merlin-7
Member
LOUMAAG
What are the dimensions of yours?
just curious...
What are the dimensions of yours?
just curious...
How to make homemade discone?
- Thread starter merlin-7
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TeRayCodA
Member
Hi,all:
I have been building homebrewed scanner antennas for about 20 years!
Take a look at my pics at:
http://hometown.aol.com/teraycoda/myhomepage/photo.html
I have been building homebrewed scanner antennas for about 20 years!
Take a look at my pics at:
http://hometown.aol.com/teraycoda/myhomepage/photo.html
Re: LOUMAAG
The one I was referring to above is a Diamond D130J , cone elements are just over 32", disk elements are 11" making a disk just over 23" in diameter. Total height, with loading coil and vertical radiator is just over 5.5 feet. You can find the assembly instructions (which provide pretty good detail) at the RF Parts Web Site.merlin-7 said:
merlin-7
Member
I started working on my new antenna but have run into a road block.
I was hoping to get this thing built over this weekend but can not find any copper sheeting. none of the home center stores around here sell it.
Any one have any ideas where I could look next?
You would think it would not be that hard to find, I know I am not thinking of some place simple...
Thanks
I was hoping to get this thing built over this weekend but can not find any copper sheeting. none of the home center stores around here sell it.
Any one have any ideas where I could look next?
You would think it would not be that hard to find, I know I am not thinking of some place simple...
Thanks
N
N_Jay
Guest
merlin-7 said:I started working on my new antenna but have run into a road block.
I was hoping to get this thing built over this weekend but can not find any copper sheeting. none of the home center stores around here sell it.
Any one have any ideas where I could look next?
You would think it would not be that hard to find, I know I am not thinking of some place simple...
Thanks
Use something else.
Brass or aluminum are usually easy to find.
merlin-7
Member
That brings up another question.
What problems is there with mixing metals on the same antenna,
Is there a problem useing an aluminum cone when the rest of the diskcone is copper?
What problems is there with mixing metals on the same antenna,
Is there a problem useing an aluminum cone when the rest of the diskcone is copper?
TeRayCodA
Member
Hi,MERLIN;
I found some at at LOWES,(Kinda pricey!)copper sheet.I have also seen some(brass shim stock)at machine/industrial shops.
good luck!
I found some at at LOWES,(Kinda pricey!)copper sheet.I have also seen some(brass shim stock)at machine/industrial shops.
good luck!
TeRayCodA
Member
No,there should not be a problem with different metals,you are looking for conductivity,as I used a brass washer with the copper disk radials soldered onto the brass washer.(for my UHF military air discone)
I did prime and paint everything.
225-400Mhz BOOMS in!
I did prime and paint everything.
225-400Mhz BOOMS in!
TeRayCodA
Member
Also,I have just finished building a 16 element discone from 3/16"alum welding rods,and 1/2"alum stock for the disk and the cone.
I used 10/32 S/S set screws,an empty plastic skoal can filled with bondo(for an insulator)-don't laugh! it's all I could think of at the time for an insulator!
I decided to deviate a little from previous plans,and made the cone element lenghts 36",and the each disk element is 13"(this is a big discone!)
as I am typing,I am listening to air traffic control,(about 100 channels)
I built everything on an old drill press,set the cone angles at 60degrees,and worked off and on for over 2 weeks(patience)
When it quits raining here, I will climb the tower,and get some pics to post.
This one is quite impressive.
Turned out great.
I used 10/32 S/S set screws,an empty plastic skoal can filled with bondo(for an insulator)-don't laugh! it's all I could think of at the time for an insulator!
I decided to deviate a little from previous plans,and made the cone element lenghts 36",and the each disk element is 13"(this is a big discone!)
as I am typing,I am listening to air traffic control,(about 100 channels)
I built everything on an old drill press,set the cone angles at 60degrees,and worked off and on for over 2 weeks(patience)
When it quits raining here, I will climb the tower,and get some pics to post.
This one is quite impressive.
Turned out great.
scansomd
Member
Impressive work! Have you given any thought to creating a ruggedized version of the SCANTENNA? :idea: I, for one, would be interested in purchasing one.
TeRayCodA said:
TeRayCodA
Member
Yes,as a matter of fact about 10 years ago,I made an equivelent to a channelmaster 5094A.I experimented with copper 1/2" pipe,lots of elbows,lots of cutting tubing,and the exaustive work sweating all of it together!
Needless to say,I ended up with a very heavy antenna,that needed a heavy duty support pipe,and pvc pipe stand offs just to stabilize the thing!
Now,it rests in my sister's attic connected to a pro-34.
It does Rx good!
Thanks.
Needless to say,I ended up with a very heavy antenna,that needed a heavy duty support pipe,and pvc pipe stand offs just to stabilize the thing!
Now,it rests in my sister's attic connected to a pro-34.
It does Rx good!
Thanks.
What are you guys using for the "hub" of your discones? (and please don't say you're turning them yourselves...)
I read in one post 2" brass washer (for the disk)? I haven't looked for this before, but would a regular hardware store have them, or would I need to find welding supplies, or something else?
When it warms up some I am thinking of trying to make the 800 MHz copper/brass discone from North Country Radio web site.
I should have a decent drillpress before long, dad can't use it anymore.
And I've been thinking about copying/improving a multi-element antenna I've seen on the web, from someone in England.
It has an element for each band of interest, all attached to a circle (or maybe a triangle) of something thick enough for them to attach to securely, that screwed into a 5/8 wave coil. Yes, that's going to be the weakest link of the thing.
I've rambled on enough now, thanks for any advice!
