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New J-pole for the barn workshop

its' more about having decent electronics than about what hunk of wire you throw on the back of them, so it would seem.
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I'd much rather have a stacked APS-14 array going to a cheaper receiver than a TOTL tuner with a folded dipole laying on the floor, any day :)

Where did you have it mounted? Near any metal objects? What were you using as a feedline?
 
JimJ[VT];2676270 said:
I'd much rather have a stacked APS-14 array going to a cheaper receiver than a TOTL tuner with a folded dipole laying on the floor, any day :)

Where did you have it mounted? Near any metal objects? What were you using as a feedline?
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Just had it in the corner in the living room, standing vertically. Used mostly as a proof of concept. Not near metal objects. RG-6 coax as a feed line with 4 5-inch turns in a coil near the connection points, fed into the 75 ohm antenna connections on the Pioneer SX-1050. Moved it around a bit to see what effects that would have...none good, it seemed to like the corner best.
 
AK 47 said:
Antenna design and use is closely associated with Murphy's Law! he he
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Tell me about it...

Best thing I could say is make friends with a ham radio guy who owns an antenna analyzer :D I love those things, you can instantly tell what the effects of adjustments are on impedance, see if you're bringing it into resonance where you want it, VSWR, all that good stuff.

Also, see if you can get it outside :) Indoor antennas are always going to be pretty limited, I wouldn't expect much out of it then.
 
I really like the idea you have to adjust the tuning and the f connector. I see Mark has a similar idea with the hose clamps, but wouldn't corrosion be a problem and eventually decrease performance? I made one for myself a year or so ago but soldered the connector to the antenna, works well for me
 
More experimenting this morning...moved it outside, tried several different placements, same results. It actually worked best *inside*, in the corner where I started. And the cheap Dipole, strung thru the venetian blinds, still works the best.

I don't know, maybe on the East Coast people find more selectivity or something with different antenna designs...but here in the fruited plain, it would seem that you either get a station or you don't. Furthermore, to add insult to injury, stations invariably come in better on crappy car radios than anything you can hook up to a receiver...that's been my lifelong finding.

So into the rafters of the garage the J-pole goes, until I need some short sections of copper pipe for something. Something my wife feels is ugly and large on the outside of our house that cost me $30 and performs worse than something I got for free in a box with a receiver isn't going to win any popularity contests around here.
 
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Louie, sorry to hear that the j-pole didn't work out for you when my own results were nothing short of astounding in my south central Ontario location. Did you copy the hookup that I made with the sliding connector or with hose clamps like Mark used? Can we see some pics of the antenna?

I don't know what to say that may help other than that mechanical and electrical devices will often respond favourably to extreme verbal threats that involve their immediate demise in a gruesome fashion:D

J.R.
 
SOTA, that's about all that I could think of -- perhaps I didn't carry it quite far enough in 'proof of concept'.

Dimensionally, it was correct for 94.7 FM, based on the calculator in the link. I did not have the sliding tuner, nor did I have the fancy leads coming off the feed points that went to a nice balun.

What I had was a chunk of RG-6. I stripped the outer casing and attached the braid to the short section connection point and the copper core to the long section connection point. From there, I then tried first 5 5" coils for a choke but then switched to 4 5" coils, and then went out to the 75 ohm connector on the SX-1050.

Inside the house, I didnt even have the 20 inch lower portion connected (low ceilings). Outside I had it connected. I tried several different spots for it, rotating it even though it's supposed to be omni. Yes, it was vertical....I know they don't work in anything but a vertical plane...we had used a J-pole for a pirate FM station once.

I'm getting ready for a weekend trip...when I get back, I may as well dink with it some more. I'm into it this far after all....and if the WAF dooms it here, I can always put it out at the cabin. :D

Theres *got* to be a way to build a better antenna than a cheap dipole...I just haven't found it yet, I guess.

Question: Can I just use 300 ohm twin lead off the connection points and go right to the 300 ohm inputs on the receiver?
 
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we had used a J-pole for a pirate FM station once.
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Ah, OK...I had some experience with that myself :D :D

I don't know what to tell ya...if HAAT is your problem, I don't doubt the J-pole isn't much better than a dipole. In that case, a tower and Yagi, or stacked array is going to be the only thing that makes an appreciable difference.

Usually, the uglier the antenna is, the better it performs :)
 
J Poles

Hi folks

Great job on the antenna SOTA and thanks for your pictures too Mark W. Mark, how did you handle the grounding? I always worry about lightening.

Marc
 
Cool project, I couldn´t resist, I built the j pole yesterday., and cet the frequency at 98mhz.
I need to get the f connector and clamps and cable to finnish it up.
I did connect it to the tuner by just wrapping the ends of the coax to the polis of the antenna and do some rough tuning on the antenna.
The results are very promising.
Im going to mount it outside, but for now it is way better then the dipole.
This is on my Accuphase T100.

bob
 
MrIgotNomoney said:
Cool project, I couldn´t resist, I built the j pole yesterday., and cet the frequency at 98mhz.
I need to get the f connector and clamps and cable to finnish it up.
I did connect it to the tuner by just wrapping the ends of the coax to the polis of the antenna and do some rough tuning on the antenna.
The results are very promising.
Im going to mount it outside, but for now it is way better then the dipole.
This is on my Accuphase T100.

bob
Click to expand...

Good to know it's working for you but we need pics, I say, pics:D

J.R.
 
I'm tempted to drag mine out of the garage rafters and piss with it some more.

Do I need to use 75 ohm coax? Or would I be better off with twin lead? Is something lost between going thru the coax and then back to the 300 ohm antenna leads on my receiver(s)? Only a couple of them have 75 ohm connectors built in.
 
Louie, I have not tried my antenna with 300 ohm since I made it to work with 75 ohm cable...I don't really know how it might work. I run RG6 from the antenna through a 75/300 converter at the tuner...there is no f connector on the tuner, just the screw terminals like you have. I believe the plans I followed called for 75 ohm cable.

Keep us posted as to what happens when you try it again...better luck this time.

J.R.
 
A bit of a dumb question, but how do you mount a J-pole on the house's exterior without inviting extraordinary destruction on your tuner (and house) during the stormy season?
 
If you go back to page 1 and look at my pics you can see that I incorporated a ground screw into the stub of the antenna. Run a wire from the screw to a ground stake and it will protect your house in the event of a lightning strike...the tuner, not so much:no:

J.R.
 
1.21 gigawatts, here we come.

When my brother was a teenager, he ran a single wire as an antenna from his bedroom receiver out the window to a fairly high point on the side yard silver maple. During a storm, you guessed it, a mighty surge used that wire as entry. It ran through the entire house and barked an angry white spark off the kitchen faucet, whereby we all were standing. ZAP!

Your J-pole looks terrific, by the way. Inspiring me to finally build one...
 
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