14/04/2025

Two versions of the cheap Chinese whip antenna from AliExpress

After following the discussions and reports on the SOTA Reflector about this cheap antenna, I couldn't resist to order one myself.

I did not buy the complete antenna set, but only the telescopic whip of 5.6m length. I didn't like the base, which has an SO-239 connector, and from the reports it seemed the radials were just rubbish (thin computer flatcable). So I intended to build my own version. 

Another inspiration came from a report by Jos, ON6WJ, in the EUQRPFOX newsgroup, who added an adjustable coil to make a 40m band antenna.



VERSION 1 - multi band, base loaded vertical 

step 1 : order a 5.6m whip on Ali Express, it arrived undamaged (not always the case it seems) 

step 2 : find a solution to mount it + add a coil for bands lower than 20m + add radials

The telescopic whip has an M10 thread at the base, and ON6WJ pointed me to these "Plate Nut Three-hole Flanges" on Ali Express : https://nl.aliexpress.com/item/1005007182945817.html

I used a thick wall PVC tube of 40mm, made a round wooden insert to which the flange is fixed, the wooden insert itself is then fixed with three Parker screws.

 


Now, how to put this construction in the ground ?

Another inspiration came from this "weed cutter" (top item in the picture above), an idea from good friend  Geert ON5GL.

Now, this weed cutter is very handy to put up a 6m fishing pole from Decathlon, but is too thin for the 40mm PVC tube, there is too much slack to keep the antenna stable.

I had some steel tubes from a vacuum cleaner that would fit, but those are a bit heavy, so instead, I took a piece of aluminium tube (old TV antenna mast), and copied the weed cutter design (2nd item in the picture above).

The fit was not perfect, so I added a piece of bicycle inner tube over the aluminium, and now it's a perfect fit !

 


Then the coil ... I found a roller inductor in the junk box of 0.4 ... 10 µH
Then added a ringcore T130-2 with 30 windings , adding another 10 µH
With a switch I can use three different settings: direct connection to the whip, 0.4 -10 µH and 10.4 - 20 µH.

The whole circuit is mounted on an aluminium plate , and attached to the PVC tube with two 'PVC 40mm clips' (normally used to fix tubes to the wall)

For the radials, I took the lengths of the set of radials from a Yaesu Atas-25 (https://www.yaesu.com/jp/manuals/yaesu_m/ATAS-25_EJ.pdf

The real lengths as measured by an owner of such an antenna were 2.18m + 3.00m + 6.71m (tnx Rob ON4ROB).

For transport, the whip + ground stake fit inside the PVC tube, not lightweight like for SOTA, but maybe handy for POTA. 

Whip is well protected inside the tube

And how does it work ?

I did a few POTA activations in a local park, setting up was very easy.

Here a few pics that show the steps to set up the antenna.

Put ground stake in the ground

Put base assembly on the stake

Put whip on top and attach radials
  



Extend whip to correct length


Operate !

I could tune the antenna on all bands 20m-10m, by adjusting the length of the whip. With the 0-10µH coil, I could tune 30m and 40m, and with the 10-20µH setting, I could use it on 60m. The lowest frequency I could reach was 4.755 MHz.

I suppose I could also use this antenna on 6m, but did not check that band.

Conclusion : this would be a 9 band antenna which doesn't need a lot of real estate to setup.

BUT ... I was not satisfied !

When operating SOTA or POTA, I like to switch bands very often (to hunt  for S2S or P2P QSO's).
With this setup that means I have to go to the antenna, adjust the length of the whip, or change the tuning of the coil ... too much fiddling !

So I came up with ...

VERSION 2 - multi band, NON-resonant whip antenna.

My favourite SOTA antenna is a 9.15m non-resonant wire with a 9:1 UNUN. Using an autotuner, I can use all bands from 60m to 10m, and have made many QSO's that way. 

So my idea was to change the whip, which is about a quarter wave on 20m into a non-resonant whip, by adding 1.4m of wire, and make the total length of the antenna around 7m.

Then using either a 9:1 UNUN (or a 4:1 UNUN), let a ATU-100 autotuner do its thing.


This makes for a much slimmer antenna, as seen in the picture above.

Some more POTA activations in the local park proved that it worked. I had QSO's all over Europe, and some DX as well (K and EA8).


