Amateur Radio

​M0KWR

My interests and activities 

  
The inverted L sets the standard for 160 metre antennas but the draw back is getting a good ground radial system. This is required to reduce your ground losses and radiate a decent signal. It’s easy to warm the ground with 95% ground losses on 160. Yes 100 watts in 5 watts out. Top band is not easy but that’s what makes it more interesting and this drives me to improve what I have.
 

Radiating some RF sounds easy, one of the old sayings you have no doubt heard many times is ” it loads up with my tuner” this doesn't mean you are radiating any RF a dummy load gives you a great SWR but doesn’t radiate a signal. How many times do you hear” my
G5RV loads up brilliant on 160” the amusing thing about this is, if you have room for a G5RV you have room to put up something that will put out a reasonable signal on 160. Yes I know what you will say… but I want to work all bands. Then read on.
Most systems only achieve about 30% efficiency and that’s very good for 160 metres A little improvement can make all the difference between a poor signal and a strong one, especially when your maximum permitted power is 32 watts, you’ll need all the help you can get.

A simple 125ft piece of wire and a ground stake will get you on 160mtrs but not very far and with the noise level on 160 you may not even be heard when you make a call.
If you can’t lay any ground radials a starting point is to try a couple of raised counterpoise wires the more the better and don’t worry too much about the length just make them as log as you can.
You can get really good results using an FCP (folded counter poise) inverted L. The transformer is the important bit. Check out the web site if you want to try an FCP it has all the info you will need with links to published results. http://www.w0uce.net/K2AVantennas.html

I used the folded counterpoise inverted L for over 2 years with great results but I wanted to improve my 160 meter signal so the decision was made to relocate my inverted L to the bottom of my garden where I could put out some ground radials. This would need a new installation of coax to run the length of the garden.

I installed a new length of LDF450, 120 feet of from the shack to the base of my new inverted L position at the bottom of the garden.(I know over kill LDF on 160) The LDF was band new and I picked this up at a local rally and cheaper than RG213. This was installed down the garden and a 1.1 current balun added to the end of the coax.

Over the past couple of months installing another 10 -100ft radials in the lawn and adding 5 100 ft raised and folded radials My earth mat is growing and now has over 5000 ft of ground radials some buried and some raised with 8 solid copper ground stakes 5 ft long, the difference its made has been well worth the effort. The resistance is now below 16 ohms and I have to use a tuner in the shack to tweak the SWR. I was not happy about tuning the coax and I was getting some odd readings in the shack compared to readings at the base of the L so an alternative tuning method was needed. I either make up a basic L network to tune the L for one spot on the band or use a remote tuner.
The L network would be cheap but not being able to tune for a different part of the band or any other band without going down the garden with my analyser was not a good idea, especially on dark rainy night, so I opted for the SG230 tuner at the base of the L.


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I have added wire to 7 fence panels as shown. Aprox 700 ft of wire connected to my earth system. It all adds to the radial system and this may work for you. I used grey wire and you can hardly see it. Add this to your existing L and get a perormance increase.
I used the SGC  tuner for a while and it worked very well with the option of getting a signal out on other bands but it was loosing a fair bit of my precious power on 160 mtrs so i went back to a shunt coil. To date the shunt coil and resonator version is the most efficient L i have used on 160 mtrs. My 260 ft doublet works very well but it is a cloud warmer due to its low height and the only L to get any where near the doublet performance is this one. 
Converting my 160 meter dipole into a doublet.  
I installed home brew 600 Ohm Ladder Line on my 260 ft dipole to make it into a doublet.
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  After using the doublet as a dipole fed with RG214 coax I decided to turn it into a multi band doublet and also to see if i notice the difference between the two antennas.

I used 4mm insulated multi strand wire. Over kill I know but it will handle anything I can put through it.

The ladder line goes into a relay box which isolates the doublet. This stops interaction with my inverted L. I then run the ladder line into a 1 - 1 current balun . This allows me to run a 4 foot length of RG213 into the shack and connect to my tuner.

It does tune on all bands but how efficient it is on the higher bands I can't be sure. It is an amazing performer on 160 meters and 80 meters. These are my 2 main bands I operate on but I do venture on to the higher bands when I do a bit of PSK or RTTY.

The doublet is  50 feet above ground in an inverted V configuration. It’s too low really for 160mtrs but it does work very well around Europe. 80 meters is even better but it’s no DX antenna due to its height above ground.

Conclusion is ..It’s a great multi band antenna and if you have the room you would not be disappointed.
  

FCP Inverted   L

You can get really good results using an FCP (folded counter poise) inverted L. The transformer is the important bit. Check out the web site if you want to try an FCP it has all the info you will need with links to published results. http://www.w0uce.net/K2AVantennas.html