K1TTT Technical Reference


Home | Weather | Webcams | Tech Reference | BIG!



Subj:   CONTESTER's coax cable attenuation charts
Date:   95-11-12 11:49:54 EST
From:   donovanf@sgate.com (Frank Donovan)
Sender: owner-cq-contest@tgv.com
Reply-to:       donovanf@sgate.com (Frank Donovan)
To:     CQ-CONTEST@tgv.com
 
I developed and have been using the following charts for some years.  
The CONTESTERs I've given copies to have found them most useful as 
well.  The first table is the common attenuation per 100 ft chart, but 
with specific values for each ham band.
 
The second table is in cable feet per dB, which can be very handy for 
tradeoff analysis (e.g. do I really need to use Andrew LDF5 for my 1000 foot 
run to my Beverages or is RG-8X good enuf?).
 
The third table shows the results of just such a tradeoff analysis, each 
entry in the table represents the cable length in feet before Andrew LDF5 
offers a 1 dB advantage vs the various cables listed
 
The last table is identical to the third table, except these trades are 
for Andrew LDF4.
 
Enjoy...
73!
Frank
W3LPL
donovanf@sgate.com    <----reply address
                       
                            CABLE ATTENUATION  (dB per 100 ft)
           
             1.8   3.5   7.0  14.0  21.0  28.0  50.0   144   440  1296 
 
LDF7-50A     .03   .04   .06   .08   .10   .12   .16   .27   0.5   0.9
FHJ-7        .03   .05   .07   .10   .12   .15   .20   .37   0.8   1.7
LDF5-50A     .04   .06   .09   .14   .17   .19   .26   .45   0.8   1.5
FXA78-50J    .06   .08   .13   .17   .23   .27   .39   .77   1.4   2.8
3/4" CATV    .06   .08   .13   .17   .23   .26   .38   .62   1.7   3.0
LDF4-50A     .09   .13   .17   .25   .31   .36   .48   .84   1.4   2.5
RG-17        .10   .13   .18   .27   .34   .40   .50   1.3   2.5   5.0
SLA12-50J    .11   .15   .20   .28   .35   .42   .56   1.0   1.9   3.0
FXA12-50J    .12   .16   .22   .33   .40   .47   .65   1.2   2.1   4.0
FXA38-50J    .16   .23   .31   .45   .53   .64   .85   1.5   2.7   4.9
9913         .16   .23   .31   .45   .53   .64   .92   1.6   2.7   5.0
RG-213       .25   .37   .55   .75  1.0    1.2  1.6    2.8   5.1  10.0
RG-8X        .49   .68  1.0   1.4   1.7    1.9  2.5    4.5   8.4
 
 
                            CABLE ATTENUATION (Ft per dB)
 
             1.8   3.5   7.0  14.0  21.0  28.0  50.0   144   440  1296
 
LDF7-50A    3333  2500  1666  1250  1000   833   625   370   200   110
FHJ-7       2775  2080  1390  1040   833   667   520   310   165    92
LDF5-50A    2500  1666  1111   714   588   526   385   222   125    67
FXA78-50J   1666  1250   769   588   435   370   256   130    71    36
3/4" CATV   1666  1250   769   588   435   385   275   161    59    33
LDF4-50A    1111   769   588   400   323   266   208   119    71    40
RG-17       1000   769   556   370   294   250   200    77    40    20
SLA12-50J    909   667   500   355   285   235   175   100    53    34
FXA12-50J    834   625   455   300   250   210   150    83    48    25
FXA38-50J    625   435   320   220   190   155   115    67    37    20
9913         625   435   320   220   190   155   110    62    37    20
RG-213       400   270   180   130   100    83    62    36    20    10
RG-8X        204   147   100    71    59    53    40    22    12
 
 
             FEET REQUIRED FOR 1 DB ADVANTAGE LDF5-50A VS:
 
             1.8   3.5   7.0  14.0  21.0  28.0  50.0   144   440  1296
 
LDF4-50A    2000  1430  1250  910    715   625   435   250   165   100
RG-17       1666  1430  1110  770    560   475   420   120    60    30
FXA12-50J   1250  1000   770  525    435   355   255   120    75    40
9913         835   590   455  320    280   220   150   85     53    29
 
            
             FEET REQUIRED FOR 1 DB ADVANTAGE LDF4-50A VS:
            
