Search results
An 80-10 end-fed half-wave antenna can be a very good performing part of an HF station. But its performance depends heavily on a well-designed and carefully constructed 49:1 unun, which matches the long wire impedance to within tuning range of operation. But the perfor-mance of an end-fed antenna is also very dependent on height above ground.
12 sie 2016 · A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. So, if you connect a length of wire that presents an impedance of about 450 Ω to the input, you’ll get an impedance of about 50 Ω on the output. In fact, the 9:1 unun that I built is actually an autotransformer.
24 paź 2018 · UNbalanced antenna fed with Unbalanced coax, is a virtual guarantee of braid common-mode coupling. Many amateurs find this out the hard way with either an increase in noise ingress from the shack, or perhaps undesirable directional characteristics.
Works really, really well. Time Owned: 6 to 12 months. I'm using a Nelson Antennas 9:1 balun end-fed 71 foot wire, about 4 metres above ground from a difficult urban back yard. It consistently out-performs my multi-band dipole and is now my main antenna for all bands from 10 to 40 metres.
I recently replaced the 20W-rated 49:1 unun for my EFHW with a new 200W-rated 49:1 unit, and the new SWR graph is completely different. Does this mean there’s a problem somewhere, or why is it so different?
2 sty 2018 · From eBay I got a very cheap 9:1 UNUN antenna transformer for EF (End Fed) longwire antennas. To read more about the EF antennas, please google and you find a lot of info. The unit I tested look like this inside in a small plastic box: The connector for the coax is BNC.
My ZeroFive 10-80 Freestanding Groundplane Vertical Antenna with Unun is absolutely fantastic. Antenna shipped very well protected as any quality item should be. Very easy to assemble, my advice is to purchase Tom’s custom fold over base that has “J” hooks for concrete mounting.
