Re: Topband: Looking for hi-Z antenna
It isn't the feedpoint impedance that matters, it is the antenna radiation resistance that matters. For example, if we take a quarter wavelength vertical having radiation resistance of 36 ohms and add a wire to make it a folded vertical having input impedance of 144 ohms it still has a radiation resistance of 36 ohms. The ground loss eats up the same amount of RF energy. To increase the radiation resistance the current-area must be increased. Two ways to do that are to lengthen the antenna (up to 1/4 wavelength) or top load it. On 60 meters1 the HF2V is a 32' base loaded vertical having a radiation resistance of ~1.5 ohms. Top loaded this can be increased to ~5.5 ohms, potentially increasing your signal by almost 6 dB. The HF2V manual mentions top loading on page 11. *HF2V manual* https://static.dxengineering.com/global/images/instructions/but-hf2v_ck.pdf Dave KH6AQ On Wed, Mar 10, 2021 at 3:07 AM Richard Quick wrote: > I have as much of a compromised antenna for 160 as you can get. > A Butternut HF2V with a 160 coil, mounted on a chain link fence. > I have a small lot with overhead power lines across the back of the > property, and Am looking for a better idea. > I’m thinking a hi impedance feed point antenna ie:450 ohms would require a > much less extensive ground radial system than say, an inverted L with low > impedance. Easier to match a 450 Ground than 37 ohms. > Am I nuts? Anyone with ideas along this line of thinking? > > > > Rich - W4RQ Amateur Radio: The Original Social Media > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Looking for hi-Z antenna
Rich Roughly how big is your back yard? Any trees over 30' high? ( I did work Antarctica from Texas once with a Bnut HF-9V and about 8 radials, so even a blind pig finds a truffle now and then ...but your instincts are correct about there being better alternatives ...8^) Dave NR1DX On 3/10/2021 8:07 AM, Richard Quick wrote: I have as much of a compromised antenna for 160 as you can get. A Butternut HF2V with a 160 coil, mounted on a chain link fence. I have a small lot with overhead power lines across the back of the property, and Am looking for a better idea. I’m thinking a hi impedance feed point antenna ie:450 ohms would require a much less extensive ground radial system than say, an inverted L with low impedance. Easier to match a 450 Ground than 37 ohms. Am I nuts? Anyone with ideas along this line of thinking? Rich - W4RQ Amateur Radio: The Original Social Media _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector -- Dave manu...@artekmanuals.com www.ArtekManuals.com -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Looking for hi-Z antenna
I have as much of a compromised antenna for 160 as you can get. A Butternut HF2V with a 160 coil, mounted on a chain link fence. I have a small lot with overhead power lines across the back of the property, and Am looking for a better idea. I’m thinking a hi impedance feed point antenna ie:450 ohms would require a much less extensive ground radial system than say, an inverted L with low impedance. Easier to match a 450 Ground than 37 ohms. Am I nuts? Anyone with ideas along this line of thinking? Rich - W4RQ Amateur Radio: The Original Social Media _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
