Best coax for aircraft radios

[ELIPPSE]

If you would like to have the finest low-loss, light-weight coax cable
for your aircraft radio installations, get Andrew FSJ1-50A Heliax
Superflexible Foam Cable. It's pricier than the RG's, but the
performance is so far superior that your com, VOR, Xpndr, and whatever
will give you range performance like you've never seen. Andrew also has
a matching BNC male connector, the F1PBM. The cable is rated at 6.4kW
peak power, minimum bend radius of 1", and 0.54 oz/ft. Compare that to
RG58 at 0.35oz/ft. It is 0.29" OD, whereas RG58 is o.116" Isolation or
leakage is at least 300dB due to the solid outer jacket, vs 45dB at
best for RG58, and more likely 25dB after being flexed around. Anyone
who uses an RG cable in their aircraft with this stuff available
doesn't really care about good radio rx/tx! Check out their catalog
pages on www.andrew.com .

[UltraJohn]

ELIPPSE wrote:

> If you would like to have the finest low-loss, light-weight coax cable
> for your aircraft radio installations, get Andrew FSJ1-50A Heliax
> Superflexible Foam Cable. It's pricier than the RG's, but the
> performance is so far superior that your com, VOR, Xpndr, and whatever
> will give you range performance like you've never seen. Andrew also has
> a matching BNC male connector, the F1PBM. The cable is rated at 6.4kW
> peak power, minimum bend radius of 1", and 0.54 oz/ft. Compare that to
> RG58 at 0.35oz/ft. It is 0.29" OD, whereas RG58 is o.116" Isolation or
> leakage is at least 300dB due to the solid outer jacket, vs 45dB at
> best for RG58, and more likely 25dB after being flexed around. Anyone
> who uses an RG cable in their aircraft with this stuff available
> doesn't really care about good radio rx/tx! Check out their catalog
> pages on www.andrew.com .


Between this and the props . . . .

Hey man this isn't rec.aviation.marketing!

[UltraJohn]

UltraJohn wrote:

> ELIPPSE wrote:
>
>> If you would like to have the finest low-loss, light-weight coax cable
>> for your aircraft radio installations, get Andrew FSJ1-50A Heliax
>> Superflexible Foam Cable. It's pricier than the RG's, but the
>> performance is so far superior that your com, VOR, Xpndr, and whatever
>> will give you range performance like you've never seen. Andequipmentas
>> a matching BNC male connector, the F1PBM. The cable is rated at 6.4kW
>> peak power, minimum bend radius of 1", and 0.54 oz/ft. Compare that to
>> RG58 at 0.35oz/ft. It is 0.29" OD, whereas RG58 is o.116" Isolation or
>> leakage is at least 300dB due to the solid outer jacket, vs 45dB at
>> best for RG58, and more likely 25dB after being flexed around. Anyone
>> who uses an RG cable in their aircraft with this stuff available
>> doesn't really care about good radio rx/tx! Check out their catalog
>> pages on www.andrew.com .
>
>
> Between this and the props . . . .
>
> Hey man this isn't rec.aviation.marketing!
Replying tomy own!
It was mainly meant for the other posts he sent at the same time touting the
same prop in an obvious marketing ploy.

Now as far as the cable goes. Hey at lest than 20 feet for most runs you
don't need heliax and actually 58 is usable for most. There are plenty of
better than 58 available locally such as some of the micro rg8's. also as
you stated your heliax is twice+ the size so that can be a concern and also
your quote of 300db. . well I can't prove otherwise but I doubt it. In any
case the equipment and connectors you use it with has so much more leakage
than that that it would be overkill if it did have 300db isolation. Lastly
who needs cable rated at 6.4kw for transmitters running 5 watt (comms) to
maybe a couple hundred (transponders)?
Anyway I'm sure its great cable, Andrews is a very reputable company but it
is way overkill for most homebuilders!
John

[[email protected]]

Andrew Heliax is fine cable - just what you need to run
up a tower (it comes in many sizes). But in an airplane?
Like the man said - it's overkill. I'd recommend RG142.

