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Sota Oblong for 2 meters

Here a my blog article about an Oblong antenna for 144 mhz.
Horizontal polarization, easy to transport and easy to construct.
Ready for the post coronavirus activations

36 cm x 69 cm wire size!!

Unfortunately the article is written in italian but it’s easily translated in english with google!!

73 de In3aqk, from dolomiti mountains

Central connections

Hugly balun

The antenna in it’s magnefincence

The boom support hihi

The boom support

6 Likes

Another version - I constructed this 2m rectangular loop in September 2019.

Andrew VK1AD

5 Likes

I confirm Andrew an implementation of the same antenna of VK3YE, you VK1AD and others.
Really impressive the performance and simplicity!
Thanks for sharing!

73 de in3aqk

Hallo

The oblong is a very effectiv lightweight antenna. It is one of my favorites - mainly because there is the possibility to attach a vertical shortwave antenna to the pole. It is totally underrated.

https://www.qsl.net/dk7zb/Quadlong/4xoblong-2m.htm

Nice to see, that you like it too.

73 Armin

2 Likes

The simplicity of the 2m rectangular loop is brilliant. If you are in to 2m SSB or FM activations then the rectangular loop is an excellent lightweight option.

Andrew VK1AD

Hi Armin
With time on my hands, I have collected all the parts together to build one of these antennas.
The “driven” element shown in the DK7ZB article looks like it has an insulated tube with the end of the brass elements pushed into it. Do you have the measurements for the overall length of the element, the size of the gap if any, and the points that the coax are connected please?
Thanks
73
Tim
G4YTD

Hallo Tim

All horizontal elements are the same length. The driven element is separated in the middle. Feeding is near the end. But that and the distance between the two halves are not critical.
I made it with small brass tubes, soldering is fine. It is held inside by a small wooden stick (shish kebab stick :innocent: ) and fixed by heat shrink tube. The SWR and bandwidth is great.

73 Armin

1 Like

Thanks for confirming Armin, and the picture helps :slight_smile:
Looking forward to testing this on the hills when the madness is over!
Stay safe.
73
Tim
G4YTD

Rectangle Loop for 2m

This is what i have built recently its a bodge or heathkit design made from 8mm Ali tubing form an old 2m yagi beam that came from an old 15m beam elements.

!

But it works. Did some brazing with low temp rods BUT do note when doing this you nearly have to melt the Ali tubing to bring the metal to temp to use the Ali low temp rods. And made me bends out of 6mm Ali tubing with 4mm metal studding bars. Idea was to allow me to make bends of right angles with the bar inside the 4mm tubing and bend it with out breaking or folding on itself and inserted into the 8mm tubing and low temp brazed on the joints,

Now according to the net the max gain you get of a FW loop is a circle and next up is a rectangle shape side fed both giving tad more gain over other loops designs being cause its 50 ohm impedance and not Q fed.

So next task is to get hold of some 6mm ali tubing and a mini pipe bender and make a seamless type and this time side short side fed it as unsure if impedance is badly effected of long sided of rectangle fed like i have here.

Then into phase 2 of making 2m Moxons out of Ali tubing. Idea is to hang it vertical for vertical polar and hang it flat as in Hoz into hoz polar the TX. And all all you need is some fishing wire on each corner and suspend from your squid pole when out portable.

Tis antenna will be light weight no extra supports the Ali tube does that on tod and a simple direct 50 ohm feed point for FW loops and Moxon versions.

Also going to look into doing a 6m Fw Loop. But make it so it easy comes apart to transport and make ready for going on air. And Moxon version of course. For use at home or portable.

Some of you may remember that days before UHF was mobile peoples used these rectangular antennas as mobile antennas back in the day one or two older gents of the ham nature informed me.

2E0FEH KERNOW

1 Like

Did Aluminium low temperature soldering rods grant a good electrical contact? I have also the same rods and I was not sure.

From the specifications:

Electrical Conductivity 24.9% of CU

Aluminium has 61% respect CU

Yes not a problem just make sure the surfaces are clean.

Double checked with the meter for resistance till very low between the two sides of the loop

1 Like

Hello group. I’ve never used one of these before. What is the advantage of this design over a simple horizontal dipole? Thanks.

Here at SOTA it is mechanically interesting, if you use plastic tube and wire:

  • easy to build
  • small weight
  • small pack size

Otherwise it is the advantage of a quad over a dipole:

  • less noise
  • little extra gain
  • less sensitive to external influences in swr

The disadvantage: it is more sensitiv to wind.

73 Armin

2 Likes

I add to what DL6GCA stated, horizontal polarized.
For more gain consider the double o triple oblong
73 de In3aqk

For SOTA VHF activity, why not consider a stock X-200 or X-300 Colinear? A Diamond X-200 weighs nothing and be assembled in 6 or 7 minutes.

There’s an awful lot to be said about spraying RF 360°

Back in 2011, I made 244 contacts from G/SP-004 Shining Tor, which may still be the record for a SOTA single day VHF FM activation. It was done with an X-300 colinear, FT-857 and about 7 Watts.

I did end up spoiling a brand new 20Ah SLAB, by over discharging it. I watched the voltage meter on the 857 fall to just over 9.5 Volts when I finally pulled the plug. However, I was having so much fun, I didn’t care.

https://reflector.sota.org.uk/t/marathon-on-sp-004-shining-tor-quick-report/5518

My best ever 2m FM contact, while working with the X-300 was with SA7CKN, a distance of 1070 Km, during a lift, from G/SP-013 back in 2015. This would have been a nice 2m contact with a beam and working ssb.

Well worth a try.