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 Post subject: Antenna Install
PostPosted: Thu Feb 18, 2016 5:41 pm 
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Joined: Tue Jul 03, 2007 8:11 pm
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Location: Puget Sound
Anyone see a problem here?

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 Post subject: Re: Antenna Install
PostPosted: Thu Feb 18, 2016 6:39 pm 
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Site Admin
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Joined: Thu Feb 19, 2004 8:32 pm
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Location: Kenmore, Wa.
No service loop, only one bracket mount, tie wraps...... I could go on. Let me guess, public safety? Regardless, looks a lot better than some of my weekend warrior installs :).

-Marcus


Last edited by Marcus on Thu Feb 18, 2016 7:46 pm, edited 2 times in total.

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 Post subject: Re: Antenna Install
PostPosted: Thu Feb 18, 2016 6:46 pm 
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Location: Not Gulfport
Marcus wrote:
No service loop, only one bracket mount, tie wraps...... I could go on. Let me guess, public safety?


Is it just me or does the coax look like a flat ribbon cable?

Also, the metal tower will totally screw up the radiation pattern of that antenna - unless it's mounted higher -- it won't radiate efficiently nor effectively. Hmm, is that tower bracket all metal there -- i.e. no isolation from the tower? If so, it may short the antenna... and/or at least affect its resonance.


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 Post subject: Re: Antenna Install
PostPosted: Thu Feb 18, 2016 9:08 pm 
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Angus Cheeseburger
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Nice "J pole" ;)

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 Post subject: Re: Antenna Install
PostPosted: Fri Feb 19, 2016 10:00 am 
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Joined: Tue Jul 03, 2007 8:11 pm
Posts: 2136
Location: Puget Sound
nickcarr wrote:
Marcus wrote:
No service loop, only one bracket mount, tie wraps...... I could go on. Let me guess, public safety?


Is it just me or does the coax look like a flat ribbon cable?

Also, the metal tower will totally screw up the radiation pattern of that antenna - unless it's mounted higher -- it won't radiate efficiently nor effectively. Hmm, is that tower bracket all metal there -- i.e. no isolation from the tower? If so, it may short the antenna... and/or at least affect its resonance.


Its LMR400 and is fairly taunt. They actually used donuts to mount the cable on the way down to the repeater. No grounding of the coax to the tower anywhere I saw.

Ive been told coverage sucks. Wonder why. Oh yea- this was a "professional install".

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 Post subject: Re: Antenna Install
PostPosted: Fri Feb 19, 2016 8:46 pm 
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Bringer of Light
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Location: Depends on the day of the week
Are you willing to hint at the installer?

I've got a lot more pictures of stuff like that if you guys want more.

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 Post subject: Re: Antenna Install
PostPosted: Sat Feb 20, 2016 5:18 pm 
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Location: Not Gulfport
jrw14493 wrote:
I've got a lot more pictures of stuff like that if you guys want more.


Sure then I don't feel so bad about my earlier antenna installs at home. :P


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 Post subject: Re: Antenna Install
PostPosted: Sat Feb 20, 2016 7:51 pm 
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Joined: Thu Dec 02, 2010 6:02 pm
Posts: 124
Looks ok to me?

Much better than this MSF/Mag mount and extension cord. This picture has been circulated on the web for a long time, but is indeed my photo.


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 Post subject: Re: Antenna Install
PostPosted: Sat Feb 20, 2016 8:43 pm 
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Bringer of Light
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Location: Depends on the day of the week
Looks VHF-ish. 2M?

I've got a city testing out a repeater location. Repeater is their old R1225 with a mag mount stuck to the metal roof of a city pump house on a high spot in town. That cheesy setup is working better than their current Repeater setup which was a "professional installation."

It could be ugliest things you've ever seen but if there's little to no site noise, it will outperform.

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 Post subject: Re: Antenna Install
PostPosted: Sat Feb 20, 2016 8:58 pm 
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Bringer of Light
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Location: Depends on the day of the week
Here's the first one. Repeater is a MTR2000 with two DB224's. RX antenna was inverted and clamped the bottom of the TX antenna. The repeater was running at 100 watts and straight to the antenna. No cans or isolator. Can you say 360 watts ERP? This was the sole thing in the RX line between the antenna and RX port on repeater. Yes, that's bailing wire holding the connector to the side of the can.


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 Post subject: Re: Antenna Install
PostPosted: Sat Feb 20, 2016 9:06 pm 
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jrw14493 wrote:
Looks VHF-ish. 2M?

I've got a city testing out a repeater location. Repeater is their old R1225 with a mag mount stuck to the metal roof of a city pump house on a high spot in town. That cheesy setup is working better than their current Repeater setup which was a "professional installation."

It could be ugliest things you've ever seen but if there's little to no site noise, it will outperform.


Public safety VHF


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 Post subject: Re: Antenna Install
PostPosted: Sun Feb 21, 2016 11:19 am 
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Location: Puget Sound
jrw14493 wrote:
Here's the first one. Repeater is a MTR2000 with two DB224's. RX antenna was inverted and clamped the bottom of the TX antenna. The repeater was running at 100 watts and straight to the antenna.


I know a certain state agency that likes to run their transmitters this way and will until they get caught by the DNR. The MTR2000 could be bought with an unboard circulator on the 100watt model. Its how we bought all of ours. The transmitters are very clean compared to earlier radios (and a few you can buy new today) and have filtering to avoid harmonics. We run true bandpass cans on all of ours however. I wouldn't get any real heartburn over it unless I was trying to protect a receiver right up close. You know- like the receiver on that same radio. Fairly good split?

That passcan is awesome! Yikes!!

Highband has become noisier than lowband over here. We all measure between 6 and 10dB of site noise constantly (depending on the day) no matter who I ask. My lowband measurements are around 3dB right now (just looked)but do creep up at regular intervals.

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 Post subject: Re: Antenna Install
PostPosted: Mon Jun 20, 2016 10:54 pm 
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Location: Puget Sound
1. Rust gonna happen! Intermod anybody?
2. What the **** is the coil for? Lightning? Seriously next to a metal roof?? How about the loss figures? (Dont coil RF cable in a perfect circle. RF 101. Yes I know 100% shielded cable.. blah blah. Don't talk about fight club!)
3. Not above the metal roof. I know the picture doesn't show it.
4. Took the alerting receiver antenna down when he put this up.
5. Not really sure what the base of the pipe is doing down there but our belief is it is just sitting there connected to nothing. After tonight's storm cells that passed through the area it may not be there anymore.


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 Post subject: Re: Antenna Install
PostPosted: Sun Jul 10, 2016 8:49 pm 
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Bringer of Light
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Easier to buy pre-terminated coax rather than to cut to length and do it right...this another install from "those guys?"

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