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What antennas are others in our area using?

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#1
So I just purchased my first base scanner antenna(a Centerfire tri-band 150/450/800 ground plane). Mainly because I was having issues receiving the Placer P25 system from my location about a half mile north of Roseville PD.

I actually setup my Larsen tri-band mag mount, basically another ground plane, on my truck in the garage along with building a simple so329 based plane to get a good base comparison and test going. In general its amazing how much better a proper antenna is over a RS 800 or RH77CA portable rubber duck(the two most highly regarded ones on the site).

Unfortunately my new Centerfire may wind up in the attack when I get it due to HOA restrictions unless I can find a way to hide it towards the back of the house in a way that doesn't result a long coax run. Obviously neither is that great of a situation for maximizing performance :/

Ultimately I'm looking be able to reliably pick up the Roseville, Placer, and Sacramento Systems. I am however somewhat concerned about Sacramento when they make the switch to P25 as I was averaging 2-3 bars on my bcd325p2 during test with signal strength bouncing higher on the current analog talk-groups. It's kind of scratchy sometimes.


Anyways my first base antenna purchase has me curious..
What antennas are others in and around our area are using for scanning purposes here?
Also what systems do you monitor?
 

iMONITOR

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#2
Tell the HOA it's an HDTV antenna. If they don't believe you, show them it works...it will! I don't think they can ban TV antennas. Mine can't.
 
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#3
Tell the HOA it's an HDTV antenna. If they don't believe you, show them it works...it will! I don't think they can ban TV antennas. Mine can't.
Yeah that's a tricky situation. Even TV antenna are specifically stated as banned when we bought the house(the one exception is satalite dishes). I got one of those high pitched roofs so it's possible I might be able to mount it higher in the attic space then I would from the eaves.
 

gmclam

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#4
Reception & Sites

What antennas are others in and around our area are using for scanning purposes here?
Also what systems do you monitor?
At home I have a discone feeding a multicoupler and several scanners. I am able to monitor from Shasta county to the north and Merced county to the south.

When it comes to systems, the answer is less clear. It depends on time of the season, time of day, the band the system is in. For example; Merced and Stanislaus are on 800MHz and too far away (although VHF comes in great). I can get one site of the EBRCS most of the time. Simplex Stockton on 450MHz P25 comes in only a night.

Placer county VHF P25 is interesting. I only get a 16% decode rate on site 001, for which I am in the coverage area. And I get 99% decode rate on site 005, for which I am not in the coverage area. Go figure. Roseville and both Sacramento sites are no problem 24/7.
 
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#5
Check out your attic and if its wood construction with no lath or foil backed insulation and the roofing material is fairly transparent to RF it might be your best bet. I'm not impressed with the Centerfire antenna and the Larsen tri band on a ground plane mount should work fine for the public service bands.

Yeah that's a tricky situation. Even TV antenna are specifically stated as banned when we bought the house(the one exception is satalite dishes). I got one of those high pitched roofs so it's possible I might be able to mount it higher in the attic space then I would from the eaves.
 
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#6
Placer county VHF P25 is interesting. I only get a 16% decode rate on site 001, for which I am in the coverage area. And I get 99% decode rate on site 005, for which I am not in the coverage area. Go figure. Roseville and both Sacramento sites are no problem 24/7.
Yeah placer is kind of weird. From what I've seen its almost like the primary control channel frequencies have a much stronger signal output compared to the other system frequencies as are part of the same trunks/zones. I wouldn't be surprised if there are some repeaters out that haven't been fully upgraded from the analog yet side which carry only certain frequencies on P25 side. Then we have the obvious "simulcast" issue with scanners on top. It all makes for a very location dependent reception situation.

btw I may be adding more scanners myself with the rtl-sdr sticks being so cheap :D
 
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#7
Check out your attic and if its wood construction with no lath or foil backed insulation and the roofing material is fairly transparent to RF it might be your best bet. I'm not impressed with the Centerfire antenna and the Larsen tri band on a ground plane mount should work fine for the public service bands.
Oh man don't tell me that now lol.

Actually I was going build my own ground plane around an SO-239 stud mount utilizing either 3/32" or larger sized rods for the radials and elements, basically something better built then your typical wire ground plane, but found out quickly that buying the Centerfire would be cheaper than anything I could make myself. Plus I wasn't exactly sure of the best method to attach two or three vertical elements to the top of 3/8" thread on the mount. The original thinking was something along the lines drilling holes in a brass bolt cap or acorn nut attached as a hub/ferrule.
 

Duster

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#8
Placer county VHF P25 is interesting. I only get a 16% decode rate on site 001, for which I am in the coverage area. And I get 99% decode rate on site 005, for which I am not in the coverage area. Go figure. Roseville and both Sacramento sites are no problem 24/7.
This is because of the location and signal footprint from Site 5, which is on Signal Peak in the Sierras. I drive the 80 corridor often from Colfax to Vacaville, and Site 5 will often override the other Zones, even when I'm in the footprint of the other zones. I've been in visual sight of a tower on the West Zone and still had the scanner lock on Site 5. That mountaintop is a great location for wide-area coverage in all bands.
 
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#9
I believe your home made SO-239 ground plane will have better engineering and materials than the Centerfire thing. It would be hard to design and make a home made antenna that would outperform a Larson Tri-band on a ground plane mount.

Oh man don't tell me that now lol.

