[NLRS] 50Mhz antenna modeling question

[tosca005 at umn.edu]

On May 16 2007, Matt Burt wrote:

> I have built a few antennas for six and now feel the need for something 
> small enough for the rover and yet capable of a little forward gain.
> ...
> practical. Of course I have used 3 or even a four element at 15-18ft and 
> had good luck.
>
> Any way armed with an old DOS program for calculating dimensions I came 
> up with a 2 ele 50Mhz antenna of the following specs:

Matt:

Antenna modeling is one of those things I have always wanted to get 
involved with, since I am a computer geek and software developer, but it's 
been several years since I could find any time to do any programming for 
fun, and so it's been on the back burner. Which is a long way of saying I 
can't help with your actual question. So why am I writing at all?

I feel the need to ask a question that may impact on your whole process. 
Although I am familiar with the KISS principle (Keep It Simple, Stupid!), 
and sometimes even adhere to it, I don't see the reason for trying to make 
a two-element yagi for 6 Meter roving. Why not at least 3 elements? That 
should still allow for a very manageable boom length suitable for roving, 
and provide better gain at the same time. You even said you have had good 
luck in the past with 3 and 4 element yagis, so why consider dropping all 
the way down to 2 elements?

Since I am so frustrated by trying to work rovers that I can't hear and 
that can't hear me, I advocate "lots of antenna" when roving, rather than 
"the least antenna feasible". My "perfect" rover antennas would all be 10 
feet long so they were street legal when pointed in any direction, but 
since I haven't found a set of 10-foot antennas, and don't have the time 
now to delve into antenna modeling the way I hope to eventually, so can't 
design and build my own, I use what I can that comes close to 10 feet. My 
loopers for 902 and up, for example, are all the 12 foot models, rather 
than going down to 8 or 6 foot booms. OTOH, due to lack of time to fiddle 
with antennas, I also tend to go out with a full 6M5X antenna on 6M since 
that's the only 6M antenna I own that is not attached to my tower, and 
that's a BIG antenna by rover standards! And I use the rear portions of M 
squared antennas for the next 3 bands up so that they are cut off at 
something close to 10-12 feet in length. I'd really rather have a set of 
"optimal" 10 or 12 foot long antennas on the 4 lower VHF/UHF bands, but I'd 
also rather occasionally go out than only dream of what could be.

Anyway, I'd consider evaluating a 3 or 4 element design before spending a 
lot of effort on the 2 element, unless I'm missing something fundamental 
here.

73 de WØJT