[UK-CONTEST] OT: Aerial installation advice

[Callum MØMCX]

In my opinion, ECO 15 is fantastic, almost indestructable and sports a  
number of other key characteristics that would appeal to the very keen  
amateur. I bought a drum a year or so ago along with a few custom  
connectors. Of interest, the Pl259 connectors use exactly same fitting  
technology as N Type which means you can change from 259 to N in  
moments. Really fabulous and well worth the single cost effort.

Callum McCormick
Via iPhone
07976 631881
http://www.m0mcx.co.uk/
http://www.barclayanderson.com/

On 14 Mar 2010, at 15:06, David G3YYD <g3yyd at btinternet.com> wrote:

> Keith
>
> I suggest you look at the difference in loss between Ecoflex 15 and
> Westlake 103. On a 20m run for 2m the loss difference is very small  
> but
> Ecoflex 15 costs a lot more especially if you use the bespoke
> connectors. You can use ordinary RG213 connectors with W103, but  
> need to
> file down the inner conductor to fit the plug used. Takes a few  
> minutes.
> By the way fill the mating part of the connector/socket and the  
> threads
> with Petroleum Jelly ( XYL's Vaseline) to assist in moisture  
> rejection.
> I also use a sacrificial small length of RG213 with in line connectors
> to the W103. The RG213 also takes the rotation motion as the W103   
> has a
> copper tape covered by a copper braid and although the braid will help
> with cracks in the tape, I prefer to avoid the potential problem. If  
> it
> leaks at the antenna end or I need to unwrap the antenna connector I
> only need to cut back a bit of the RG213 and put the connector back on
> rather than loose the whole W103 length. Ecoflex is better if water  
> gets
> into a connector as it is a foam dielectric while W103 has tubes of  
> air
> running down its length so it fills with water. So ensure well sealed
> connectors.
>
> Incidentally it is not the dielectric that reduces the loss per se but
> the larger diameter inner conductor that reduces the loss that is
> enabled by the lower capacitance of the air filled dielectrics over
> solid. QED fatter cables with the same dielectric have lower loss
> because the inner conductor is larger, but copper costs. Very large
> diameter coax uses a tube for the  inner conductor to save cost and  
> weight.
>
> Do you really need a mast head pre-amp? It will reduce the dynamic  
> range
> of the RX and if it is say a FT897 or a TS2000 then you are already  
> in a
> poor dynamic range position without the pre-amp. On the other hand  
> if it
> is an excellent transverter into a K3 or similar you should not need  
> the
> pre-amp either as the transverter noise will be well below band noise
> even with 30m of W103. Also it is something else to go wrong and is
> possibly a right pain to fix when it goes wrong. 70cm and above is
> different with band noise very much lower than 2m plus increased coax
> loss. On 70cm if you have a Tetra mast near by then excellent bandpass
> filtering will be required to stop overload of the RX system.
>
> 73 David G3YYD
>
> On 14/03/2010 11:12, Keith Maton wrote:
>> There's a lot of knowledge on here so I hope you'll excuse me this  
>> slightly OT post although it does have a contesting connection :)
>>
>> We did some aerial work at the club contest station a couple of  
>> weeks ago and it's made me realise that I need to improve my home  
>> station.  I have a 9 element Vargarda fed with some "RG-213".  I'm  
>> going to upgrade this to EcoFlex 15, replace the old rotator and  
>> fit a masthead pre-amp.
>>
>> Is it worth me taking the effort to replace the entire coax run  
>> right to the aerial or simply trim back the current stuff to the  
>> stub mast where the pre-amp will be located and run the new cable  
>> from there down to the shack?  That will leave me with 2-3 metres  
>> of the existing cable.
>>
>> I know it will make a slight difference replacing that tail but  
>> will it be too negligible to even notice?
>>
>> 73
>> Keith, G6NHU
>> Martello Tower Group, G0PKT
>>
>>
>>
>>
>>
>>
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