Hi Dick -
A correction and some additional points. Correction - I mentioned once 40
foot 160 m slopers. That should be 140 foot. Additional point(s) - the tower
is grounded with four ground rods, I have 6 100 foot (non reasonant) raised
radials grounded at the tower and roughly 10 feet high and the ends of the
160m slopers are also about 10 feet high. I think the radials are there
mostly just to make me feel good. I've never measured the current in them.
Gene / W2LU
----- Original Message -----
From: "Gene Fuller" <w2lu@rochester.rr.com>
To: <rlvz@aol.com>; <towertalk@contesting.com>
Sent: Saturday, January 02, 2010 6:04 PM
Subject: Re: [TowerTalk] Half sloper recommedations needed
> Hi Dick -
>
> I can just tell you my experience. I"m using 3 quarterwave slopers from a
> 100 foot tower on 160. A rely box at the top of the tower selects which of
> the three is on the coax. Coax shield is connected to the top of tower.
> Since it's about 200 feet from the tower to the station I have a "line
> flattener" at the base of the tower tunerd for best SWR at the station.-
> Also switching from RG-213 comming down the tower to 75 ohm hard line to
> the
> station). I made no attempt to tune/resonate the sloper. Although the
> "F/B"
> ratio may only be a very few db I figure it's worth it to have more than
> one. Wouldn't you think it was great if you could have 4 or 5 KW instead
> of
> 1.5 for the price of an extra wire and a relay ??? Since I have 3 bent
> halfwaves on 80 ( operated as one driven and two reflectors) I have 3
> quarterwaves on 160 (140 feet each) placed between the 80m halfwaves.
> Bottom
> line - both the 160m quarterwaves and the 80m halfwaves seem to work very
> well. I really don't know if my 7-60 MHz LP on the top of the tower is in
> the picture. The 40 foot 160m slopers are probably somewhat acting as
> aditional reflectors on 80. They were originally installed as 80 m
> reflectors when what are now 80m bent vertical dipoles were actually 80m
> sloping dipoles. Running the bottom half of the sloping dipoles back
> towards
> the bottom of the tower was VERY worthwhile - canceled the horizontal
> component bringing the rad angle from 28 down to 18 degrees. One driven
> and
> two reflectors is only good for about 4 dbi but the 18 degree takeoff more
> than makes up for the low gain.
>
> Good luck with whatever you wind up with.
>
> Gene / W2LU
>
>
> ----- Original Message -----
> From: <rlvz@aol.com>
> To: <towertalk@contesting.com>
> Sent: Thursday, December 31, 2009 4:27 PM
> Subject: [TowerTalk] Half sloper recommedations needed
>
>
>> Hi Guys-
>>
>> I'd appreciate your recommendations on building a Half Sloper for 160-m.
>> I realize that some folk have had excellent results with Half Slopers
>> and
>> others have had terrible results with them! That's why I'm asking for
>> advise on how to construct my Half Sloper!
>>
>> Question 1: Most antenna articles say when constructing an Inv. Vee is
>> to
>> keep the minimum angle between wires at 90 degrees or greater. Since
>> Half
>> Slopers almost never have a 90 degree angle between the sloper wire and
>> the
>> tower is this one reason why many Half Slopers don't work very well...
>> lots
>> of signal cancellation?
>>
>> Question 2: I have a 90' tower with a Tribander on top which makes it
>> very
>> close to a 1/4 wave for 160-m. I installed an Inverted L on this tower
>> with 85' vertical and the Inv. L radiating efficiency is very poor due
>> to
>> heavy coupling between the Inverted L and the tower. (some models say
>> that
>> alot of RF is shorted right to ground!) Therefore, I am thinking of
>> going
>> with a Half Sloper connected near the top of the 90' tower with the
>> sloper
>> wire running NE towards Europe. If I anchor the end of the sloper wire
>> about
>> 200' from the tower the angle is only going to be about 45 degrees. Do
>> you think this will work any better towards Europe than my heavily
>> coupled
>> and inefficient Inv. L? (another weakness with my Inv. L is that I have
>> a
>> minimal radial system as it must be pulled up each Spring).
>>
>> Question 3: Rather than build the Half Sloper on the 90' tower would an
>> Inv. L on my 60' tower with 55' vertical and the rest horizontal running
>> NE
>> towards Europe likely outperform the Half Sloper at 90' towards
>> Europe...
>> keeping in mind that this is a temporary antenna so I can only put down
>> a
>> minimal radial system as the radials need to be removed in Spring.
>>
>> I realize that I'm likely to get a variety of opinions on this and that
>> is
>> fine! Please let me know which of the above options you believe is most
>> likely to provide the best 160-m. signal towards Europe.
>>
>> Happy New Year!
>>
>> 73,
>> Dick- K9OM
>> Edgewater, Florida
>>
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
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>
> _______________________________________________
>
>
>
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