Topband: Supporting Ladder line

[donovanf at starpower.net]

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 at ippt.pan.pl> 
To: topband at contesting.com, donovanf at 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 
> 
>