Coax into antenna - is it broken?
Submitted: Sunday, Dec 30, 2007 at 19:51
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margro
Hi everyone
Somehow I have been able to pull the end of the coax cable out of the shaft of my RFI antenna when uninstalling from my last car. I've been quoted $25 to 'fix it', but it seems to me just a matter of pushing the cable back up the shaft. Anyone with any suggestions?
Also, when installing my Uniden
UHF Radio into my new car, I've managed to buy red and black cable with different amperage (black is 20 Amp and Red is 25 Amp)...I know that both are
well and truly more than I need, but does it matter that they are different Amps? I plan to connect directly to the battery.
Thanks in advance for your help...posting a question here is always very helpful to me!
Cheers
Mark
Reply By: Oldsquizzy (Kununurra) - Sunday, Dec 30, 2007 at 20:23
Sunday, Dec 30, 2007 at 20:23
Pay the 25 dollars ...needs to be fixed properly
AnswerID:
279003
Reply By: stocky - Sunday, Dec 30, 2007 at 21:02
Sunday, Dec 30, 2007 at 21:02
Yeah - $25 is ok for the time it takes to do it PROPERLY if your paying a radio tech for a pro job - its a little more involved that pushing it back in :-)
A hint for anyone using an antenna where the coax exits thru the mounting bolt/spring ie RFI CD921 or GME AE47xx series inc the big white fibreglass ones!
Leave approx 1 - 1.5" of coax vertical after it exits the mount BEFORE looping it back to the barwork and cable tying off etc - if you bend the antenna around after you have it mounted you will see why it is needed - I have seen many brand new antenna coax's broken by people "doing a neat job" and tying the coax back TIGHT to the barwork
While the RFI type and the similar GME types can be fixed *fairly* easily - the AE4701/2/3/5/6 type have a CRIMPED on end and is basically a "buy a new cable set" fix - you cant successfully reuse the crimp fitting
AnswerID:
279004
Follow Up By: Eric Experience - Sunday, Dec 30, 2007 at 21:33
Sunday, Dec 30, 2007 at 21:33
Stocky.
Thanks for
the tip. I have done just that and broken the wire inside the spring on a no name black stick antenna. Can you explain how to get the spring of the antenna? Eric
FollowupID:
543106
Follow Up By: stocky - Sunday, Dec 30, 2007 at 22:07
Sunday, Dec 30, 2007 at 22:07
Depends on the antenna - if its one of the "poly pipe" black sticks I think you have done your dosh - AFAIK the cable actually forms part of the "driven element" in those and cant be replaced :-(
you MIGHT get the spring undone if you can get a grip on the bottom of the antenna and some vice grips on the spring - wont be pretty but you havent got much to lose! Most have a LIBERAL coating of lock-tite on the treads so they NEVER come off :-(
FollowupID:
543116
Reply By: 96 GXL 80 series - Sunday, Dec 30, 2007 at 21:44
Sunday, Dec 30, 2007 at 21:44
Not having a go at you or anything like that.
To me it sounds like you have not had much to do with Coax cables.
You have an inner cable (Centre conductor) and an outer cable being the copper braid or Shield..
These have to be separated from each other, so you best get the $25.00 out and pay someone that knows what they are doing or you will be up for more $$$$'s for repairs to your radio.
Cheers
96
AnswerID:
279007
Follow Up By: 96 GXL 80 series - Sunday, Dec 30, 2007 at 21:48
Sunday, Dec 30, 2007 at 21:48
PS.
If you get a chance to look over his shoulder and see what he is doing, it might help if you happen to have one break out in the bush.
It will get you out of trouble anyway.
FollowupID:
543109
Follow Up By: margro - Sunday, Dec 30, 2007 at 22:04
Sunday, Dec 30, 2007 at 22:04
You're pretty accurate..not a lot of experience, although I did install the coax on my old AM radio! I figured if I pulled the braid down, and pushed the cable from where it came, all would be good!! I think I might need to invest the $25!!
FollowupID:
543114
Follow Up By: 96 GXL 80 series - Sunday, Dec 30, 2007 at 22:07
Sunday, Dec 30, 2007 at 22:07
Yes a bit different to a car radio as this one you ust it both for
RX & TX so it has to be right.
FollowupID:
543115
Reply By: disco1942 - Sunday, Dec 30, 2007 at 23:37
Sunday, Dec 30, 2007 at 23:37
Mark
The 20 or 25 A rating of your cable is just the current that will warm up the cable. You should always aim to use cable with a far higher current rating than your load current if you wish to keep the voltage drop to a minimum. If your cable is of ample current rating it matters not that they are of slightly different size.
Those of us who know what we are doing take no notice of the current rating. We look for the size of the cross section of the cable which is the factor to use in he voltage loss formula. We look for the dimension on the cable reel that has mm2 after it (where that 2 is a little figure slightly higher than the mm and means squared.)If the cable is over a metre or two long and you are drawing a current equal to its rated current then your voltage loss will probably be more than the recommended 3%.
PeterD
PeterD
AnswerID:
279018
Reply By: Member - Garth J (NSW) - Monday, Dec 31, 2007 at 12:11
Monday, Dec 31, 2007 at 12:11
Mark,
This site has instructions and pictures showing how to correctly terminate coax into a plug.
Checkout the UHF radios under Communications in the Topics section.
Cheers
Garth
AnswerID:
279046
Follow Up By: stocky - Monday, Dec 31, 2007 at 18:16
Monday, Dec 31, 2007 at 18:16
Its not the plug he needs to terminate :-)
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543272