Cutting coax cable

[SatNav]

1. This thread got way way off track some time ago and would suggest those that continue to talk way outside the envelope of the original question simply stop complicating what is really a very simple solution.

2. Finga's summary was close to the mark and should have been the end of the over complications and totally way off centre continuation.

[foxx510]

Yes and no. Easy solution is to not cut coax, yes, but it would be nice to get an answer from GME who have given us two different answers. I for one would always install an antenna with the minimum of coax if possible for neatness and less attenuation.

[SatNav]

1. The solution is really quite simple, go for some of the other aerial manufacturers and you won't have to worry if you want to cut or not as as it won't matter.

[oldboot]

Some of us are more interested in the why rather than the to cut or not.

cheers

[foxx510]

I guess it means they can build antennas without a matching circuit in the base, which is probably cheaper.

[oldboot]

Yes and no. Easy solution is to not cut coax, yes, but it would be nice to get an answer from GME who have given us two different answers. I for one would always install an antenna with the minimum of coax if possible for neatness and less attenuation.

of course I would agree in principle......I like neat wiring as much as the next bloke....up ... probaly more

But at these frequencies as mentioned before, loss in the cable will not be an issue or measurable with normal instruments at cable lengths under 10 meters.




As for my postition on "line of sight"......it is a relevent issue as it influences the expectations of performance.

In my training line of sight meant just that and the expectation of the public is the same.......2Ghz microwave regardless of power is line of sight......direct unbroken path antenna to antenna ( I spy with me little eye something beginning with A)...........160Mhz at 25 watts in practice is nothing like restricted to line of sight.....it will travel over, arround and thru quite substantial obsticles at short range....at longer distances it may far less toleant of obstruction.

If anybody is telling me this is wrong or misleading, it is very easy to prove otherwise.......I don't care about the theory or what is reitten in the books it is reality that concerns me.

cheers

[oldboot]

I guess it means they can build antennas without a matching circuit in the base, which is probably cheaper.

Exactly.


Or there may be "other reasons"

One designer may be happy with one method of matching that gives a 50 ohm terminal impedance at the base of the antenna......another designer may perfer a design that gives a 50 ohm impedance at the end of a half wave of coax.

As for the 50 ohm impedance there is no natural, simple, unmodified antenna that gives a 50 ohm feed point impedance.....regardles of the form of the antenna there has to be some manipulation to achive a 50 ohm feed point impedance.


Remember also some of these designs may be very old......the original design work may have been done in the seventies.......or even the 50's.... so the manufacturer may have no idea of the reasoning of the designer........they just keep building it to the drawing.

cheers

[finga]

For God's sake leave it fellas.
If you want to ramble I've made a thread for you all.
Here...go for your lives http://www.ausfish.com.au/vforum/sho...d.php?t=142361

[foxx510]

Ooops. I think we've been told. Sorry for nerding up the place.

[Fatenhappy]

Therealandy ....

I'm with you as I think the threads gone right away from the intent of the original question, but glad we live in a democracy where we can have an open debate....

Have a good one !!!


Cheers
Greg

[oldboot]

Afterall this is a discussion forum.....with 70 odd posts and over 800 views there are obviously people interested in discussing whatever the the subject has evolved to.

would we be having this " oh this is off subject"... "stop your rambling" issue if we were discussing crab bait or the price of tackle.

I don't think so.

We all know what the simple solution is and that was very clear in the first hand full of threads.......discussions evolve on online forums........it is a series of statements sometimes only linked by a thin connection... that is why it is called a thread.

Has the thread gon off the original subject?..... most definitely.

Have any of the posts been not connected or irrelivent?......I honestly think not one.

So if this discussion frustrates you or offends you, you are always free to not partisipate or read the responses...........if this discussion still interestes you, you are completly free to continue partisipating.

If the discussion was getting agressive or unhelpfull or whatever i am sure the mods will do what they see fit.

So far there has been no difinitive answer on the why or the how.
I and others have postulated on the possible reasons.....I am most interested in some serious fcats if they can be found by interogation of the manufacturer, actual tests, or reverse engineering of the product.

cheers

[garman1]

I have watched this "thread" with interest, I am an amateur and found not being able to change the length of the coax interesting. I never had the answers so I didn't join in, till now. I find having someone start another "thread" and try to shift people to it odd? I thought only moderators could do that...... In the end hopefully we will find out can you cut the coax and clean it up or do you have to have a great roll of coax under the dash? The original question may still be answered.

