Today's Message Index:
----------------------
1. 12:35 AM - Re: RG-180 Coax? (Denny)
2. 05:45 AM - RG180 coax? (Fergus Kyle)
3. 07:35 AM - GPS Antenna Ground Plane (BAKEROCB@aol.com)
4. 09:27 AM - Use of mobile TV LCD monitor? (Dr. Andrew Elliott)
5. 09:37 AM - Re: Re: RV-List: GPS Antenna (Larry Bowen)
6. 10:14 AM - Re: Re: RV-List: GPS Antenna (Robert L. Nuckolls, III)
7. 10:41 AM - Re: Re: RV-List: GPS Antenna (Larry Bowen)
8. 11:48 AM - Re: RG-180 Coax? (richard@riley.net)
9. 02:04 PM - Transient suppression (Frederic Livesey)
10. 02:21 PM - threaded BNC on GPS antenna? (Dan Checkoway)
11. 02:58 PM - Re: threaded BNC on GPS antenna? (Jim Daniels)
12. 03:35 PM - Re: threaded BNC on GPS antenna? (Dan Checkoway)
13. 04:03 PM - Re: Re: RG-180 Coax? (LarryRobertHelming)
14. 07:17 PM - RG180 coax? (richard@riley.net)
15. 08:36 PM - BNC Connector (PeterHunt1@aol.com)
16. 09:01 PM - Re: Transient suppression (Robert L. Nuckolls, III)
Message 1
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--> AeroElectric-List message posted by: "Denny" <dennymortensen@cableone.net>
I may be wrong on this but the only reference I can find to RG-180 shows it
as 95 ohms impedance. I think you will find that RG-400 is 52 ohms, the same
as RG-58. If I am correct I believe you have just purchased a nice cloths
line as it will not be good for use in your airplane. Also attenuation is
the same as loss IE the bigger the number the worse it is. An example of
this is 3db is the same as half the power. 10 watts in to the coax at the
radio would mean 5 watts showing up at the antenna 6 db loss would mean 2.5
at the antenna. It has been a few years since electronics class so I am a
bit rusty but I think you will have to find another batch of coax. Sorry for
the bad news but just tell the miss what a great deal you just got on a new
cloths line.
Denny
dennymortensen@cableone.net
Cozy #1145
Just Starting
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of
richard@riley.net
Subject: AeroElectric-List: RG-180 Coax?
--> AeroElectric-List message posted by: richard@riley.net
I've just bought a large reel of RG-180 coax surplus. It's either the
biggest bargain I've ever found, or it's money down the drain.
Message 2
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--> AeroElectric-List message posted by: "Fergus Kyle" <VE3LVO@rac.ca>
--> AeroElectric-List message posted by: richard@riley.net
I've just bought a large reel of RG-180 coax surplus. It's either the
biggest bargain I've ever found, or it's money down the drain.
Compared to RG-400, it's smaller, lighter, bends tighter and has more
attenuation - at 1 ghz and 100', it's 19.2 DB lost, vrs 14.1 for RG
400. The center core is 7 strands instead of 19. The rest of the specs
are:
M17/95-RG180
Center Conductor.0120"(7/.004")SCCS
Dielectric .102" PTFE
Shield SPC
Jacket FEP
Diameter .141
Minimum Recommended Bend Radius 0.7
Temp. ( C) -55 +200
Weight (lbs./MFT) 19.8
M17/128-RG400
Center Conductor .0384"(19/.008")SC
Dielectric .116" PTFE
Shield SPC (2)
Jacket FEP
Diameter .195
Minimum Recommended Bend Radius 1.0
Temp. ( C) -55 +200
Weight (lbs./MFT) 50.0
Have I just bought myself a pile o'trouble, trying to find a crimp center
connector that will fit the smaller center conductor?
Richard,
You may have a winner there, but have left off the most
important quality - the impedance. The ohmage built into the coaxial cable
by the dimensions chosen by the maker are what dictate its ability to
transfer the signal seamlessly to the antenna. This value is nominally
50ohms - just the way early coax was built, so is a usual standard and most
units and antennas are designed for 50. There are however many others - 70
for TV and entertainment, 90 for other uses, etc.
While you CAN transfer impedance from one value to another
electronically, it adds complexity, weight and cost to the project. I don't
know what FEP is for a jacket, but doubtless Bob will. The only other
necessary dimension is what connectors will fit the coax and match other
units.
