Cheap 1/4 wave antenna whip from AliExpress

Hi Andy,

I’m so glad to hear from you on new summit.
I couldn’t find any on Aliexpress, the options are confusing.
We’re in a rainy and stormy season. I’ll get back to the topic soon.

73
Carlos
PY2VM

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I get you. There are times I don’t really feel like taking my camera (not too often thankfully!), but I don’t feel it collides too much with SOTA either. What helped me use my camera more is find what the right way to carry it; I use one of those quick release rucksack strap attachments. The camera is accessible but doesn’t hamper my movement; it works great. I also chose a small and light camera and was even willing to drop the viewfinder (the Z30 doesn’t have one).

I don’t have a portfolio but you if you’re on facebook you can follow me; I post some series publicly.

Take your camera on your next SOTA activation! I see great photos on your blog…

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I knew I had something in a box somewhere…

This coil is wound so you can clip a crocodile clip to the wire without shorting the turns together.

Wire diameter = 1.75 mm
Spacing between turns = 0.75 mm
Coil outside diameter = 53.25 mm
Total weight is 110 g (including Paxolin and Polyethylene formers and bolts etc.)

The bottom contact is a 4 mm banana plug and top contact is a 4 mm banana socket

Maybe you can make something based on these photos and measurements?

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Mine turned up last night. Luckily they just left it on my front porch, and it was completely undamaged. No mail slot here :laughing:

Today after work I took a walk to a park that is a few KMs from my house so I could test the antenna. The ribbon cable radial was crap so I made my own consisting of 4 radials, each 3.5m long.

The antenna took about one minute to set up. The SWR was looking good on 20 with the whip fully extended. I called CQ once and got a reply. Had a nice QSO with AE7CG down in Prescott, AZ. Good signals both ways. After that I had a QSO with AC6YY/QRP down in San Jose, CA. Good signals both ways.

I had posted on Slack that I was QRV, and @WB6POT asked me if the antenna would tune up on 30. I went over to 30 and the KX2 tuner was up to the task! I had QSOs with Peter and @N0DNF on 30.

Next I tried 17 meters. By shortening the antenna by two sections, the swr was great. Got a good report from @KE6MT. Over to 15 next, and again I was able to get a good swr without using the ATU by adjusting the length of the whip. Called CQ and got a good RBN hit in Hawaii.

Back to 20 and had a QSO with WB5BKL in Texas. At this point I was getting very cold (temps close to 0C) and it was getting dark. Time to pack up and walk home!

I am impressed with the antenna considering how inexpensive it was. The quality seems good! Hopefully this weekend I will be trying it on a summit.



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Late to the party. Anyway, here is my version:
I purchased only the whip which arrived last Friday in good conditions despite the rather lousy wrapping. For the ground spike, I chose a slightly different approach with an aluminium profile and a solid insulator. And I added eight radials, each 2.5 metres long.

As far as tuning is concerned, I found it practical to count the segments from the base. At 28MHz, exactly 6 segments must be fully extended, the rest remains collapsed. At 14MHz, all segments are fully extended except the top most, which is shortened by 50%. There are values for 18/21/24MHz as well. This way, I only need a small chart and can do without any markings on the whip (which wouldn’t last long anyway). Setup is done in one or two minutes. Next I need a loading coil for 30/40m.

The activation last Sunday went well: Lots of QSOs on 20m and DX on 10 m (1 x PY, 3 x W) despite kp = 4.

Ground spike:

Six segments extended for 28MHz (~ 2.5m):

… and (almost) fully extended for 14MHz (~ 5.3m):

73, Roman

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Hi Roman

On Sunday for our S2S (G/NP-028 to DM/BW-064) I gave you 599 so it must work well! I assume you were using the whip for our QSO. How much power were you running? I was using 5W (you sent me 559).

