Indeed Viki, all part of the learning curve. More than once, I have to admit, I have called and called on the FT-817 with a beam, before giving up and trying in desperation on the handheld with RD. Then it is suddenly easy to make contacts! In my case, it was something like a feeder in need of repair or such.
Jimmy and I were in a group of six calling you from North West England at one point! Sorry we weren’t able to hang around until you had fixed the problem. Roy G1NUS and Karen 2E0XYL were two others that I remember were trying to answer your calls - did you work them in the end?
Yes, the VX7, having a wideband receiver, can be prone to picking up lots of unwelcome rubbish from nearby commercial masts. One possible action, as you discovered, is to disconnect the bigger aerial and return to the supplied helical antenna. I should also think that a beam would give you more chance of avoiding QRM, rather than a dipole. You can play around with the beam, changing direction headings and even polarisation. Although 2m FM is traditional done using vertical polarisation, so is a whole bunch of commercial stuff. So you can find that working with horizontal polarisation can significantly reduce this kind of disruption.
The irony is that most people trying to work you will be on vertical as well, so your logbook won’t be as full, but it is another way of beating the mush.