I wanna make an antenna but have no clue... [Archive] - Glock Talk

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king catfish
12-03-2005, 17:19
Well, to make the question short, I want to hit the 2m repeater of my choice with 5W.

Currently I'm set up OK for HF; however, I cannot reach the 2m repeater of my club. The only VHF/UHF radio I have is an FT-817 (which I love), but it only runs 5W max. The rubber ducky that comes with the radio for VHF/UHF does not do the trick. So, I'd like to put up an antenna on my roof. The problem is, I have no idea how.

I made a wire dipole for HF and put it up in the atic. Can I do the same for a VHF/UHF antenna? I have seen plans for J-poles and Yagis, and I'm pretty sure I can build them, but they all seem to require soldering or welding, and I don't have the equipment (or the knowledge) for that. Is there an easy answer?

Any discussion on the matter would be helpful. Thanks!

EUPHER49
12-04-2005, 07:33
King,

I really don't want to come off sounding critical but soldering and homebrewing go together like coffee and grounds. Learning how to solder with both a torch and a pencil/iron would be a valuable skill to aquire. Even the most crude antennas require some soldering. If you are a member of a club someone there should be able to show you the rudiments. The equipment isn't all that expensive and would open up all kinds of possibilities for antenna ( or other) construction. A ham really needs to know how to solder!

That said, I'm a big fan of J-poles for VHF/UHF. They are easy to build and adjust and they give a decent amount of gain. A functional J-pole can be built using a short piece of 450 Ohm ladder line.


The other requirement for antenna building is an SWR meter. This needs to be one that covers the UHF/VHF spectrum. HF ones won't work! You might pick one of these up, used, at a hamfest or Ebay or borrow one. Once you learn to solder you need to know where to solder the wires to the antenna. (or know when you've clipped too much length off the main element ;f )

One last comment: Use the best coax you can find. RG-58 for VHF/UHF simply is a waste of money. (You'll want something in the RG-8 family.) For short runs, like mobile installations it's OK but for longer runs like at home, you might as well install a dummy load.

Good luck...

Oh, and when you do get something going give me a shout, cuz I'm sure there's a repeater that both you and I could hit out there somewhere. Spring City comes to mind. And maybe the Delano...

king catfish
12-04-2005, 08:54
Thanks for the info. That gives me some stuff to chew on. I'll let you know when I have something going (probably not very soon, but as soon as I can get it in).

Thanks!

R. Emmelman
12-04-2005, 20:38
Greetings,

To give you a simple answer, yes you could make a 2-meter dipole. Another trick is to take a 2-meter mobile magnet mount and place it on a file cabinet or fridge. If you want something simple outside you can solder a 18" wire (weld-rod works good) to the center of a SO239 connector and solder three or four radials to the body. As far as coax you can go aganst convention and use RG-6 (used for satellite dishes). Even though it is 75-ohm it will work.

http://www.hamuniverse.com/2mgrnplane.jpg

THis is from http://www.hamuniverse.com/2metergp.html

73 de Rich
WI9NDY
in INDY

VOB
12-19-2005, 18:51
Originally posted by king catfish


I made a wire dipole for HF and put it up in the atic. Can I do the same for a VHF/UHF antenna? I have seen plans for J-poles and Yagis, and I'm pretty sure I can build them, but they all seem to require soldering or welding, and I don't have the equipment (or the knowledge) for that. Is there an easy answer?

Any discussion on the matter would be helpful. Thanks!

I would respectfully suggest that you get some basic wire tools and learn how to use them. It will expand your horizons in ways you can't even begin to contemplate.

But the easy answer is buy a diamond and clamp it to your chimney.

R. Emmelman
12-20-2005, 05:16
An investment in a good soldering station is well worth it. Make sure to get one that is grounded, has replacable tips, and adjustable temperature. Also get a small diameter SN60 rosin-core solder.

Rich WI9NDY / AFA1CY
http://www.marsregionone.org/MARS_logo.jpg
http://www.marsregionone.org/aflogo.gif

WD8T
12-20-2005, 06:13
I've built lots of these. They are very cheap(less than $5) and work very well.

