Hey Amateurs! I’ve built several 49:1 ununs with good success.
One of my units is setup more or less permanently in my front yard starting at my 2nd floor window then sloping down to a tree and making a left at about 40 feet in on a 40-10 meter setup. Fortunately, this compromised antenna is connected to an IT-100 tuner and my desktop IC-7100.
The other ones are in my backyard where I perform most of my antenna experiments since the HOA police doesn’t monitor back there as much.
One issue with my backyard 49:1’s is that on 40 meters, my SWR is kinda high. Now, my operating position in my backyard is at my kitchen table. Usually I have my Icom 705 running barefoot. This means any high SWR (usually about 2.5) and the IC705 starts folding back power to 5 watts instead of the full 10 when I’m connected to an external battery.
Since cycle 25 has come around, I’ve been band-hopping on FT8 and checking out 40, 20, 15, and 10 with good success. Previous to this, I only really made sure my EFHW worked well with a < 1.5 SWR on 40 and 20. Not so much anymore.
Since the 66 foot wire is in a much lower position, nowhere near 1/4 wavelength above the ground, I decided to try and remedy the situation by experimenting.
Sure I can bring down my MFJ manual tuner and/or bring down the 7100 which isn’t as fickle with higher SWR.
I made another EFHW but this time I added 2 more turns to make it a 64:1. I additionally tapped it at the 49:1 like “traditional” EFHWs. I connected it to my NanoVNA and lo and behold 40, 20, 15, and 10 were all below 2:1 SWR. I made FT8 contacts on all 4 bands this evening. I didn’t check the SWR on the 49:1 position but probably will just to make sure I’m not crazy and that 64:1 does work better in this situation, which is an inverted V starting at 1 foot off the ground where the transformer is, then going up to about 10 feet to my pergola and then coming back down to about 3 feet off the ground in a E-W direction more or less. I’ve made a FT8 QRP QSO to Alaska so I know it has potential!
So next time you’re winding a 49:1, add 2 more turns and try it out!
73,
AE0RS
