Shorted HD7698P?

[wackywach]

I recently acquired the 7698 and it performed terribly compared the old RS VU75. I took down the antenna to inspect but visually nothing appeared wrong including the phasing stubs from the UHF and VHF (the VHF phasing lines are a bit unusual than what I'm use to seeing). Out of curiosity, after removing the housing and balun, I checked for continuity on the UHF stubs and all is ok here but the VHF was shorted between the stubs. It was also shorted to the boom! The only thing I can think of is one of the elements was being shorted to the boom from the rivets that hold them to the plastic mounts. After I had wiggled each of the elements, the short to the boom dissappeared but was still shorted between the stubs. It appears the very rear elements was the source. After removing the end cap on the boom I discovered something that didn't look right. This pair of elements has a rivet that goes from one element thru the phasing stub, thru the boom, back thru the opposite stub and into the opposite element not so with the rest of the elements. It seems to me that these rear elements should either be in 1 of 2 states. They are reflectors and are connected electrically to each other (and possibly to the boom) but are not active, that is, not on the phasing stub OR they are active on the phasing stub but not to each other or to the boom, such as the VU75. Question: Exactly how is this antenna supposed to be built involving these pair of elements? Are they shorted together? To the boom and phasing stubs as well?

Scott

[winegard]

Good morning wackywach -

The last set of elements are the reflector elements and will read a direct short using an ohm meter since they are tied together with the long rivet going through the boom.

[wackywach]

Thank you for responding. I always understood in most cases that the rear elements are the reflectors and are tied together. What confused me was that not only are the elements connected to each other but so are the stubs. Just to clarify, the elements are connected to the stubs and the boom. Am I correct in understanding that?

Scott

[winegard]

The elements are riveted to the phasing channels (lines) which feed the signals to the antenna housing. The elements are no riveted through or to the boom. Electrically using an ohm meter you will read a short to the elements through the reflector rivet to the boom but RF wise the short is not seen by the TV signal on the phasing lines.

[wackywach]

Again, thank you for responding to my query. You've answered my question in the second half of your answer. The difference between dc ground and rf operating above it did cross my my mind but I needed to clarify the antenna's construction. Also, I should have been more specific when I meant "elements". In my mind I was referring to the rear or reflector elements. In any case, when I was originally checking with the dvm, there is an intermitten between the stubs and the boom so I better take a closer look at that rivet on the reflector elements. If I run into anymore problems I will certainly be back.

Scott