Re: Unusual experiment - "fairy-lights" antenna. Can you beat that?

by Andrew Thu Dec 09, 2021 7:56 pm

Here's another "fence antenna" idea

http://www.kk5jy.net/porch-loop/

rx only, ok, but may be worth a try Smile

by **Ivan** Thu Dec 09, 2021 7:25 pm

Hi Harry,

"I employed a timer to switch the lights off during the day to save a bit of power."
Yes, it was some 20 - 25 years ago. As you wrote, tungsten filament lamps were common.

"Here in Märsta there is a lot of criminality, gunshots, rapes, break-ins, and things outside have a tendency to disappear if they are not screwed down. Two months ago someone set fire to 200 cars in a multi-story car park. So some lighting is necessary."
How sad and how annoying!

"Having said that, the cost of electricity in Sweden has risen ..."
I will rather keep my opinion about the "new green deal" for myself.

"Now they are pushing electric cars and increasing the price of diesel and benzine. If the power grid is running at 90% capacity, then I wonder how they will be able to charge cars?"
Maybe everyone will get an accessory to his green car - a crank operated generator to charge the battery. Ha ha!

"I apologise for writing a lot"
Feel free, I am glad I can chat with you.

"I am working over the weekend. On-call Friday 17:00 to Monday 07:00, but I have to go in..."
I had to spend one weekend (usually) a month on-call, having to respond and start solving the problem in 6 minutes day and night. A call often meant going to the location (4 hours of time to get there). I felt it very frustrating. I am happy I do not have to serve this any more.

Very best regards from Ivan

by Andrew Thu Dec 09, 2021 7:19 pm

Ivan wrote:
Andrew wrote:
Hey Harry, the lights along the fence could be used to put together a (RX only) beverage antenna !!!
Hi,
a 40 m long fence is rather short for a Beverage, but it is just fine for a 3,5 MHz center-fed or end-fed dipole (RX and TX).

VBR from Ivan

sure, but it's low on ground, so radiation for a dipole or emdfed will be almost NVIS

by **Ivan** Thu Dec 09, 2021 7:05 pm

Andrew wrote:
Hey Harry, the lights along the fence could be used to put together a (RX only) beverage antenna !!!

Hi,
a 40 m long fence is rather short for a Beverage, but it is just fine for a 3,5 MHz center-fed or end-fed dipole (RX and TX).

VBR from Ivan

by Andrew Thu Dec 09, 2021 5:50 pm

Admin wrote:Hi Ivan,
The DC to the LED lamps is ON 24/7. I have not tried using it with the lamps OFF.

It was a spur-of-the-moment decision to try fairy lights. I had the ferrite, the coax, and I had spent a couple of hours putting up the lights.

The antenna is the string on the fence. There are more lights now, especially at the back of the house. Now up to about 2000 lamps. There are more to come.

I want to put a shooting-star on the roof. Could be good for 10 meters

BR Harry

Hey Harry, the lights along the fence could be used to put together a (RX only) beverage antenna !!!

by **admin** Thu Dec 09, 2021 12:05 pm

Hi Ivan,
I will get a couple more pictures later. That photo was taken before the snowfall and there are more lamps added since then - now about 2000 of them.

You wrote: "I employed a timer to switch the lights off during the day to save a bit of power."
I used to use a timer when we lived in Lunda. In those days the lamps were all tungsten filament lamps, and they could draw up to 20 Watts for one string.
Today they are all high-efficiency LEDs and the total power consumption is about 25 Watts. I am seeing the little specification labels on each string are typically 3.6 Watts. So I switched OFF the 30 Watt outside security light, so the decorations draw about 5 Watts less than the security lamp.

Here in Märsta there is a lot of criminality, gunshots, rapes, break-ins, and things outside have a tendency to disappear if they are not screwed down. Two months ago someone set fire to 200 cars in a multi-story car park. So some lighting is necessary.

