external antenna for viper 5901
Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=117159
Printed Date: May 17, 2025 at 7:31 AM
Topic: external antenna for viper 5901
Posted By: fredddy9
Subject: external antenna for viper 5901
Date Posted: October 22, 2009 at 11:52 AM
Hi,
I'm planning to purchase Viper 5901 and just have a question whether its possible to use an external antenna instead of that stick-on windshield provided with the alarm.
I already have a hole drilled in my trunk lid so why not use it for an external antenna? i think it would definitely boost the range.
I just don't know what type of antenna should it be, 1/4 wave 433Mhz? Knowing this i could just cut original antennas and connect a coaxial 50ohm cable instead and run it to a new external antenna on a trunk lid. But since i don't know what type frequency/wave does the transmitter uses i don't know whether it works.
Any ideas appreciated! thanks.
Replies:
Posted By: howie ll
Date Posted: October 22, 2009 at 12:38 PM
It won't work anyway it's 900mhz on that baby. They don't use coax and the leads are data with an amplified head.
Posted By: t&t tech
Date Posted: October 22, 2009 at 12:53 PM
Do you mean outside the car?
Posted By: fredddy9
Date Posted: October 22, 2009 at 2:27 PM
Yes, outside the car although with cable shielding grounded to the car body.
Thanks for the info about that 900mhz. So maybe i could use a GSM car external antenna? like these ones:
As i wrote i already have unused antenna on a trunk lid, so thats why i'm trying to get a advantage of it.
Posted By: t&t tech
Date Posted: October 22, 2009 at 3:33 PM
Would it be visible? Would it be easily removable?
Posted By: t&t tech
Date Posted: October 22, 2009 at 3:34 PM
Also, that antenna has the led and valet switch built in, are you planning to discard these and use the off board ones?
Posted By: fredddy9
Date Posted: October 22, 2009 at 4:20 PM
Yes, visible as i wrote on the top of a trunk lid, just like the police cars. Even if its removable (screwed in) nobody would know that its for alarm paging. While original viper antenna on the dash certainly would get an attention which i want to avoid.
My plan was to leave that box with valet switch, remove original antennas and run a coaxial cable to an external antenna outside the car.
After some reading i found out that at 900mhz setup requires a specific length cable, so i'd have to order a custom made one along with an antenna. I think the idea sounds good but it might be difficult to tune the antenna to the cable, and connecting a cable to the valet box might be an issue too.
Too bad DEI doesn't offer such external antenna as an option.
Posted By: t&t tech
Date Posted: October 22, 2009 at 4:36 PM
I'm glad you realized it's more trouble than it's worth! 
Posted By: howie ll
Date Posted: October 22, 2009 at 5:43 PM
Could have saved yourself a right old go-round here if you'd have taken in my original post, tell me what car because it's quite easy to locate the original aerial behind the instrument cluster. The bulge there wil raise the antenna so that it "looks" through the windscreen, just get another LED and Valet switch. N.B. showing the antena is almost as good a deterrent as an LED.
Posted By: fredddy9
Date Posted: October 23, 2009 at 1:05 AM
howie ll wrote:
Could have saved yourself a right old go-round here if you'd have taken in my original post, tell me what car because it's quite easy to locate the original aerial behind the instrument cluster. The bulge there wil raise the antenna so that it "looks" through the windscreen, just get another LED and Valet switch. N.B. showing the antena is almost as good a deterrent as an LED.
the car is an old lincoln, and its dash is completely flat, so no matter where i hide viper-antenna it will still be under the windshield edge.
I got an idea to hide viper-antenna inside the 3rd brake lamp which is mounted at the bottom of the back window, but the antennas would stick out and i would probably have to extend the cable between the 5901 and Valet-box.
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