So right now I have a Bc125AT and I am going to get an sds100 soon. I want to have an antenna on my car so I can achieve extended range. I like the “ghost” style and sharkfin style but I am open to having an actual antenna. I know that the roof of my car has the highest range so ideally I would mount it there. I do not like the aesthetics of a magnet mount. I also do not want to drill through my roof - though I may have to. I have a 2016 4Runner and my mounting locations are the roof or front hood. I have seen nmo mounts that are attached to ditch light mounting brackets and I could ground that for a ground plane. Would that be sufficient? What would my range be with a ghost antenna? i am concerned with drilling through my roof for water sealing and the possibility I could mess it up. Could I remove my sharkfin and find like a nmo mount or a scanner antenna that would fit? Please help
Sds100 antenna mounting
No real way to gauge range especially on a moving vehicle that is driving past all kind of things that could block rf signals.
Should I do a roof or hood mount for a ghost antenna
It depends. How strong are the agencies you want to monitor? You may be able to get away with something which is not the best because you don’t need it. Ideally, the center of the vehicle is considered best for ground plane effect but it’s also impractical for most. So stay away from drilling holes or swapping out equipment that came with the vehicle. I’d get a lip mount and attach it to the hood and mount a decent gain antenna on it. Find a way to route the cable inside. Then start thinking about powering using an external speaker with the SDS100… it’s definitely going to need both.
NMO mounts have been in use for many, many years.
The 'gold standard' of communications antenna mounts
Probably every cop car you have seen in your life has one or more NMO mounted antennas.
Yes, you have to drill a hole, but when done properly, an NMO mount will not leak - they have a rubber seal that prevents this (IF MOUNTED PROPERLY). And there are rubber plugs available that you can use if it is ever removed.
I probably installed 4-500+ MNO mounts back in the AMPS days - not one of them ever leaked.
True NMO mounts use a 3/4" hole.
There are some variants that will use a 3/8" hole.
The size of the hole depends on what mount you purchase.
Mounting on the front hood is less than desirable.
The vehicle body blocks signal from the back.
Center of the roof for NMO.
The 'gold standard' of communications antenna mounts
Probably every cop car you have seen in your life has one or more NMO mounted antennas.
Yes, you have to drill a hole, but when done properly, an NMO mount will not leak - they have a rubber seal that prevents this (IF MOUNTED PROPERLY). And there are rubber plugs available that you can use if it is ever removed.
I probably installed 4-500+ MNO mounts back in the AMPS days - not one of them ever leaked.
True NMO mounts use a 3/4" hole.
There are some variants that will use a 3/8" hole.
The size of the hole depends on what mount you purchase.
Mounting on the front hood is less than desirable.
The vehicle body blocks signal from the back.
Center of the roof for NMO.
mmckenna
I ♥ Ø
NMO roof mounts do not leak if installed correctly. Unfortunately there seems to be a subset of the amateur radio community that loves to spread the 'leak' claims. I've been installing NMO mounts for several decades now, and I have never, ever, ever had one leak.
Anyone that tells you that they leak either has never installed one, or probably shouldn't be allowed to screw in a lightbulb, never mind install antennas.
So, roof mount if you want performance.
Mounting on ditch light brackets won't give you a ground plane. Running a separate wire to ground doesn't give it a ground plane. DC grounds and RF ground planes are different things. The antenna would need to be mounted on a flat conductive surface to have a ground plane, and the bracket won't provide that. Also, setting it off to one side, like the hood brackets, gives it a lopsided ground plane that will result in some amount of directionality. It also puts the antenna down below the cab, that will result in some shielding.
If you want the best performance, mount it on the roof at least 19" in from any roof edge for VHF frequencies and above.
Ghost antennas, or the 'low profile' antennas can work OK on UHF and above. They are not a good choice for VHF, and I haven't seen anyone make a respectable low profile multi band antenna. If you are going to do this right, then use a good antenna.
I've been running a Larsen multiband antenna on my work and personal truck for about 5 years now, connected to a multiband Harris radio. I've been happy with that antenna in my application. I've also use the EM Wave multiband antenna, and it's worked just as well. I'd run either one for a scanner antenna if I needed to. The Larsen is a bit thinner and blends in better.
Your vehicle, your choice, but don't listen to the people that tell you that NMO mounts leak. They have no clue what they are talking about.
- Joined
- Feb 22, 2007
- Messages
- 6,321
I agree 100% with those saying just drill the hole on your roof in the very center. As has been said, no fear of leaking and if you have a lease car you can actually use touch up paint and let it dry on small cap that would go over the hole.
I also agree, if your signals are strong like you were listening to just one system that you were close to, the undercover type antennas can work but if you're going to go to all the trouble and you want the most from your SDS 100, this is the antenna I use, for listening, it'll give you great coverage on VHF High, UHF 1 and 2 and 7-800 MHz.
Drill a hole.
Jefferson county simulcast in Alabama… control freq is 857.4 I belive. How much gain will be lost with a lip mount? I once used a lip mount on my 4Runner and it kind of sits at a angle… do you have any suggestions on antennas and mounts?
Do you have any suggestions for navigating around airbags and such and the process it makes me very nervous drilling lol
Ok thank you so much so the ghost antenna would not be the best idea even if it wasn’t a dual or multiband?
Okay thank you. I also have a cb on my car with coax running through the trim… is running a separate coax cable near it going to cause interference?
mmckenna
I ♥ Ø
I've never seen a real multiband antenna like that. I know e-bay sells some, but they can't be good performers. You can't cram 19" of whip into a 3" tall can and get any real performance out of it.
