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Fred Klein
Joined: 26 Mar 2012
Posts: 503
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 Posted: Wed Oct 15, 2014 3:48 pm Post subject: RG393 coax |
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All,
In my as-yet-non-airworthy Europa, I’m about to replace the RG58 coax originally installed for COM and XPNDR antennas. Both my newly purchased COM and (mode “S”) XPNDR are part of the Dynon SkyView suite. Dynon sez the RG58…though perhaps adequate for the COM...will be very unsatisfactory for the XPNDR, and the folks there refer me to “Antenna Cable”, p. 230, (chap 11-p.12) in the SkyView installation guide where various coax cables are considered.
(I cannot seem to include a link to the SkyView Installation Guide)
On p. 231, (chap.11-p.13) there is a chart which appears to state that RG400 (M17/128) is fine IF its length is less than 8’-4”. I find that this M17/128 is the spec. for the RG400 sold by suppliers like Aircraft Spruce, SteinAir, and B & C.
The chart also lists an RG304 for lengths up to 12’6”, and RG393 for lengths up to 17’-3”.
There is also a link below the chart to manufacturer’s data which is more specific…there is clearly a special realm reserved for coax cables.
I’ve located a source for the RG393 where I can buy a minimum of 100 feet at $6.89/ft…and I’m having trouble swallowing.
I’m skeptical of the notion that SkyView customers are using coax other than the widely available RG400 (M17-128), and I’m VERY reluctant to spring for this RG393. I do intend to replace ALL of my RG58.
Can someone who has some keen knowledge on this subject give me some guidance?
…with appreciation,
Fred
[quote][b]
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ceengland7(at)gmail.com
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| Posted: Wed Oct 15, 2014 9:16 pm Post subject: RG393 coax |
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I'd ask myself if the new xponder operates at a different frequency, impedance, & power level from the old one. If it's the same......
Charlie On Oct 15, 2014 6:54 PM, "Fred Klein" <fklein(at)orcasonline.com (fklein(at)orcasonline.com)> wrote:[quote]All,
In my as-yet-non-airworthy Europa, I’m about to replace the RG58 coax originally installed for COM and XPNDR antennas. Both my newly purchased COM and (mode “S”) XPNDR are part of the Dynon SkyView suite. Dynon sez the RG58…though perhaps adequate for the COM...will be very unsatisfactory for the XPNDR, and the folks there refer me to “Antenna Cable”, p. 230, (chap 11-p.12) in the SkyView installation guide where various coax cables are considered.
(I cannot seem to include a link to the SkyView Installation Guide)
On p. 231, (chap.11-p.13) there is a chart which appears to state that RG400 (M17/128) is fine IF its length is less than 8’-4”. I find that this M17/128 is the spec. for the RG400 sold by suppliers like Aircraft Spruce, SteinAir, and B & C.
The chart also lists an RG304 for lengths up to 12’6”, and RG393 for lengths up to 17’-3”.
There is also a link below the chart to manufacturer’s data which is more specific…there is clearly a special realm reserved for coax cables.Â
I’ve located a source for the RG393 where I can buy a minimum of 100 feet at $6.89/ft…and I’m having trouble swallowing.Â
I’m skeptical of the notion that SkyView customers are using coax other than the widely available RG400 (M17-128), and I’m VERY reluctant to spring for this RG393. I do intend to replace ALL of my RG58.
Can someone who has some keen knowledge on this subject give me some guidance?
…with appreciation,
Fred
| Quote: |
ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
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[b]
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Kellym
Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ
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| Posted: Wed Oct 15, 2014 9:32 pm Post subject: RG393 coax |
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The Skyview transponder sold for US market is 250 wats, mode S, using
the standard 1030 and 1090 Mhz frequencies that all Mode A and C
transponders use. In other words the difference is in the pulsed
message, not the frequency or power.
It is difficult to see why more than 8 ft of cable would be needed for a
2 place aircraft, unless the antenna needs to be in an unusual location.
Also difficult to see why the com radio would need better than RG-58
cable unless it has less noise rejection than the radios designed 30
years ago that worked just fine at ranges as far as 120 nm with
sufficient altitude.
