Long overdue various upgrades of my 5/16 wavelength (~ 170 ft) 160m Inv L have been occuring throughout this month of January during some milder (and less windy) days! Hoping for improved transmit performance in CQWW 160 CW (and perhaps 160m SSB event in Feb?) after disappointing results in recent Stew Perry Topband Distance Challenge.
Primary upgrade: a newly installed *elevated* radial system to hopefully reduce existing ground losses…the menace of vertical attennas, esp. on 160m. Three non-resonant 1/8 wave (65 ft) elevated radials were installed, gullwing style, going from 4 ft at feedpoint up to about 10-12 above ground. NO attachment to the already existing on-earth radial system is made, although those radials (18 various length wires mostly shorter than 1/4 wavelength) help reduce the losses from the new elevated system!
Research has shown NON-resonant radials in an elevated position on verticals causes negligible current deviations amongst those radials, thus reduced losses. Due to our poor New England soil conductivity ( a “2” here whereas some Midwestern soils register a very good figure of “30”) l’m hoping the above ground radials will be even more effective in isolating the Inv L from ground losses. And typical for above ground radials, just 4 radials is typically required … I opted for 3 somewhat symmetrically placed wires with my limited 100′ x 200′ space.
In addition, the Inv L was adjusted for a more ideal approximately “up 80 ft/over 90 ft” length and a more robust near 2000 pF series matching capacitor installed. Only the use of an SWR Analyzer awaits for final tweaking (warmer months??)… but for now it requires very little in-shack tuning across the band. Multiple mechanical attachment improvements and relocated feedpoint at the DX Engineering lowband-specific Balun itself round out the system changes.
Six recent Eu contacts and Reverse Beacon Network test reports show the new system is getting out at distance with my 100 watts. Contesting will put it to an even better test of course!
Hope to work many of you on Topband this weekend … or in the near future!!
Good luck/73,
Bill W1WBB
Trustee of AI1TT
Hi BIll!
What works on 160? this is a great experiment, especially if you could disconnect them and do a/b testing with RBN , WSPR or pskreporter. I unrolled 4 135′ radials for this weekend to augment the 16 65′ radials at present, all on surface. Some hear me , some don’t, just like before :). Last night’s Eu propagation seemed poor to mediocre despite the low A and K numbers. GL and let’s see what tonight will bring.
Dave K1SX
Dave (and others) –
As I stated in my recent CQWW160mCW contest 3830scores.com write-up, the elevated radials provided a *noticeable* improvement over my previous modest on-ground radial system, certainly throughout North America. Not only more QSOs than ever before for me in this event (707 total) but far fewer repeat requests and ?? sent my way. The existing on-ground radials (DISconnected from the antenna entirely, a must with elevated radials!) now act as a helpful ground screen to boot.
I felt fairly loud and had some great sustained runs averaging 75-80 Q’s per hour (and had 125 QSOs in the first 1h 50m!). After checking logged SEC with CQ Zone I found I actually worked 17 Zone 3 West Coast stations, a lot for me, as well.
With my apparently improved signal I also had more uncopyable stations try and call me than I can ever remember (a bummer) likely due to my increasing local noise levels, so improving the RX antenna situation is the next needed upgrade … good ears on 160m/80m are becoming more and more important (and it’s not great being an ‘alligator’ on receive on the low bands).
I DID perform some basic A/B comparisons between non-elevated and then elevated ground radial systems with the RBN a few weeks ago and the elevated system appeared favorable.
But I wasn’t hearing Eu well at all during the contest weekend so I just didn’t try to work many of them. Not one Eu got logged Sat eve (RL3A gave me a W1? multiple times). So I just concentrated on maximizing domestic QSOs and mults as I was hearing pretty well to the west. My 10-point DX QSO count was thus very poor, but I attribute that to lousy Eu propagation more than anything. But overall, I had a good time being heard well across NA. A few Zone 3 guys even called me, a real rarity!
For 160m the minimum suggested non-resonant elevated radial length is 1/8 wavelength (which is what I used, just to keep things simple) but lengths up to 110+ feet seem to be effective. A minimum of two opposing above ground radials is suggested, although diminishing returns appear to be the case when using four or more of these non-resonant type wires. Mounted heights for the radials at least 10-12 feet (or a bit more) above ground are highly recommended. And placing them in a symmetric layout is good practice, if possible.
Perhaps others may want to experiment on their own (in warmer WX!) with above-ground radials for their low-band antennas. K2AV.com offers much info on improving Inv L antennas and offers his idea of the Folded CounterPoise (or FCP) as a singular above ground radial system. The Topband Email Reflector has lots of good info on this subject too.
73, Bill W1WBB