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Testing Rhombic loop at EA2/NV-092


#1

Hello,

In today’s activation I tested a Rhombic loop made with 27 meter long light wire.
I had already used that as a Delta loop in a previous activation:

Due to the fact it is a long loop, using it as a Delta is a bad idea as the wires bend towards ground too much. That’s why I decided to install it today as a Rhombic loop.

I installed it on a 7m long fishpole but seem it is not long enough to create a good rhombic profile. Next time I’ll try to use a longer pole…

When I arrived in the summit weather was just fine. My plan was to start on 21 Mhz and then test it downwards: 21 - 18 - 14 - 10 - 7 MHz and check it both on SSB and CW.
The plan soon changed when after the first calls in 21 SSB a big storm arrived with hail. I had just time to cover the rig with a nylon shelter, put my hood on and, without being sure what to do, I decided to wait for it to stop, because so far I had just logged 2 qso so far.

I had to hold the shelter with my hands and I waved it every now and then to remove the increasing hail and water. Was that a clever idea?

Well, 15 minutes later the storm passed and I could continue, looking for qualify although it all was wet and muddy. For that reason I decided to do a quick activation: only SSB and forget about CW.

The loop worked fine, I could tune it in 21 - 18 - 14 and 7 MHz with the aid of the ZM-2 tuner.
Let me thank SP8RHP who was very kind to chase me on 18 - 14 and 7 MHz with good signal reports both ways.
The qso with M3FEH on 7 SSB was also rewarding due to it was a QRPx2.

Just before leaving the summit I had a look on Sotawatch and I tried to chase S2S to Manuel HB9DQM/P. I could log him on 7 CW, my only morse qso of the day. All in all, 22 qso in a hurry.

I will need to test the Rhombic again in the future. It’s not an all-summits antenna, but I love to test new antennas from time to time. I’ll try to catch some DX next time with it, weather permitting.

VY 73 de Ignacio.

A view of Pamplona, my home city, as seen from the summit. Oh those rainy moving clouds…


#2

Ignacio, I’m trying to understand the photo…

  1. Was this a loop installed in a vertical orientation with the two ends pulled out into a Rhombic shape
  2. Was it a true Rhombic with ladder-land and a termination resistor.

More info please, and thanks for posting…
Richard // N2GBR


#3

Hi Richard,

I think I used a mix of both things; see the sketch of what I did:

  • Ladder line for multiple band operation,
  • attached vertically to the pole
  • Without a resistor.

So what you see in the photo is one side of the rhomb pulled outwards by the rope.

Is it appropriate to call this a Rhombic loop then?
Thanks for your assesment.

73 de Ignacio


#4

:+1: 73 cu, Heinz
https://www.mathsisfun.com/definitions/rhombus.html

That’s what the antenna experts usually mean by rhombic antennas:
https://www.antennex.com/w4rnl/col0707/amod113.html
http://www.ipellejero.es/hf/antenas/rombica/english.php

Conclusion: The name Loop for your antenna would probably be a bit less “misleading”, hi.


#5

It’s a Rhombic Jim …but not as we know it. On 70cm perhaps.


#6

I think that orientation is normally called a diamond Quad if fed at one of the corners. I used one for 10m on several activations during the 6/10 challenge.

A rhombic is usually in the horizontal plane for horizontal polarisation. If terminated in a suitable resistance, it is unidirectional, if not it is bidirectional.

Andrew VK1DA/VK2UH


#7

Thanks Andrew,

I think you’re done with it! My post should have been named:
“Testing a Diamond quad antenna at EA2/NV-092”.

Thanks all contributors for helping me identifying my version of this antenna :wink:
Promise to perform more tests in the future and post results.
73 de Ignacio