As for the isolation - engineers have an inside joke that
goes something like this:

Oh say can you see.....
Three Hundred Dee Bee....

This is a range greater than that between the smallest
detectable signal to an unimaginable amount of power.
In other words, it doesn't exist in the natural world.
AFAIK, nobody makes anything with "300 dB of isolation".
Any engineers out there who would care to comment?

David Johnson

[rocky]

wrote:
> Andrew Heliax is fine cable - just what you need to run
> up a tower (it comes in many sizes). But in an airplane?
> Like the man said - it's overkill. I'd recommend RG142.
>
> As for the isolation - engineers have an inside joke that
> goes something like this:
>
> Oh say can you see.....
> Three Hundred Dee Bee....
>
> This is a range greater than that between the smallest
> detectable signal to an unimaginable amount of power.
> In other words, it doesn't exist in the natural world.
> AFAIK, nobody makes anything with "300 dB of isolation".
> Any engineers out there who would care to comment?
>
> David Johnson
>
I used to work with andrews 3 1/8 coax for broadcast stations. With 25kw
input there is almost no measurable radiation from the cable. Andrews
uses a SOLID copper outer jacket that is far superior to any foil or
braid jacketed cable. But for RG58 in a 10 foot cable a 1db loss is very
minor. Larsen antennas does sell a RG58 low loss cable, mainly used for
cellular service.

[Scott]

I missed the original post, so...

What was the original poster's concern about isolation? I'm not aware
of any repeaters in use aboard aircraft. Is he worried about signals
leaking out of the coax of say com1 transmitting and getting into the
receiver of com2? I wouldn't think there would be much need to
worry...more RF will get into the com2 receiver by the RF leaving the
antenna. Seems to me that no matter what kind of "isolation" the coax
cable has, the worst thing that can happen is that he would experience a
little desense on com2 receive while he's transmitting on com1, but it
wouldn't make too much difference...if he's talking on com1, he won't be
able to concentrate too much on what is being received on com2 anyway...

RG-142 is nice cable, but it's not quite as flexible as RG58. The loss
in 10 or 20 feet of RG58 isn't really worth the extra cost in my opinion...

Scott

wrote:
> Andrew Heliax is fine cable - just what you need to run
> up a tower (it comes in many sizes). But in an airplane?
> Like the man said - it's overkill. I'd recommend RG142.
>
> As for the isolation - engineers have an inside joke that
> goes something like this:
>
> Oh say can you see.....
> Three Hundred Dee Bee....
>
> This is a range greater than that between the smallest
> detectable signal to an unimaginable amount of power.
> In other words, it doesn't exist in the natural world.
> AFAIK, nobody makes anything with "300 dB of isolation".
> Any engineers out there who would care to comment?
>
> David Johnson
>

[Philippe]

Scott wrote:

> I missed the original post, so...
me too...

[...]

On experimental planes, we don't realy need better than RG58.
Who need more than 2m/6ft long cable?
If you see the difference beetwen the best cable and a RG58, on 6ft long you
can't realy get a real better signal on the air with a better cable.

By
--
minicab F-PRAZ
Philippe Vessaire ҿӬ

[[email protected]]

Scott > wrote:
: RG-142 is nice cable, but it's not quite as flexible as RG58. The loss
: in 10 or 20 feet of RG58 isn't really worth the extra cost in my opinion...

... and at least the stuff I tried in my PA-28 had a copper-clad steel center
conductor. It screwed the compass when run up the support between the two halves of
the windscreen. I had to re-swap it back to RG-58 (MIL-C-17).

Stupid compass.... :)

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

[ELIPPSE]

I worked with an X-band extreme-accuracy Atlas guidance radar at
Vandenberg AFB. It was necessary to have at least 150dB isolation to
prevent interference in our test simulator. Solid jacket cable was the
only thing that would allow this kind of performance. The Andrew cable
was also the only kind that did not generate noise when flexed or
vibrated, which was very important in our test operations. Remember
that the transponder puts out 100W-400W peak. Leaking cables in close
proximity can cross couple. Cable leakage also effects the apparent
radiation pattern of antennas, generating undesired sidelobes and
cancellations. Consider the 20' long com run from the instrument panel
to the antenna buried in the tip sail of the VariEZ or LongEZ that
passes near the extreme RFI generated by the engine's ignition. Has
anyone ever had spark noise in their com radio?

