Duff antenna?¿

I picked up a sirio 2016 second hand cheap and alas I think I know why so cheap, it appears to be short circuit across the center pin and thread on the so 238 on the base of the antenna .
Would it be possible for someone to take a measurement of a known good one and post it up just in case I'm barking up the wrong tree .
This would be much appreciated thanks in advance 
Davy

Good morning Dave. That model of antenna is a DC grounded type and will show a short between the centre pin and thread. I know it can feel unnatural, but DC works differently to RF.

That is very much appreciated,thank you for your quick reply
Regards Davy

You will find many antennas like that.

Every day is a learning day
Other than specific antenna testing device is there any handy way of testing?
Here's where I'm at ... New rig , new RG213 cable with new pl259 plugs continuity of core and screen,not short between core and screen .
Swr is mad high regardless of any amount of adjustment (cherry picker put to good use)
Set works perfectly in the motor and magmount.
Points to the antenna.again thanks in advance

The verdict is in ,the cheap 2nd hand antenna was not so cheap at all,I experimented with the magmount and was surprised what a little bit of tinkering achieved.
First I cut a 600 mm disk of 6 mm plate and centered the magmount on it ,set it on the garage roof then I coupled it to the coax with a standard so239 male/male connector it works!.
On fm got out to about 15 miles give or take.
Gonna  have to just buy a new home base antenna as the experiment has proved the rig and the coax