[amsat-bb] Re: Feed Line Loss @ Freq vs. Price

[MM]

Over the years, I have tried many different flavors of
cable, trying to reduce losses, even using TV hard
line with transformers, etc.
I finally settled on "Custom Cut" with factory
installed connectors, using the LMR-600 "Super Flex"
cables for all of my VHF/UHF applications.

One of the best features besides less loss, is the
fact that you can use the Super Flex version to go
around a Rotor.  It also means fewer connectors, since
you do not need to change from a hard line to a
flexible coax to reach the rotor.

For the 2 meters and the 440 band, I do not even
bother calculating coax loss for those bands in my ERP
calculations any more since the loss is so much lower
that RG-8.
When I run ATV modes on 440, I have melted a few RG-58
coax cables in the past.  Now all of my patch cables
are at least LMR-500, and the rest LMR-600SF.  

No worries.
No worries about coax loss
No worries about shield leakage’s
No worries about cable voltage and power limitations

If you’re a beginner, use what ever you can afford. 
Later, when you want to focus on a specific aspect of
Ham, then start fine-tuning your station.  If you need
lower losses and higher ERP, it’s still cheaper to
Size-Up your coax, than it is buying a Bigger amp.

WF1F



--- Steve Raas <sraas at optonline.net> wrote:

> To any one interested , I just did some comparisons
> to 3 different cables @
> 146, 435 & 1268.100 Mhz for any one that might want
> the info.
> 
>  
> 
> Andrews LDF4-50A ½” Hardline Loss
> 
>  
> 
> @ 1268.100 Mhz 40’ = 1.01 DB Loss
> 
> @ 435.100   Mhz 40’ = 0.568 DB Loss
> 
> @ 146.000   Mhz 40’ = 0.3212 DB Loss
> 
>  
> 
>  
> 
> LMR-600/CNT-600
> 
>  
> 
> @ 1268.100 Mhz 40’ = 1.16 DB Loss
> 
> @  435.000  Mhz 40’ = 0.68 DB Loss
> 
> @  146.000  Mhz 40’ = 0.40 DB Loss
> 
>  
> 
>  
> 
> LMR-400/CNT-400
> 
>  
> 
> @ 1268.000 Mhz 40’ = 1.8 Db Loss
> 
> @   435.100 Mhz 40’ = 1.08 Db Loss
> 
> @   146.000 Mhz 40’ = 0.60 Db Loss
> 
>  
> 
>  
> 
> Now for the interesting info
..
> 
>  
> 
> COST
> 
>  
> 
> 40’ Andrews LDF4-50A (Hardline)Terminated with dual
> ‘N’ Male connectors -
> $98.34 +  Shipping
> 
>  
> 
> 40’ LMR-600/CNT-600  Terminated with the same ‘N’
> male – $111.30 +  Shipping
> 
>  
> 
> 40’ LMR-400/CNT-600 Terminated with the same ‘N’
> male - $ 49.78 +  Shipping
> 
>  
> 
> Note the Shipping charges to my location were the
> same regardless of cable
> type @ 13.82 pr/run
> 
>  
> 
>  
> 
>  
> 
> I posted this info for an interesting comparison..
> the best cable (of the
> three) is cheaper than the 2nd lowest loss cable!!!
> The reason I took the
> freq so low was for those whom may want to run a tx
> converter on 146 or 435
> for a 1268 uplink.
> 
>  
> 
> For me, none of theses cables @ 40’ provide low
> enough loss to run 1268Mhz
> from in the shack.. trying to keep the loss below
> 1.0 db. Just at a glance
> you could gain .0788 DB running a 146 I.F. to a TX
> converter or  .112 db
> running a 435 Mhz I.F. to a tx converter with the
> Hardline. A total loss of
> between 1.01 dB – 1.18 dB by running 1268Mhz In
> shack, depending on the
> cable. However a .32 db feed loss on 1268 (running a
> rx/tx converter on
> 146Mhz) is OUTSTANDING if you run the ½” hardline.
> 
>  
> 
> Also keep in mind that as long as your I.F. dosen’t
> change, neither will
> your loss! 
> 
>  
> 
> The cost difference is $ 12.96 . ( how ironic )
> Between the Hardline &
> LMR/CNT-600
> 
>  
> 
> A lot of people use the LMR-400/CNT-400  which is
> less expensive yes, but
> with ½ dB more loss on 146 ,  1 dB more loss on 432
> , & a whopping 2 dB more
> loss on 1268 vs. the LMR-600/CNT-600 cable, slightly
> more vs. the Hardline
> it dosent seem logical to run it for an in shack,
> microwave application. (
> see below actuall watt loss )
> 
>  
> 
>  
> 
> Now that’s the raw dB #’s
 lets break this down to
> good ole fashon WATTS!
> 
> Now, for uplink  @ 1268.100Mhz loosing 5.244 watts
> dosent seem like much,
> however.. try looking for an amp for $ 48.56 Cents,
> the difference ‘could’
> be a SSB uplink quality ( if your running 1268Mhz in
> shack )
> 
>  
> 
> 40’ of Andrews LDF4-50A with 15 watts in @ 1268.100
> =  11.88 Watts at the
> other end  / 3.12 Watts lost
> 
>  
> 
> 40’ of LMR-600/CNT-600   with 15 watts in @ 1268.100
> =  11.355 Watts at the
> other end / 3.645 Watts lost
> 
>  
> 
> 40 of LMR-400/CNT-400    with 15 watts in @ 1268.100
> =  9.756 Watts at the
> other end / 5.244 Watts lost or OVER 1/3rd of your
> R.F.
> 
>  
> 
>  
> 
> 40’ of Andrews LDF4-50A with 15 watts in @ 435 = 
> 13.156 Watts at the other
> end  / 1.84 Watts lost
> 
>  
> 
> 40’ of LMR-600/CNT-600   with 15 watts in @ 435 = 
> 12.867 Watts at the other
> end / 2.133 Watts lost
> 
>  
> 
> 40 of LMR-400/CNT-400    with 15 watts in @ 435 = 
> 11.762 Watts at the other
> end / 3.238 Watts lost 
> 
>  
> 
>  
> 
>  
> 
> 40’ of Andrews LDF4-50A with 15 watts in @ 146 = 
> 13.928 Watts at the other
> end  / 1.072 Watts lost
> 
>  
> 
> 40’ of LMR-600/CNT-600   with 15 watts in @ 146 = 
> 13.741 Watts at the other
> end / 1.259 Watts lost
> 
>  
> 
=== message truncated ===


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