[ELIPPSE]

DME and the transponder are in the 960MHz to 1215MHz range. At 1GHz,
RG58 has 17.5dB/100ft., RG142 has 13.0dB/100ft., and FSJ1-50A has
6.0dB/100ft. If I was operating under extreme conditions, I would want
the best performing equipment available to me. Sometimes 1dB can make
the difference between getting a signal or not! Ask the guys talking to
the spacecraft out among the planets.

[ELIPPSE]

Sorry that you think this is a marketing ploy. I thought that this was
a forum for information exchange. I just wanted to pass along my
experiences working with all kinds of coax under a lot of extreme
conditions, and the lessons learned from them.
As far as the props, If you had designed a prop that gave performance
so far beyond the others available and this performance was
demonstrated in the best way, wouldn't you want to share that with
others? I don't sell cables or props or ignitions; I leave that to
others. I guess there are some of you who don't care that there is a
revolution in prop design that can give you markedly better
performance. Or coax that will up your radio's performance. Perhaps you
don't also want me to share with you the research I and another have
done to keep your prop bolts tensioned regardless of temperature or
humidity. When all you do is put down others who want to share, you can
suppress that sharing!

[RST Engineering]

I have rarely read such unmitigated horsepuckey in my engineering career.

Jim



"ELIPPSE" > wrote in message
oups.com...
> If you would like to have the finest low-loss, light-weight coax cable
> for your aircraft radio installations

[[email protected]]

ELIPPSE > wrote:
: DME and the transponder are in the 960MHz to 1215MHz range. At 1GHz,
: RG58 has 17.5dB/100ft., RG142 has 13.0dB/100ft., and FSJ1-50A has
: 6.0dB/100ft. If I was operating under extreme conditions, I would want
: the best performing equipment available to me. Sometimes 1dB can make
: the difference between getting a signal or not! Ask the guys talking to
: the spacecraft out among the planets.

That's a completely different problem than aircraft communication. Most of it
is ancient tech with fairly wide SNR margins, and your 4.5db/100' shinks to only
0.45db for a normal run of 10' in a GA aircraft. That's down in the noise (pun
intended) for signal degredation and about the same loss as putting a connector on the
end. IIRC the main reasons for RG142 are ruggedness (read: bitch to work with),
longevity (won't rot out in 40 years), and materials (RG142 on fire is supposed to be
at least slightly less hazardous than RG58 on fire).

-Cory
--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

[Peter Dohm]

I really like RG142 as well, especially the low loss and low leakage
in a fairly small and light cable. But for short runs, it is still overkill
for much of anything besides a radio altimeter.

Peter

> wrote in message
oups.com...
> Andrew Heliax is fine cable - just what you need to run
> up a tower (it comes in many sizes). But in an airplane?
> Like the man said - it's overkill. I'd recommend RG142.
>
> As for the isolation - engineers have an inside joke that
> goes something like this:
>
> Oh say can you see.....
> Three Hundred Dee Bee....
>
> This is a range greater than that between the smallest
> detectable signal to an unimaginable amount of power.
> In other words, it doesn't exist in the natural world.
> AFAIK, nobody makes anything with "300 dB of isolation".
> Any engineers out there who would care to comment?
>
> David Johnson
>

[ELIPPSE]

Horsepuckey, unmitigated or otherwise, does not constitute a cogent
review of the technical information presented. It would be much more
enlightening to all if the respondent had replied with a discussion of
the technical merits as he sees them from his own perspective of
theoretical and practical experience, rather than to launch into the
vitriol of an ad hominem attack. This type of attack is often a shield
for the attacker's own ignorance or incompetence! I presented the
specs; he, for his part, should show how and in what way they are not
applicable, along with his own recommendations, especially with
practical examples of received and transmitted power levels and cable
lengths. It would also be interesting to see, from his vantage point,
what testing he has done on the effect of signal leakage in coax on the
their concomitant creation of sidelobes resulting in attenna pattern
distortion and signal dropout. Only in this way may all who are
interested in the proper selection of cabling for their aircraft be
able to intelligently make, what is for them, the proper choice of
cable and connector type based on performance and economics. We report,
they decide!