Basically, most of us (unlike hams) use only 20 or 30 feet of
coax to connect to antennas, so saving a lot of money is not possible by
collaring industry or forces surplus. It's easier, not much more expensive
and almost as efficient to go with the flow (RG400 or 58). The hams play
around with impedance transfer because they are likely using 100ft or so and
they're pikers when it comes to laying out industry dollars. Saving $100 is
important, saving $2 on an aircraft can be a disaster.
The stewradesses used to ask. "When can you tell a captain is
cheap?". The answer is "when another one notices it".
Ferg
Message 3
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| Subject: | GPS Antenna Ground Plane |
--> AeroElectric-List message posted by: BAKEROCB@aol.com
8/24/2003
Hello Fellow Builders, The instructions that I received with the antenna that
came with my Garmin GNS 430 said that a 15 inch diameter metal ground plane
should be installed under the antenna. This did not make much sense to me so I
called Garmin.
The tech told me that the large ground plane was not required. When I told
hiim where the antenna was going to be installed -- aft of the firewall inside
the fiberglass skin area between the firewall and the windshield he made a
suggestion. He suggested that some sort of metal sheilding be installed under
the
antenna. His reasoning was that there was a lot of electromagnetic garbage
that existed in that area from various engine and avionic sources and a metal
shield under the antenna would help diminish any adverse effects on the
antenna's performance from those sources.
I have mounted my GPS antenna on a small aluminum shelf suspended from the
underside of the fiberglass skin between the firewall and the windshield.
'OC' Baker, Builder of KIS TR-1 #116 4/14/97 - ?/?/?
Message 4
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| Subject: | Use of mobile TV LCD monitor? |
--> AeroElectric-List message posted by: "Dr. Andrew Elliott" <a.s.elliott@cox.net>
Has anyone out there tried using one of the small monitors available for
portable DVD players as the display for cockpit information, either GPS
or instruments? The small screens, about 3x5", are less than $150. I
know resolution isn't that high, but a PDA is only 240x320.
Andy Elliott
N48DE/AA-1(TD,160)/KFFZ
"World's Fastest (Grumman) American"
http://members.cox.net/n48de/forsale/
Message 5
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| Subject: | RE: RV-List: GPS Antenna |
--> AeroElectric-List message posted by: "Larry Bowen" <Larry@BowenAero.com>
Yes, a standard BNC will fit. Good news.
What about this smaller wire? Its "RG174A/U MIL-C-17F". Will the same
tools I use for the BNC/RG400 work with this smaller wire?
Thx,
-
Larry Bowen
Larry@BowenAero.com
http://BowenAero.com
2003 - The year of flight!
> -----Original Message-----
>
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> --> <bob.nuckolls@cox.net>
>
> At 02:37 PM 8/23/2003 -0400, you wrote:
> >--> AeroElectric-List message posted by: "Larry Bowen"
> >--> <Larry@BowenAero.com>
> >
> >Related, but different -
> >
> >I was planning on using the stock ant that came with the Garmin 196
> >(any reason why I shouldn't?), and mounting it on the glare shield.
> >Only problem is the plug at the end is rather large, maybe 1/2" in
> >diameter. So I'll have to drill a big hole in the glare
> shield to pass
> >it through. Any way to avoid this? Disassemble? Splice? Something
> >else?
>
> Is the connector something nice like a BNC connector
> like this . . .
>
http://www.aeroelectric.com/articles/RG58/RG58_Not5.jpg
or something else? If it's a BNC or other popular connector,
you could just cut it off and replace it.
Bob . . .
Message 6
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| Subject: | RE: RV-List: GPS Antenna |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 12:37 PM 8/24/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Larry Bowen" <Larry@BowenAero.com>
>
>Yes, a standard BNC will fit. Good news.
>
>What about this smaller wire? Its "RG174A/U MIL-C-17F". Will the same
>tools I use for the BNC/RG400 work with this smaller wire?
No, not if you put your connector on "the right way" . . .
but try putting an RG-58/RG-400 connector on using technique
described in http://www.aeroelectric.com/articles/RG58/RG58.html
and I think it will be just fine.
Bob . . .
Message 7
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| Subject: | RE: RV-List: GPS Antenna |
--> AeroElectric-List message posted by: "Larry Bowen" <Larry@BowenAero.com>
OK. So I'll use the existing RG174A/U MIL-C-17F, lop off the end, feed
it through the small hole in the glare screen, attached a BNC using the
technique outlined in the artcle below.
Thanks,
-
Larry Bowen
Larry@BowenAero.com
http://BowenAero.com
2003 - The year of flight!
