[amsat-bb] Exciting Coax

[Miles (WF1F)]

I just use "LMR" Super-flex cable for everything.

For short runs in  a car 15-20 feet, I use LMR-240 Super-flex.
Its 0.240 in diameter and has measurably less loss at 20 feet (400 mc 
and higher) than typical 0.195" coax.


In the Shack:
For HF, I use LMR-500 flexible with runs up to 200 feet.
It can handle full legal limit without melting.

For VHF and UHF runs of 100' or less, I use LMR-600 Super-flex.
It is flexible enough to go around a rotor.
Normal RG-8 coax is 0.405 inches in diameter.
LMR 600 is 0.600 inches in diameter.
The Greater the diameter, the lower the loss.
Its not the Name stamped on the cable that's important, it is the 
diameter of the cable.
All 405 cable will have similar losses. It does not matter if its a 1$ 
per foot or 20$ per foot, 405 cable will have similar losses.
If you need less loss, go with thicker cable or hardline.

The loss with 600 is so much lower than 405 cable, i just do not count 
DB 's any more.

Also, avoid splices, etc.

WF1F



On 1/22/2018 9:03 PM, anderson58625 wrote:
> Reading the subject line, I may have somehow mixed sarcasm with a potential
> pun (eye of the beholder!) <grin>.  Sorry for that.
>
>   
>
> I seek to avoid investing in a set of cable producing hardware (or assembled
> cables) which I will regret later.  I am hoping to get some guidance
> regarding coax for:
>
> 1)      IF patch between equipment (male-male BNC's)
>
> 2)      2m feedline (N-connectors) (<50')
>
> 3)      70cm feedline (N-connectors) (<50')
>
> 4)       A later potential for feedline carrying microwave frequencies
> (>1GHz)
>
>   
>
> The frequency & loss-rate charts for coax are informative, but I'm not sure
> I'm seeing which connectors will fit what cable brand/types.  With the
> variables of loss, dimensions, flexibility, and potential proprietary
> crimping systems, etc., I don't have enough experience or information to
> confidently make an online materials order.  Things were much easier down
> here with just HF frequencies, RG-213, and good quality (weather protected)
> PL-259's! <grin>
>
>   
>
> For IF patch cables, I figure these are conveying HF so the cable type/loss
> at 1-3' isn't very important.  But, there is also shielding:  A
> consideration?
>
> .       Any thoughts on IF cables?
>
> .       Plus, I've never attached a BNC to a cable.  Easy?  Avoid it?
>
> .       Plan on a new crimper/die?
>
> .       Or, if premade would be cheaper (just a few IF patch cables), any
> quality sources to recommend?
>
>   
>
> For the 2m & 70cm feedlines, I know flexibility may be a consideration on
> rotating/elevating masts.  Of course, I'm sure a rigid feedline may be
> superior elsewhere, but I am not at that point yet.  Still, advice on that
> subject is gratefully appreciated.  I need to provide good questions to hope
> for good answers, so what feedline you would recommend for:
>
> .       Reasonable flexibility/portability
>
> .       2m-23cm
>
> .       Modest power
>
> .       <50'
>
> .       For use with n-connectors
>
>   
>
> The benefit of you knowledge and experience is much appreciated.
>
>   
>
> 73
>
>   
>
> Mark W9AT
>
>   
>
>   
>
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