[RST Engineering]

Double horsepuckey, and I don't appreciate your snide side emails. If you
have something to say to me, have the intestinal fortitude to post it in the
newsgroup.

What you recommended was a howitzer to kill an ant. Showing how and why 300
dB is a meaningless number is meaningless to somebody who doesn't have a
concept of how impossible that is to measure.

Signal leakage distortion of the antenna pattern is possible to measure on
the pattern range. With the coax inside of a metal structure the concept is
meaningless, as is it meaningless when the coax is bundled with other
wires...a 99+% probability.

Plonk.

Jim




"ELIPPSE" > wrote in message
oups.com...
> Horsepuckey, unmitigated or otherwise, does not constitute a cogent
> review of the technical information presented. It would be much more
> enlightening to all if the respondent had replied with a discussion of
> the technical merits as he sees them from his own perspective of
> theoretical and practical experience, rather than to launch into the
> vitriol of an ad hominem attack. This type of attack is often a shield
> for the attacker's own ignorance or incompetence! I presented the
> specs; he, for his part, should show how and in what way they are not
> applicable, along with his own recommendations, especially with
> practical examples of received and transmitted power levels and cable
> lengths. It would also be interesting to see, from his vantage point,
> what testing he has done on the effect of signal leakage in coax on the
> their concomitant creation of sidelobes resulting in attenna pattern
> distortion and signal dropout. Only in this way may all who are
> interested in the proper selection of cabling for their aircraft be
> able to intelligently make, what is for them, the proper choice of
> cable and connector type based on performance and economics. We report,
> they decide!
>

[Dude]

"ELIPPSE" > wrote in message
oups.com...
> Horsepuckey, unmitigated or otherwise, does not constitute a cogent
> review of the technical information presented. It would be much more
> enlightening to all if the respondent had replied with a discussion of
> the technical merits as he sees them from his own perspective of
> theoretical and practical experience, rather than to launch into the
> vitriol of an ad hominem attack.

His attack was not ad hominem. I may not be an engineer, but I did take
Latin.

In fact, by usenet standards I would judge his comments as only border line
rude. He likely felt free to snipe because your reputation here is already
poor due to several missteps in ettiquette.

This type of attack is often a shield
> for the attacker's own ignorance or incompetence!

I also took Psych, Communications, and Logic. You made an obvious
statement and that may or may not apply, and then qualified it with "often"
so that you really didn't say anything. Which is good, because as I said
before, I took Latin, and this IS an ad hominem attack.

I presented the
> specs; he, for his part, should show how and in what way they are not
> applicable, along with his own recommendations, especially with
> practical examples of received and transmitted power levels and cable
> lengths.

Maybe he should, or maybe he doesn't need to. Remember, "they decide".

It would also be interesting to see, from his vantage point,
> what testing he has done on the effect of signal leakage in coax on the
> their concomitant creation of sidelobes resulting in attenna pattern
> distortion and signal dropout.

Interesting to whom? If you don't respect his opinion, why do you care about
his perspective?

Only in this way may all who are
> interested in the proper selection of cabling for their aircraft be
> able to intelligently make, what is for them, the proper choice of
> cable and connector type based on performance and economics. We report,
> they decide!

Actually, I, like many aviators, tend to go with what is tried and true
until I see a desirable benefit that would result from a change. While a
seriously detailed investigation and discussion may bring about new
knowledge, its not like our we are all failing as it is.

You are obviously a bright guy, but there are lots of those folks already
here. Perhaps you should try to avoid any heavy arguments for a bit.