> -----Original Message-----
> From: Robert L. Nuckolls, III [mailto:bob.nuckolls@cox.net]
> Sent: Sunday, August 24, 2003 1:14 PM
> To: aeroelectric-list@matronics.com
> Subject: RE: AeroElectric-List: RE: RV-List: GPS Antenna
>
>
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> --> <bob.nuckolls@cox.net>
>
> At 12:37 PM 8/24/2003 -0400, you wrote:
> >--> AeroElectric-List message posted by: "Larry Bowen"
> >--> <Larry@BowenAero.com>
> >
> >Yes, a standard BNC will fit. Good news.
> >
> >What about this smaller wire? Its "RG174A/U MIL-C-17F".
> Will the same
> >tools I use for the BNC/RG400 work with this smaller wire?
>
> No, not if you put your connector on "the right way" . . .
> but try putting an RG-58/RG-400 connector on using technique
> described in http://www.aeroelectric.com/articles/RG58/RG58.html
> and I think it will be just fine.
>
> Bob . . .
Message 8
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| Subject: | RE: RG-180 Coax? |
--> AeroElectric-List message posted by: richard@riley.net
Fergus, you're right on the impedence mismatch. It's
90, vrs 50 for RG400. It was only $50, so no great
loss.
Message 9
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| Subject: | Transient suppression |
--> AeroElectric-List message posted by: Frederic Livesey <fred.livesey@zetnet.co.uk>
Hi, having just purchased a evaluation board for the Motorola Oncore 12+
GPS unit ( hoping to make Moving Map System) I find in the instructions
the following:- The low cost Evaluation Board is NOT DESIGNED to be
plugged directly into an automotive electrical system for power.
Automotive systems are extremely noisy(spikes,transients, etc)and the
evaluation board is not fitted with the requisite transient suppression
circuitry. It will most likely work for a while, but operation under
these conditions is not recommended.
When running the board on a 12volt power supply the 5 volt regulator
gets rather warm so I intend to make a separate power supply using the
LM 317 regulator (adjustable) anyone have any ideas how to include the
transient suppression circuitry or is this another of those magic tales
Bob
Regards
Fred
Chester
UK
Message 10
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| Subject: | threaded BNC on GPS antenna? |
--> AeroElectric-List message posted by: "Dan Checkoway" <dan@rvproject.com>
Whoa...I just started messing around with crimping BNC connectors for my
antenna wires. Working great.
But then I took a closer look at my GPS antenna, an "AeroAntenna Technology,
Inc." AT575 antenna (http://www.aeroantenna.com/html/aviation.html) that
came with my GX60. Lo and behold it sports a *threaded* TNCF connector.
What the...?
Is this typical among GPS antennas? Can anybody recommend a P/N for
crimp-on connector for RG-400?
Thanks in advance,
)_( Dan
RV-7 N714D
http://www.rvproject.com
Message 11
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| Subject: | Re: threaded BNC on GPS antenna? |
--> AeroElectric-List message posted by: Jim Daniels <jwdanie@comcast.net>
> Is this typical among GPS antennas? Can anybody recommend a P/N for
> crimp-on connector for RG-400?
Dan, look carefully in your GX60 stuff. My GX65 included an Amphenol
79875 connector. The Amphenol documentation lists two RG400 TNC
connectors, the 79875 (clamp) and the 31-4452 (crimp) per this document:
http://www.amphenolrf.com/products/CatalogPages/tnc_catalog.pdf
Digi-Key:
79875 $17.35 yikes!
Mouser:
79875 $9.23
31-4452 $8.75
Jim
Message 12
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| Subject: | Re: threaded BNC on GPS antenna? |
--> AeroElectric-List message posted by: "Dan Checkoway" <dan@rvproject.com>
Nevermind (sort of)...looks like the AMP 31-2373 (Mouser 523-31-2373, at
$5.71 it's $2 cheaper than Digikey) will do the trick. Please let me know
if there's any reason I shouldn't go ahead and order this...
Thanks,
)_( Dan
----- Original Message -----
From: "Dan Checkoway" <dan@rvproject.com>
Subject: AeroElectric-List: threaded BNC on GPS antenna?
> --> AeroElectric-List message posted by: "Dan Checkoway"
<dan@rvproject.com>
>
> Whoa...I just started messing around with crimping BNC connectors for my
> antenna wires. Working great.
