CB antenna mount concerns

[TJM]

So I went to have my CB installed today, and brought a Diamond K400 mount and a 4' firestik 2. The first problem that I had was that the one I ordered didn't have the adapter or any cable. Not a big deal on the cable but the adapter part was a hard stop.

The second issue was that, per the installer, the firestik 2 was a bit too heavy for that mount and it might tear up the metal where it is mounted when the antenna flexes from wind or striking objects. I don't think I'll hit that many things, I'm not going through the Flintstones carwash or anything, but I see his point. I asked if a flexible spring mount between the firestik and the Diamond would help and he seemed to think it would, just not sure how much.

Has anyone mounted this setup on the rear hatch, and if so, have you had any issues? Should I get a shorter antenna and just deal with the loss of range? If you used a Diamond, which one? I can't figure out if I need the K400 CNMO, SNMO, S, or what.

 

[Humble Leader]

So I went to have my CB installed today, and brought a Diamond K400 mount and a 4' firestik 2. The first problem that I had was that the one I ordered didn't have the adapter or any cable. Not a big deal on the cable but the adapter part was a hard stop.

The second issue was that, per the installer, the firestik 2 was a bit too heavy for that mount and it might tear up the metal where it is mounted when the antenna flexes from wind or striking objects. I don't think I'll hit that many things, I'm not going through the Flintstones carwash or anything, but I see his point. I asked if a flexible spring mount between the firestik and the Diamond would help and he seemed to think it would, just not sure how much.

Has anyone mounted this setup on the rear hatch, and if so, have you had any issues? Should I get a shorter antenna and just deal with the loss of range? If you used a Diamond, which one? I can't figure out if I need the K400 CNMO, SNMO, S, or what.

before you get into mounting, the firestik 2 is a 5/8 wave antenna which means it needs a ground plane. mounting on the rear hatch is not going to be enough ground plane. you can mount it there but your performance will be compromised. not a big deal if you're only looking at short distance, but longer distance you will notice it. a solution is to get a half wave antenna which does not require a ground plane. they make no ground plane antennas as well so make sure if you mount it there to have the right antenna

I have a comet rs730 which is similar to the diamond mount. I have a ham radio and the longest whip I have is only 40" and doesn't weigh very much since it's a thin metal whip. the firestik weighs close to 1lb I believe which is still under the weight limit of the mount, but coming up on it. you have 4 large set screws to secure the mount I don't think you have to worry. more than likely you will break or snap the antenna vs rip the mount from the vehicle. adding a spring means you might have to shorten the antenna length or you could have distortion. I also use an NMO mount with my comet

 

[TJM]

before you get into mounting, the firestik 2 is a 5/8 wave antenna which means it needs a ground plane. mounting on the rear hatch is not going to be enough ground plane. you can mount it there but your performance will be compromised. not a big deal if you're only looking at short distance, but longer distance you will notice it. a solution is to get a half wave antenna which does not require a ground plane. they make no ground plane antennas as well so make sure if you mount it there to have the right antenna

I have a comet rs730 which is similar to the diamond mount. I have a ham radio and the longest whip I have is only 40" and doesn't weigh very much since it's a thin metal whip. the firestik weighs close to 1lb I believe which is still under the weight limit of the mount, but coming up on it. you have 4 large set screws to secure the mount I don't think you have to worry. more than likely you will break or snap the antenna vs rip the mount from the vehicle. adding a spring means you might have to shorten the antenna length or you could have distortion. I also use an NMO mount with my comet

So I have my HAM license as well and will likely eventually put a mobile rig in the vehicle, but that's a ways down the road. For now, is there an antenna you'd recommend? Would Comet have a better option? This is still just CB, so mostly comms with other vehicles while on the trail or just the amusement of the trucker talk on the highway. The HAM setup isn't something I've even delved into yet.

 

[hoppyjr]

So I have my HAM license as well and will likely eventually put a mobile rig in the vehicle, but that's a ways down the road. For now, is there an antenna you'd recommend? Would Comet have a better option? This is still just CB, so mostly comms with other vehicles while on the trail or just the amusement of the trucker talk on the highway. The HAM setup isn't something I've even delved into yet.

