Hi Rys,
Simply change the turns ratios of the reflection transformer and
matching transformer to correspond to the approximate termination
impedance and feed impedance. 4:1 transformers work well for a
reversible BOG and a 9:1 transformers works well for an elevated
Beverage.
For a reversible Beverage, its very important that the unused coax
be terminated in approximately a 75 ohm resistor. If you use a single
coax feed, the switch box at the feedpoint must use a resistor to
terminate the unused feed transformer. Its possible to optimize the
termination resistor value to improve the front-to-back ratio, but the
improvement is small especially in the case of a BOG.
RG-174 has approximately 1 dB loss per 100 feet on 160 meters which
is quite acceptable for a 220 foot BOG. You should use 6:1 transformers.
73
Frank
W3LPL
----- Original Message -----
From: "Ryszard Tymkiewicz" <rtym@ippt.pan.pl>
To: topband@contesting.com, donovanf@starpower.net
Sent: Wednesday, January 10, 2018 11:50:20 AM
Subject: Re: Re: Topband: Supporting Ladder line
Hi Frank..I understand in the case of BOG we should use both
transformers T1 and T3 with
4:1 impedance ratio... ?
I wonder if it is possible to use RG174 which unfortunately has quite
big attenuation even on 160m?
73 Rys
SP5EWY
> A reversible Beverage or BOG can be constructed out of a single run
> of RG-6, there's no need to form an open wire line out of two runs
> of RG-6,
>
>
> See ON4UN's Low Band DXing, Volume 5, page 7-88 and fig. 7-118
>
>
> 73
> Frank
> W3LPL
>
>
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