: Tue, 9 Oct 2018 22:57:54 +1300
From: Greg - ZL3IX
To: topband@contesting.com
Subject: Re: Topband: Beverage F/B using oscillator
Message-ID:
Content-Type: text/plain; charset=utf-8; format=flowed
Hi Ashraf,
The rule of thumb I use is 2D^2 /lambda, where D is the largest
dimension of the antenna
decided to get out of my wall and try a Beverage on ground.
www.iv3prk.it
Enviado desde Outlook<http://aka.ms/weboutlook>
De: Topband en nombre de Ashraf Chaabane
Enviado: martes, 9 de octubre de 2018 10:07
Para: topband@contesting.com
Asunto: Topband: Be
As a point of reference - I have 4 terminated beverages from 200 - 350m long
(also 2 unterminated bererages). I use them on 40 - 160M. I typically see
10 - 25dB of front to back on these beverages. On 40M and 80M, while
contesting, if I am not careful to first listen on the transmit antenna
tenna need to be lifted from local groundlevel by say 2-
10m?
Or can this test be done just as reliable on groundlevel?
73
Mark, PA5MW
-Original Message-
From: Topband On Behalf Of F Z_Bruce
Sent: Tuesday, October 09, 2018 3:01 PM
To: ash.kf5...@gmail.com; Topband
Subject: Topband:
Of F Z_Bruce
Sent: Tuesday, October 09, 2018 3:01 PM
To: ash.kf5...@gmail.com; Topband
Subject: Topband: Beverage F/B using oscillator
Good information.
Finding the best BOG F/B.
I use an model MFJ-5014 white noise generator off the 'back' of the BOG
antenna. Then tune the receiver to find
Good information.
Finding the best BOG F/B.
I use an model MFJ-5014 white noise generator off the 'back' of the BOG
antenna. Then tune the receiver to find the 'minimum noise' signal frequency.
Adjust the BOG antenna length to bring it into 160 meters..
Care must be taken not to create
Hi Ashraf,
The rule of thumb I use is 2D^2 /lambda, where D is the largest
dimension of the antenna. So if your Bev is 320m long you need to be
over a km away. If only 160m long you need to be 300 m away.
73, and I hope to work you one of these days at my SR.
Greg, ZL3IX
On 2018-10-09
Hi All,
I used a 1.843 oscillator to check NA beverage F/B. The mesurements were
taken 160m away from each end of the antenna. Noise level was constant. I
had 4 dB difference between front and back signals.
Is that what I should expect? Is 1 wavelength distance enough to do this
experience?
This