>
> But then I took a closer look at my GPS antenna, an "AeroAntenna
Technology,
> Inc." AT575 antenna (http://www.aeroantenna.com/html/aviation.html) that
> came with my GX60. Lo and behold it sports a *threaded* TNCF connector.
> What the...?
>
> Is this typical among GPS antennas? Can anybody recommend a P/N for
> crimp-on connector for RG-400?
>
> Thanks in advance,
> )_( Dan
> RV-7 N714D
> http://www.rvproject.com
>
>
Message 13
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| Subject: | Re: RE: RG-180 Coax? |
--> AeroElectric-List message posted by: "LarryRobertHelming" <lhelming@sigecom.net>
I know what you mean. I remember before getting on the slicky slope when
$50 was real money.
do not archive
Indiana Larry, RV7 Tip-up TMX-O-360 ACS2002 Dynon CNS430 Digitrak
Bought some stainless steel towel racks today for just $21.
----- Original Message -----
From: <richard@riley.net>
Subject: AeroElectric-List: RE: RG-180 Coax?
> --> AeroElectric-List message posted by: richard@riley.net
>
> Fergus, you're right on the impedence mismatch. It's
> 90, vrs 50 for RG400. It was only $50, so no great
> loss.
>
>
Message 14
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--> AeroElectric-List message posted by: richard@riley.net
Fergus, you're right, it's a different impedance, 90 vrs 50 for RG400. Ah,
well, it was only $35.
Message 15
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--> AeroElectric-List message posted by: PeterHunt1@aol.com
Larry,
If you are installing a Garmin 430 I suggest getting top of the line antenna
lead-in and connectors. I just installed the antenna on my Garmin GNS 530. I
purchased Coaxial cable (part number RG-142 Coax) and Amphenol RFX BNC
connectors (part number 31-2-RFX) from Gulf Coast Avionics. 800-474-9714 or
www.gulf-coast-avionics.com.
This BNC connector is a male connector which fits the Garmin as well as Van's
antennas. The feature which I like is that it requires no crimping (no need
for a questionable crimping tool). A tiny male tip gets soldered to the
internal wire. Then you just assemble the parts and screw the connector together.
If the instructions on the Amphenol package are not clear, just let me know.
The antenna cable I am suggesting is a little costly at $4.00 a foot. I just
don't think it is wise to install an expensive Garmin 430 and then try to
save $10 on cheap antenna lead-in and connectors. IMHO.
Pete
RV-6, panel
N216PH reserved
Message 16
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| Subject: | Re: Transient suppression |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 10:02 PM 8/24/2003 +0100, you wrote:
>--> AeroElectric-List message posted by: Frederic Livesey
><fred.livesey@zetnet.co.uk>
>
>Hi, having just purchased a evaluation board for the Motorola Oncore 12+
>GPS unit ( hoping to make Moving Map System) I find in the instructions
>the following:- The low cost Evaluation Board is NOT DESIGNED to be
>plugged directly into an automotive electrical system for power.
>Automotive systems are extremely noisy(spikes,transients, etc)and the
>evaluation board is not fitted with the requisite transient suppression
>circuitry. It will most likely work for a while, but operation under
>these conditions is not recommended.
> When running the board on a 12volt power supply the 5 volt regulator
>gets rather warm so I intend to make a separate power supply using the
>LM 317 regulator (adjustable) anyone have any ideas how to include the
>transient suppression circuitry or is this another of those magic tales
>Bob
>Regards
>Fred
>Chester
>UK
Take a peek at http://216.55.140.222/temp/Power_Cond.gif
This circuit was shared with another reader wanting to put
a good firewall between his 5v powered microcontrollers and
the little dragons that live on the 28v bus of his airplane . . .
in particular, he wanted an input power conditioning circuit
that would pass DO-160.
In his case, he also wanted backup battery support that would
disconnect automatically if bus power was available.
In a nutshell, here's how the parts work. The LM7805 fixed
regulator (and even LM317 in the high voltage versions)
wouldn't stand off 80v surge. In your case, you're looking
for 40v parts which IS possible at the integrated circuit
level. None the less, for small current draws (less than
a couple hundred mils) I usually include a zener/capacitor
paralleled across the input to the 3-terminal regulator
and a healthy source-limiting resistor upstream.
The notion is that none of the expected short transients will
push past the capacitor, none of the long ones will push past
the zener. The 3-terminal regulator can be depended on for
voltage regulation and noise reduction (what it does best)
without having to stand off full DO-160 stress levels. I'm
pretty sure this philosophy will work well for your application
too.
Bob . . .
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