Today's Message Index:
----------------------
1. 05:24 AM - Re: Z13-8 modification and LSE ignition wiring (Tailwind1)
2. 06:17 AM - Re: Can radials of home made ground plane be tapered? (donjohnston)
3. 06:37 AM - Re: Re: Can radials of home made ground plane be tapered? (Charlie England)
4. 06:43 AM - Re: antenna analyzer? Antennas (Finn Lassen)
5. 07:59 AM - Re: antenna analyzer? Antennas (Robert L. Nuckolls, III)
6. 08:06 AM - Re: Re: Can radials of home made ground plane be tapered? (Robert L. Nuckolls, III)
7. 09:50 AM - Re: Can radials of home made ground plane be tapered? (rparigoris)
8. 10:19 AM - Re: How do you figure C-Rating of a battery? (rparigoris)
9. 11:09 AM - Re: Re: How do you figure C-Rating of a battery? (Charlie England)
10. 11:39 AM - Re: How do you figure C-Rating of a battery? (rparigoris)
11. 12:01 PM - Re: Re: How do you figure C-Rating of a battery? (Charlie England)
12. 12:54 PM - Re: antenna analyzer? Antennas (Finn Lassen)
Message 1
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| Subject: | Re: Z13-8 modification and LSE ignition wiring |
Thank you all for your replies to the questions.
T Mikus
--------
Flying Sonerai II with A80 Continental. Wittman W10 Tailwind under construction,
O360, dual LSE electronic ignition, airframe complete and covered, engine hung,
cowl built. Working on electrical, instrumentation, and other details.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498578#498578
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| Subject: | Re: Can radials of home made ground plane be tapered? |
I would have to agree. I've had the antenna for a GTN625 installed in a fiberglass
airplane with no groundplane for 5 years and never had a problem with reception.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498580#498580
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| Subject: | Re: Can radials of home made ground plane be tapered? |
On Sun, Sep 27, 2020 at 3:53 PM rparigoris <rparigor@hotmail.com> wrote:
> rparigor@hotmail.com>
>
> Hi Bob
>
> See page 2-5 of GA-35 antenna installation manual:
> https://static.garmin.com/pumac/190-00848-00_f.pdf See page 6-8 of GDL-82
> installation manual: https://static.garmin.com/pumac/190-01810-00_06.pdf
>
> Ron P.
>
> I'd be at least a little suspicious of some tech writer 'boilerplating'
installation text from the last install manual he was working on. :-)
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| Subject: | Re: antenna analyzer? Antennas |
I guess ideally a tapered carbonfiber tube (perhaps wrapped with copper
table within another tapered carbonfiber tube).
I wonder if the carbon material is conductive enough for our purposes.
Finn
On 9/27/2020 8:51 PM, Charlie England wrote:
> RE: brass for antenna. If you're talking about outside the canopy, you
> might want to re-think it. My 1st RV4 had the stainless wire whip ELT
> antenna mounted there, until it didn't. It broke off at the stress
> riser where it entered the long composite mounting cone. Behind the
> canopy is a really 'dirty', turbulent area. Maybe you could
> silver-solder a length of stainless tubing? Or 1/2" copper tape
> wrapped on a 'glass arrow shaft. I bet it'll still need some kind of
> support a few inches above the skin.
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| Subject: | Re: antenna analyzer? Antennas |
At 08:43 AM 9/28/2020, you wrote:
>
>I guess ideally a tapered carbonfiber tube (perhaps wrapped with
>copper table within another tapered carbonfiber tube).
Can you easily conduct the experiment? Sounds
interesting.
>I wonder if the carbon material is conductive enough for our purposes.
No. Antennas on our carbon aircraft at Hawker-Beech
required a beefed up ground plane. We also had to add
a distributed ground system for electrics . . . super pain
in the you know what . . .
Bob . . .
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| Subject: | Re: Can radials of home made ground plane be |
tapered?
>
>I'd be at least a little suspicious of some tech
>writer 'boilerplating' installation text from
>the last install manual he was working on. :-)=C2
Yeah, AC43-13 was a prime example of 'suggestions' offered
up by folks who never touched an airplane. EAA was invited
to comment on an 'upgrade' to the document ready for imminent
release back about 1995.
I was invited to comment on the electrics. I think a dozen
or more EAA members participated in other areas. EAA sent
a rather comprehensive data package to the FAA . . . the
document release was pushed out 10 months or so . . . and
they still didn't get all the potholes patched.
