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Mobile homebrew
- Thread starter Bandit1
- Start date
Bandit1,
If you are going for a mobile antenna, then get a 3/8" fiberglass flag pole like the ones used for bikes etc., and some epoxy,
use solid copper wire, not stranded, and use a gauge of 18 or bigger, but you don't need anything bigger than about 14 gauge unless you are running serious power.
epoxy the wire on to the fiberglass rod. cut the rod to 108" BUT! leave a few inches of wire hanging free at each end of the fiberglass pole.
now get yourself some 3/8x24 (fine thread) threaded rod, and a barrel nut for it, preferably 2" long or so, and a regular nut for it.
now cut the threaded rod so that it will seat about halfway in the barrel nut, and stick out about 1/2" or so, being sure to leave enough room for the regular nut so you can tighten it against the barrel nut. this will hold the threaded rod in place.
be sure to de-burr the ends of the rod so that nuts will go over them.
now peel back just enough wire off of the fiberglass rod in order for it to fit down in the barrel nut, coat the end of the rod in epoxy (i might use JB weld here for added strength), and shove the fiberglass rod into the barrel nut.
let the epoxy cure while you are making sure the rod is sticking straight out of the barrel nut.
once cured, using a high wattage soldering gun, solder the copper wire to the side of the barrel nut.
now just make sure that whatever mount you are using has a secure connection to the body of the vehicle and you are all set to check your SWR.
it will probably be low in frequency because of the extra wire sticking out the top, so if your SWR is higher than 2 on channel 20, cut an inch off.
keep checking until you can get a 1.5 SWR on channel 20. don't cut off any more wire than about 2" more than the extra on top. if your SWR is still too high after cutting off all of the extra wire, then you have another problem in your installation.
remember that a 1/4 wave antenna (102" whip) has an impedance of 36 ohms, so a 1.5 SWR is what you are looking for.
there is no point in trying to get lower, and if you do, it's because you have losses in the system.
get it down to 1.5 and call it good.
there are plenty of tutorials online for a 1/4 wave HF groundplane antenna for home use.
LC
If you are going for a mobile antenna, then get a 3/8" fiberglass flag pole like the ones used for bikes etc., and some epoxy,
use solid copper wire, not stranded, and use a gauge of 18 or bigger, but you don't need anything bigger than about 14 gauge unless you are running serious power.
epoxy the wire on to the fiberglass rod. cut the rod to 108" BUT! leave a few inches of wire hanging free at each end of the fiberglass pole.
now get yourself some 3/8x24 (fine thread) threaded rod, and a barrel nut for it, preferably 2" long or so, and a regular nut for it.
now cut the threaded rod so that it will seat about halfway in the barrel nut, and stick out about 1/2" or so, being sure to leave enough room for the regular nut so you can tighten it against the barrel nut. this will hold the threaded rod in place.
be sure to de-burr the ends of the rod so that nuts will go over them.
now peel back just enough wire off of the fiberglass rod in order for it to fit down in the barrel nut, coat the end of the rod in epoxy (i might use JB weld here for added strength), and shove the fiberglass rod into the barrel nut.
let the epoxy cure while you are making sure the rod is sticking straight out of the barrel nut.
once cured, using a high wattage soldering gun, solder the copper wire to the side of the barrel nut.
now just make sure that whatever mount you are using has a secure connection to the body of the vehicle and you are all set to check your SWR.
it will probably be low in frequency because of the extra wire sticking out the top, so if your SWR is higher than 2 on channel 20, cut an inch off.
keep checking until you can get a 1.5 SWR on channel 20. don't cut off any more wire than about 2" more than the extra on top. if your SWR is still too high after cutting off all of the extra wire, then you have another problem in your installation.
remember that a 1/4 wave antenna (102" whip) has an impedance of 36 ohms, so a 1.5 SWR is what you are looking for.
there is no point in trying to get lower, and if you do, it's because you have losses in the system.
get it down to 1.5 and call it good.
there are plenty of tutorials online for a 1/4 wave HF groundplane antenna for home use.
LC
Last edited:
sure,
here are some pics and a couple of links for more info:
threaded rod:
https://www.whitecap.com/shop/wc/p/3-8-x-24-zinc-plated-threaded-rod-277atz3824
Barrel nut:
http://www.zieglerbolt.com/38-24-x-1-18-hex-coupling-nut-12-zinchex-coupling-nut-12-zinc-2
looks like the standard length for the barrel nut is 1 1/8" so a 2" may be too hard to find.
the inch and an eighth size should work just fine.