             1.8   3.5   7.0  14.0  21.0  28.0  50.0   144    440  1296
             
RG-17         -     -     -    -     -     -     -     220     90    40
FXA12-50J     -     -   2000  1250  1100  835    625   250    145    65  
9913        1430  1000   715   500   455  345    235   135     75    40
RG-213       910   600   285   200   150  120    85     45     20    12
 
 

 
 
Here another chart, which complements the first one in some ways:
 
-----------------------------
Technical data of coax cable:
-----------------------------
 
------------------------------------------------------------------------------
Attenuation dB / 100 m
-----------------------
 
Type      f/MHz: 10   30   50  100  145  200  400  435  500 1296 2320 3000 5000
-------------------------------------------------------------------------------
RG-11 AU        2,2  4,0       7,5      11,0           19,0           60,0
RG-55                              16,0           29,0      52,0 77,0 90,0 127
RG-58 CU        4,6  8,0 11,0 16,3 20,0 24,0 36,0 40,0 47,0 90,0 140  180  272
RG-142 AU       7,0  9,0      14,0 15,0 20,0 28,0 30,0 35,0 49,0 72,0 95,0 128
RG-174 U       12,0 17,0      29,0 34,0 45,0 55,0 60,0 70,0 110  175  220  325
RG-188 AU      12,0 17,0      28,0 32,0 40,0      58,0 68,0 113  165  268
RG-196 AU      22,0 27,0      43,0      62,0 95,0      102            300
RG-213 U        2,0  3,6  4,3  6,3  8,2  9,5 14,5 15,0 17,0 26,0      55,0 89,0
RG-213 US-100   1,8  2,45 3,2       5,9           10,1      21,1
RG-214 US       1,8  3,2  3,9  5,7  7,6  9,0 13,0 13,5 15,0 23,5      45,0
RG-223 U        4,0  7,0      13,0 18,5 20,0 30,0 34,0 38,0 60,0 85,0 100  151
RG-316 U       12,0 17,0      28,0 32,0 40,0      58,0 68,0 113  165  268
H100                 2,1  2,8       4,9            8,8      16,0 23,0
H155            3,1  3,4  6,5  9,4 11,2           19,8 21,9 34,9
H500            1,3       2,9  4,1            8,7           17,4 24,1
Aircom-plus     0,9            3,3  4,5       7,4  7,5      14,5 21,5 25,0 34,1
Aircell-7            3,7  4,8  6,9  7,9           14,1      26,1
CF1/4"Cu2Y           2,5            5,5            9,0      18,0
CF3/8"Cu2Y           1,6            3,8            6,5      13,0 16,0
CF1/2"Cu2Y           1,2            3,0            5,6      10,0
CF5/8"Cu2Y           1,0            2,5            4,0      7,2  10,0
TU-165                                  29,0 41,0                     120
TU-300                                  17,0 25,0                      75
TU-545                                   9,0 14,0                      45
4/S-60          2,0  4,0       7,0                     19,0
60-7-2          2,0            7,0      10,0           17,0
------------------------------------------------------------------------------
Maximum power in Watt at:
------------------------------
 
Type  f/MHz: 10   30   50  100  145  200  400  435  500 1296 2320 3000 5000
------------------------------------------------------------------------------
RG-11 AU                             420  300                       95
RG-55          power handling like RG-223 U
RG-58 CU         550            240  125  100   90        49   31   30   20
RG-142 AU       3200           1500            850       460  320       175
RG-174 U         200             95   57   42             30   18   13
RG-188 AU        550            380            260       130   90        75
RG-196 AU                             85   57                       18
RG-213 U        2000            800  420  300  290            100   95   65
RG-213 US-100   2000            800  440  420  400       220  140        70
RG-214 US       2000            800  440  420  400       220  140        70
RG-223 U         950            300            200       100   68        40
RG-316 U         550            380            260       130   90        75
H100            2100           1000            530       300
H155           power handling like RG-58 CU
H500           power handling like H100
Aircom-plus    power handling like H100
Aircell-7       2960      850                            190
CF1/4"Cu2Y      2700           1200            750       400
CF3/8"Cu2Y      4700           2800           1200       680  520
CF1/2"Cu2Y      6400           2800           1600       850
CF5/8"Cu2Y      9000           4000           2300      1350  950
TU-165                               170  110                       32
TU-300                               660  450                      150
TU-545                              1700 1200                      370
---------------------------------------------------------------------------
 