Ron


Originally posted by R. Emmelman
Greetings,

To give you a simple answer, yes you could make a 2-meter dipole. Another trick is to take a 2-meter mobile magnet mount and place it on a file cabinet or fridge. If you want something simple outside you can solder a 18" wire (weld-rod works good) to the center of a SO239 connector and solder three or four radials to the body. As far as coax you can go aganst convention and use RG-6 (used for satellite dishes). Even though it is 75-ohm it will work.

http://www.hamuniverse.com/2mgrnplane.jpg

THis is from http://www.hamuniverse.com/2metergp.html

73 de Rich
WI9NDY
in INDY

R. Emmelman
12-20-2005, 09:07
The first one I built was made fron 1/4" aluminum tubing from an old CB antenna. Since you can not solder to aluminum I "attached" it to a piece of 2X4 and used screws to connect the coax to the elements. Suprisingly it worked and had low SWR (SWR did go up a little when it rained :)). I used that antenna for quite a few years.

Rich
WI9NDY
With a DJ596 on my left hip
and a G22 on the right!

lomfs24
12-20-2005, 14:31
While it's good to know how to solder and build your own antenna I know people who have made a quick L bracket that you can quickly screw on the gable portion of your roof and attache a NMO mounted mobile antenna.


I know it's a quick and dirty solution but it would work. You should learn how to make your own stuff later too.

king catfish
12-20-2005, 16:37
Originally posted by VOB
I would respectfully suggest that you get some basic wire tools and learn how to use them. It will expand your horizons in ways you can't even begin to contemplate.

But the easy answer is buy a diamond and clamp it to your chimney.

I understand you, but what I didn't mention was that my time is very limited and with the short amount of time I can allocate to the hobby, I can either acquire some wire tools and learn how to use them, or I can research the easiest and fastest way to spend some quailty time doing what I'd like to do, which is communicate via CW.

I think you're selling me short. I believe I CAN imagine how it would expand my horizons. In fact, I have, among other things, cultivated live corals, trained wild-trapped hawks to hunt for me, taught myself CW, learned how to fence and became a fencing coach, and learned and taught karate for years. I can program in Java and VB and am well-versed in HTML. I am currently earning a biology degree and I am a regulatory inspector in the pharmaceutical industry by day. I grow exotic hot chile peppers in the summer. I powerlift. I run. I was a soldier, awarded my CIB in Somalia. This is a very small sampling of the things I do or have done. My horizons are not in need of expansion.

I do not make a habit of taking the easy way out. I carefully weighed my decision, and came to the conclusion that I would rather not learn to solder and just want an antenna.

I didn't think I needed to explain half my life story to avoid the implication that I'm limited and lazy. I think your post was anything but respectful and I'll thank you to keep your wisdom to yourself. I see this forum has the same old stupid crap that the amateur radio hobby has always had. Everyone wants to tell everyone else how to enjoy themselves. Stuff it.

VOB
12-20-2005, 19:33
Originally posted by king catfish
I didn't think I needed to explain half my life story to avoid the implication that I'm limited and lazy. I think your post was anything but respectful and I'll thank you to keep your wisdom to yourself. I see this forum has the same old stupid crap that the amateur radio hobby has always had. Everyone wants to tell everyone else how to enjoy themselves. Stuff it.

I honestly wasn't thinking you're lazy, and I'm just trying to help with your question.

TheBigCA
12-23-2005, 14:59
You know what, I had a good answer for you but decided

YOU *#@q$)#$)#$( STUFF IT, YOU SELF-IMPORTANT MORON.

Yes, you need to expand your horizons - dealing with people in a respectful and thoughful way, without pissing them off.

Kiss my *****.

king catfish
12-24-2005, 22:10
So, I should have posted as you did? With lots of symbols to denote cursewords and calling someone a moron? Is that the example you'd like me to follow?

Doesn't the street go both ways? Shouldn't he have answered ME in a respectful way without "pissing" (your word, very classy) me off? it's ignorant and arrogant to suggest someone expand his horizons when he asks for a bit of advice. This is the reason why the hobby is almost completely made up of old men. Because young people don't want to hear your pedantic crap. Your way is not the only way. Stop fearing change and get over yourselves or our hobby will likely die with you.

