The difference in the vertical radiation angles between
the 5/16 and Inv L is small because with both antennas
most of the radiation comes from the vertical section.
Radiationwise, these two atennas are essentiall the same.
If you are looking for a high angle antenna for short
distance (100 - 300 km) communications, you should look at
an NVIS antenna; i.e. a low dipole. Fortunately, on 160,
almost any dipole mounted lower than 30 meters (100 feet)
will have a lot of high angle radiation.
GL es 73,
George, AA7JV
On Tue, 27 Jul 2010 16:47:21 +0200
tzikas tzik <tzitzikas77@gmail.com> wrote:
> hi. thank you for your answer. What elevation angle has
>the 5/16 inverted L
> and what elevation angle has the 1/4? Must i will reduce
>the total lenght
> from 5/16 to 1/4 for higher local signal or the
>difference is just a little
> bit, and to keep the 5/16 inverted L? If i keep the 5/16
>inverted L what i
> must change to increase the signal? Now i am using 6
>radials (4 1/8 and 2
> 1/4).which are constructed with insulated wire and are
>placed on the ground.
>
> Moreover, what do you think about T antenna?
> My transmitting area is like this draw:
> http://tzitzikas.webs.com/transmitter_area.JPG
> In the front of transmitter's house, there is a third
>building with 6
> floors. So, the vertical portion of my antenna is found
>between 3 buildings.
> I think it is a problem for the signal transmittion.
>What do you propose?
> Now, for match system with my 50ohm transmitter, i am
>using a variable
> series capacitor (0-500pf).
>
> On Mon, Jul 26, 2010 at 11:11 PM, Guy Olinger K2AV
><olinger@bellsouth.net>wrote:
>
>> There is very little difference in the pattern of a 5/16
>>inverted L
>> and 1/4 inverted L that has the bend to horizontal at
>>the same height,
>> assuming a bend even roughly half way. The lower the
>>bend the higher
>> the maximum lobe takeoff, but it's a mild change. 29
>>degrees vs. 49
>> degrees is not correct, all other issues held constant.
>>
>> 73, Guy.
>>
>> On Sun, Jul 25, 2010 at 11:49 AM, tzikas tzik
>><tzitzikas77@gmail.com>
>> wrote:
>> > Hi. I have a transmitter for 160m band about 200-300w
>>r.f output power.
>> Now
>> > i am using an (5/16)X(wave length) inverted L. I am
>>looking for an
>> antenna
>> > which will provide strong local signal. I have read
>>that the 5/16
>> inverted L
>> > has about 49o elevation angle and the 1/4 inverted L
>>has about 26o
>> elevation
>> > angle. So, i think that 1/4 inverted L, provide more
>>strong local signal.
>> > what do you think about this?
>> > Now with 5/16 inverted L it very easy to match it with
>>the 50ohm
>> transmitter
>> > by using only a series variable capacitor. I am afraid
>>that with 1/4
>> > inverted L it will be more difficult to match it with
>>the transmitter.
>> What
>> > i need (coils and capacitors) to match it? thank you
>>very much
>> > _______________________________________________
>> > UR RST IS ... ... ..9 QSB QSB - hw? BK
>> >
>>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
|
