CB antenna - single or dual stick?

[KenP]

You might as well install your dream stereo now, too.

[CslRkH2]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rodster:
I'd guess my best reception will come from the back, the sides will be even and in front will be the weakest. Agreed?

I grabbed this off the Firestick site.
Because of the imperfect world, we almost always recommend 18' (5.5m) when our products are used. We do so with good reason too! At 18' the voltage curve has dropped back to the zero voltage point where the cable meets the antenna which reduces the reactance within the cable itself (a null cable if you would).
</div></BLOCKQUOTE>

I agree. By placing it in the middle does that make it hard to get to? If your OK with a middle of the roof location, why not mount in the exact middle through the mesh GOBI deck?

Dick R is on the money with the distinction between Electrical Ground and RF ground. BOTH are important in this install. You must have an electrical ground or you will have a SWR reading of 3+. This is bad and can negatively effect your CB Radio. When you are tuning...If the lower CB channels are "worse" than the upper channels then this is an indication of an insufficient ground place (RF ground plane). This info can be found on FireStik.

I used that exact coax cable you had pictured, the mounting location I showed in my pic, and achieved at ~1.7 at channel 1 and a ~1.4 at channel 40. This means I had a little bit of a weak RF ground plane. The closer to the metal H2 roof you can the better (I had better and almost equal readings at 1 & 40 before the GOBI install; I think the few inches of elevation away from the roof caused this change).

[CslRkH2]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dick Renaud:

In radio, every little thing adds up to major difference in results. You can short cut it if you don't care about the extra distance or clarity.

As a cop and emergency worker for many years I always go the extra step for the added security in that one situation when you REALLY need the extra. </div></BLOCKQUOTE>

Totally agree, all the time you spend tuning will pay off because you will be able to hear and be heard more clearly and from a greater distance.

[ree]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dick Renaud:
...
...
...
...
Al this may be a bit of over kill for raw CB, but I have had CBs in many diffent vehicles and building and have found that with a few simple steps you can get a lot more from your equipment. </div></BLOCKQUOTE>

Damn, why does every thing have to be more complicated that I thought it was going in

Dick, thanks for all this good info. Got a follow up question on the CB ground, though. With a mini handheld, where the whole thing fits in the palm of your hand, grounding the radio chassis doesn't seem to make a lot of sense. It's not real practical to attach a ground strap to the back of it. So this just limits the potential of these small radios right?

[ree]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rodster:
Here's the current state of the project. </div></BLOCKQUOTE>

Ha, ha! Now you get to fuss with those little retainer clips on the bottom of the cup holder tray that slide around when you try to remount the damn thing That alone is enough to keep me from opening up my center console one more time unless it's a national emergency.

[KenP]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Carl:
I agree. By placing it in the middle does that make it hard to get to? If your OK with a middle of the roof location, why not mount in the exact middle through the mesh GOBI deck? </div></BLOCKQUOTE>I had mine mounted through the mesh on the driver's side. I ran into two problems. The first being the joint not being long enough to go through the mesh and two thick washers.

The second is I had to use two smaller washers against the mesh so everytime the antenna hit a tree it moved and started loosening by rocking back and forth. You have to use two very wide washers to hold it to the mesh.

[rodster]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by CslRkH2:

By placing it in the middle does that make it hard to get to? </div></BLOCKQUOTE>

Nope, and that's one of the reasons I put it where I did -- ease of access. I open the sunroof, reach up, slide up the spring-loaded sleeve that contains the pivot joint and lean the whole thing down.

I considered putting it on the driver's side for easy access but then I wouldn't have the full benefit of the what roof I have now. Plus, it just looks better in the middle.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">If your OK with a middle of the roof location, why not mount in the exact middle through the mesh GOBI deck? </div></BLOCKQUOTE>

No can do. I carry recovery gear and other stuff up there regularly. I need the rack space.

Appreciate the other input, too, CslRkH2!

[Dick Renaud]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ree:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dick Renaud:
...
...
...
...
Al this may be a bit of over kill for raw CB, but I have had CBs in many diffent vehicles and building and have found that with a few simple
steps you can get a lot more from your equipment. </div></BLOCKQUOTE>

A handheld was not intended to be used in a vehicle and if it is you don't ground it, you make sure that the external antenna has a good ground plane and if you use a 12 volt lighter plug for power find one with an RF filter in line. Most HAM hand helds offer these. Hand helds and vehicles are really not compatable.
I use an Yeasu 7R VHF hand held and mag antenna for use with rental vehicles etc. It works good with VHF repeaters, but CB is a different animal and much more prone to noise in the reciever and poor transmit power and SWR. It is a big comprimise, but better than nothing.

