[TowerTalk] Cushcraft/MFJ Traps

[Jim Brown]

On 9/13/2019 5:38 AM, jimlux wrote:
> I'm not so sure about the efficiency aspect for shorter antennas - sure, 
> for "very short", the matching network losses will increase, but the 
> actual antenna efficiency isn't different (I^2*R losses are usually 
> pretty low)

There are (at least) two important dimensions related to gain of a Yagi. 
One is the length of the elements. The other is boom length, and it is 
well known that boom length is strongly correlated to forward gain. When 
I said "compromised dimensions" I was talking about both. This link is 
to an Excel spreadsheet that summarizes the performance of VHF Yagis. 
Note that the sort is by boom length, and the strong correlation to 
gain. http://www.bigskyspaces.com/w7gj/VE7BQH%20Charts.xls  The 
spreadsheet will display well in alternative spreadsheet programs like 
Open Office, Libre Office, and Google Sheets.

And, of course, as others have noted, there's the matter of the 
bandwidth of the gain as well as the beamwidth. The spreadsheet also 
includes this data.

73, Jim K9YC