On 10/15/2014 10:14 PM, Charlie England wrote:
| Quote: |
I'd ask myself if the new xponder operates at a different frequency,
impedance, & power level from the old one. If it's the same......
Charlie
On Oct 15, 2014 6:54 PM, "Fred Klein" <fklein(at)orcasonline.com
<mailto:fklein(at)orcasonline.com>> wrote:
All,
In my as-yet-non-airworthy Europa, I’m about to replace the RG58
coax originally installed for COM and XPNDR antennas. Both my
newly purchased COM and (mode “S”) XPNDR are part of the Dynon
SkyView suite. Dynon sez the RG58…though perhaps adequate for the
COM...will be very unsatisfactory for the XPNDR, and the folks
there refer me to “Antenna Cable”, p. 230, (chap 11-p.12) in the
SkyView installation guide where various coax cables are considered.
(I cannot seem to include a link to the SkyView Installation Guide)
On p. 231, (chap.11-p.13) there is a chart which appears to state
that RG400 (M17/128) is fine IF its length is less than 8’-4”. I
find that this M17/128 is the spec. for the RG400 sold by
suppliers like Aircraft Spruce, SteinAir, and B & C.
The chart also lists an RG304 for lengths up to 12’6”, and RG393
for lengths up to 17’-3”.
There is also a link below the chart to manufacturer’s data which
is more specific…there is clearly a special realm reserved for
coax cables.
I’ve located a source for the RG393 where I can buy a minimum of
100 feet at $6.89/ft…and I’m having trouble swallowing.
I’m skeptical of the notion that SkyView customers are using coax
other than the widely available RG400 (M17-128), and I’m VERY
reluctant to spring for this RG393. I do intend to replace ALL of
my RG58.
Can someone who has some keen knowledge on this subject give me
some guidance?
…with appreciation,
Fred
*
ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
*
*
*
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Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
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djtoddb
Joined: 26 Mar 2010
Posts: 14
Location: Mesa, AZ
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| Posted: Wed Oct 15, 2014 10:10 pm Post subject: RG393 coax |
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What makes the RG400 better/different than the RG58 for the transponder use?
Todd Bristol
On Wednesday, October 15, 2014 10:14 PM, Charlie England <ceengland7(at)gmail.com> wrote:
I'd ask myself if the new xponder operates at a different frequency, impedance, & power level from the old one. If it's the same......
Charlie
On Oct 15, 2014 6:54 PM, "Fred Klein" <fklein(at)orcasonline.com (fklein(at)orcasonline.com)> wrote:
[quote]All,
In my as-yet-non-airworthy Europa, I’m about to replace the RG58 coax originally installed for COM and XPNDR antennas. Both my newly purchased COM and (mode “S”) XPNDR are part of the Dynon SkyView suite. Dynon sez the RG58…though perhaps adequate for the COM...will be very unsatisfactory for the XPNDR, and the folks there refer me to “Antenna Cable”, p. 230, (chap 11-p.12) in the SkyView installation guide where various coax cables are considered.
(I cannot seem to include a link to the SkyView Installation Guide)
On p. 231, (chap.11-p.13) there is a chart which appears to state that RG400 (M17/128) is fine IF its length is less than 8’-4”. I find that this M17/128 is the spec. for the RG400 sold by suppliers like Aircraft Spruce, SteinAir, and B & C.
The chart also lists an RG304 for lengths up to 12’6”, and RG393 for lengths up to 17’-3”.
There is also a link below the chart to manufacturer’s data which is more specific…there is clearly a special realm reserved for coax cables.
I’ve located a source for the RG393 where I can buy a minimum of 100 feet at $6.89/ft…and I’m having trouble swallowing.
I’m skeptical of the notion that SkyView customers are using coax other than the widely available RG400 (M17-128), and I’m VERY reluctant to spring for this RG393. I do intend to replace ALL of my RG58.
Can someone who has some keen knowledge on this subject give me some guidance?