[UltraJohn]

ELIPPSE wrote:

> I worked with an X-band extreme-accuracy Atlas guidance radar at
> Vandenberg AFB. It was necessaspecializedt least 150dB isolation to
> prevent interference in our test simulator. Solid jacket cable was the
> only thing that would allow this kind of performance. The Andrew cable
> was also the only kind that did not generate noise when flexed or
> vibrated, which was very important in our test operations. Remember
> that the transponder puts out 100W-400W peak. Leaking cables in close
> proximity can cross couple. Cable leakage also effects the apparent
> radiation pattern of antennas, generating undesired sidelobes and
> cancellations. Consider the 20' long com run from the instrument panel
> to the antenna buried in the tip sail of the VariEZ or LongEZ that
> passes near the extreme RFI generated by the engine's ignition. Has
> anyone ever had spark noise in their com radio?


Your x-band does not compare with homebuilt even when talking about
transponders and dme. Even 20 foot run for a com radio doesn't require that
high a caliber cable. You will probably find that most of the noise from
ignition isn't from the center conductor but from the shield and also then
antenna itself. Most people do not run there coax next to their ignition
wires anyway! Use a little common sense, it's a heck of a lot cheaper!
John


PS my background is in microwave measurements etc that doesn't mean I need
to engineer my homebuilt around top end specialized cable.

[GeorgeB]

On Tue, 11 Jan 2005 15:21:38 -0800, "RST Engineering"
> wrote:

>What you recommended was a howitzer to kill an ant. Showing how and why 300
>dB is a meaningless number is meaningless to somebody who doesn't have a
>concept of how impossible that is to measure.

Aw Jim, 0.1 microvolt to 1 Megavolt is "only" 260 dB ... <g> ...
assuming 50 ohms, that is good receiver sensitivity vs 20 Gigawatt ...
we have Gigahertz, why not Gigawatt ... OH, you mean that a large
power plant turbine-generator is on the order of a Gigawatt ... OH ...

Methinks he doesn't understand large (and small) numbers ...

[Scott]

Quite true, but I'm a low and slow guy. I nver fly THAT high up ;) For
us terrestrial types, I still don't think a dB or two is going to make a
ton of difference. I routinely talk 75 miles from 2000 feet with my
handheld at 1 Watt, through about 15 feet of RG-58 driving one of those
flexible ELT whip antennas.

Scott



ELIPPSE wrote:

> Ask the guys talking to
> the spacecraft out among the planets.
>

[ELIPPSE]

Hi, John!
On the example I gave it was for a LongEZ or VariEZ where the cable run
is 20' from radio to the tip sail antenna. The coax passes within less
than 12" from an ignition lead on some of these planes, depending on
how the cable is run.

[ELIPPSE]

Hi, Dude!
It's funny! Here I post some info about a cable, and its
characteristics, that I had a lot of excellent results with, and which
I installed on my Lancair. I thought that this forum was for the
exchange of information. I expected some replies such as: "Yeah, that
cable has some good low-loss characteristics, but after checking the
prices on the mfg's. site, I decided that the performance I'm getting
with the cable I presently use is good enough for me." OK, that's
reasonable! Or: "I'm building this hot Lancair IVP and I want the best
cable I can get; money is no object! Thanks for the tip" OK, that's
reasonable too! But do I get a discussion on the relative merits of
this cable and others? No, I get a bunch of sharks and their sycophants
who want to prove to each other just how smart they are and how they
can take down this new guy."Who does he think he is, anyway?"
I've met this type over and over in the Aerospace world. Those who
can't get up a decent technical discussion and then hide their
ignorance behind insults. Too bad that they don't see that when others
see this type of diatribe over some little innocent posting, that
they're afraid of posting something themselves and incurring this type
of wrath. What a stifler of open discussion! The political world is
full of this kind; look at the last election. I expected that on a
homebuilder's site, at least, that that kind of thing would be
dispensed with so that a dialogue of builder-helping-builder would
prevail! Silly me! I guess even in homebuilding small egos prevail. Too
bad there are not more like Corky Scott and the ones who contacted me
about the ELIPPSE prop, looking for more performance. They weren't
taken-in by these egomaniacal types who can't stand it if someone
doesn't kiss their boots and acknowledge them as the pre-eminent
authorities on everything! But as for me, as I get information that I
think others may want to know, I will post it on the forum and ignore
the sharks.

