----- Original Message -----
From: "Joe Subich, W4TV" <lists@subich.com>
To: <topband@contesting.com>
Sent: Wednesday, November 30, 2011 12:12 AM
Subject: Re: Topband: Inverted L
>
> > What is more, it has the same low loss and similar power handling
> > capabilities as RG-213/U. http://vk1od.net/transmissionline/RG6/
>
> While that may be true for loss at the lower HF range, it is not the
> case in the upper HF/Low VHF and UHF range. RG-6 will show from 1 to
> 5 dB more loss depending on frequency. In addition, RG-6 will not
> handle the same power levels as good quality RG-213 at any frequency.
>
> 73,
>
> ... Joe, W4TV
Since this is the Topband reflector and a 160M inverted L is the subject
then RG-6 is fine. Ive been using about 100' of it for about 13 years to
feed an 80M sloper and there hasnt been any problem at 1200W SSB/CW and some
1200W PEP on AM the past few years even into moderate VSWR.
For the antenna under discussion a 10 to 13A open frame relay can be used to
switch a coil in and out by running the 12 or 24VDC control voltage thru the
coax. There are examples in handbooks, antenna manuals or see the Ameritron
RCS-4 schematic for what is needed.
You could even get creative and select several band segments, all having low
VSWR.
Carl
KM1H
>
>
> On 11/29/2011 11:48 PM, Mike Waters wrote:
>> On Tue, Nov 29, 2011 at 9:51 PM, Peter Voelpel<df3kv@t-online.de> wrote:
>>
>>> Be careful with cheap tv cable. Some are just steel wire with a very
>>> thin
>>> copper layer ... on 160m you might run into too high losses.
>>>
>>
>> Very true. But the 1000' rolls of Commscope RG-6 I bought cheaply off of
>> eBay had a sufficiently thick coating of copper.
>>
>> CATV-type Commscope brand quad aluminum shield RG-6 is all I use here to
>> feed my antennas. The copper coating on the steel-cored center conductor
>> is
>> thick enough to use even below 160 meters. At 1 MHz, it has just .25 to
>> .38
>> dB/100 ft loss.
>>
>> Here's the full specs for two types:
>> http://awapps.commscope.com/catalog/uniprise/product_details.aspx?id=25253
>> http://awapps.commscope.com/catalog/uniprise/product_details.aspx?id=34310
>>
>> What is more, it has the same low loss and similar power handling
>> capabilities as RG-213/U. http://vk1od.net/transmissionline/RG6/
>>
>> Why spend big bucks on name-brand copper coax?
>>
>> 73, Mike
>> www.w0btu.com
>> _______________________________________________
>> UR RST IS ... ... ..9 QSB QSB - hw? BK
>>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
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>
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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