Having said that, the cost of electricity in Sweden has risen from about $0.25 to almost $1.00 in the past month. Over the past 30 years they have shut down a nuclear plant and are trying to phase out fossil fuels. 17% of Sweden's electricity came from wind-power. But at the moment there is no wind, so the prices are rising. They don't muck about with any 10%'s in Sweden: increased by about 300%.

Now they are pushing electric cars and increasing the price of diesel and benzine. If the power grid is running at 90% capacity, then I wonder how they will be able to charge cars? One household may use 35kW/h in one month, but an electric car can use than in just one day (capacity typically 200kW/h). Now apply that to 3,500,000 vehicles and the figures just simply do not add up. Maybe I will have to get my illicit alcohol still back into action pirat

Yes, the fairy-lights are an excellent opportunity to install another antenna. As you saw in that picture, the fence is the opposite side of the house to the neighbours, and last Saturday I noticed that the electrical interference is much lower than I get from my dipole at the bottom of the garden. It will probably be a lot lower when the mains-powered fairy-lights are taken down. I honestly expected them to increase the QRM by coupling noise from the mains, but no!! Remarkably quiet, considering the compromises.

As you see from the picture, the fence is about 40 metres long from front to back. That could be used to support an 80m dipole. The last 10 metres is almost 2m above the ground, so there are more possibilities. Time for more head-scratching Smile

In the picture you can see that I did increase the height of the corner post to 2 metres, so perhaps I could hang a very thin wire? I have a few km of 0.8mm enameled magnet-wire.

Sorry to hear that you have an iron fence Crying or Very sad

That does limit your options a bit, but maybe the iron fence could become a good counterpoise for a vertical antenna? But I am sure that you have already thought of that.

Ok, thank you very much for your response. I apologise for writing a lot, but I have a free lunch break at work today, mainly because I am working over the weekend. On-call Friday 17:00 to Monday 07:00, but I have to go in a 23:00 tomorrow to shut down non-essential equipment. Saturday I have to go in and try to re-start it all - estimated 8 to 10 hours. Sunday I will probably hafta go in for a few hours because something is certain to have problems. When you shut down 376 SMPSU's there is always one or two that do not like the shock of restarting on a Sunday.

Very best regards, Ivan, and keep smiling santa

Harry - SM0VPO

by **Ivan** Thu Dec 09, 2021 5:48 am

Hi Harry,
your house looks awesome! I used to decorate my garden with Xmas lights when my children were small, but never so many. I employed a timer to switch the lights off during the day to save a bit of power.

Installing Xmas decorations and lights makes a good opportunity to install hidden antenna wires. No neighbour will mention placing an extra insulated wire together with the light chains. That wire stays in place all the year round after the celebration. Very Happy

The drawback is the work is done in cold weather.

A wire placed on top of a wooden or plastic fence may be a good HF antenna despite of its small height. My fence is of iron and overgrown by bushes, so it does not work for me. Sad

VBR from Ivan

by **admin** Wed Dec 08, 2021 9:31 pm

Hi Ivan,
The DC to the LED lamps is ON 24/7. I have not tried using it with the lamps OFF.

It was a spur-of-the-moment decision to try fairy lights. I had the ferrite, the coax, and I had spent a couple of hours putting up the lights.

The antenna is the string on the fence. There are more lights now, especially at the back of the house. Now up to about 2000 lamps. There are more to come.

I want to put a shooting-star on the roof. Could be good for 10 meters Very Happy

Unusual experiment - "fairy-lights" antenna. Can you beat that? House-10

BR Harry

by **Ivan** Wed Dec 08, 2021 5:01 pm

Hi Harry,
"My reasoning was that all the lamps would have the same RF on both terminals, common mode, and therefore not have any bad effects. No harmonics, just the lamps flickering a little with more than 10 Watts."
Was the DC current of the lights on or off? If the LEDs flickered, the current through them changed. But if the DC current was on at that time, they probably operated in the linear part of the charasteristics and no harmonics were produced.

