8 antennas for mobile install

[Stringer619]

Yes, 8 antennas. I'm an overnight tv news photog. I wanted to put my plan out there and see if anyone see's ANY ways to improve before I drop $300+. I just bought a brand new 2013 Dodge Grand Caravan. With a vehicle that expensive, I want to do my antennas right in every way possible. The placement (roof), the coax (dual shield), power source (clean from aux battery/battery isolator), etc. Hell will freeze over before I remove the headliner and do any changes or add any antennas after this initial install, so I want to do it right the first time, with the best (reasonable) quality materials and best installation locations/techniques. The initial install will likely take 2 days. There is far too much to remove to get to the underside of the roof. No way in hell am I doing it twice. "Measure twice cut once", or in this case, "research twice, install once". Ok you get the point.

800MHZ - Larsen NMOKHFUD mount/wire - Larsen NMO3E825B antenna
800MHZ - Larsen NMOKHFUD mount/wire - Larsen NMO3E825B antenna
800MHZ - Larsen NMOKHFUD mount/wire - Larsen NMOQSPEC800B or NMOQ800B antenna
800MHZ - Larsen NMOKHFUD mount/wire - Larsen NMOQSPEC800B or NMOQ800B antenna
800MHZ - Larsen NMOKHFUD mount/wire - Larsen NMOQSPEC800B or NMOQ800B antenna
800MHZ - Larsen NMOKHFUD mount/wire - Larsen NMOQSPEC800B or NMOQ800B antenna
800MHZ - Larsen NMOKHFUD mount/wire - Larsen NMOQSPEC800B or NMOQ800B antenna
39/151MHZ - Larsen NMOKHFUD mount/wire - Larsen NMOQB antenna

Larsen NMOKHFUD: High frequency newer-style NMO mount shipped with Larsen UDCOAX, which is RG58/U Dual Shield (100% duofoil, 95% braid) solid center conductor, considered by Larsen as their "preminum coax" for 800 and 900MHz.

Larsen NMO3E825B: 3dB gain 800MHz antenna for two of my scanners that have a hard time picking up a distant system.

Larsen NMOQSPEC800B: Zero gain 800MHz 4" whip antenna for 5 of my scanners that generally have amazing reception. The real problem is my area is extremely extremely RF-rich and celltowers absolutely destroy the audio when passing by.

Larsen NMOQ800B: Alternate option to the above antenna. Simply because I like the RGSS gasket more than the cheap piece of junk flat o-ring seal the NMOQSPEC800B antennas come with. I wish I could have the NMOQSPEC800B with the better RGSS gasket, but I've tried and it doesn't fit.

Larsen NMOQB: Zero gain tunable whip for 136-512MHz. I'll likely cut it for 151MHz, but 39MHz is really more important to me. One scanner will scan both (in an either-or situation). I can't put a 4 foot whip on my tall van's rooftop for 39MHz. In past experience scanning 39MHz with this very antenna cut to 151MHz, it wasn't completely awful but it left A LOT to be desired. For my 39MHz, I MIGHT consider a NMO trunk lip mount for my hood. Basically a 49" whip mounted opposite of the AM/FM stereo antenna. But that would mean a 9th scanner unless 151MHz works on a 39MHz antenna. I would really prefer one scanner and one antenna for 39/151MHz, but I don't think that's possible.

 

[prcguy]

Seems like a lot of 800 antennas where one would do fine with a few accessories. I would use one good 800 antenna with a band pass filter (about 856 to 868MHz for SD area?) to keep out cell phone towers then feed an 8-port Stridsberg multicoupler.

The lower frequency antenna(s) could feed specific scanners or you could combine with the 800 antenna using a diplexer. I have an old antenna for CB that was a wire with tuning box that stretches across a window making a tuned slot antenna that worked surprisingly well, especially on large vans. I suspect this antenna would work fine at 39MHz and way better than a whip tuned for VHF hi.
prcguy

 

[Stringer619]

I've heard good things about the Stridsberg but for some reason I can't help but be skeptical that it doesn't affect the signal negatively in any way when compared to separate antennas. However, my real reason I'm hesitant to go with the Stridsburg is because it has to be powered. I have an auxillary battery and battery isolator, so I guess it shouldn't be an issue. 100ma isn't that much compared to the rated 500-750ma per scanner.

I'm looking at the MCA208M. Seems a bit pricey, but I suppose drilling 4 antenna holes in a brand new vehicle and running 4 wires sounds better and easier than drilling 8.

This would then be my new proposed plan. Thoughts?