Just out of curiosity, I built a 4:1 UNUN, and checked wether my ATU-100 could tune any differently, compared to the 9:1 UNUN.

I put the ATU-100 at the antenna base, so that the coax to the transceiver had no influence.

To the ground post I connected only 1 counterpoise of 4m.

Resulting SWR after tuning with a 2.5W carrier:


So my preference goes to the trusted 9:1 UNUN I have been using for years.

73,

Luc ON7DQ

20/02/2025

SOTA/POTA Winter Tour 2025


Doing the same SOTA Winter Tour every year gets a bit boring after a while, so this year I decided to do the tour in reverse. And to have some more time on each summit, I left out ON/ON-006 La Croix Scaille. I will probably visit this summit anyway later this year, during a family holiday.

Also I took my KX3 GO-box this time, with the trusted random endfed antenna, with two lengths  of wire (9.15m and 22.30m).

DAY 1 : Thursday, Feb 20, 2025

I left my QTH Ostend at 05:10 local time, had my breakfast along the highway, then went to my first stop, where I arrived at 08:35.

ON/ON-004, Bois de Hazeille - 586m, 6 Points + POTA BE-0453


The parking spot at 50.033045, 5.422340 is actually already in the activation zone for SOTA and POTA, but I still went a little into the forest, to find a quiet place to operate.

Since I started using the IC-705 I hadn't used my KX3 much. I had forgotten how easy it is to set up my station, just open the box, connect the antenna, put on the headphones and start operating, all within a few minutes time (see a video of my setup procedure here). 

The weather was dry but still cold at 5°C, can you tell from the picture ?


When driving to the parking spot, I had passed a large white pickup truck, and sure enough, after some 15 minutes that truck passed by on the main road, and then came driving into the forest to where I was. It was a young park ranger, checking out what I was doing. But after a short talk, and assuring that I would stay on the roads, all was OK and he left.

Since I used the longer wire for this activation, I could make a few QSO's on 80m and 60m, followed by big pile-ups on 40m and 20m. Result : 79 QSO's in just under 55 minutes, great !
This included 1 S2S and 2 P2P.

Here a map of my contacts:



ON/ON-010 Baraque Fraiture  - 651m, 8 points


Not the most scenic view, I just operated from the parking lot at 50.253847, 5.732054
Temperature was only 4°C here, and it was rather damp and foggy.

Result : 45 QSO's here, including 6 S2S. Here the QSO map:



ON/ON-013, Bois de Hodinfosse - 568m, 6 points

Parking spot as usual, at  50.316070, 5.841752

Only change here, there used to be a patch of forest that was cleared, which gave a nice panoramic view over the valley to the south. But new trees were planted a few years ago, and have now grown to the point where the nice view is obscured ...
There was also a strong wind, so I went up the hill into the forest where the wind was a bit less.
Since there is a little walking involved on this summit, I took my light aluminium table, and a "kids camping chair", that I found in a sports store for only 6€, you can still see the price tag in the picture, hi.
The label says it can withstand  100kg, so it should be ok for my "lightweight 75 kg".
It was perfect for my activation, so I am satisfied with my purchase.  


Result here : 29 QSO's with 1 S2S, here the map:


ON/ON-011, Sur Clair Fa - 601m, 8 points



Drive up summit now !

Last year, I tried to find a new approach for this summit, from the small village of  Logbiermé.
But coming from the East, Google Maps tried to send me over some forest roads, and eventually I had to return and take my ususal parking spot near the horse riding school of Mont-Le-Soie.
See last years' report here

Since I reversed my tour this time, I had more luck, and found the correct route to Logbiermé, coming from the West, via Vielsalm > Grand-Halleux > Vau > Logbiermé.
The ride over there is quite scenic, so an adventure in itself.

From ON/ON-013 tot ON/ON-011

Now the last part of the road can be viewed in Google Streetview up to position 50.341552, 5.966317
There is no forbidden sign there, so I drove further on the gravel road, and was glad to find a parking spot where that roads takes a bend to the left, in a side road at position  50.337468, 5.972298
I saw several cars also taking this road.
The side road is leading straight to the trig point, but is not possible to drive with a regular car, maybe it can be done with a 4x4, there is nothing that forbids it ...
 