73 Richard

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Thanks for the S2S-QSO and the excellent report, Richard! I was using the whip and my KX3 at about 10 W.
Since my smartphone (running Ham2k) refused to accept the ‘/’ in your call sign, I didn’t look at the S-meter. I had to estimate your signal strength by ear. You weren’t as strong as the stations with real S9. Somewhere in a range between 559 to 579 I’d say. The difference shouldn’t be more than half an S-Unit with 3 dB difference in output power, though…

73, Roman

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I will have to try that. I don’t recommend anyone use the ribbon cable that ships with the antenna… I tested it on the bench and only a few of the wires were connected to the ring terminal. I cut off the shrink wrap and all they did was strip a few of the wires and crimp them. The wires are TINY and very fragile looking.

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I admire your aluminium spike solution Roman and I wish the ground around VK1 was less of granite, sandstone, quartz, shale and red clay.

The ground is so compact and hard I rely on a tripod support. Carrying a jackhammer to the summit is out of the question.

image

Thanks for sharing :+1:

73, Andrew VK1AD

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Thanks for sharing your experience, Josh.
I recommend using a wire that stays where you put it. The one I used (from the junk box) rolled up at once. I ended up putting small rocks on each end to keep the radials in place. The diameter seems uncritical. Mine is approx 1mm^2 but I guess it can be thinner.

I’m sorry to hear that, Andrew. For my experiments I had a small rubber mallet with me, which I used to drive the spike into the ground. But I can’t do that for every activation. We’ll see how it all works out. Maybe one can jam the spike between some rocks?

73, Roman

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I have been using these Telescopic antenna’s from Aliexpress plus the JPC-12 for close to 2 years now. On some of the summits here in NZ it is nothing but barren rock peaks with a few inches covering of topsoil. The aluminium spikes that come with these antennas are nearly impossible to drive into the ground without the risk of damaging the threads. Solution?

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I carry a reasonably sized stainless steel tent spike with me. With this I am always able to find a rock somewhere and drive the spike into the ground to form a hole that the antenna spike just drops into. And then if that fails I have also made a small collar from a piece of plastic cutting board that I use to tie thin nylon rope guys. I have never failed to get these antennas to stand close to upright yet except in extreme high winds.

Cheers
Phil ZL3CC

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To fix my antennas to ground I use this design. It’s an aluminum pipe with thin wall combined with a shaft of a wood screw. It can be easily screwed in by hand in many different soils. If ground is soft and wet, you can screw it in till pipe is dissapearing half to get additional support. On rocky summits you find cracks or gaps between rocks to use it.

It’s made from spare parts and design could be weight improved by using a thinner screw or drilling holes in the pipe, but I’m happy as it is. Maybe the next version will get these improvements.

73, Berthold, DK1BZ

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Do you then just drop the spike of the vertical into the pipe??? Or is this for putting up fibreglass/carbon fibre poles???

A picture of one of your antennas erected using this would be helpful Berthold.

Cheers
Phil ZL3CC

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Hi Phil, thanks for your questions. Target of my post was to show an alternative to a spike. So I didn’t explain the antenna. Your second assumption is right. The device, I use to erect a fibre pole for my linked dipole. Screw it in, insert the pole into the pipe end, add the wires and stretch the pole, done. I only found this picture. It shows the complete antenna, so the fixture is hardly to see.

For verticals I use the wood screw design too. See Short vertical on three Summits in Allgaeu Alps

The vertical is cheap, if you don’t count the hours you spent, but it is not from AliExpress.
I guess, I’m somehow antenna mad (-;

73, Berthold, DK1BZ

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Anyone got a viable visual method of determining which end is which?

Berthold,

Is it possible to see in detail the fastening of the wood screw in the aluminum tube (e.g. a cross-sectional sketch?)

IMG_0665

Test it with multimeter once and carve the red plastic. I used a dremel.

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Heinz

I am using a “Stockschraube” and cut a M8 counterpart into the aluminum.

73 Peter

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Peter,

Thanks for the info.

I hadn’t heard of “Stockschrauben” (stacker bolts) until now.
Thought it might be a connection known in classical mechanical engineering as a “Presspassung” (press fit).

73, Heinz

Great picture by the way :wink:

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