…with appreciation,
Fred
| Quote: |
ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
|
--> http://www.matronics.com/con================
[b]
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wrmaxwell(at)bigpond.com
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| Posted: Wed Oct 15, 2014 10:19 pm Post subject: RG393 coax |
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It has lower loss, which becomes more critical as you go up in frequency. Waht is OK at VHF, frequently isn't once you start working at microwave frequencies.
Bill
On 16/10/2014 5:08 PM, Todd Bristol wrote:
[quote] What makes the RG400 better/different than the RG58 for the transponder use?
Â
Todd Bristol
Â
On Wednesday, October 15, 2014 10:14 PM, Charlie England <ceengland7(at)gmail.com> (ceengland7(at)gmail.com) wrote:
I'd ask myself if the new xponder operates at a different frequency, impedance, & power level from the old one. If it's the same......
Charlie
On Oct 15, 2014 6:54 PM, "Fred Klein" <fklein(at)orcasonline.com (fklein(at)orcasonline.com)> wrote:
| Quote: | All,
In my as-yet-non-airworthy Europa, I’m about to replace the RG58 coax originally installed for COM and XPNDR antennas. Both my newly purchased COM and (mode “S”) XPNDR are part of the Dynon SkyView suite. Dynon sez the RG58…though perhaps adequate for the COM...will be very unsatisfactory for the XPNDR, and the folks there refer me to “Antenna Cable”, p. 230, (chap 11-p.12) in the SkyView installation guide where various coax cables are considered.
(I cannot seem to include a link to the SkyView Installation Guide)
On p. 231, (chap.11-p.13) there is a chart which appears to state that RG400 (M17/128) is fine IF its length is less than 8’-4”. I find that this M17/128 is the spec. for the RG400 sold by suppliers like Aircraft Spruce, SteinAir, and B & C.
The chart also lists an RG304 for lengths up to 12’6”, and RG393 for lengths up to 17’-3”.
There is also a link below the chart to manufacturer’s data which is more specific…there is clearly a special realm reserved for coax cables.Â
I’ve located a source for the RG393 where I can buy a minimum of 100 feet at $6.89/ft…and I’m having trouble swallowing.Â
I’m skeptical of the notion that SkyView customers are using coax other than the widely available RG400 (M17-128), and I’m VERY reluctant to spring for this RG393. I do intend to replace ALL of my RG58.
Can someone who has some keen knowledge on this subject give me some guidance?
…with appreciation,
Fred
--> http://www.matronics.com/con================
|
[b]
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user9253
Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan
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| Posted: Thu Oct 16, 2014 4:58 am Post subject: Re: RG393 coax |
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Fred,
From what I have read on previous posts, RG-58 is fine for the com radio.
You did not say how long the transponder coax is in your Europa. How long is it? If the length is excessive, can you move the transponder closer to the antenna as suggested in the Skyview installation manual?
I suggest that you call SteinAir and ask their advice. If it necessary to use expensive cable, SteinAir can sell you only the length needed with professionally installed connectors.
For others, here is a link to the Skyview installation guide:
http://www.dynonavionics.com/downloads/Install_Guides/SkyView_System_Installation_Guide-Rev_R_v11.0.pdf
See pages 11-12 through 11-13
Joe
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nuckolls.bob(at)aeroelect
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| Posted: Thu Oct 16, 2014 8:43 am Post subject: RG393 coax |
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| Quote: |
I'm skeptical of the notion that SkyView customers are using coax other than the widely available RG400 (M17-128), and I’m VERY reluctant to spring for this RG393. I do intend to replace ALL of my RG58.
Can someone who has some keen knowledge on this subject give me some guidance? |
Your gut reaction is on track . . .
Coax cable decisions for the vast majority of GA feed line
decisions is not unlike deciding which laundry soap to
use on your wash-n-wear shirts. Unless they are contaminated
with something extra-ordinary . . . like road tar . . .
the dirt-removing performance offered by any of the dozens
of choices on the laundry soap isle will produce satisfactory
results.
Take a peek down the 'laundry soap' isle for coax
cable . . .
http://tinyurl.com/kjjvuel
Who ever called out RG-393 for a general aviation
antenna installation should be banished for 30 days
to each lunch at McDonalds. This stuff has a 10AWG
center conductor and an outside diameter of 0.4"
If the coax was FREE, you'd still have to find connectors
and tools to install them . . . lots of $thrashing$ around
just to get 1db of loss in a 10' run at GPS frequencies.