Further data:
-----------------
                                                                      resist.
             Z                             dimensions      bending-   DC/1000m
Type         Ohms  pF/m Vk   diel. screen. inn./diel./out. radius kg% inn./out.
---------------------------------------------------------------------------
RG-11 AU       75   67  0,66 PE      60dB  1,2  7,3  10,3   50mm  13,9  22  4,1
RG-55  (2%) 53,3 94  0,66 PE      100%  0,9  3,0   5,3   30mm   5,0
RG-58 CU       50  101  0,66 PE      60dB  0,9  2,95  5,0   25mm   4,0  39 13,5
RG-142 AU      50   95  0,7  PTFE    80dB  0,95 2,95  4,95
RG-174 U       50  101  0,66 PE      55dB  0,50       2,5
RG-188 AU      50   95  0,7  PTFE          0,51       2,7
RG-196 AU      50   95  0,7  PTFE          0,3        1,9
RG-213 U       50  101  0,66 PE      60dB  2,25 7,25 10,3  100mm  15,3   6  4,1
RG-213 US-100  50  101  0,66 PE      60dB  2,25 7,25 10,3   90mm  15,5   6  4,1
RG-214 US      50  101  0,66 PE      80dB  2,25 7,25 10,8                6
RG-223 U       50  101  0,66 PE      80dB  0,9  2,95  5,3
RG-316 U       50   95  0,7  PE            0,51       2,5              DC/100m
H100           50       0,84 PE/air  100%  2,5  6,9   9,8  150mm  11,0
H155           50  100  0,79 PE/cell 100%  2,5  3,9   5,4   35mm   3,9 1,5 1,7
H500           50   82  0,81 PE/cell 80db  2,5  7,0   9,8   75mm  10,7
Aircom-plus    50   84  0,84 PE/air  100%  2,7  7,2  10,3  100mm  15,0
Aircell-7      50   74  0,83 PE/cell 100%  1,85 5,0   7,3   25mm   7,2 ,86 ,85
CF1/4"         50            foam    100%             8,0
CF3/8"         50            air     100%            15,0
CF1/2"         50            foam    100%            15,9
CF5/8"         50            air     100%            23,0
TU-165         50   95  0,7  PTFE    100%  0,51       2,19
TU-300         50   95  0,7  PTFE    100%  0,93       3,58
TU-545         50   95  0,7  PTFE    100%  1,63       6,35
4/S-60         60   75  0,77 PE-cell 50dB  1,4  4,9   7,0   60mm  59    12 11
60-7-2         60   85  0,66 PE            1,5  6,6   8,8
---------------------------------------------------------------------------
 
Further information:
--------------------
 
Type            inner conductor         screen
---------------------------------------------------------------------------
RG-11 AU        7x0,4  Cu, extruded     Cu, annealed        75 Ohms !
RG-55           1x0,9  Cu, tin plated   Cu, tin plated      double screen
RG-58 CU       19x0,18 Cu, extruded     Cu, tin plated
RG-142 AU       1x0,99 st/Cu, silver p. Cu, silver plated   double screen
RG-174 U        7x0,16 steel/Cu, ann.   Cu, tin plated
RG-188 AU       7x0,17 st/Cu, silver p. Cu, silver plated
RG-196 AU       7x0,1  st/Cu, silver p. Cu, silver plated
RG-213 U        7x0,75 Cu, annealed     Cu-braid, annealed  MIL
RG-213 US-100   7x0,75 Cu, annealed     Cu-foilbraid    MIL-C-17
RG-214 US       7x0,75 Cu, silver p.    Cu, silver plated   double screen
RG-223 U        1x0,9  Cu, silver p.    Cu, silver plated   double screen
RG-316 U        7x0,17 st/Cu, silver p. Cu, silver plated
H100            1x2,5  Cu, plain-soft   Cu-foilbraid soft
H155           19x0,28 Cu, plain-soft   Al-foilbraid tinned
H500            1x2,5  Cu, plain-soft   Cu-foilbraid plain
Aircom-plus     1x2,7  Cu, plain-soft   Cu-foilbraid plain
Aircell-7      19x0,37 Cu, plain-soft   Cu-foilbraid plain
CF1/4"Cu2Y      1x                                           Cell-Flex
CF3/8"Cu2Y      1x                                           Cell-Flex
CF1/2"Cu2Y      1x                                           Cell-Flex
CF5/8"Cu2Y      1x                                           Cell-Flex
TU-165          1x0,51 Cu, silver p.    Cu-tubing, plain    semi-rigid
TU-300          1x0,93 Cu, silver p.    Cu-tubing, plain    semi-rigid
TU-545          1x1,63 Cu, silver p.    Cu-tubing, extruded semi-rigid
4/S-60          1x1,4  Cu, silver p.    Cu                  60 Ohms !
60-7-2          1x1,5  Cu, annealed     Cu, annealed         60 Ohms !
 
