Slinky antenna question

[jaymot]

I'm getting a Nooelect Smart SDR HF bundle and am planning to build a portable Slinky vertical for it for HF using a ring light tripod (meant for photographic lighting) and some PVC pipe as a base, with the but-end of a 3-plus meter telescopic fishing pole stuck in the end supporting a somewhat stretched-out steel Slinky Jr. knock-off. I plan to paint the Slinky to prevent rust and solder a pigtail of wire to the bottom using a circle lug, tin the other end of the pigtail, and feed it into the 9:1 balun that comes with the bundle, then run RG58 into the house. The ends of the Slinky toy appear to be braised or clamped together to form solid circles. My question is, would it be better to cut the slinky on the bottom end where the pigtail and balun will go so it acts as a single long wire or is it OK to leave it the way it is as a closed-end helix?

Thanks.

(Before anyone tells me a dipole would be better, I wouldn't be able to get one high enough and I read that verticals are less finicky about how high they are. I don't really have the room for a dipole either. )

 

[consys]

I cut mine and rolled a crimp loop for the connection as I didn't trust soldering steel- which I also did any way. I left the brazed loop at the far ends (dipole in my case) as a hanging loop. I was after the maximum wire element length I could get in a forty foot attic. I cannot say which way is better so likely haven't help you. But I always find different thought processes, and the continued use of a childhood toy interesting.

 

[jaymot]

I actually considered having the slinky electroplated with brass but I think that at HF frequencies there's not much if any skin effect, so that wouldn't really help it as an antenna as it might at higher frequencies. The steel will still be the actual antenna.

In this post JustLou shared a picture of his slinky indoor horizontal and I see that he left the ends the way they were. As he says it "works pretty well" I suppose it doesn't really matter if I cut the end coil or not.

 

[jaymot]

Just a quick follow-up: I didn't cut the end of the slinky and it seems to work pretty well. I set up the antenna in my small back yard, not as far away from structures as I'd like but I had nowhere else to put it. I'm in the Philippines so I mostly pick up China but the other night I got a religious station broadcasting from Anchor Point, Alaska. On my previous cobbled-together attempts at antennas I mostly just got noise, so I'm pretty happy with it. It's no resonant dipole 30 meters in the air or HF discone on the roof but it's not bad either.

 

[W0JOG]

For listening to HF, propagation dictates that vertical or horizontal, either will likely be about the same in overall results as the signal has been bounced off the ionized atmosphere anyway and assumes some of either polarization. Don't believe me? Take your portable SW radio in hand and rotate it as you listen to see where signal peaks. It'll change almost like you were listening to wave action, which you are.

As to mounting the antenna, do what you wish of your plans but learn that all the ideas won't amount to a db of difference. Just protect it from weather and get what ever up as high as you can or as long as you can. I'd put it in the attic horizontal, but I've only been SWLing 70-some years, so what do I know? I started out with a bed spring, graduated to a short wire to nearest tree and built on from that as I could. There weren't all these commercially-made and -hawked antenna toys to throw money at back then.

73 de W0JOG

 

[jaymot]

In the late 1980s I lived in a studio apartment on the top floor of an old brick 4-story walk-up in Seattle with my unit having windows facing east. My antenna back then was a strip of aluminum foil long enough to reach from wall to wall above the main "bedsit" room above the windows, doubled over on itself to increase the thickness and sturdiness and thumbtacked to the wall, with a wire alligator-clipped to it leading to my receiver. My typical weekday evening after getting home from work at around 5 to 5:30PM was to listen to Radio Nacional D'Amazonia (aka "Radio Capybara") for a while, then start dinner as reception was lagging for a while after Brazil went off the air. While my dinner was cooling a bit after cooking I'd listen to the Voice of Greece. After dinner Radio Tahiti was my main entertainment, followed by Aussie pop music on ABC until bedtime. Mostly due to solar cycle 22, not to my "antenna" but it just goes to show, you do whatever you can to get some sort of antenna put up so you can start hearing things.