Discussion in 'Amateur Radio Equipment Reviews' started by AA9ZZ, Jun 14, 2008.
Counterpoise rods that are effective on 40? Amazing.
I don't think so.
The Cuschcraft R series vertical antennas (R4, R5, R6000, R7, R7000, R8) are End Fed Half-Wave Vertical Antennas (EFHA)
Steve Yates, AA5TB covers the analysis of the End Fed Half-Wave Antenna on his web page
He also talks about Moxon's earlier discussions on the EFHA
Tom, W8JI also discusses EFHA here:
Joe Everhart, N2CX
I have experiemented with 2 hustler 5 btv verticals and compared them ground mounted.One with no radials to one with 8 per band.The difference is about 1 s-unit on average after a number of qso's gain for the one WITH radials.
I also installed a roof mounted vertical with and without radials.
the same difference.All verticals need some kind of counter poise to have "the other half" of the antenna. HOWEVER, what can be used in place of radials is very interesting.I mounted a vertical on the top of my pool screen enclosure with way better results than a ground mounted with 8 radials per band. Your right, the GAP is a "vertical dipole" connection in the center. No radials for this "no vertical" vertical.
In my best under standing that vertical antennas best used in restricted spaces probable some us don't have a big yard to lay down ground radials so why radials must be used in order for top performance when you have them to cut to length for each band being used there verticals on the market no radials required but in the big bucks range like we all can afford them.
The question itself "Good HF No Radial Vertical?" to me is an oxymoron! That is unless your talking about a vertical dipole.
We can get verticals to work , and sometimes without ground radials .
I had an Cushcraft R5 used , sold as a vertical not needing ground radials .
But its still about doing any number of things to make something work [ varies depending on too many things , to mention a general install ] .
My rig , a damaged Yaesu FT-897D , only puts out about 3 1/2 watts on 20m , about 2 watts on 75-80m and have contacts from AK , HI , southern Argentina and Eastern Europe - Croatia etc. .
This is mostly last winter with bad conditions / low sunspot .
I do use an antenna analyzer to tune my tuner [ a Palstar AT2K ] , even though it is 20m - 10m antenna , I could tune all of 6m , 75m , 80m , but none on 40m .
I set up a used Butternut HV-9 , on the ground without radials , on most bands it was about 1/2 an S-unit better .
Traded off the R5 , going to mount the HV-9 on a mast about 25' in air , with a homebrew counterpoise [ same dimensions as Butternut ] , just need to get some time to get it up [ without viagra ]
The point being do your best to learn what the RF science says to do , then find a way to make what you have work .
BINGO! (Bulls-eye, even
http://www.w0btu.com/Optimum_number_of_ground_radials_vs_radial_length.html and scroll down.
See W9GB's post, above.
The R5 is a halfwave vertical. I had one for years and it worked as intended,
" One commonly repeated myth or "theory" is that end-fed half wave antennas, being resonant, do not require a counterpoise. "
I used the R-series of Cushcraft verticals for years. While I do NOT like the R-8 (can't tune individual bands well), they performed well in my experience. I worked the world with 100 watts. Of course, I never put a full set of radials under any of those to see whether they would perform better or not. Mine were roof mounted on chimneys, so maybe that helped a bit. I never used one mounted on the ground.
Everything is a compromise, but someone with limited space who doesn't have room for a full set of radials will get decent performance from these.