Topband: Vertical dipoles in the real world

[wa3mej at comcast.net]

Tom, 

  All you say is correct and anecdotal evidence is spotty at best and I understand this. But sometimes some of the guys, being big DXers have insights that I and many others dont have. Having worked for a few years in an EMC environment and a few years in a metrology lab I know that there is a lot more to measurements than just having a piece of test equipment ... are we doing the measurements correctly, is the equipment calibrated so that the date is accurate and reliable?  Can we even afford the equipment in the first place.  I for one being retired can not purchase an analyzer or even an FSVM so this was the next best thing.  



I often rely on the RBN to pick up spots and then record the data and can do A/B comparisons but that requires you to have both antennas up at the same time and separated by some distance (the far field would be great) but most of us dont have this capabilities.  I think I have said this before (it wasnt just flattery on my part) your web site has many topics that  would be a great loss to the community should they go away for any reason. 



This 20M dipole that I modeled (if I have modeled it correctly) appears to have low takeoff properties that are only exibited by a few antennas on TB (19deg) again if I have modeled it correctly. The RDF is not as good as some and the impedance is terrible but strictly as a receiving antenna and assuming you can actually get the 19deg TOA it would make a great receive antenna for the restricted space set.. say the guys with the inverted L FCP antennas. 

The antenna also seems to (again if modeled correctly) work fairly well on all of the bands 20 and above for transmitting and has nice TOA on these bands. WIth correct matching it could make some guy just starting out or with restricted space ( an apapartment dweller maybe) a means to stay active in their senior years when they cant keep up with a house.  



and Tom its because of the CFA and EH antenna that I am asking the questions.. I am skeptical of the data that I have.. 



I will be glad to provide to anyone that wants it.. the information that I have gleaned from eznec... 

Jim 
http://www.qsl.net/wa3mej/index.htm 
----- Original Message -----
From: "Tom W8JI" <w8ji at w8ji.com> 
To: PaulKB8N at aol.com, wa3mej at comcast.net, topband at contesting.com 
Sent: Friday, September 21, 2012 2:58:17 PM 
Subject: Re: Topband: Vertical dipoles in the real world 

> I put up a short vertical dipole for 40M.  It is 25' tall and has top  and 
> bottom X-shaped capacitive hats that are 42.5" square with a perimeter 
> wire 
> attached.  The lower capacitive hat is about 6' above the ground. 
> 
> While the antenna is resonant just under 9 mHz, it works very well on 
> both 
> 30M and 40M.  My "go-to" antenna on 40M is Double Zepp about 90' on a 
> side.  I frankly did not expect this short vertical dipole to be 
> competitive 
> with the DZ, yet it was! 

Hi Paul, 

How high was the DZ? What direction was it oriented compared to the 
reporting stations? What is the feed system? 

We really need articles describing ways to reasonably compare systems. There 
is a small helical magnetic loop antenna that was in an eHam article and is 
on U-tube that, if we believe the video, has well over 10 dBd gain!! The 
CFA, the EH antenna, the Isotron, the CTHA antenna, and the list goes on and 
on. 

It might not be about what is right with antennas being evaluated, but what 
isn't right or detailed with references. 

73 Tom