[UltraJohn]

Ellipse
My original post (and I think I started the replies) had more to do with the
fact you came in with your first appearance with multiple post (4 or 5)the
one with the coax was probably the most innocent with plenty of merit
( although I still believe for the vast majority of homebuilders it is
gross overkill for the money). Go back and read your post on the prop,
which has it's own merits I'm sure. The point is you flooded the news group
with it and it was written as a "look at this prop go here and get it"
post.
I believe you meant well but you came on very strong and that's were the
objections mainly came from. I'm sure you have a lot of positive input to
this group and yes I do read your post!
So I hope you'd go back a review and see where we came from. My intention
was not to make you feel unwelcome but when I do see multiple posts (more
than 2) directing me to a product, I'm skeptical.
I hope that everyone can let this thread die and go on. If people want to
discus the merits or use of the cable consider starting a new topic on it
all over!
John

[[email protected]]

ELIPPSE wrote:
> It's funny! Here I post some info about a cable, and its
> characteristics, that I had a lot of excellent results with, and
which
> I installed on my Lancair. I thought that this forum was for the
> exchange of information.

Elippse,

To be fair, your initial post on this subject was not quite so
benign. It contained the following :

> It's pricier than the RG's, but the
>performance is so far superior that your com, VOR, Xpndr,
>and whatever will give you range performance like you've
>never seen.

and

>Anyone
>who uses an RG cable in their aircraft with this stuff
>available doesn't really care about good radio rx/tx!

Those are some pretty strong claims and the writing style just
screams "get your snakeoil here!". I think several responders pointed
out that the difference in cable loss in a typical light aircraft
installation were negligible and stated exactly why they thought so.

In a nutshell, this is Usenet. If you post claims like those above,
the response you got here is pretty typical.
John Galban=====>N4BQ (PA28-180)

[Dude]

"ELIPPSE" > wrote in message
oups.com...
> Hi, Dude!
> It's funny! Here I post some info about a cable, and its
> characteristics, that I had a lot of excellent results with, and which
> I installed on my Lancair. I thought that this forum was for the
> exchange of information. I expected some replies such as: "Yeah, that
> cable has some good low-loss characteristics, but after checking the
> prices on the mfg's. site, I decided that the performance I'm getting
> with the cable I presently use is good enough for me." OK, that's
> reasonable! Or: "I'm building this hot Lancair IVP and I want the best
> cable I can get; money is no object! Thanks for the tip" OK, that's
> reasonable too! But do I get a discussion on the relative merits of
> this cable and others? No, I get a bunch of sharks and their sycophants
> who want to prove to each other just how smart they are and how they
> can take down this new guy."Who does he think he is, anyway?"
> I've met this type over and over in the Aerospace world. Those who
> can't get up a decent technical discussion and then hide their
> ignorance behind insults. Too bad that they don't see that when others
> see this type of diatribe over some little innocent posting, that
> they're afraid of posting something themselves and incurring this type
> of wrath. What a stifler of open discussion! The political world is
> full of this kind; look at the last election. I expected that on a
> homebuilder's site, at least, that that kind of thing would be
> dispensed with so that a dialogue of builder-helping-builder would
> prevail! Silly me! I guess even in homebuilding small egos prevail. Too
> bad there are not more like Corky Scott and the ones who contacted me
> about the ELIPPSE prop, looking for more performance. They weren't
> taken-in by these egomaniacal types who can't stand it if someone
> doesn't kiss their boots and acknowledge them as the pre-eminent
> authorities on everything! But as for me, as I get information that I
> think others may want to know, I will post it on the forum and ignore
> the sharks.
>

Look. Your post obviously did not get the replies you expected. You can
blame everyone here, or perhaps you could reexamine your own post. You know
what you intended to say, and how you wanted it recieved. We did not. All
we saw was a pretty hard pitch about some cable. My initial reaction was not
"cool, I should look into using that". My initial reaction was "wow, this
guy thinks we are all stupid for not doing it his way."

So, you can try to tell us how we should have felt, and how we should have
responded, but you are only doing EXACTLY what you are accusing us of doing.
We now know what you meant, and you now know what we were thinking about
your post. Perhaps you can see that we are not egomaniacs either?