Whipped up a quick 2M dipole

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Lawless

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I did a little reading and decided to whip up a 2M dipole to mess around with on my HT. I used an old stainless antenna whip but stiff 10G copper wire would also work. I just bent a little "J" into one end so it fit around the bolts. I had this little plastic block in my junk drawer and used that for the base (wood could probably be used). I used two 6mm bolts to secure the stainless and the terminals to the plastic block after I soldered the terminals to an old piece of 18' coax that already had a PL259 on the other end.

I then notched a piece of 1" PVC to mount to the block using a zip tie and a couple of drilled holes. The coax needs to leave the antenna at a 90* angle for a couple of feet. I wound a choke out of the coax to keep RF off of the feedline, basically 6 turns wrapped tight and touching on the 1" PVC. I wrapped that well in electrical tape and finished with a few zip ties. The elements are 18.25" which is a little short but from what i read the first little bit of coax will also radiate until the choke so it should be pretty close.

I need a PL259 to SMA female adapter before i can try it out. I ordered it.

Anyway, when I was done putting it together, I coated everything around the terminals with clear silicone sealer and hung it up on the shack. I routed the coax into the radio bench and it is sitting there waiting for me to try it out.








 
Next project... Turn that into a Yagi...
 
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Well crafted! Now, if you go about 0.15/0.20 wavelenth behind it and put a 39" +/- rod, you'll have *gain* and some front to back .... all with very little work! Drill a hole thru the mast a little bit behind where that intermediate electrical tape loop is (or ~ 0.2 x 2M--- 16" or so in my head ) and fasten in that ~39" rod .

You did a very nice job
 
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One other suggestion (and maybe you already did this)... I'd order a SMAPL259 pigtail not an adaptor .... the SMA is a pretty tiny connector , while the PL259 is a big honking thing that, when connected to coax, is a good way to ruin whatever the SMA will be screwed in to with it's leverage. A pigtail (12" length or so) of SMAcoaxPL259 will help prevent potential damage.

Now I'll shut up :)
 
Be sure to check and get the correct SMA gender.
 

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JohnFreeman;n65453 said:
Well crafted! Now, if you go about 0.15/0.20 wavelenth behind it and put a 39" +/- rod, you'll have *gain* and some front to back .... all with very little work! Drill a hole thru the mast a little bit behind where that intermediate electrical tape loop is (or ~ 0.2 x 2M--- 16" or so in my head ) and fasten in that ~39" rod .

You did a very nice job
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So I just put the rod in the PVC vertically and it's not connected in any way to the coax? Will the antenna still be omni-directional?
 
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JohnFreeman;n65531 said:
One other suggestion (and maybe you already did this)... I'd order a SMAPL259 pigtail not an adaptor )
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Yep, ordered a 20" pigtail
 
htperry;n65549 said:
Be sure to check and get the correct SMA gender.
Click to expand...

I got a SMA female to SO239.
I sent pics of this antenna project to htperry before I finished it or posted it so if i was doing something wrong he would tell me before i posted it LOL
Thanks for always being available Howard.

Thanks JohnFreeman for the suggestions. You are always helpful and courteous.
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Lawless;n65875 said:
So I just put the rod in the PVC vertically and it's not connected in any way to the coax? Will the antenna still be omni-directional?
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Yep, that'll work. There's also versions that are grounded to the boom or not... spacing and length of the reflector will vary depending in what you read, whether to add a director (shorter and in front) or a reflector (longer in rear) first....all are details that can be experimented with , but yes. There's also tradeoffs between spacing, element length, gain and bandwidth.

You're right in questioning the directivity. --- it will be directional towards the dipole end of the boom. That's how gain works.... you reduce the amount of signal that is not going in the direction you want it to, and redirect it in the direction you DO want it to go. By the way, if you add a director and reflector... you'll probably pick up something on the order of 3dB gain. That's the equivalent of DOUBLING your transmitter power.. You'll really notice the difference on simplex contacts and/or distant or fringe repeaters.
The yagi design .... the tradeoffs between element spacing, element length and placement are all exactly the same at HF as they are at 2m, but with MUCH more simple mechanical implementation.

