Topband: 160M ant advice

[Robert Harmon]

Gene, AD3F also suggested a cage.  It looks like a great way to go. You 
mentioned using a flat
wound AM BC coil in your matching arrangement.  I have a Gates flatwound 
roller inductor that may
have been used in AM BC.  It is huge, about 8 inches in diameter and 16 
inches long.  The spacing
between the flat coils is about 1/2"  I have it stashed away for that 
special project,  looks like I have the
special project now, hihi.
I will check out W8JI's information too, that's what I need the most 
right now, shunt feeding is new to me.

thanks Herb,
Bob
K6UJ

On 12/18/15 9:38 AM, Herbert Schoenbohm wrote:
> If you have such a structure IMHO the best thing you can do is to 
> shunt feed it.  It is really easy to do.  Just drop a three or four 
> wire "cage" down from the 60 foot level supported by two pieces of 
> galvanized water pipe extending each about 24-36 inches from the 
> tower. ..... and feed the wires at the bottom with a series capacitor 
> or two capacitors with an Omega match. You can then tap this wire down 
> to the tower at two foot increments.    To prevent having to move a 
> "sweet point" tap up and down the tower it may be easier to measure 
> the impedance and the inductive reactance and make a network to match 
> what you have.  The three or four drop wires should be at least 24 
> inches from the tower and can avoid changes with wire sway by holding 
> them tight with some nice hardware store springs after you attach some 
> good porcelain insulators. In my case I use a flat wound AM BC coil to 
> ground which is tapped from the ground up and a series vacuum cap from 
> the cage wire to the coil so i can get a perfect match.  This way I 
> can use a single coil and a single variable and by tapping the coil I 
> can cover  a wide range of impedance.  For a really great synopsis of 
> information of shunt feed methodology just visit W8JI.com and it is 
> all there for you.
>
>
> herb Schoenbohm, KV4FZ
>
> On 12/18/2015 1:11 PM, Robert Harmon wrote:
>> Stan,
>>
>> With shunt feed I would gain the 18 foot mast with the yagis, the 
>> total overall height is 108 feet.
>> I haven't really considered shunt feeding.  I see your point of the 
>> wires with an L in proximity to other
>> antennas.  That was a worry I had with the 40 meter yagi and the L. I 
>> will look into shunt feeding.  I have ON4UN's book, probably should 
>> start there to bone up.  Any other resources to learn abut shunt 
>> feeding ?
>> The top band archives probably has a lot of discussions about shunt 
>> feeding also.
>>
>> thanks Stan,
>> Bob
>> K6UJ
>>
>>
>>
>> On 12/18/15 1:36 AM, Stan Stockton wrote:
>>> Bob,
>>>
>>> There is no reason I can think of to not shunt feed the tower as it 
>>> is with either ground radials or elevated radials.  An inverted L 
>>> isn't as good as a vertical for DX and you would just be adding 
>>> clutter and horizontal wires in proximity to your other antennas.  
>>> Shunt feeding a tower is very, very simple.
>>>
>>> 73... Stan, K5GO
>>>
>>>> On Dec 17, 2015, at 8:06 PM, Robert Harmon <k6uj at pacbell.net> wrote:
>>>>
>>>> I am planning an install of a 160M inverted L  and would like 
>>>> critique from you top banders.
>>>> I was originally planning a separate tower for 160 but my XYL has 
>>>> squashed the idea  :-)
>>>> My tower is 90 feet fully extended with a 18 foot mast currently 
>>>> used for a Force 12 WARC plus 10/15 beam
>>>> on top and a N6BT DXU-32, 2EL 40 and 3EL 20  12 feet below.
>>>> At the top of the top section I have a 10 foot fiberglass pole I 
>>>> plan to extend out to support the vertical, so it will be 10 feet 
>>>> away from the tower.
>>>> I am thinking of feeding the vertical and having 4 elevated radials 
>>>> at the 14 foot level.
>>>> So the vertical wire will about 76 feet long.
>>>>
>>>> I am wondering if I would be better lowering the feedpoint & radial 
>>>> tie ins down from 14 feet say to 8 feet and have more length in the 
>>>> vertical portion of the L or better to have the 14 feet elevation 
>>>> for the radials ?
>>>>
>>>> Also the horizontal leg of the L on top will be about 5 feet below 
>>>> the 40/20 yagi only 10 feet out from the tower,
>>>> do you think this is OK as far as interaction between the yagi and 
>>>> the 160 L ?  Anything else I should consider ?
>>>> I have never had a decent 160 antenna, just hoping I can work 
>>>> something out with my existing situation
>>>>
>>>> thanks in advance,
>>>>
>>>> Bob
>>>> K6UJ
>>>>
>>>> _________________
>>>> Topband Reflector Archives - http://www.contesting.com/_topband
>>> _________________
>>> Topband Reflector Archives - http://www.contesting.com/_topband
>>>
>>
>> _________________
>> Topband Reflector Archives - http://www.contesting.com/_topband
>
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>