In the past few days, I've been looking at building another antenna. My random wire is nice, but it's just not cutting it on the HF bands for DXing. 80 meters is a no-go for DX constantly and while I can get it to tune, it just has too much NVIS propagation. Time for something different, and I may have found the answer.
Rybakov Revelations
Walt, K4OGO, was a HUGE inspiration as to why I chose this antenna. He's made at least 3 or 4 iterations of the antenna, and has successfully used them all on 40 through 10. Not bad at all!
The Rybakov is by no means a new design. In essence, it's just a random wire but oriented vertically. Most will tell you to use radiator lengths around 25 to 29 feet in length. You'll need to use a 4:1 UNUN in this setup as this is an UNbalanaced antenna. Several easy 4:1 unun designs can be found online.
Here's a basic drawing of what a Rybakov looks like:
Not much to it. As for a vertical pole, you can use those long fishing poles sold on places like Amazon, eBay, etc.
In this configuration, the antenna is expected to perform well on 20 through 10 meters, though some have claimed that 40, 30, 80, 60, and 6 meters are also possible.
Get Low
We can get on 80 and 60 meters with this antenna, but it requires one thing that will limit many hams - length.
As the antenna increases in length, tipping over may become an issue. But that's not to say we have to run vertical. We DO have the horizontal space too.
The easiest solution? Set it up in an inverted L! In order to do this, add on 25 more feet of wire to make 50 feet. Then, string the radiator up 25 feet and run it horizontal 25 feet. Kind of like this:
Now remember wire lengths aren't static. Experiment! Maybe you find that 53 feet works better than 50 feet. Also, don't worry about keeping the horizontal plane horizontal. A slight slope is okay and might work better for your setup. Just string it up along the fiberglass pole you have and string it over as straight as you can. That's all!
Making the Unun
I have previous experience making ununs, especially when I made the EARCHI random wire that I currently use.
This one is a bit different. It involves using a T200-2 core, which is much larger than the T130-2 I used for the 9:1 unun. I'm going to still use 18AWG wire, though some sources claim 20AWG is better. 18 gauge is what I'm using as it's what I have on hand.
The antenna wire is 22AWG, so this antenna will only be good up to 50W digital/CW and 100W SSB. I don't plan on going over 30W digital since my antenna tuner is limited to that, and SSB doesn't take very much. On CW I only operate on 20W or less, so I'm good here too. To hang it I have 2 options.
First, use the pre-existing tree mount.* This is easy as I already have a pulley system in the tree that hoists my random wire about 25 or 30 feet into the air (I think). 22AWG is quite weak when it comes to tension so I'll likely have to affix the transformer to a stake in the ground. The radials will be 4 17 foot wires. I ordered a 100 foot spool off of Amazon, which will leave me with about 7 feet left over. 25 feet for the radiator, 17 for 4 radials equals 93 feet in total.
The other option is to buy a fiberglass pole. These run anywhere from $100 to $120, which I think I'll wait on. 80 and 60 meters can wait, as I have yet to even lay a finger on the Pixie Sixtie project. 40 through 10 will suffice me just fine, and I'm more than active on these bands. Here soon though I'll purchase one to use for my inverted L setup on 80 and 60 meters. One brand that has received great reviews is the Jackite line of fiberglass poles. These come in 28 and 31 feet options, but I think I'll just get the 31 foot should I want to use it on its own to support an inverted vee, a dipole, etc.
To make the unun, we'll need a T200-2 toroid, two strands of enameled or insulated wire, and that's it, really. Wind it anywhere from 13 to 19 times, but I'd recommend 16 times. If you want to ensure that it's truly 4 to 1, you can measure this using a NanoVNA. Place a 200 ohm resistor (100 + 100 in series) across the output of the unun and connect the S11 to the input. If everything reads correctly, you should see at least a 1:1 VSWR match on the frequencies you desire, at most maybe 3:1. Refer to the drawing below:
With this setup and construction, power levels of 250 to even 300 watts continuous are possible. If you do plan to go QRO, make sure you use a heavier radiator/radial wire gauge.
*SIKE! The tree's too short
Well, the pulley is 18 feet up. That's 7 feet short. Bummer :\
But not all hope is lost! We need to go higher, and luckily that tree has more branches further up. I'll need to get good arbor throwing skills. With just some thin mason cord and a counterweight, this is certainly doable!
And as for the inverted L? Still doable - just 50ish feet of wire with the horizontal segment counterweighted in the other tree. Trees are great, aren't they? Of course I will buy a fiberglass pole later on, but for now? I've spent enough on this antenna ;)
The key with this one is to use a tree that's tall enough. Of course, the trees on the property should be plenty tall to support this antenna but I will make sure to secure the unun so the 22AWG wire doesn't carry all the tension. The unun needs to be at least 6 inches off the ground according to many other reliable hams, and I'm planning on mounting it at least a foot off the ground.
Honestly I think I'll put the transformer in a food container and waterproof it by lining the lid and container lip with waterproof material, whatever that may be.
Of course, there is an alternative...
Walt has gone back and has made a SHORTENED Rybakov at only 17 or 17.5 feet - this would fit perfect! The only caveat I'm aware of (I haven't confirmed it as I'm waiting on the parts...) is it's kind of iffy on 40 and 30 meters. He has coined it the 17-Five antenna, and this might be what I'm going for. 17.5 foot radiator with 4 or more radials of the same-ish size. This antenna would work best on 20 through 10 meters, and Walt has also shown that it could work on 6 meters as well.
Now quit reading this and build an antenna!
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