Damn, why does every thing have to be more complicated that I thought it was going in

Dick, thanks for all this good info. Got a follow up question on the CB ground, though. With a mini handheld, where the whole thing fits in the palm of your hand, grounding the radio chassis doesn't seem to make a lot of sense. It's not real practical to attach a ground strap to the back of it. So this just limits the potential of these small radios right? </div></BLOCKQUOTE>

[Dick Renaud]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dick Renaud:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ree:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dick Renaud:
...
...
...
...
Al this may be a bit of over kill for raw CB, but I have had CBs in many diffent vehicles and building and have found that with a few simple
steps you can get a lot more from your equipment. </div></BLOCKQUOTE>



Damn, why does every thing have to be more complicated that I thought it was going in

Dick, thanks for all this good info. Got a follow up question on the CB ground, though. With a mini handheld, where the whole thing fits in the palm of your hand, grounding the radio chassis doesn't seem to make a lot of sense. It's not real practical to attach a ground strap to the back of it. So this just limits the potential of these small radios right? </div></BLOCKQUOTE> </div></BLOCKQUOTE>

A handheld was not intended to be used in a vehicle and if it is you don't ground it, you make sure that the external antenna has a good ground plane and if you use a 12 volt lighter plug for power find one with an RF filter in line. Most HAM hand helds offer these. Hand helds and vehicles are really not compatable.
I use an Yeasu 7R VHF hand held and mag antenna for use with rental vehicles etc. It works good with VHF repeaters, but CB is a different animal and much more prone to noise in the reciever and poor transmit power and SWR. It is a big comprimise, but better than nothing.

[rodster]

Dick -- I believe by "handheld" he's referring to this Cobra unit, which is more of an all-in-one than handheld.



I still have a few questions for you, Dick, but need to get back outside to handle a few more install details. Then I'll finally come in, thaw out, shower and see if I can still form a sentence. If not, I'll be back at it in the morning. Thanks for everyting!

[KenP]

He may be referring to the Midlands unit, also. That is truely All-in-One.

Rod has a PM.

[rodster]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KenP:

Rod has a PM. </div></BLOCKQUOTE>

And he answered it.

[rodster]

Progress!

The antenna is on, the coax is run and tomorrow I'll run power and ground, tune and then button everything up. If you own the Cobra unit (and if you care ) , you can see where I'm headed. After all this, I better be able to talk to my dad in Florida!

[rodster]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dick Renaud:

You are attempting to keep the resistance of the cable balanced with the radio and antenna to get maximume power transfer. </div></BLOCKQUOTE>

I hear two possible things here (and I may be way off so bear with me, please):

1. More length = more impedance which = less transmit power?

and/or

2. There is possibly a formula for calculating optimum coax length on a properly grounded vehicle when radio and antenna specs are known?

------

Like Phil said earlier, in the end a basic CB setup will no doubt do more than I ever need it to normally do, i.e., communicate with other moving trucks that are fairly close.

BUT, I'll take your advice and do the extra grounding and homerun power because I fully expect the CB will give way to a ham unit soon. The purpose of that radio will be much broader and maximum performance will absolutely be desired. Plus, even if it's only a CB today, I'd still like to get the most out of it because, well, because I can and I enjoy the tinkering.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">One last thought, the Firestick is a great antenna because you can tune it easily and retune it any time you add something to the roof a9lights, bars etc). </div></BLOCKQUOTE>

I had a choice between Firestik and Wilson. The shop owner was very high (to say the least) on Wilson so based on his recommendation and my desire for a flex unit, I bought the Wilson Silver Load Flex 4 . Any thoughts on that?

You mentioned the antenna can be retuned when something new is added to the roof ...

When I'm headed off-road, I mount quite a bit of metal recovery gear on the roof rack. Will that effect the tune? If yes, given that I'll most often use the radio when off-road, would you advise I tune with the gear on?

Thanks much, Dick. I'm grateful for your time and input. Same goes for anyone else that wants to chime in!

[rodster]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ree:

That alone is enough to keep me from opening up my center console one more time unless it's a national emergency. </div></BLOCKQUOTE>

Now that's funny!