I think I've got a copy of my submission around here somewhere . . .
it would be interesting to review it 25 or so years later!
That 7.5" radius figure from Garmin doesn't approach any
multiple of 1/4 wave at the frequency of interest. Unless
going for an 'infinite' g.p. then you'd think they would
call out some odd multiple of 1/4 wave at freq of interest.
Bob . . .
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| Subject: | Re: Can radials of home made ground plane be tapered? |
Hi Group FWIW I called Garmin and Stein Air and both said to use a ground plane.
I also called Vans. On their RV-12 they install the GA-35 on a small bracket
FWF. I called them and asked about a ground plane and they said that the lower
cowl acts as a ground plane. Here's a post from a guy in the Vans Forum: "I
can tell you this...originally I installed mine under the cowl with little to
no ground plane. It worked....
Later I installed a bigger ground plane and the signal levels definately increased."
It was posted in reply from a 12/30/2012 question in Vans Forum, he doesn't
say what model plane he had, precisely what antenna or how large of a ground
plane. I have now heard of several Europa's and a Long EZ using the GA-35 without
a ground plane with good success. Ron P.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498586#498586
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| Subject: | Re: How do you figure C-Rating of a battery? |
Hi Charlie Thank you for thinking of me! For back up I need something small to
fit in headrest. The HF unit is too big and too heavy.
FWIT here's my take:
Harbor Freight in my experience has been less than truthful when it comes to specs
and quality / reliability is an issue. I was working on a project a while
back and they offered a 18aH jump start pack. It had a battery that was marked
18aH. It was a 12aH battery in a 18aH case! We took out the supplied chargers
and I had a pile of them for a while. After 25 uses failure rate was 10 or 15%.
Just awful. Since we took apart hundreds of units, workmanship was also awful.
Northern tools isn't any better.
For another project I needed 100 amps for a short time. I purchased from Northern Tools one of their 4,000 amp jump packs. At room temp it would put out 40 amps for 3 seconds. If it was cold out probably only 20 or 25 amps.:https://www.northerntool.com/shop/tools/product_200676383_200676383
Their# is 216-464-8131
Their 4,000 amp unit can put out ~ 40 amps for 3 seconds at minimum of 10.9 volts,
after 15 seconds down to ~35 amps and if it were cold probably 20 or 25 amps.
The battery is only 8aH. (I didn't test capacity but question that as well).
Ron P.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498587#498587
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| Subject: | Re: How do you figure C-Rating of a battery? |
On 9/28/2020 12:13 PM, rparigoris wrote:
>
> Hi Charlie Thank you for thinking of me! For back up I need something small to
fit in headrest. The HF unit is too big and too heavy.
> FWIT here's my take:
> Harbor Freight in my experience has been less than truthful when it comes to
specs and quality / reliability is an issue. I was working on a project a while
back and they offered a 18aH jump start pack. It had a battery that was marked
18aH. It was a 12aH battery in a 18aH case! We took out the supplied chargers
and I had a pile of them for a while. After 25 uses failure rate was 10 or
15%. Just awful. Since we took apart hundreds of units, workmanship was also awful.
> Northern tools isn't any better.
> For another project I needed 100 amps for a short time. I purchased from Northern Tools one of their 4,000 amp jump packs. At room temp it would put out 40 amps for 3 seconds. If it was cold out probably only 20 or 25 amps.:https://www.northerntool.com/shop/tools/product_200676383_200676383
>
> Their# is 216-464-8131
>
> Their 4,000 amp unit can put out ~ 40 amps for 3 seconds at minimum of 10.9 volts,
after 15 seconds down to ~35 amps and if it were cold probably 20 or 25
amps.
>
> The battery is only 8aH. (I didn't test capacity but question that as well).
>
> Ron P.
Yeah; if you watched the entire video, he shows the 2,800mAH battery in
the 12,000mAH case. Unfortunately, finding truth in marketing,
especially while discussing starting batteries, is a fool's quest.
Having said that, can you really fit the same power *and capacity* in
the same space, with nimh batteries? The battery itself looks to be less
than a third the volume of the case.