I read in one post 2" brass washer (for the disk)? I haven't looked for this before, but would a regular hardware store have them, or would I need to find welding supplies, or something else?
When it warms up some I am thinking of trying to make the 800 MHz copper/brass discone from North Country Radio web site.
I should have a decent drillpress before long, dad can't use it anymore.
And I've been thinking about copying/improving a multi-element antenna I've seen on the web, from someone in England.
It has an element for each band of interest, all attached to a circle (or maybe a triangle) of something thick enough for them to attach to securely, that screwed into a 5/8 wave coil. Yes, that's going to be the weakest link of the thing.
I've rambled on enough now, thanks for any advice!
merlin-7
Member
I bent some copper into a cone with a 5/8 hole at the top.
Than I soldered a 12 inch piece of 5/8 copper pipe to it.
I used 5/8 copper because 1/2 inch pvc would slide inside it.
AT the top is a 5 inch brass ring soldered to a disk that I cut out of the sheet of copper.
Up the center is a copper 1/4 inch rod soldered to the top disk with fiberglass insulators between the cone and the disk.
At the bottom of the disk, I took a 3/8 brass bolt,cut the head off, drilled a 1/4 inch hole down the middle of it and soldered it to the copper rod. The treads of that bolt stick out the bottom of the 5/8 copper pipe. I added another insulator with a hole driled thru it so I could put a not on it to hold the dick and cone together.
The top elements are stainless rods that I recycled from an old CB base antenna.
I used PL259 connectors, the type on CB antennas (I should really of used N connectors) but that is what I had to work with.
The bottome elements on the cone are aluminium ( I will change them to brass when I find some or have some $$ to buy them.
I am still learning and thanks to the great people here every little sugestion that someone gives me helps me make the antenna that much better.
Wal mart has different size brass rings in there crafts dept.
Than I soldered a 12 inch piece of 5/8 copper pipe to it.
I used 5/8 copper because 1/2 inch pvc would slide inside it.
AT the top is a 5 inch brass ring soldered to a disk that I cut out of the sheet of copper.
Up the center is a copper 1/4 inch rod soldered to the top disk with fiberglass insulators between the cone and the disk.
At the bottom of the disk, I took a 3/8 brass bolt,cut the head off, drilled a 1/4 inch hole down the middle of it and soldered it to the copper rod. The treads of that bolt stick out the bottom of the 5/8 copper pipe. I added another insulator with a hole driled thru it so I could put a not on it to hold the dick and cone together.
The top elements are stainless rods that I recycled from an old CB base antenna.
I used PL259 connectors, the type on CB antennas (I should really of used N connectors) but that is what I had to work with.
The bottome elements on the cone are aluminium ( I will change them to brass when I find some or have some $$ to buy them.
I am still learning and thanks to the great people here every little sugestion that someone gives me helps me make the antenna that much better.
Wal mart has different size brass rings in there crafts dept.
TeRayCodA
Member
-sigh- No, not turning the hubs,I am simply drawing a circle on some 1/2"thick aluminum stock,cutting it out,and drawing the element holes,then center punch them,and drill at 60degrees.
merlin-7
Member
TeRayCodA
I think I understand how a discone works now but I have another question for you...
Would there be any advantage instead of using a flat disk to using a very steep cone ontop. Say a 10 degree cone ?
I was thinking this may increase the surface area of the disk and cone over all frequencys the dimensions of the antenna was designed to cover.
Just an idea if I understand the principals involved.
I think I understand how a discone works now but I have another question for you...
Would there be any advantage instead of using a flat disk to using a very steep cone ontop. Say a 10 degree cone ?
I was thinking this may increase the surface area of the disk and cone over all frequencys the dimensions of the antenna was designed to cover.
Just an idea if I understand the principals involved.
OK2BCK
Member
I am just about to build couple of discone antennas to cover 100MHz to 2GHz for my new AR3000A.
Will post results soon!
Great webpage!
Will post results soon!
Great webpage!
gcgrotz
Member
I made one once out of copper screen with 12g household wire (stripped) and sewn in along the seam which I soldered, and around the circle on the bottom edge. The disk was another piece of screen with 4 horizontal support wires also soldered. It worked very well but wasn't durable enough for outdoor use. In fact, it kind of smashed up real easily. Used an N connector (highly recommended above UHF) and ran the coax down inside 1/2" plastic pipe for about 4 feet.
OK2BCK
Member
what will be the freq. range?
I might be taking it maybe too seriously involving a CNC machine to drill 16 holes around the discs for radials and also with the size...72cm tall and 83cm in diameter. But I have just got the receiver of my dreams (been wishing for it number of years) now so I go hard! By the way is anyone able to tell me how to predict the 'highest' efficient frequency on this size discone? I have used commonly known calculator downloaded from web to get dimensions. Lowest frequency set to 100MHz. (now thinking to go as low as 60MHz; 140cm in diameter!!)
The second discone I am planing to put together (data from web again) is solid copper sheet body, designed to be efficient from freq. of 700MHz and higher. This one is about 10cm in diameter.
Have a good day!
I might be taking it maybe too seriously involving a CNC machine to drill 16 holes around the discs for radials and also with the size...72cm tall and 83cm in diameter. But I have just got the receiver of my dreams (been wishing for it number of years) now so I go hard!
By the way is anyone able to tell me how to predict the 'highest' efficient frequency on this size discone? I have used commonly known calculator downloaded from web to get dimensions. Lowest frequency set to 100MHz. (now thinking to go as low as 60MHz; 140cm in diameter!!) The second discone I am planing to put together (data from web again) is solid copper sheet body, designed to be efficient from freq. of 700MHz and higher. This one is about 10cm in diameter.
Have a good day!
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