Extending that to be a yagi would be a simple project and a good use for your TV rotor!
 
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JohnFreeman I don't have a rotor but I remember my dad had one for the TV waaaaaay back before cable was available here.
 
John is providing you some very good elmering. Also, keep in mind, the construction of, and the feeding of a Yagi, is not nearly as complicated as some may lead you to believe.
 
Lawless;n66038 said:
JohnFreeman I don't have a rotor but I remember my dad had one for the TV waaaaaay back before cable was available here.
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Ah, OK.... I'm confusing you with someone else who posted here that they found a TV rotor at work in a scrap pile.

More coffee for me!


Here's another bit of semi-useless trivia: Stainless steel sucks as an electrical conductor. It's 30-40 *times* more lossy than copper.

Sooo...why would one use it for antennas?

1) It's on hand and it works. This is a very good reason!

2) From a MECHANICAL standpoint, it works great (doesn't rust, is self supporting, etc)

3) The very fact that it's lossy makes it APPEAR to be a good antenna conductor (" antennas made from it are broad band compared to coppper!" -- which is a true.... but it's because you're lowering the "Q" with a lossy conductor and heating the element rather than radiating RF).


Now... does it make any practical difference? Probably only if you're at a really marginal situation to begin with, or running very high power.

The message is not to criticize your very nice implementation......but to explain that it's perfectly OK to use either copper or aluminum rod....and in fact much better electrically...than more exotic materials. Brass or Aluminum solid rod are fine for antennas and can be had relatively cheaply, and (brass, copper) are easy to solder to.
 
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Well I hit the repeaters I use the most very easily with just the whip on my HTs (even from in the house), they are about 15 miles but high on the WRAL TV tower.
This antenna was just for fun more than anything, but also for practical experience in building antennas. I had great success with the 80M OCF and want to experiment with making the HT perform as well as it can. I am reading about slim jims and J-poles now LOL, so the wheels are turning.
 
^^ And thus goes ham radio :)

Here's something to consider. When you get your radiated power from your antenna system efficiency you can dramatically reduce the power from your transmitter, saving your batteries in proportion (if you're on emergency power sources )
 
JohnFreeman;n66122 said:
^^ And thus goes ham radio :)

Here's something to consider. When you get your radiated power from your antenna system efficiency you can dramatically reduce the power from your transmitter, saving your batteries in proportion (if you're on emergency power sources )
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EXACTLY!!! Antenna system 'efficiency' is the key..
 
boys, this antenna works fantastic. I got my adapter jumper today and the fellows I was chatting with said it sounds like a 25w mobile.

 
Very nice... Congrats...

Add a reflector and a director, and you'll have a nice beam, with some gain, and a little rejection.
 
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I even ordered me a jen-yoo-ine Baofeng hand mic to use with this fine setup :)

Got some shiz coming to use the other one in the truck.
 
We have over 50 Baofengs in service within our group. Overall pleased with the performance. Several have failed, however for the price, you toss it, and get a new one.
 
Lawless;n72213 said:
I even ordered me a jen-yoo-ine Baofeng hand mic to use with this fine setup :)

Got some shiz coming to use the other one in the truck.
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This morning there was a discussion about the Baofeng mic having a low audio signal. If you have issues with it, the recommendation was that the Kenwood mic will work with it.
 
The Kenwood programming cable also works well with the Baofeng.
 
noway2;n72613 said:
This morning there was a discussion about the Baofeng mic having a low audio signal. If you have issues with it, the recommendation was that the Kenwood mic will work with it.
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I actually saw a review where the "new" Bfeng mic was rated as great. That's the model I ordered so I hope it works well. At the price it's no biggie either way.

I like having fun and success with cheap stuff, it's a character flaw LOL
 
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