Topband: Supporting Ladder line

donovanf at donovanf at
Wed Jan 10 16:31:03 EST 2018

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 

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. 


----- Original Message -----

From: "Ryszard Tymkiewicz" <rtym at> 
To: topband at, donovanf at 
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 

> 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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