The parking spot is in the activation zone (altitude is 580m there), so I set up a short distance from my car.
Result : 71 QSO's with 3 S2S, here the map:



I was a bit ahead on my schedule, and had never walked to the real summit, so I put away my radio stuff, and walked to the trig point. As you can see, not a road for a normal car.


I didn't stay long at the trig point, there was a strong wind. Just took the time to take some pictures.
It must be a nice place when the sun is shining ...





The road to my AirBnb in Amel near Sankt-Vith took me along another worthwile stop, the monument for Eddy Merkckx (https://en.wikipedia.org/wiki/Eddy_Merckx)  near Stavelot.
Merkckx, nicknamed "The Cannibal", was Belgiums' most famous cyclist. 
The monument is at position 50.383278, 5.937278


I had booked a nice apartment in a small village called Amel near Sankt-Vith, in the German speaking part of Belgium. It was more than what I needed, but it was the only place available which suited my intended route. So after unpacking, and having my dinner, I still needed to make a few radio contacts ... because on this evening it was also time for the ...

NTC QSO Party

Temporary /P shack for the NTC QSO Party

It was already dark and cold outside, so I didn't feel going on the road again to operate /P, instead I draped my antenna wire from the kitchen , through the living room, the bedroom and finally into the bathroom, in a kind of zigzag setup ... and it worked !

Zig-Zag random wire

Now, I always participate in the mechanical keying section of this QSO Party, but I forgot my travel cootie in the car. So I had to use the Palm Pico paddle on its' side, as a straight key, which did the job just as well. I made another 10 contacts in the QSO Party, not bad for 15W and an indoor random wire.


DAY 2 : Friday Feb 21, 2025

I had only planned two summits on this day, since it was still a long drive home in the afternoon.
First stop was along the German border, at ...

ON/ON-009, Iverst - 693m, 8 points


I arrived at 09:20 local time, and parked at my regular spot, GPS pos 50.408333, 6.369756
It was foggy and there was a light drizzle, so had to take my umbrella, and started operating in my simple 'tent'.


I had put up the longer wire again, so had more contacts on 80m and 60m first, followed by a nice pile-up on 30m CW.
I ended the activation with 37 QSO's in the log, including 6 S2S. Here is the map:




I had a short stop for lunch at the OldSMUGGLER Café & Brotshop (GPS pos 50.352977, 6.384090), in nearby Losheim, after which it was time for my last summit:

ON/ON-001 Signal de Botrange


I arrived at the parking (pos 50.501208, 6.093355) at 12:45 local time, the sun was shining and the temperature was a pleasant 12°C. By the time I left it was already 18°C.
The nice weather attracted many walkers, so I decided not to operate next to the parking lot, but walk a little to the forest road past the trig point, and set up along it.


Using the short random wire, I had a real blast : 73 (!) QSO's in the log in 1 hour and 15 minutes.




I worked 15 US stations on 10m and 15m, and had also 3 S2S. One of those was EA8/WN2G, who was on EA8/GC-011, Montaña de Tauro, where I was in 2018, nice ! 
Here the map of all QSO's (I don't know why the EA8 station doesn't show on the map):


LoRa APRS Tracker

On each summit (except the first, where I forgot it), I switched on the little LoRa APRS Tracker that I built (see this post about it). I t seems LoRa coverage is quite acceptable in those areas, so a very useful device.
Amazing if you consider it is only 100mW and a rubber duck antenna at ground level.

Day 1 positions:


and Day 2 positions:


My impression is that the LoRa tracker even works better than the 2m APRS station in my car, which uses 25W on the mobile quarterwave antenna
(compare ON7DQ (car) to ON7DQ-7 (LoRA) for the dates of my trip).

Going home

Not much to report abbout that, except that it was a long ride, with heavy traffic, especially taking the ring around Brussels took me a long time. I left the last summit at 14:50, and arrived home only at 18:50. Tired but happy ... and so was the XYL, she was glad to see me back home in one piece! 

Some statistics :
  • total number of QSO's : 334 (+ 10 in the NTCQP)
  • activator points : +62
  • chaser points : +107
  • S2S points : +151
  • Total distance driven : 696.6 km

Thanks for reading, 73 and see you on another tour !

Luc ON7DQ