LC
here are some pics and a couple of links for more info:
threaded rod:
https://www.whitecap.com/shop/wc/p/3-8-x-24-zinc-plated-threaded-rod-277atz3824
Barrel nut:
http://www.zieglerbolt.com/38-24-x-1-18-hex-coupling-nut-12-zinchex-coupling-nut-12-zinc-2
looks like the standard length for the barrel nut is 1 1/8" so a 2" may be too hard to find.
the inch and an eighth size should work just fine.
LC
you got it.
I know people around here can seem gruff at times, (me included) but most of us do actually like to help.
some of us do tend to be a bit guarded, and that comes from years of trying to give advice on a forum only to have it ignored or argued by the people wanting the help.
there are also a lot of times where someone will post a question, and people will put in work to help them only to have the new member disappear once they got what they were after.
also, some of us are always trying to be funny, and it only translates across text about 20% of the time. (well for me anyway LOL)
i hope you find a lot of good info and advice here.
LC
I know people around here can seem gruff at times, (me included) but most of us do actually like to help.
some of us do tend to be a bit guarded, and that comes from years of trying to give advice on a forum only to have it ignored or argued by the people wanting the help.
there are also a lot of times where someone will post a question, and people will put in work to help them only to have the new member disappear once they got what they were after.
also, some of us are always trying to be funny, and it only translates across text about 20% of the time. (well for me anyway LOL)
i hope you find a lot of good info and advice here.
LC
I understand what u mean trust me.
Believe it or not....I used to be a administrator of a file sharing forum with
10,500 people most would come in to start trouble or ask for help.
Once they got it they left.
Then the owner put a 30 day limit
If the account wasn't logged in for 30 days on 31 it was deleted because to many made a account to ask a question and leave
But I understand totally. Like I said I'm no tech I have messed with radios since I was 12.
But I'm here to learn
I use to be a member of another cb site
(Won't say anything names) but I left due to everyone bieng a butt no one wanted to help
But rest assured I'm here to stay
73
(Don't have a wdx number) lol so I'll say
2CT156 it's my only callsign
Believe it or not....I used to be a administrator of a file sharing forum with
10,500 people most would come in to start trouble or ask for help.
Once they got it they left.
Then the owner put a 30 day limit
If the account wasn't logged in for 30 days on 31 it was deleted because to many made a account to ask a question and leave
But I understand totally. Like I said I'm no tech I have messed with radios since I was 12.
But I'm here to learn
I use to be a member of another cb site
(Won't say anything names) but I left due to everyone bieng a butt no one wanted to help
But rest assured I'm here to stay
73
(Don't have a wdx number) lol so I'll say
2CT156 it's my only callsign
Just FYI.
This is basically the same setup I run for a Base.
Built a basic Ground Plane with a 102" whip and 4 wire radials.
When propagation is working, I have no trouble getting out..
It is mounted on my high roof, about 30' AGL, and it is quite indiscreet
A while back I made a basic L antenna out of two mobile antennas. I drove a piece of 10' top rail fence pipe in the ground 3' then attached a L bracket with a 102" steel whip vertical and a radio shack base coil whip (54" model) horizontal.
It was directional but I talked a ton of skip on it and talked regularly to a local 35 miles south of me for a couple of months while I used it.
Perfect SWR - adjustable with the horizontal antenna as it could be trimmed and had some adjustment with a set screw.
I'm sure I posted a picture of it at one time or another as it was pretty funny looking.
It was directional but I talked a ton of skip on it and talked regularly to a local 35 miles south of me for a couple of months while I used it.
Perfect SWR - adjustable with the horizontal antenna as it could be trimmed and had some adjustment with a set screw.
I'm sure I posted a picture of it at one time or another as it was pretty funny looking.
Ya I've read from online sources that you can attach a ground plane to bottom
I even seen one guy said he cophased
2 whips on his house
One on each end
I even seen one guy said he cophased
2 whips on his house
One on each end
Here's the thread. The pic is in Post #14.
https://www.worldwidedx.com/threads/102-whip-base-install.42607/
You found it!!!! Wow that brings back some memories - I totally forgot the first pic where it was just the 102" whip attached to a pipe in the ground
The funny thing is I had multiple other antennas laying around and I ended up using that ugly setup for 6 months with great results. I forgot I also incorporated the leftovers of another antenna for those other radials in that last picture.
Fun stuff.
You found it!!!! Wow that brings back some memories - I totally forgot the first pic where it was just the 102" whip attached to a pipe in the ground
The funny thing is I had multiple other antennas laying around and I ended up using that ugly setup for 6 months with great results. I forgot I also incorporated the leftovers of another antenna for those other radials in that last picture.
Fun stuff.
I think it was your antennas that inspired me to experiment with some 4' Firestiks I had.
I made a ground plane with one as the vertical and two as radials, a horizontal dipole and an inverted V dipole. All worked really good.