Actually I was going build my own ground plane around an SO-239 stud mount utilizing either 3/32" or larger sized rods for the radials and elements, basically something better built then your typical wire ground plane, but found out quickly that buying the Centerfire would be cheaper than anything I could make myself. Plus I wasn't exactly sure of the best method to attach two or three vertical elements to the top of 3/8" thread on the mount. The original thinking was something along the lines drilling holes in a brass bolt cap or acorn nut attached as a hub/ferrule.
 
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#10
I believe your home made SO-239 ground plane will have better engineering and materials than the Centerfire thing. It would be hard to design and make a home made antenna that would outperform a Larson Tri-band on a ground plane mount.
yeah that Larsen performance is hard to beat even on a mag mount like I got for the truck. In fact I have noticed that Placer County Sheriff seems to have them installed behind their VHF band antennas on their newer Tahoe's likely for monitoring other agencies/systems. If law enforcement is using them in the area that's a solid endorsement.

I actually wondered about that option as well, getting another Larsen Tri-band(since i didn't want to use the one I had) and building a custom ground plane mount for it.
 
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#11
OK, maybe it is a bit hokey, but I am using a magnetic-mount NMO base with a Browning BR-158-S 150-170 MHz VHF NMO Antenna for listening to Placer County. This is what is feeding the Broadcastify feed for Placer County Sheriff. For the Roseville system, I am using a similar base and I don't recall now the make and model of my antenna but it was designed for 825-896 MHz and has two loaded coils on it. The Placer County system is using an Airspy Mini dongle receiver and the Roseville system is using a NOOlec RTL-SDR dongle. And now for the really hokey part, they are sitting on an old side-panel to a tower computer for their ground plane and sitting by a north-facing window near Blue Oaks and Woodcreek in Roseville.
 
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#12
OK, maybe it is a bit hokey, but I am using a magnetic-mount NMO base with a Browning BR-158-S 150-170 MHz VHF NMO Antenna for listening to Placer County. This is what is feeding the Broadcastify feed for Placer County Sheriff. For the Roseville system, I am using a similar base and I don't recall now the make and model of my antenna but it was designed for 825-896 MHz and has two loaded coils on it. The Placer County system is using an Airspy Mini dongle receiver and the Roseville system is using a NOOlec RTL-SDR dongle. And now for the really hokey part, they are sitting on an old side-panel to a tower computer for their ground plane and sitting by a north-facing window near Blue Oaks and Woodcreek in Roseville.
Haha nothing wrong with that. It seems to work well. Also reminds me of my old days before I decided to consolidate and get rid of all my old PC parts. I'm near Washington & Diamond Oaks myself. Once I get my antenna up it will most likely be to the north/north east side as well.

Anyways I think yourself and gmclam got me interested in SDR for my next project :D I've already been looking at NOOlec & RTL dongles. How do you like the NOOlec?
 
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#13
Just though I would add (although not a permanent install) I finally got around to putting my center fire antenna together.

While it helped with VHF I'm having disappointing results with it and even my home built ground planes picking up the SSRCS (800 mhz) system.

It almost seems like I'm loosing a ton of signal somewhere between my 50' RG-6 coax, ideal BNC compression connectors, and pl-259 to BNC adapter. Not sure if its just one or all components contributing but I have noticed if connect the 50' terminated cable with BNCs to my Larsen mobile I loose about half its signal strength vs without the extension.
 

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Not all RG-6 is created equal. Make sure you have coax with low(est) loss at 800MHz.
Thinking about the coax myself. I got my RG-6 off a Direct TV installer about 10 years ago. It's Applied Telecomm A660-2 dual shield 60% braid coverage. I would think it would be good quality cable but not being able to find any info online about it has me a little suspicious.
 
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#16
I may actually wind up upgrading to LMR-400 coax. With it's length I'm not so sure RG-6 is up to the task. Not to mention the SRSRCS coverage isn't all that great in Roseville to begin with.

According to the times microwave 900 MHz at 50' of RG-6 the loss would be 4.5 dB on average.
 

gmclam

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Even LMR-400 distance is fairly short

I am actually using an LMR-400 clone (Air-802) between my antenna and filter. The filter is directly connected to the multicoupler. Then I use low loss RG-6 from each multicoupler output to the receivers.

I am using this filter and this multicoupler.
 
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#18
I am actually using an LMR-400 clone (Air-802) between my antenna and filter. The filter is directly connected to the multicoupler. Then I use low loss RG-6 from each multicoupler output to the receivers.

I am using this filter and this multicoupler.
It's definitely not easy balancing line loss. More research to do when I get home.

LMR-400 has a loss of about 2.2 dB itself at 500'

I mentioned in pm that my plan is to hook up 3-4 devices between scanners/SDR sticks in the same room. Also been looking at LNA's mounted at the antenna. Which can present it's own challage of too much signal/overloading since they all seem to be about 18 dB+ gain levels.
 
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#19
I've decided to put things on hold and rethink my whole setup atm.

With the Sacramento System moving towards P25 I'm thinking I might better off with a Yagi type for it aimed at either the Gibson ranch or greenback sites.

As far as my Centerfire goes it's actually very close if not on pair with my Larsen tri-band. I wound up doing a side by side comparison in the driveway using a short jumper cable with no real noticable difference between the two.

Definitely the loss was in the long run.
 
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#20
Thought I would post this. finally got around to installing my antenna in the attic. Along with an RTL-SDR LNA attached to the antenna being powered by an Electroline Remote Power Inserter. As of right now no FM Notch Filter(waiting on it..hopefully soon).

Also thinking about maybe moving the mast over a few inches so I can mount it to the side of the valeted ceiling wall as the pipe is a little more flexible then I would like atm. Plus doing so may allow me to raise the antenna a little more.
 

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