800MHZ - Larsen NMOKHFUD mount/wire - Larsen NMO3E825B antenna
800MHZ - Larsen NMOKHFUD mount/wire - Larsen NMO3E825B antenna
800MHZ - Larsen NMOKHFUD mount/wire - Larsen NMOQSPEC800B or NMOQ800B antenna (with MCA208M to 5 scanners)
39/151MHZ - Larsen NMOKHFUD mount/wire - Larsen NMOQB antenna

The high-gain antennas can not be used on 5 of my scanners, so thats why I can't just have an 800MHz antenna for 7 of the 8 scanners. The signal is just too strong in my county. The far distant signal I'm trying to pick up for 2 of the scanners needs gain, and I am not comfortable using cheap splitters.

I guess I would just buy some of this cable for the jumpers from the MCA208M to the scanners, which claims to be the Larsen UDCOAX. I like everything to match.

Also I just recently bought a BPF-800W bandpass filter. I haven't had enough experience with it to know if it's making any difference whatsoever. Driving past cell towers still kill my radios.

 

[N5TWB]

I have a 4-port Stridsberg splitter and will tell you it works great in my area, especially on 800-MHz trunked systems. I endorse your second plan using a splitter and a bandpass filter to address your desense problems.

 

[Stringer619]

Does anyone have any regrets whatsoever in going with the Stridsberg? To be honest the only reason I would consider a multicoupler is the fear of drilling 8 holes in my brand new shiny roof instead of 4. But I'm stuck on the train of thought that a dedicated antenna to a dedicated scanner is the best scenario. It's cheaper, isolation of ports isn't an issue (I know the Stridsberg has some level of port isolation, but still), doesn't require power. It also allows me maximum flexibility to swap out antennas on a per-scanner basis. $400+ for the Stridsberg plus materials for jumpers vs $100+ of mounts/antennas. I'm not ruling it out, but the more I think about it the more I think I like the 8 dedicated antennas plan.

And N5TWB do you have the passive splitter or the powered multicoupler?

 

[Iffy]

'Holy discones'...! EIGHT scanners in a van? SETI has competition and is jealous!

 

[LtDoc]

I think this is a classic example of "analysis paralysis", just think it too deep. What's the best solution for your predicament? I really don't know. Considering the frequency bands you are talking about using, 'gain' antennas are certainly a better option than just 'smaller' ones for 'looks' sake. I've seen some rather sophisticated communications vans using VHF/UHF/SHF bands/antennas. They tend to be a very specialized resource. A real shock to the wallet of an individual.
Good luck!
- 'Doc

 

[Stringer619]

You're probably right Doc (the irony of what I just said..). I'll probably go with the 8 antennas plan. For someone who uses their vehicle and scanners 8 hours a day for their income, it's critical. Especially when a big story gets dispatched and static kills the street name.

"2nd Alarm Structure Fire, people jumping out of 3rd story windows, 1345 (static) St, radio channels are 9 (static)"

What can I say, I'm a perfectionist.

 

[LtDoc]

A 'perfectionist'? If people are involved then you're screwed to start with!
Having been there and done that with missed addresses I know what you mean. If you can't ask for a repeat, then all you can do is to keep listening. (Not telling you anything new there, huh?) You can have a perfect communications system but that human factor still plays a huge part in it.
Good luck!
- 'Doc

 

[Stringer619]

Everything is scanners.. can't ask the fire department or police dispatcher for a repeat unfortunately. I can call them, but they're busy people, so I try to avoid that.

 

[Spankymedic7]

Private message

Everything is scanners.. can't ask the fire department or police dispatcher for a repeat unfortunately. I can call them, but they're busy people, so I try to avoid that.

Stringer, check out your private inbox.

 

[N5TWB]

And N5TWB do you have the passive splitter or the powered multicoupler?

Mine is powered and has worked well in helping signal strength in marginal areas but that doesn't sound like your problem. Right now mine only runs two scanners with an occasional third scanner.

I understand the dilemma you describe and endorse the fact that it is more than a hobby for you so the criteria are different. I look forward to when you eventually post photos of your ride as those always help me when considering any upgrade on mine.

 

[SCPD]

Did you ever get your install completed on the new van? Show us some pics please!

 

[wrc1045A]

I wonder if this was completed. If reliability was desired I would go with separate antennas than to have powered splitters. If a splitter fails he losses those scanners on the splitter. I would personal have a professionally design antenna or array for the vehicle. The again I shoot for overkill


Sent from my iPhone using Tapatalk

 

[KJ6HCB]

Post some pics SDNV!