Back when I used to use CB, I went with the Larsen NMO mount CB antenna. Used a hood lip bracket and it was great.

 

[TJM]

Hoppy did that mount include a ground? Sounds like I need to have a ground plane somehow integrated to make my firestik 2 work. I'm not opposed to getting a different antenna or mount if need be, but this time I want to make sure I get the right things so I don't end up here asking what the hell I did to myself again...

 

[TJM]

Update: I talked to Troy at DX Engineering where I bought the original mount from, and they gave me an adapter part number for the mount/antenna combo. He said the paint would have to be sanded down where the set screws attach to provide ground. I asked for recommendations for a spring to attach between the antenna and mount, but I kind of inundated him with questions and I think he missed that one.

Would there be any issue mounting a Firestik medium duty spring to this set up, in the opinion of you clearly more experienced radio operators out there?

Thanks everyone!

 

[Humble Leader]

Update: I talked to Troy at DX Engineering where I bought the original mount from, and they gave me an adapter part number for the mount/antenna combo. He said the paint would have to be sanded down where the set screws attach to provide ground. I asked for recommendations for a spring to attach between the antenna and mount, but I kind of inundated him with questions and I think he missed that one.

Would there be any issue mounting a Firestik medium duty spring to this set up, in the opinion of you clearly more experienced radio operators out there?

Thanks everyone!

DX engineering is great. I've used them as a sounding board for my set up. let's not confuse ground plane with electrical ground. you can ground your mount to the body using set screws (you don't need to sand, they will bite into the paint and hold, then use some dielectric grease or fluid film around the threads as a water repellant). check with multi meter to ensure good ground. I bit all 4 of my set screws into the paint for good measure. some people only do 2

a ground plane is the reflective metal of the car's body under the mount that extends about 6-12" 360 degrees around the antenna and is mainly used for propagation. the actual amount of ground plane needed depends on the wavelength of the antenna but 6-12" is a safe bet. that's why roof mount is the most popular location but not really ideal. in real life perfect ground planes are very hard to get. even your roof may have contours, roof rails, sun roof, etc.

if you add a spring to the bottom of the antenna you have effectively lengthened it and it's factory length is based on wavelength. you may have to cut/trim the antenna to be the correct size after adding a spring (I'd check with DX on this or someone that knows CB or these firestiks well)

I don't think you need a spring, IMO, firestiks are somewhat flexible, but I have no experience using them

I would first determine where you are willing to mount your antenna. if roof is out of the question you will then need to decide if you are willing to have an imperfect ground plane under your antenna. if you are OK with this based on your needs (and many people are and have no issues) then you can firestik on a lip mount like the diamond or comet. if not, get a ground independent antenna for CB. I would ground your lip mount to the metal wherever you mount you antenna though, regardless of the antenna type

with CB the power output is far less than ham. I think 4 watts vs 50 watts. so an imperfect ground plane or partial ground plane (like hood corner) is often OK and you can get away with using any antenna.

firestik does make a no ground plane antenna. wilson makes some as well I believe.

edit: also once you decide where to mount your antenna, pick up a few antennas and experiment. see which ones work best, keep a couple and swap them in and out. I have three antennas lol. when you're ready for a ham set up you will be a pro and then can come give me advice lol

 

[hoppyjr]

Hoppy did that mount include a ground? Sounds like I need to have a ground plane somehow integrated to make my firestik 2 work. I'm not opposed to getting a different antenna or mount if need be, but this time I want to make sure I get the right things so I don't end up here asking what the hell I did to myself again...

It grounds to the inside edge of the fender. Worked great and the whip portion is tunable for SWR.

The NMO mount attached through the hole, ground is transferred through the metal mount and into edge of fender. No holes seen, never had any issues.

 

[TJM]

Awesome thank you both. And yes, DX Engineering is no doubt a great company. I get most of my HAM radio equipment there, as I'm still setting up my base station.

I might try a shorter (3') antenna as well just to see how things work out. I will keep you posted how it goes!