
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| Subject: | Re: Headset to hand-held and panel radio at same |
time?
If it doesnt work, you can build a two input audio amplifier for about $3. But
youd have to wire it in to 12v power.
On Oct 27, 2019, at 9:41 PM, Robert L. Nuckolls, III <nuckolls.bob@aeroelectric.com>
wrote:
At 04:57 PM 10/27/2019, you wrote:
>
> Is is possible to utilize a Y cable to connect a headset to a hand-held and panel radio at the same time? The situation would be no intercom panel, Garmin GTR200, Yaesu FTA-550, and twin plugs on the panel for a headset. This topic link indicates OK http://forum.matronics.com/viewtopic.php?t=37809 but it refers to an intercom panel. However, the Audio Systems chapter seems to indicate that either radio would not sense an resistance in the other so the headset would not receive much useful output. My thought is the handheld could function as a back up to the GTR200 and or second frequency monitor if the volume was turned up with out the need to change the headset plugs from one to the other.
You can try it . . . there's no risk
of damage . . . it simply would not
work as you expect.
Adding multiple audio sources together
is normally done with an audio
isolation amplifier as described
in the chapter. As to microphones,
the mic in your headset can be connected
to only ONE transmitter at a time.
You would need a XMTR1/XMTR2 microphone
transfer switch.
So if you're only needing the HT for
backup, you might as well transfer the
headphones audio with the same switch.
Bob . . .
Message 3
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| Subject: | Re: EAA award and banquet |
At 09:53 AM 10/28/2019, you wrote:
>Hi Bob,
>
>congratulation as well on your EAA award very well deserved.
>
>Cheers Werner
Thank you sir! BTW, I'm told that there are 8
chairs at 'my' banquet table. At the moment,
there are 4 chairs unclaimed. If any Listers
are so motivated/able, I'd be pleased to have
them join us. It's the evening of Nov 7th in OSH.
Bob . . .
Message 4
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| Subject: | Fwd: Help with panel design? |
P.S. A change I made since the photos were taken, was that I reduced the
breakers from 3 down to 2. One for now will be 20 amps and the other 5
amps.
They will be the two next to the starter button. In the area of the
previously anticipated 3rd breaker, I will have one of the panel attachment
bolts.
---------- Forwarded message ---------
From: Peter Feneht <peter.feneht@gmail.com>
Subject: Help with panel design?
Cc: Peter Feneht <peter.feneht@gmail.com>
Apparently I suffer from lack of knowledge, lack of experience changed with
being tempted by perfectionism. That is a miserable, stuck situation so I
am hoping you Or others in the group can help me. I have decades of hang
gliding experience and now I want to build a Xenos motor glider.
Some of the factors for locating the instrument panel items included the
size of the device behind the panel. For example a bulky item could not be
located too low because of the angle of the support structure at the bottom
edge. That=99s why smaller switches are on the bottom edge but not th
e
breakers.
Also my plan is to install all instruments switches and devices on a flat
sheet of aluminum the exact size of the panel that attaches to the
aircraft. I will use a number of bolts to attach the flat, instrument-laden
sheet to the attachment points for the instrument panel frame that will be
riveted to the Aircraft frame. That way I can just loosen several bolts and
remove the whole instrument panel for ease of access for future maintenance
repairs or troubleshooting.
Perhaps as a result of knowing my inexperience while trying to design
something that I will be happy with for a long time after I get more
experience, I asked The opinion and advice of many willing pilots in our
local chapter, Sonex and at EAA. I think those many opinions have
contributed to my confusion and hesitation.
So at the risk of getting even more confused, I humbly ask for more advice
from you and your group. I hope that the large volume of advice will settle
into some kind of consensus with which I will be comfortable in the short
and long term.
Bob, I did this from my phone so I=99m not sure it will go to the gro
up. If
it doesn=99t go to your group can you kindly forward it?
Thanks!
Peter
Sent from my iPhone
Message 5
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| Subject: | Glastar Dipole comm antennae behind doors |
>I=99ve got dipoles in the tail, one close behind
>bulkhead A, and one in the vertical tail. This
>was what was being done in TWTT back in 2006.