--
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| Subject: | Re: How do you figure C-Rating of a battery? |
Hi Charlie I already have my headrest fabricated and wired. If I were to do it
again I would do things differently. Energy density of LiFe batteries is better
than that of NiMh. My NiMh pack fits like a glove. You can see the cutout in
the aluminium plate:
http://www.europaowners.org/main.php?g2_itemId=27332
My requirement if I were to switch from NiMh to something else is to have ability
for battery and BMS to fit in existing space.:
http://www.europaowners.org/main.php?g2_itemId=30608
Capacity of NiMh is less than the HF jump pack (according to Mfg. specs.), but
size and weight is a lot less. NiMh pack will weigh under 2lbs. Original old cells
were rated for 2.2aH which would accomplish the task, newest cells are rated
for 5.0aH.
Ron P.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498589#498589
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| Subject: | Re: How do you figure C-Rating of a battery? |
On Mon, Sep 28, 2020 at 1:46 PM rparigoris <rparigor@hotmail.com> wrote:
> rparigor@hotmail.com>
>
> Hi Charlie I already have my headrest fabricated and wired. If I were to
> do it again I would do things differently. Energy density of LiFe batteries
> is better than that of NiMh. My NiMh pack fits like a glove. You can see
> the cutout in the aluminium plate:
> http://www.europaowners.org/main.php?g2_itemId=27332
> My requirement if I were to switch from NiMh to something else is to have
> ability for battery and BMS to fit in existing space.:
> http://www.europaowners.org/main.php?g2_itemId=30608
> Capacity of NiMh is less than the HF jump pack (according to Mfg. specs.),
> but size and weight is a lot less. NiMh pack will weigh under 2lbs.
> Original old cells were rated for 2.2aH which would accomplish the task,
> newest cells are rated for 5.0aH.
> Ron P.
>
> Looks nice!
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Message 12
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| Subject: | Re: antenna analyzer? Antennas |
Tried with bigger "tubing" (Did not want to spend $ and time going to
local hardware store to pick up 1/2" soft copper tubing and elbow.)
Size of wire or tubing does not appear to influence bandwidth.
So, my conclusion is unchanged: good compact vertically polarized
antenna for single-frequency use, like ELT or 144-146MHz "band".
Not usable as wideband antenna. 118-136MHz certainly is wideband.
(18/127 = 14%).
Would love to have someone else experiment with it and see if they
somehow could get 1:3 SWR over 118-136MHz.
118-137MHz, 1:4 SWR at top.
100-137MHz, 1:4 SWR at top.
You can definitely tune it to much better SWR at center frequency, but
that was not the purpose here.
Finn
On 9/27/2020 9:24 PM, Robert L. Nuckolls, III wrote:
>> I used a relatively thin wire as opposed to the recommended 1/4"
>> to 1/2" tubing, hoping it would broaden the bandwidth (according to
>> this remark:"The larger D is the higher efficiency is").
>> Bob tried to answer that for me but I'm still not sure if
>> "efficiency" is related to bandwidth ("Q").
>> Perhaps I misunderstood that and should try 1/4" tubing?
>
> Or even a radiator fabricated from flat sheet?
>
> The larger the diameter, the greater the bandwidth.
> Efficiency has to do with ohmic losses (how much
> energy goes off in heat) and again, a larger surface
> area of the radiator has lower resistance. Recall that
> currents at these frequencies flow on the skin
> of the conductor. At DC, there is a substantial
> difference between say a 1" diameter rod and a 1"
> thin wall tube. At 100 MHz there is virtually
> no difference 'cause all the 'happening' is at
> the surface.
>
>> With a whip antenna, the bigger the diameter, the broader the bandwidth.
> Exactly . . .
>
>> I also tried a 3/32" brass tube originating at very rear of canopy
>> (ground contact to turtle deck) extending forward and up along the
>> canopy. Very odd frequency response and very SWR sensitive to a hand
>> near the tip.
>
> Interesting observation . . .
>
>> At this point I'm looking at designing a streamline base for my 3/32"
>> brass tubing in Solidworks and 3D printing it, mounting the antenna
>> traditionally just behind the aft canopy skirt. Perhaps squeezing the
>> tubing into a somewhat streamline and/or stepping down to 1/8" after
>> the first 12" piece.
>
> Also interesting . . . let us know
> what you discover.
>
> I am pleased that you've availed yourself
> of this unusual piece of test equipment. You're
> gaining knowledge and experience in a manner
> that you will not forget . . . and will become
> valuable information source for those who
> follow.
>
> Bob . . .
>
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