The flag, EWW, K9AY and others loaded loop antenna are indeed two
non-resonant phased vertical phased 180 degree resulting in a cardioid
pattern that provide directivity and a good F/B. When you have another
resonant element nearby the interaction changes the pattern, depending on
the new resonant element acting as a director or a reflector the new pattern
can be very distorted, and it could be any shape. Any loaded loop RX antenna
near a resonant antenna has useless pattern and most of the time the signal
to noise ratio is the same on the flag or on the resonant antenna.
Detuning fiscally the resonant antenna is a must to improve signal to noise
ratio. No free beef here.
Another factor is the feed line of the flag, Coax does not work well because
the common mode current outside the braid works like a vertical if no choked
properly, twisted pair unshielded is the only way to avoid use of chokes.
Horizontal flag does help but needs to be high above ground.
Regards
JC
N4IS
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Guido
Tedeschi
Sent: Thursday, March 19, 2015 11:37 AM
To: topband@contesting.com
Subject: Re: Topband: 9Q0HQ
John,
the Diamond they used is quite similar to the Pemnant...
73 de Guido, ik2bcp
Il giorno 19/mar/2015, alle ore 15:39, "john@kk9a.com" <john@kk9a.com> ha
scritto:
> I am not sure what supplies that you have available in the Republic of
> Congo. A Pennant should fit in your operating area. It is pretty easy
> to build and it is not ground dependent.
>
> John KK9A
>
>
> To: topband@contesting.com
> Subject: Topband: 9Q0HQ
> From: "alfeohjt@tin.it" <alfeohjt@tin.it>
> Reply-to: "alfeohjt@tin.it" <alfeohjt@tin.it>
>
>
> Dear friends, we are doing our best effort on the low bands. Being at
> the end of the rain season, there is a storm almost every day in the
> afternoon.The soil here is very dark and moist, often we need to tune
> the high band antennas as the resonance shifts according to water
> content.On low bands the noise from static is high, 7 - 9 on 80 and
> 160. It is a little better when we are close to the sunrise.On top
> band we use a inverted L and on 80m a vertical with a parasite
> reflector.We have the feeling that ous signal is strong enough but the
> major problem is our capability to cautch the signals out of the
> noise. We used a DHDL for few days, no big help. Yesterday we change
> with a Diamond, no better result. We still use the verticals on
> receiving as it grants the better result in spite of the noise.I am
> afraid that a beverage would not help us due to the soil propriety.
> Also, there is no enough room to lay a 200m beverage.We are rather
> limitaded in resources (wires, cables) as it is no easy and fast to
> find the stuff locally.I kindly ask for your suggestion to improve our
> receiving capability.
> Best 73
> (sorry for my bad English!)
> Alfeo I1HJT 9Q0HQ crew
>
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