I have noticed several times that people talk about being able to put up
a full .250 wavelength vertical and I have wondered why almost never do
they think about making it .270 wavelength instead of .250 wavelength. The
little extra length gives a feed point impedance of 52 ohms with some
inductive reactance which can be canceled with a series capactor. This
gives a more efficient feed than a .250 wavelength and using an inductor to
get a match. I designed my 75/80m vertical this way and with 65 radials (
odd number 'cause that's all the wire I had) it has allowed me to work 280
entities with100 watts, all SSB. (Blasphemy I know, I have an ear condition
which made 13 wpm almost impossible for me).
I also use this antenna on 160m by using linear loading and an inductor
for matching. Linear loading seems to be overlooked in a lot of discussions
of antennas on this list and I wonder why. Am I missing a downside to these
matching systems? If so I would like to hear about it.
Pat Armstrong KF5YZ Heart of Texas
On Tue, Dec 20, 2016 at 12:00 PM, W0MU Mike Fatchett <w0mu@w0mu.com> wrote:
> https://www.dxengineering.com/search/product-line/dx-enginee
> ring-160-meter-thunderbolt-vertical-antennas?autoview=
> SKU&keyword=160%20vertical&sortby=BestKeywordMatch&sortorder=Ascending
>
>
> On 12/20/2016 10:24 AM, Petronel Postolache wrote:
>
>> I can't find the Vertical from DX Engineering. If you can send me a link
>> it will be great.
>> One solution might be top hat vertical, similar with
>> http://dl2kq.de/ant/3-1.htm . Not sure how much power is lost in the
>> matching unit L1, C1.
>>
>> I would love a Waller Flag too. Imposible to buy one from here (too
>> expensive) but I might wanna try build one. Preamp will be the biggest
>> problem.
>>
>> Petronel
>> YO8SEP / YP8W
>>
>> On Mon, Dec 19, 2016 at 9:30 PM, W0MU Mike Fatchett <w0mu@w0mu.com
>> <mailto:w0mu@w0mu.com>> wrote:
>>
>> Check out DX Engineering. They sell a vertical that uses 3 top
>> hat wires. Sloping back down is ok. For 80/160 you need to stop
>> the 80m energy with a coil/trap My 80 uses a very fast taper and
>> the top is only 3/8 inch or less so It cannot support a coil or t
>> wires. I probably should have planned that out better. I was
>> also going to try to phase two 80 elements over time but that will
>> not happen any time soon.
>>
>> With all the metal in the yard the AY loop may not work very
>> well. Waller Flag on the roof maybe. I would love one.
>>
>> W0MU
>>
>>
>> On 12/19/2016 12:24 PM, Petronel Postolache wrote:
>>
>>> I can try to put a 21-22m (68-70 foot) telescopic aluminium pole,
>>> made from pipes 2" to 1" diameter.
>>> It will be a bit too long for 1/4 on 80m. I can put a T top hat
>>> or run an InvL, but probably need to slope it from 70 foot to
>>> about 40 foot. What will be better ? and will I be able to
>>> match/use the antenna on 80m also ?
>>>
>>> About K9AY, I understood that the loop is influenced by close
>>> metal objects, and the property is full of wire fences, vineyard
>>> rows and other "metal" structures. That's why i was thinking
>>> about using some flag/loop at 10 feet or more above ground.
>>>
>>> 73, Petronel
>>> YO8SEP
>>>
>>> 160 and 80 will be difficult. Can you get another vertical up
>>> about 60 feet? You can top load that with a trap for 80 and have
>>> "t" wires at the top that also act as guy wires. You can also
>>> bottom load for 160 and maybe that will be good enough for you.
>>> Radials whatever you can do will help.An Inverted L with about
>>> 50ft of vertical will work ok....If you can keep the horizontal
>>> end up in the air around the same height or more. It doesn't
>>> sound like you have any tall trees to work with.For receiving I
>>> have been very impressed with a K9AP loop. 25 ft up and about 15
>>> feet out at the corners. It does not take up much space and you
>>> can reverse the direction easily with a relay. A flag or pennant
>>> will work too. You can never have enough rcv or xmit antenna! HI!
>>> Welcome to the club!
>>>
>>> W0MU
>>>
>>>
>>
>>
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