I measured the difference in loss (dB per 100 ft) between solid copper
(SC) center conductor RG-6 vs. copper clad steel (CCS) Quad-Core RG-6 coaxial
cable. The difference is insignificant on 160 meters until
cable length exceeds 350 feet. You can see the affect of the steel
core and its thin copper plating at 7 MHz and below in this table The cables
were manufactured by two different companies, but the
relative loss measurements should be valid.
A 1000 foot run of RG-6 with the more common CCS center conductor
has 6 dB loss on 160 meters vs. 3 dB loss for the less common RG-6
with an SC center conductor. For most of us, the additional 3 dB
loss in 1000 feet of CCS RG-6 will be insignificant. Solid Copper Cable
length in
Freq Copper Clad feet for a 1 dB
MHz Loss Loss loss difference
1.8 0.3 0.6 350
3.5 0.4 0.6 500
7.0 0.6 0.8 500
10 0.7 0.85 650
14 0.75 0.9 650
21 0.9 1.0 1000
28 1.0 1.1 1000
73
Frank
W3LPL
----- Original Message -----
From: "Grant Saviers" <grants2@pacbell.net>
To: "Ryszard Tymkiewicz" <rtym@ippt.pan.pl>, topband@contesting.com
Sent: Wednesday, January 10, 2018 4:23:34 PM
Subject: Re: Topband: Supporting Ladder line
The shield is always the antenna element. The coax provides the signal
return path when the direction is set with the far end as the feed point
of the antenna. Since you likely will have a preamp for the large
negative gain of a RBOG, a few db more from the coax won't matter except
for a few db gain change when switching directions.
Here is some RG174 measured loss data (1db/100')
http://www.dxing.info/equipment/rg_174_coax_bryant.dx
Much RG6 is Copper clad steel (CCS) so how much loss it has with copper
that might be less than 1.8MHz skin depth is an interesting question.
Any data out there? Solid Cu RG6 would be a safer bet. There are many
RG6 variations and ones that are flooded might the best RBOG choice.
Grant KZ1W
On 1/10/2018 3:50 AM, Ryszard Tymkiewicz wrote:
>
> 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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