Not if his coax connector in the house has no connection the coax shield (which I suspect is the case).
Originally Posted by KF5FEI
Sloping the radials from such a short height may result in them resonating much lower. Try it straight at first and set a benchmark to work from.
Hmmm... You've got an issue somewhere -- bad cable, flaky analyzer, bad connection. I basically doubled the dimensions on the 20m vertical I designed and built and then tweaked the measurements to get the SWR lowest at 7.150. I know the design works -- this is one of my portable QRP antennas that has performed well.
You aren't setting this up on top of a concrete driveway or near other metal objects, are you?
That's why I asked several posts ago what the SWR was, ignoring resonance. Sounds like it's working fine, and 16' from ground to feedpoint is a good height. I'd leave it there.
Originally Posted by KC0MS
A government which robs Peter to pay Paul can always depend on the support of Paul.
-- George Bernard Shaw
If you were measuring the antenna thru a length of coax and looking only at the reactance reading on the analyzer, it's possible to get a point where the reactance goes to zero in the 5 to 6 MHz range, but the SWR at that frequency will be huge. Actually you can move that point around by changing the feedline length.
It is good that you got the antenna working! As such, that is a good point at which to stop.
However, the length of the radials is NOT 1/4 wave using the 234/F formula! That formula is a rough estimate for a 1/4 wave radiating element taking into consideration the "end effect" which is around 5-percent. The "rule of thumb is for the radials to be 5-percent longer than the radiating element which just happens to be a true 1/4 wave which, in turn, can be calculated by 246/F.
However, there are all sorts of physical things which can, and do, affect the actual length of both the radiating element and the radials.
What are you calling resonance on the MFJ?
Minimum VSWR or zero reactance no matter what the R shows? Since the antenna feed point is not 50 Ohms you are possibly looking at the wrong thing. It also has to be measured right at the feed unless you know the electrical length of the coax used and can work a Smith Chart.
I think you may find you'll have to adjust your radials as they are not a grounplane but rather a counterpoise as I understand your description.
The soil conductivity and everything else will have an effect also any surrounding metal will have an effect. IE Light poles or even a stucco house with the cheicken wire in the walls etc. You could try dropping off or folding back half of one of the radials and see where your resonant point goes.
You'll get it.
Make sure the batteries in the analyzer are fresh.
Measure at the feed point of the antenna - and no where else. You have to measure at the antenna to measure the ANTENNA.
Include the radials, and the shield of the coax connected - but measure at the Antenna.
There are 100 reasons you could be getting these measurements. But rather than speculate on that - I suggest proper measurement technique and measuring the actual impedance of the antenna at the feed point - including the connected coax shield.
Something isn't adding up, and people are trying to help you - but you are missing some fundamental information and troubleshooting here.
I've been mislead simply because my batteries were failing. But I'm not using an MFJ.
No reason why this antenna as you have described it - would be resonant on 60m. None. Makes no sense.
Lots of possibilities (are you standing next to the antenna when you measure it?). You need to measure at the antenna, but try to get underneath it, or far enough away that you aren't detuning it with your body. When tuning my ground mounted verticals I'm usually lying prone, with the analyzer connected directly to the antenna, and the coax shield and radials also connected. (center conductor of coax not connected - you need the shield connected because it is likely a big part of the tuning until you get it properly choked).