If you REALLY want/need that kind of performance, consider
LMR-240 coax.
http://tinyurl.com/kw9s2n8
MUCH less expensive and easier route (0.24" diam) but
still problematic for acquisition and personal installation
of the desired connectors. Fortunately, there are folks
who will build a custom length of this cable with the
right connectors for a fraction of the cost of RG-393.
Contact this guy . . .
http://tinyurl.com/nz9cjpg
On the other hand, if you have connectors and tools for
RG400/RG141 . . . this stuff would probably be just
fine. I still have some 141 on hand . . . tell me what
connectors you need and I can probably make an attractive
offer ($0.13/inch and $5/connector). LMR-195 is superior
performance to RG58 and on a par with 400/141 . . . and
uses same tools/connectors as the RG series coax. I've
installed about a half dozen connectors on LMR-195 . . .
it's a little finicky but it's just another process to be
learned. Cool thing is that it's really inexpensive.
Bob . . . [quote][b]
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Fred Klein
Joined: 26 Mar 2012
Posts: 503
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| Posted: Thu Oct 16, 2014 9:59 am Post subject: RG393 coax |
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Gentlemen…thank you for your helpful replies…
re: RG58 for COM
Dynon sez, "Regarding your choice of routing and coaxial cable, in my personal experience as an Amateur Radio Operator, while RG58 coaxial cable will work, and work acceptably in the absence of other signals and potential interference, it is overall a poor coaxial cable. In the long run, especially now while you have the luxury of easy access during the build process, you will be much better served, overall, in the long term, by using the much better RG400 coaxial cable. It will much better resist potential radio frequency interference sources within the fuselage.
"Put it this way - with RG58, your COM radio will be "listening" not only to signals coming in from the antenna, but also all the "birdies" from within the fuselage. With RG400, your COM radio will only be listening to the signals from the antenna.”
re: Length of run for XPNDR coax in my aircraft…
At present, the run is approx. 8 feet, however, this routing puts it in the same raceway as my 4AWG feeder AND 4AWG ground…(battery and XPNDR antenna are aft of the cockpit)…when upgrading my coax, I was anticipating changing the routing so that it is separate from these heavy duty power lines and this would increase the length of coax to about 13 feet…I MAY be able to relocate the XPNDR antenna to reduce that distance to 10 feet.
re: Bob’s comment:
| Quote: | Your gut reaction is on track . . .
Take a peek down the 'laundry soap' isle for coax
cable . . .
http://tinyurl.com/kjjvuel
|
…I can only respond w/ a “…geesus…”…as I previously noted, my eyes were opened to a whole new world of coax…it looks like a very deep rabbit hole…one which I need not explore further.
OK…moving forward…
I’m going to order some RG400 (M17/128) for my XPNDR…and keep it in the raceway alongside the 4AWG feeders to keep the run as short as possible. In doing so, I am relying on my memory of an older post of Bob’s which stated, if I recall correctly, that there is NO EVIDENCE of coax performance being compromised by adjacency to 12v power feeders. (I’d appreciate a correction if I’m in error.)
And since my set up allows for swapping out the RG58 for my COM antenna anytime, I think I may just leave it in for now and replace it w/ RG400 only if problems show up.
I’m having one of those days where I say, “…screw it…I want to get this puppy airborne…”
Fred
[quote][b]
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nuckolls.bob(at)aeroelect
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| Posted: Thu Oct 16, 2014 10:57 am Post subject: RG393 coax |
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| Quote: | I’m going to order some RG400 (M17/128) for my
XPNDR…and keep it in the raceway alongside the
4AWG feeders to keep the run as short as
possible. In doing so, I am relying on my memory
of an older post of Bob’s which stated, if I
recall correctly, that there is NO EVIDENCE of
coax performance being compromised by adjacency
to 12v power feeders. (I’d appreciate a correction if I’m in error.)
|
Correct.
Bob . . .
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