[TowerTalk] Inverted Vees

[Jim Brown]

On 6/15/2020 8:09 PM, Wes Attaway (N5WA) wrote:
> This has been an interesting discussion.

> The comparative results are very interesting in the sense that as Jim Brown
> explains the nulls can be very deep but also fairly sharp.  I find it
> interesting to switch around between these antennas on different bands and
> different times of day because the best RX results are often not what you
> would expect.

Yes, I often do that, but it's easy to be fooled by signal to noise and 
AGC. To reduce that possibility, it can often be necessary to turn off 
AGC when making comparisons.
> 
> In addition to focusing on the directional peaks and nulls you also have to
> think about the elevation angles that come into play.  These angles, over
> any particular path and band, can change from hour to hour and affect the
> results that you get.
> 
> I often see the same things Jim does where a signal is stronger off the end
> of one antenna than it is off the expected main lobe direction of another
> antenna.

That's not what I meant in my last paragraph below. They pretty much 
behave as expected, but I work a lot of east coast when I'm working JA 
on a dipole that has the east coast sort of off the end, and a lot of JA 
when I'm working the east coast on the antenna with JA sort of off the 
end. So my point is that yes, the nulls are there, but so broad or deep 
that the antenna doesn't work well enough in those directions to make QSOs.

73, Jim K9YC

> 
>     -------------------
> Wes Attaway (N5WA)
> (318) 393-3289 - Shreveport, LA
> Computer/Cellphone Forensics
> AttawayForensics.com
>     -------------------
> 
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
> jimlux
> Sent: Monday, June 15, 2020 4:36 PM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Inverted Vees
> 
> On 6/15/20 1:45 PM, Jim Brown wrote:
>> On 6/15/2020 11:18 AM, john at kk9a.com wrote:
>>> Also an inverted V does not have the big nulls that a flat dipole has
>>> making the inverted V's orientation is less critical.
>>
>> Calling the nulls "big" is not accurate -- the nulls ARE deep, but they
>> are also relatively narrow in angle. i have dipoles at right angles to
>> each other for 80 and 40 at 120 ft. On any given signal, I rarely see
>> more than 10 dB difference between them, and I work a lot of east coast
>> stations on 80M on the antenna that's off the end to them. And I've
>> worked a lot of JAs on the antenna that's broadside to the east coast
>> and EU.