Just looking for some thoughts on mounting an Austin Spectra mag mount on my roof. Good idea? Bad idea?
Mobile antenna on the roof
- Thread starter snowman3725
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W2NJS
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On a car roof always is best if you can. A mag mount may damage your car's paint finish and may come unstuck in high winds. Drilling a hole for a permanent roof antenna is always the ultimate installation for mobile radios. I have an old Austin dualbander antenna that I still put on my car's roof NMO mount from time to time; must be twenty years old and still works great.
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After receiving poor performance from a Diamond Discone Antenna on a 21 foot tower, I put my Austin Spectra antenna with a mag-mount on one of the roof vents and the Spectra out performed the Diamond.
RadioDaze
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On the roof of what - Your vehicle or your home?
The roof on my house, sorry about that
For a while it would be good,but a mag-mount antenna is not built for staying outdoors all the time.So in time it would start to break.
Did you have to extend the cable at all?
I purchased a base conversion kit that included an NMO mount and four radials. This base kit turns any mobile NMO antenna into a base antenna. The Austin Spectra screws directly onto it; so will any mobile antenna that uses an NMO mount. I used LMR-400 cable for the coax run.
Here is what it looks like:
Larsen BSAKIT Base Conversion Kit
I suppose you could home brew something if you're good at working with metal.
Here is what it looks like:
Larsen BSAKIT Base Conversion Kit
I suppose you could home brew something if you're good at working with metal.
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How is the Larsen base conversion kit with the Austin Spectra working out for you?
I just brought the Larsen conversion kit and already have the Ausitn Spectra. Hopefully I will get the setup up this weekend.
Right now the Austin Spectra is with a magnetic base on a roof vent which out performs a Diamond Discone antenna. I am using LMR-195.
It works well, but it's only a couple of feet above the roof. I would like to have it higher, but I live in an antenna restricted area.
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Great news. My pole is only just over 5 feet about the roof, the items should be here in a few days.
What would be the best low loss cable for a run of about 50 feet?
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Really depends on the frequency range you are going to monitor. My listening is VHF-HI, 800, & 900, therefore, I use a very low lost coax because of the 800 and 900, I use LMR-195 which is thin and flexible.
Freq range is 154 to about 485. I plan on adding a tuned 800 antenna as well so that range I'm not concerned with
What feed line? That's a question that a coax comparison/spec chart comes in very handy. Select a cable that has low losses at the highest frequency of use. Then compare costs. Those losses are in 'dB's, so small differences (usually less than about 3 dB) are almost meaningless.
- 'Doc
- 'Doc
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Do you have an estimate on the coax length from antenna to scanner.
Below is a coax cable calculater.
Welcome to Times Microwave | Coaxial Cable - Attenuation & Power Handling Calculator
Awesome tool right there, think the LMR 400 would be best suited
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You might want to try Scanner Master who advertise on RR. They sale LMR-400 50 foot with connectors.
by far lmr400 is best cable out in my opinion i have 150fr of it they helpful people on RR told me about it i thought it was gonna be just some old cable well its low loss and very tuff and water resistant
http://www.timesmicrowave.com/products/lmr/downloads/22-25.pdf
http://www.timesmicrowave.com/products/lmr/downloads/22-25.pdf
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