But, the nice thing is that with an NMO mount, you can try all this stuff yourself. Just don't expect a 'ghost' antenna to have any meaningful performance on VHF. They work OK single band on UHF or 800.
mmckenna
I ♥ Ø
If your vehicle has side curtain type airbags, just make sure you route the coax between them and the roof skin. You want to make sure the coax doesn't get in the way of deployment. Ideally, route cable away from them. Usually going to one of the pillars, like the one directly behind the drivers seat, will work just fine.
mmckenna
I ♥ Ø
No. Decent coax has a good shield and this shouldn't be a problem.
While you are doing this work, consider installing a second NMO mount and get the CB antenna up there on the roof. With a good ground plane under it, it'll work well.
Okay cool do you know if any of those antennas above are flexible
mmckenna
I ♥ Ø
Both the Larsen and EM Wave have springs on the base. I've run my work truck up overgrown site access roads and hit a lot of tree branches. Never once damaged an antenna, mount or roof skin.
If you want multiband and a lot of flexibility, I'd recommend the Larsen NMO-150/450/758SF The "SF" in the model number gets you a more flexible whip material. It's what I'm running on my work truck and personal truck:
Mobile Antenna Tri-Band 150-165,450-470,700/800MHz Larsen NMO150/450/758
Tri-band antenna covers 150-174, 430-520 & 750-870, 100 Watts, Whip Length 16.5"
theantennafarm.com
I'll also add:
If you are going to go through the process of installing a permanent NMO on the roof of your vehicle, don't buy the cheapest Chinese mount you can find (looking squarely at Tram/Browning and the ham brands). Stick with Larsen, Laird, PCTel, or EM Wave. The Chinese brands use poorly installed connectors. It's really not worth saving $3 on this part of the installation.
And, seriously, consider installing more than one mount while you are doing all this work. You -will- find a reason to use it once it's there.
Oh, one more thing, you do not need to remove the headliner to install the 3/4" style mounts, they mount completely from the outside. If you go with the 3/8" mounts mentioned above, you do need access to both sides of the roof to install.
- Joined
- Feb 22, 2007
- Messages
- 6,321
That's a good price for the "SF".. original poster, it is a very good performing antenna and pairs nicely with the sds100. I am very satisfied with it.Both the Larsen and EM Wave have springs on the base. I've run my work truck up overgrown site access roads and hit a lot of tree branches. Never once damaged an antenna, mount or roof skin.
If you want multiband and a lot of flexibility, I'd recommend the Larsen NMO-150/450/758SF The "SF" in the model number gets you a more flexible whip material. It's what I'm running on my work truck and personal truck:
Mobile Antenna Tri-Band 150-165,450-470,700/800MHz Larsen NMO150/450/758
Tri-band antenna covers 150-174, 430-520 & 750-870, 100 Watts, Whip Length 16.5"
I'll also add:
If you are going to go through the process of installing a permanent NMO on the roof of your vehicle, don't buy the cheapest Chinese mount you can find (looking squarely at Tram/Browning and the ham brands). Stick with Larsen, Laird, PCTel, or EM Wave. The Chinese brands use poorly installed connectors. It's really not worth saving $3 on this part of the installation.
And, seriously, consider installing more than one mount while you are doing all this work. You -will- find a reason to use it once it's there.
Oh, one more thing, you do not need to remove the headliner to install the 3/4" style mounts, they mount completely from the outside. If you go with the 3/8" mounts mentioned above, you do need access to both sides of the roof to install.
Be careful, I have seen online the old model Larson tri band that was the same exact antenna but did not have the heavy duty NMO mount but was still NMO.. it has no spring at all, as you can imagine, it is a disaster waiting to happen on a roof mount.
It sure was easier back when the "M" in NMO was actually The Bat Wings.....
You got them from them when they shipped radios.
Didn't have to worry about QC or what sized hole.
Tessco when they stopped shipping the radios with them....
You got them from them when they shipped radios.
Didn't have to worry about QC or what sized hole.
Tessco when they stopped shipping the radios with them....
mmckenna
I ♥ Ø
I still have a few of those new in the bag. Pretty sure Motorola didn't manufacture those themselves, just resold/repackaged someone else's.
Never had an issue with QC using the Larsen mounts.
Did install an NMO on my dad's truck many years ago. He didn't know and bought a Tram mount at HRO. Mount was OK, but I had to cut the UHF connector off the end to route the cable and then reinstalled a new UHF connector.
That cut off UHF connector sat on my bench for a couple of months. One day, while bored, I decided to dissect it.
I carefully cut off the over-molded plastic cover/strain relief. Under that was one of the most poorly installed connectors I've ever seen. The shield retention was accomplished by what I can only describe as someone smacking it with a center punch to hold in place long enough to do the over molding which hid the awful connection. Did it work? Probably, but no way I'd ever do a connector install like that. It was sheer laziness.
Not even crimped with the correct crimpers:
Yes, you can not go wrong with the Larsen. I had one but where I am now does not require multiband. Great suggestions and explanations above.
Still, the one question that I always ask which is referred to above is “exactly what do you want to listen to and where will your driving take you in relation to the sites?” Otherwise it can be overkill on an antenna or you may not have good reception no matter what you use.
Still, the one question that I always ask which is referred to above is “exactly what do you want to listen to and where will your driving take you in relation to the sites?” Otherwise it can be overkill on an antenna or you may not have good reception no matter what you use.
