[TowerTalk] 80-m. Inverted Vee vs. Dipole Performance

[Tom Haavisto]

Take a 1/4 wave length of wire (half an inverted vee), and connect the
hot side of the coax to this.  Shield from the coax is attached to the
tower.  Signal is vertically polarized, and may show a small null off
the back of the antenna.  You may have to adjust the angle of the
sloping wire for best SWR.

Tom - VE3CX


On Wed, Sep 15, 2010 at 12:07 PM, Al Williams <alwilliams at olywa.net> wrote:
> what is a half sloper? is it a half inverted vee (which is a sloper)?
>
> k7puc
>
>
> ----- Original Message ----- From: "Tom Haavisto" <kamham69 at gmail.com>
> To: <RLVZ at aol.com>
> Cc: "Tower Talk" <towertalk at contesting.com>
> Sent: Wednesday, September 15, 2010 8:53 AM
> Subject: Re: [TowerTalk] 80-m. Inverted Vee vs. Dipole Performance
>
>
> I have an inverted vee installed on a 48 foot tower - apex is around 45
> feet.
> On another (64 foot) tower, I have 2 half-slopers - one for phone, one for
> CW.
>
> I have found the half-slopers work very well working DX, and have been
> my primary 80 meter antennas for a number of years.  Also work well
> for working North America
>
> I installed the inverted vee about a year ago so I could do some A/B
> comparisons.
>
> Working DX, the slopers are far better.  i was listening to a local
> about 30 miles away running QRP.  He was about S2 on the sloper, S9 on
> the inverted vee.  For most of my operating, I end up using the
> sloper.
>
> One thing I also did was to install a number of radials around the
> tower with the slopers.  For a relatively simple antenna, it works
> very well.  Given a choice, the inverted vee would be the first one to
> go away.
>
> Tom - VE3CX
>
>
>
>
> On Sat, Sep 11, 2010 at 1:56 PM,  <RLVZ at aol.com> wrote:
>>
>> Hi Guys,
>>
>> I'd appreciate your thoughts and recommendations on the following 80-meter
>> antenna setup:
>>
>> I operate portable from a QTH in Wisconsin for several weeks each year.
>> This site has a short 50' tower, a small Hy-Gain TH-3 Mk3 Tribander on
>> top,
>> and non-conductive guy wires. For a 80 meter antenna I've been using an
>> Inverted V with apex at 47' and the ends at 15' above ground. This
>> 80-meter
>> Inverted V seems to work pretty well on Stateside q's and fairly well on
>> DX... but I've never done an A/B comparison with another antenna to
>> compare
>> results. I base my results on how well it busts pileups in contests.
>>
>> Thought: Most people I've heard of who have modeled Inverted Vee's
>> typically say "the Inverted Vee is a poor performer" and "you're much
>> better off
>> with a flat-top dipole". But a few people contend that an Inverted Vee has
>> some vertical polarization which lowers the angle of radiation. So in
>> this case, if the flat-top dipole was at 47' (less than a quarter wave) it
>> would still be a cloud warmer.
>>
>> Question: Since the flat-top dipole at 47' would be a cloud warmer, it
>> seems to me that even if the Inverted Vee only had a very small amount of
>> vertical radiation that the low Inverted Vee could perform as well as or
>> better
>> than the low dipole on qso's over 1,000 miles. Do you agree that the low
>> Inverted V might outperform the low flat-top on q's of a 1,000 miles or
>> more? If anyone has done A/B comparisons on a low Inverted Vee vs. a low
>> flat-top dipole please share the results. I am thinking that modeling
>> software
>> may not give the Inverted Vee any allowance for vertical polarization...
>> which could be why they often model poorly.
>>
>> I'd really appreciate it if anyone had A/B comparison information you
>> could share on a low Inverted Vee do compared to low flat-top dipoles. I
>> relaize I could shunt feed this tower but that would require radials and
>> it's
>> more work than I'd like to invest into a portable antenna.
>>
>> Thanks & 73!
>>
>> Dick- K9OM/9
>> _______________________________________________
>>
>>
>>
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