[Antennas] Verticals, <2/1 VSWR bandwidth?

[Philip Atchley]

Hi,

Another quick question here (I'm always full of them).

My Roof mounted (over about 1200 Sq/ft of sheetmetal roof) Hustler 6BTV 
vertical has the following bandwidths of less than 2/1 SWR. . .

40 Meters is 230KC wide, centered at 7120KC.
75 Meters is 48KC wide, centered at 3730KC.
It dips to a nice low 1.1/1 at resonance.

My desires are to improve the overall antenna system here with separate 
verticals for the low bands and high bands and add inverted Vees for 20, 15 & 
10 meters to augment the high band vertical.  (I'm trying to minimize traps on 
the low band antennas).

Late this fall I plan on replacing the  Hustler 6BTV antenna with a Butternut 
HF-2V vertical, set up for 80/40 meters only (no 30 or 160).  Although the 
Hustler is working well with no radials, I expect to put a number of radials 
for 40M under the HF-2V, there is NO room to put out 80 Meter radials, though 
I expect that the sheetmetal roof will provide sufficient groundplane (better 
than nothing, like a BIG MOBIL setup ;-)

Questions:
1.  I would expect that I would get a wider usable bandwidth on both bands, 
SWR wise.  Anyone have any idea what bandwidths I can expect on this antenna 
(SWR <2/1)?

2.  Since the HF-2V is a full sized vertical on 40M, I would expect that it 
would outperform the Hustler with traps.  Thoughts?

3.  Though they would be short, would those 40M radials help any on 75M.  This 
may be a myth, but somewhere I read that a gazillion short radials of 20 feet 
or so were more effective than just a few longer ones?  Remember this will be 
over a sheetmetal roof that is already part of the antenna ground system.

4.  Does that Butternut "TLK" top loading device really improve the bandwidth 
of the antenna, by how much?  The Butternut site doesn't say a whole lot about 
it.

5.  Finally, should I just lay the radials on the metal roof, or would it be 
better to tie them off in the corners of the mobile home so that they are 
lifted (very) slightly above the roof?

73 de Phil,  KO6BB
SWL QSL GALLERY: http://photobucket.com/albums/y123/KO6BB/
THE BEACONEER'S LAIR:    http://www.geocities.com/ko6bb/
Merced, Central California, 37.3N  120.48W  CM97sh