Boo hoo, I won't get to hear your "good answer". My loss, I guess, huh? How will I ever get over it? My suggestion is that you perhaps grow up a little bit. Typing in all caps for emphasis does not exactly indicate a mature outlook. Work on it, and perhaps try again later.

PoiDog
01-02-2006, 11:41
King Catfish, here is a compromise you might like, a J-pole that's pre-made. Just run coax to it and away you go.

http://www.kb9vbr.com/products.htm

I've seen these at hamfests for right around $20, so this price is in line.

Now you won't have to mess about with soldering if you don't want to. Sounds like your plate is pretty full already. Enjoy the hobby!

king catfish
01-03-2006, 17:53
Originally posted by PoiDog
King Catfish, here is a compromise you might like, a J-pole that's pre-made. Just run coax to it and away you go.

http://www.kb9vbr.com/products.htm

I've seen these at hamfests for right around $20, so this price is in line.

Now you won't have to mess about with soldering if you don't want to. Sounds like your plate is pretty full already. Enjoy the hobby!

An excellent offering! Thank you very much. I think this is right up my alley.

martho
01-03-2006, 19:20
With 5W and VHF, what type of coax are you planning on using?
How long is the run?
How far is it to the repeater?
How high is the repeater antenna?
Do you have a clear shot to the machine or is there a ridge or obstruction between you and the machine?

5 watts with good coax and a decent antenna can be made to work. If you are going to use RG-58, have a 50' run and then a poor antenna, things are not going to be any better for you than the rubber duck.

I don't really see a water pipe J pole as the answer to your problems unless you are right next to the machine.

king catfish
01-09-2006, 17:21
Originally posted by martho
With 5W and VHF, what type of coax are you planning on using?
How long is the run?
How far is it to the repeater?
How high is the repeater antenna?
Do you have a clear shot to the machine or is there a ridge or obstruction between you and the machine?

5 watts with good coax and a decent antenna can be made to work. If you are going to use RG-58, have a 50' run and then a poor antenna, things are not going to be any better for you than the rubber duck.

I don't really see a water pipe J pole as the answer to your problems unless you are right next to the machine.

As far as coax, what do you suggest? I think I am currently using poor quality stuff, but it would be easy to replace. The run is about 25 feet.
I do not know how high the repeater antenna is. A little research should provide the answer. I'll look into it.
I have a clear shot to the repeater.

Thanks for your help. Sorry I'm so ignorant of antennas. I really have been focusing on practicing morse code and never had a base station before. I worked mobile out of my car for a couple of years, and that's it. I got out of the hobby for a little while because of time constraints and other things right after I got my general ticket, and I was just looking for a way to put my CW practice to work.

Thanks again.

martho
01-09-2006, 19:05
Let's figure out what coax you are using and then we can go from there.

http://www.cablexperts.com/cfdocs/tech_data.cfm?BSKT=0&USA_ship=1


Here is a table to show you dB of loss per 100 feet. If you are using the thin coax, RG58, and have approx 25', you are losing almost 2dB of signal in the coax. Every 3 dB, your power output is cut in half. So, with 25' of 58, your 5W has now become 3W. Add the insertion loss of PL-259's and any barrel connectors, and the SO-239 of the antenna and you are somewhere in the neighborhood of 3dB.

There is always going to be some loss in coax no matter what you buy or how much you spend. If you are running something better than RG58, I would say its not worth the effort to upgrade as it will work fine.

I know the antenna costs about $100, but I would say the Diamond X50 or the Comet GP3 are about the best antenna for the money and will work wonders over a copper pipe J pole. (they are available in the used market for about $50)

There are some 440 machines in your area so you will want to consider the performance on 440, too. http://www.qsl.net/n3sme/repeater.html
We dont even want to get into the loss of RG58 at 440!!!

One thing to remember about this hobby. Doing things cheaply will work however they will work poorly in most situations. You get what you pay for and spending some $$$ up front will make things much better in the long run. Cheap coax and cheap antennas usually fail over time.