Best cable for mobile discone

PropHumm

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I am building a chase vehicle for extreme newsgathering. For my scanners, I have 1 SDS200, 2 BCD996P2's and 2 BCT15x's . . and will be adding at least 2 more SDS200's in the next couple months. My choice for antenna was the Diamond D220R Discone to cover all the frequencies and feed all the scanners with the single antenna. I am getting ready to purchase a Stridsburg MCA208M 8 port multicoupler to feed the scanners. I have options for the output connectors, being TNC, N, or BNC. My thought was to go with BNC because of the scanners having BNC jacks. Where I am not sure is what cable I should use.
 

cg

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That would be... interesting... to have a large discone on a vehicle. Unless you are outfitting a semi truck, your cable runs will be very, very short. You can use a good quality BNC/BNC jumper. Pomona is a bit pricey but very good quality. You can spend anywhere from $5 to $125 per 18 inch jumper.
I personally would look at several mobile antennas targeting certain bands and use a couple 4 port Stridsbergs.

chris
 

vagrant

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1. Larsen NMO 150/450/758 antenna - That covers the frequencies where the action is and it is better than that discone.
2. LMR-240UF - This coaxial cable is thin and flexible enough for long or short runs with lower attenuation. UF = Ultraflex
3. Depending on where you are, you may need to put an FM broadcast filter inline on the coax from the antenna. FM radio stations are not a scanner enthusiasts friend. Pager signals around 152 MHz can also be a problem, so you may need to add a filter there too.
4. BNC is fine. Make sure you do not go cheap on the BNC patch cables. You will get what you pay for, even if they are short jumpers. Beware!

That will be quite a few scanners. I presume you will dedicate each one to a particular service, or maybe two for local PD and the others for Sheriff, Fire and perhaps State Police. I'm figuring you will also monitor a nearby city/suburb as well, or perhaps local metro PD. Tell us more.
 

prcguy

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I would not use a Diamond D220R for public service monitoring, I believe its top whip is tuned to the amateur bands and the Discone part probably doesn't come into play until 400MHz or higher. As mentioned, a Larsen tri-band would probably work better. Or a Laird WPD136M6C or a Maxrad BMAXSCAN1000 or a Comtelco, bla bla bla.

All these resonate within the VHF/UHF/800 public service bands at the minimum and a few like the Laird work fine in the 2m, 70cm, 23cm amateur bands. Then there is the COMPACtenna Scan III which is no slouch and covers a good chunk of the VHF/UHF/700/800bands very well. I believe any of these antennas will work much better and more consistent than a Diamond D220R for chasing sirens, uhhh, I mean, news gathering.

As for cable, it depends on how long the run is. Again, as mentioned, Times LMR-240UF would be one of my first choices and if the run was very short like under 10ft maybe LMR-195 and this is for the run from the antenna to the multicoupler. If the runs are short from the multicoupler to the radios, like 2ft then I would use a good quality RG-58 or LMR-195 because the multicoupler has extra gain per channel and you can afford a little loss in the cables to the radios.
 

PropHumm

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Yeah I can share all of this! What Forum would be best for posting my chase vehicle build?
 

vagrant

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Probably just stay with this thread. A moderator will move things if necessary, but your buildout here seems appropriate as you take whatever advice, or not, and move forward it. They may just change the title to better fit.
 

mmckenna

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Please don't install that antenna and expect anyone to take you seriously as a news gatherer.
That's a joke of an amateur radio antenna, and a poor joke at that. They are the antennas that people point and laugh at when you see them in the parking lot at the local ham fest. Yes, we do, and I have, many times.

Use one single Larsen NMO-150/450/756 on a permanent mount NMO base mounted smack in the middle of the vehicle roof. Do it right, do it once, and you won't regret it. Don't cut corners with cheap Chinese/hobby/amateur grade antennas, mounts, connectors, etc.
If you are in an area that uses low band VHF, consider adding a dedicated low band antenna and connect it to a dedicated radio.

Run that antenna to your multi-coupler and split it off to all your radios's's's's's's's'…...

The standard RG-58 that comes with the NMO mounts will work fine. You are not going to have enough cable length to be a problem, unless you are driving a Greyhound bus and want to mount the antenna on the rear and your radios up front.
 
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