>
>I measured the fraction of reflected energy
>(measured in terms of what=99s called =9CSWR=9D)
>and the impedance of both antennas a few years
>ago. The ideal impedance is 50 ohms (to match
>the coax). The ideal SWR is unity. For an
>antenna in a free-field (like on a pole), one
>would hope for an SWR less than 1.5 over the
>full VHF aviation band. For less than ideal
>circumstances, < 2.0 or even 3.0 might be considered tolerable.
Actually, if one can get 3:1 or less over the
entire spectrum of interest, then performance
for aviation purposes will be adequate . . .
ASSUMING that locality conditions don't add
factors un-related to SWR.
Emacs!
>As you can see in the attached graphs, impedance
>is all over the map, and rarely near 50 ohms.
>The SWR seems to indicate that the front antenna
>is barely tolerable up to 127 MHz, above which
>it gets pretty bad. Conversely, the tail antenna
>is pretty crappy until 116 MHz, then tolerable right up to 135 MHz.
The aft antenna (vertical fin?) does show a smooth
curve with pronounced dip at 130MHz. This suggest
the antenna is doing a reasonable job of accepting
energy from the feedline over the range of interest.
Further, it's under 3:1 SWR . . . I'd call it
good.
The front antenna plot suggests complete lack
of resonance at any point in the explored spectrum.
I'm assuming this antenna is wrapped around the
inside surface of the composite shell with a
predominantly vertical polarization.
If the SWR scan had been taken lower frequency,
I suspect that a pronounced dip in SWR would
be discovered . . . the trend of the plot as
it approaches 113Mhz suggests this.
It makes sense. Close proximity of either/both
CONDUCTIVE or DIELECTRIC features tend to
lower the resonant frequency of a radiator.
Pasting the antenna to the inside surface of
the fuselage will lower it's resonant frequency
measurably . . . proximity to steel structure
inside the fuselage will lower it more . . .
perhaps MUCH more.
Suggest the ends of the forward antenna be
shortened a bit and new scan taken . . . start
at some much lower frequency to see if there's
a real resonance artifact down there.I suspect
that the interaction with conductive structure,
such as the cage in front and the tail spar in
the rear have more to do with the anomalies than
the modest curvature. Not only that, the coax is
connected to both antennas directly. Since the
coax is an unbalanced=9D conductor, and a dipole
antenna is balanced=9D, there is supposed to be
something called a balun=9D between them. I don't
know if it was ignorance, cheapness, or
weight-consciousness behind the absence of a
balun, but no doubt that=99s also part of the problem.
A BALUN can improve on energy transfer between
feedline and antenna but the thing needs to be
RESONANT in the range of interest first.
I'm fiddling with an dual-band (121.5/406) ELT
antenna intended for installation on the inside
surface of an RF friendly composite fuselage. Looking
at the value of some BALUN options. Discoveries
would applied to the VHF comm antenna being
discussed here.
Get the SWR down and 'centered up' first.
Bob . . .
Message 6
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| Subject: | Re: EAA award and banquet |
I'd love to....but am too far away and have a conflicting schedule. Bob and the
table - enjoy; well deserved!Rumen
----- Original Message -----
From: Robert L. Nuckolls, III <nuckolls.bob@aeroelectric.com>
Sent: Mon, 28 Oct 2019 11:48:35 -0400 (EDT)
Subject: AeroElectric-List: Re: EAA award and banquet
At 09:53 AM 10/28/2019, you wrote:
Hi Bob,
congratulation as well on your EAA award very well deserved.
Cheers Werner
Thank you sir! BTW, I'm told that there are 8
chairs at 'my' banquet table. At the moment,
there are 4 chairs unclaimed. If any Listers
are so motivated/able, I'd be pleased to have
them join us. It's the evening of Nov 7th in OSH.
Bob . . .
Message 7
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| Subject: | Re: EAA award and banquet |
Sounds a great night, not available here as well. Enjoy
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=492024#492024
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