Basically, it's a slim jim j-pole. They won't light the world on fire, but work well for what they are.
You can't beat a flexible roll-up stuff it in a bag antenna for VHF/UHF when you have absolutely nothing else. And yes, I was stuck in a storm with no power and no access to an outside antenna when I strung up a similar antenna for 2M and was able to communicate to the outside world on simplex. It shouldn't be your primary antenna, but it is magic when you have nothing else.
Great slim Jim antenna . One thing , Your SWR will change some in the PVC pipe , most people miss this point . It must be in the clear for proper SWR . Joe @ N9TAX.com Has much info on his home web page . Check it out . He sells them on his web 2wayelectronix.com .
I have used these for years, both in and out of pvc. I used to hang them with a paper clip and a bit of string from the suspended ceiling in my windowless, reinforced concrete and steel first floor office. They were wonderful.
Not sure where the Slim Jim comments come from. I think if you look closely at the top end you will discover that it's not bridged across and therefore not a Slim Jim. The isolated segment on the side above the notch has no functional electrical purpose. I built this one a couple of years ago and added a couple of ferrite beads on the coax at the feed point. I hung it in the clear between trusses in the attic and it's been working a charm ever since. Even with a few feet of snow on the roof (plywood and asphalt shingles) , hitting the local repeater or working simplex line of site around town has never been an issue, even low power on the old IC-O2AT. This antenna is well worth the small effort and nil cost it takes to build.... it's a keeper.
I have a Professor Ed Fong model in the schedule 40 PVC pipe he specifies. Very surprisingly good SWR metrics when placed by a PVC T-Connector to my painters pole.