"That must have been an old bed. Today there is very little metal in them. I bet you were happy that it worked so well."
I was 8 years old. If it did not work, maybe I would never start with radio. I had no place to make an outdoor antenna in that old flat. When we moved, the metal frame was thrown to scrap.

"But I know that you are a very inventive person "
You are too kind!

"I was willing to bet money that you would be the first person to respond to the post "
It was good luck that I logged in just now.

VBR from Ivan

by **admin** Wed Dec 08, 2021 4:07 pm

Ivan wrote:Hi Harry,
I expect the LED lights would produce a lot of harmonics when transmitting. Maybe you could be heard on several bands simultaneously?

My very first RX antenna was the metal frame of my bed. It gave a strong signal of AM broadcasting in a brick house and with grounding to metal water pipes...

VBR from Ivan

Hi Ivan,
I had thought about that but it looked clean on the analyser. I did check it.
My reasoning was that all the lamps would have the same RF on both terminals, common mode, and therefore not have any bad effects. No harmonics, just the lamps flickering a little with more than 10 Watts.

Ok on the bed-frame antenna. That must have been an old bed. Today there is very little metal in them. I bet you were happy that it worked so well. It just goes to show that a little thinking "outside the box" can give some good benefits. But I know that you are a very inventive person Very Happy

I was willing to bet money that you would be the first person to respond to the post Laughing

Best regards - Harry - SM0VPO

by **Ivan** Wed Dec 08, 2021 3:47 pm

Hi Harry,
I expect the LED lights would produce a lot of harmonics when transmitting. Maybe you could be heard on several bands simultaneously? Unusual experiment - "fairy-lights" antenna. Can you beat that? 1f632

Unusual experiment - "fairy-lights" antenna. Can you beat that? 1f632

My very first RX antenna was the metal frame of my bed. It gave a strong signal of AM broadcasting in a brick house and with grounding to metal water pipes...

VBR from Ivan

by **admin** Wed Dec 08, 2021 3:07 pm

Hi again,
On Saturday I was able to find some time to play, not a lot, but enough to have a bit of fun with antennas. I have 100's of ideas but no time, so I did just a little bit on a couple of ideas.

In the 80's I once loaded a 145MHz rig to an artificial Xmas tree, and that was both fun and productive.

This past week I have been outside decorating the house with around 2000 LED lamp for Xmas, and that really please Maj-Lis. One string was stapled on top of a new fence, only about 1m above the ground, and 50m long. So I stuffed a part of the wire lead to the power unit through a split-ferrite (the ones you clamp around power cables) and made up a kind of balun (or unun in this case).

I thought I would get terrific interference from the mains power supply, but that was not the case. Yes, there was some, but only on 3.5 MHz and a little on 7MHz. The Xmas-lights gave me less QRM than I get from my dipole, but the dipole is closer to the neighbours house. My Xmas-lights are on the side of the house farthest from any neighbour. I had to keep the power down to below 10 Watts so that the lights would not blink with modulation when I speak.

First contact with the fairy-lights antenna was Russia, and the next was Italy. It seems that you can always guarantee a contact an Italian station Wink

It just goes to show that you can use just about ANY wire or metal as an antenna.

In Cambridge (Grunty Fen) after I got my A-class HF license, I loaded up my FT-101ZD (still got it) into an electric fence around a field. It was out in the countryside and there were no neighbours. That worked very well, but I did have the sense not to have the fence power unit switched ON Very Happy

. On one another occasion I bought a 432MHz Yagi at a rally, so I tied it to the roof of the car. Just for a giggle I connected it to the radio, and used it on the local UHF repeater all the way home from the rally.

So what is the most WeIrDe antenna you have ever used? I am certain there are interesting and amusing stories yet to be told, stories that can provoke more ideas.

Best regards from Harry - SM0VPO

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