Oddly enough, before pulling the center console apart I found one clip under the seat while looking for a renegade lock washer. I didn't know what it was until I pulled the cupholder out. When I did pull it out, I salvaged one clip while another went to China, current address unknown.

I'm thinking two-sided 3M stick-it-like-you-hate-it tape. Eh?

[Dick Renaud]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rodster:
Dick -- I believe by "handheld" he's referring to this Cobra unit, which is more of an all-in-one than handheld.



I still have a few questions for you, Dick, but need to get back outside to handle a few more install details. Then I'll finally come in, thaw out, shower and see if I can still form a sentence. If not, I'll be back at it in the morning. Thanks for everyting! </div></BLOCKQUOTE>

If he is talking about the Cobra 75 it is not a handheld(portable)I am refering to, it is considered a remote head even though the controls are in the mic. If he is talking about the Cobra 75 the small radio pack that mounts under the dash should be chassis grounded and can be grounded with a strap from the mounting screws if it is not mounted to solid chassis metal.

[Dick Renaud]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rodster:
[quote]Originally posted by Dick Renaud:

You are attempting to keep the resistance of the cable balanced with the radio and antenna to get maximume power transfer. </div></BLOCKQUOTE>

I hear two possible things here (and I may be way off so bear with me, please):

1. More length = more impedance which = less transmit power?

You are close, but impedance should remain constant at 50 ohms. Length = resistance which = heat which = power loss. the more lenth the more loss and at about 4 watts or less output power at best (the 5 watts is input power) you need all you can retain. Also, there is some increase in recieve (mostly in noise reduction) with shorter coax.

I had a choice between Firestik and Wilson. The shop owner was very high (to say the least) on Wilson so based on his recommendation and my desire for a flex unit, I bought the Wilson Silver Load Flex 4 . Any thoughts on that?

Wilson is a good antenna, but generally longer and more difficult to tune. If the additional length is not a problem its fine. I should mention that a flexable antenna changes radiation pattern as it sways back and forth or lays back at high speed. The Firestick is ridgid and holds it pattern better. I would use a spring with a firestick to take minor hits better, but as mentioned earlier, a ridgid antenna on the trail may be damaged. The only antenna that will take the trail is a short rubber antenna and you loose distance with that. A comprimise that we used to use on police vehicles is a Larsen with an NMO mount mounted into the roof with a backer plate. The Larsen is very flexable and with a solid mount will take a lot of abuse as long as it is not hit to close to the base.

You mentioned the antenna can be retuned when something new is added to the roof ...

When I'm headed off-road, I mount quite a bit of metal recovery gear on the roof rack. Will that effect the tune? If yes, given that I'll most often use the radio when off-road, would you advise I tune with the gear on?

Absolutely tune with everything on that you will normally run with. Anything in proximity to the antenna can de-tune it. One addition though, the rack etc should be grounded to the roof with braid. The regular mounts are not a very good ground. Also, any loose body metal ( hood, lift gate etc) should be Bonded (grounded) with braid. Again, refer to Alans web site referenced in my earlier post.

[ree]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dick Renaud:
If he is talking about the Cobra 75 it is not a handheld(portable)I am refering to, it is considered a remote head even though the controls are in the mic. If he is talking about the Cobra 75 the small radio pack that mounts under the dash should be chassis grounded and can be grounded with a strap from the mounting screws if it is not mounted to solid chassis metal. </div></BLOCKQUOTE>

Sounds like there's a decent solution for the Cobra. I went with the Midland 75-822 so I could have true portability in one unit. Instead of a little box like the cobra for wiring it in, it's only got a slide on adapter that has tails for a 12V power jack and the coax. So I guess I don't get a good ground. If it's an issue, I can upgrade the CB to a non-portable.

[Dick Renaud]

Portables work ok at short range in a vehicle with an external antenna. The problem is because there is no provision for grounding they do pick up alot of noise on both TX and RX. If you need to go portable it is a comprimise that you must accept. If you can afford it, I would put the Cobra in the vehicle and have the Midland for portable ops. For Ham, I have an ICOM IC-7000 (HF/VHF/UHF) in the vehicle and a Yeasu FT 7r (VHF/UHF) for portable ops. Again, you have to decide what the use will be and what you are willing to accept in distance and quality. The ultimate would be a 100' tower, Beam antenna and rotor with a half acre ground plan and a 1000 watts.

It is really what is practical for you.

[ree]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dick Renaud:
...The ultimate would be a 100' tower... </div></BLOCKQUOTE>

Ken,
Can you do the photochop on this?