[Antennas] 40m mobile antenna e.r.p. compared

[CBoone]

ANY antenna less than a 1/4wl vertical will have less radiation and lower
ERP.......
The longest antenna you can put on the roof will be the best..those with TOP
loading will radiate better than center loading of same length...regardless
of the make, those are the only specs to base on. As long as the antenna is
raised off ground (and keep the radials from touching ground), 4 should work
ok... (Too bad you cannot throw up a small wire long dipole and feed it with
a tuner....would likely be better depending on the height above gnd!)

Chris
WB5ITT

> -----Original Message-----
> From: antennas-bounces at mailman.qth.net 
> [mailto:antennas-bounces at mailman.qth.net] On Behalf Of Sam Morgan
> Sent: Saturday, April 30, 2005 11:07 AM
> To: antennas at mailman.qth.net
> Subject: [Antennas] 40m mobile antenna e.r.p. compared
> 
> Hello folks,
> 
> I have spoke with my landlord and it seems I will get the ok 
> for an antenna of a size comparable to a mobile antenna 8' to 
> 10', might sneak it up to 12'?
> 
> The roof is flat and made of rolled shingle. 
> The size of the roof is 29'x49'.
> The roof height is 19' above ground.
> 
> Antenna base will be placed on a metal plate 2'x2' located in 
> the center of the roof, with four 1/4 wave radials extending 
> from the plate.
> 
> For this case lets limit the frequency(s) to 40m only. I know 
> the bandwidth may be limited, but I'll address that aspect in 
> another post.
> My question is, which antenna would have the highest 
> effective radiated power. (least loss) I will probably be 
> running 25w or less, so this factor is a big concern to me.
> 
> In THIS post I'm looking for comparisons of commercially 
> available antennas.
> 
> (I'll be asking in a seperate post some questions related to 
> a homebrewed antenna(s)) 
> 
> Antennas I am reading about include the following:
> 
> http://www.hamstick.com/9106.htm (40m hamstick)
> 
> http://www.mfjenterprises.com/products.php?prodid=MFJ-1662 
> (screwdriver)
> 
> something created from parts from these folks:
> http://www.dxengineering.com/Sections.asp?ID=47&DeptID=24#Top
> 
> ----
> If I win the lottery perhaps one of these:
> 
> http://www.texasbugcatcher.com/index.html
> 
> http://www.qth.com/n7lyy/
> 
> http://www.hiqantennas.com/HiQ2580.htm
> 
> to bad this one is 20' .. it's so..so..<not> cheap ;-\ 
> http://www.hiqantennas.com/HiQ-tune-a-vert.htm
> 
> http://thescrewdriver.com/
> 
>