Keep going guys, I have a navman radio and navman base etc and about 10 metres of coax rolled up under the dash in a 4.3 mtr quintrex. The aerial is about 1 metre from the radio, years ago I would have chopped the cable and shortened it for neatness and to make sure I never caused any probs because of the coil of coax etc and maybe some losses. But now I don't have the gear I will simply coil it up and zippy it up in place.

We are in the elecronic section, with radio/safety questions, ...NOW.......to cut or not to cut, that is the question, lets get the answer.

[finga]

Afterall this is a discussion forum.....with 70 odd posts and over 800 views there are obviously people interested in discussing whatever the the subject has evolved to.
Maybe some are asking what the.....??

would we be having this " oh this is off subject"... "stop your rambling" issue if we were discussing crab bait or the price of tackle.
If someone asked about the price of prawns at the Pin you wouldn't what to know about the spawning cycle of a yabbi would ya.

I don't think so.

We all know what the simple solution is and that was very clear in the first hand full of threads.......discussions evolve on online forums........it is a series of statements sometimes only linked by a thin connection... that is why it is called a thread.
So what's the definitive answer??
Has the thread gon off the original subject?..... most definitely.

Have any of the posts been not connected or irrelivent?......I honestly think not one.
Back to my example of the prawn and yabbi... they're are connected but why bother mentioning the story about the spawning cycle of a yabbi?? I only wanted to know the price of a prawn.

So if this discussion frustrates you or offends you, you are always free to not partisipate or read the responses...........if this discussion still interestes you, you are completly free to continue partisipating.
I'm only concerned about the poeple that may read and wonder...what the hell.... about a fairly basic question and get lost in the mumbo jumbo.
It was a basic question..Can a particular coax be cut?? Not how does an aerial work and how can I get it to work better.

If the discussion was getting agressive or unhelpfull or whatever i am sure the mods will do what they see fit.
Not agressive, but sidetracked and to a lot maybe unhelpful as they got lost in the blurb

So far there has been no difinitive answer on the why or the how.
I and others have postulated on the possible reasons.....I am most interested in some serious fcats if they can be found by interogation of the manufacturer, actual tests, or reverse engineering of the product.
It wasn't asked in the original question
cheers

So when someone reads the thread title and says...gees I better read to see if I can cut my coax and comes across pages upon pages of this...what is he/she supposed to think?
They are not going to read about propagation and the likes to see if they can cut a coax.
I think I made a definitive answer way back...by saying read the instruction sheet. If they say the length can be altered then do so. if not don't...especially if the item in question is under warranty.
Please don't get me wrong...to see blokes having a discussion is good.
But consideration to other people with no background knowledge on the subject but wanted to find a simple answer to a simple question without reading volumes about theories or research or what-ever must be considered.
If you want to know why aerials work or discuss design or theories then start another thread. It's quite simple.

[finga]

I have watched this "thread" with interest, I am an amateur and found not being able to change the length of the coax interesting. I never had the answers so I didn't join in, till now. I find having someone start another "thread" and try to shift people to it odd? I thought only moderators could do that...... In the end hopefully we will find out can you cut the coax and clean it up or do you have to have a great roll of coax under the dash? The original question may still be answered.

Keep going guys, I have a navman radio and navman base etc and about 10 metres of coax rolled up under the dash in a 4.3 mtr quintrex. The aerial is about 1 metre from the radio, years ago I would have chopped the cable and shortened it for neatness and to make sure I never caused any probs because of the coil of coax etc and maybe some losses. But now I don't have the gear I will simply coil it up and zippy it up in place.

We are in the elecronic section, with radio/safety questions, ...NOW.......to cut or not to cut, that is the question, lets get the answer.

Do you want the long version or the short version of the answer??

[Fatenhappy]

Hey Garry ....

I also run Navman gear which has suited my application amply in the past.

I was going to do a reinstallation of the same gear yesterday to our cat for its refit but weather and other comittments prevented me getting that done as well.

Its my intention to do this shortly (within the next week or so) and will be cutting the coax at that time. I will take measurements before and after and will be happy to give you the answers when I have them ....

Cheers
Greg