---------------------------------------------------------------------------
 compiled by Gerko PE1OYF @ PE1OYF
 corrected and completed by DJ5RH
 translated by DL5UH
 
 
 
 
 
 
 
 
 
 


 
 
 
 
 
 
 
 
 
 
Discussion of SWR loss:
 
 
Robert Hummel wrote:
> 
> >The mismatch of VF has no more effect than the SWR - it all comes out the
> >other end, even though some of it takes a lot of trips back and forth to
> >get there, losing only what is often called the "copper loss," but is
> >really the loss characteristic of the design of each individual cable.
> 
> Can't help but throw in my two cents here...
I'll see your two cents and up you a nickle.
 
> 
> With the utmost respect to Press (who knows his cable), the idea that "all
> the power goes to the antenna eventually" is one of the most persistent and
> pernicious myths in ham radio. In my mind, it's right up there with "RG-8
> is essentially lossless at HF."
 
RG-8 in the relatively short lengths used by most amateurs for decently
matched antennas is as lossless as anyone will ever need.
 
> 
> The idea that an SWR mismatch at an interface doesn't directly cause a loss
> in thru power is valid only in the very special case of steady-state power
> transmission. Amateur radio transmission, however, is not steady-state. It
> is more like impulse transmission, and that makes all the difference.
> 
> Consider a single sharp dit going into a mismatched junction. Part of your
> dit gets transmitted, part gets reflected. At some junction back toward the
> transmitter, lets assume that all the reflected power gets reflected back
> toward the antenna. At the junction, some more of that original dit power
> (now delayed by a coax round-trip) gets radiated. Was that your intent? Did
> you mean to transmit DIT Dit dit .... (echoes continue)?
 
Consider 300 baud rtty or equivalent cw speed if you can copy that
fast...
at worst case you get 300 pulses per second, make it worse by making it
50% duty cycle so each pulse is 1/600th of a second... and since i hate
odd fractions make it even worse at 1msec pulses since that is a nice
round number.  now pick a frequency... worst case would be 1.8MHz, but since
i like round numbers lets figure it at 1MHz.   now, a one 1msec pulse sent
with a carrier frequency of 1MHz contains 1000 cycles of the carrier.  if you
have a mismatch where 50% of your power is being reflected you will be
within .1% of steady state in 10 cycles leaving 990 steady state ones to
go.  double the frequency to get into the 160m band and you have 1990 nearly
steady state cycles out of 2000.  take that to 10m and it really is meaningless.
 
> 
> Now, if you really transmitted a series of dits and dahs or a complex audio
> waveform, all reflected/radiated signals that are not time coincident with
> the original signal contribute to your radiated power, but only as noise.
> The effect is that you are transmitting a noisy signal that's weaker than
> you think.
> 
 
now, i have shown that a series of normal dits and amateur legal hf data
rates can't do this... but this is an important consideration as has been
noted in other applications.  consider the data rates seen in video or
high speed digital links.  in these the 'echos' of the dits show up as
ghosts on the picture or distorted data bits on the digital stream.  
 
> Consider the analogy of a 4" diameter pipe that goes through an abrupt
> transition to a 2" pipe. At some certain steady, constant pressure on the
> 4" inlet, a measurable amount of water will flow into the pipe and --
> behold! -- the same amount comes out at the 2" end. This is the steady
> state situation.
> 
> But, now consider that you turn on the water briefly, enough to fill the
> entire 4" diameter of the pipe for let's say 1 foot in length. This packet
> of water (neglecting friction the way we neglected loss in the coax
> example) will fly down the 4" pipe like a bullet in a gun barrel. But when
> it hits the 2" abrupt transition, part of the water will be reflected back.
> At the 2" outlet, you will see far less water come out than you put in.
 
to go back to my discussion above... to fill a piece of coax with a wave
for a 1 foot length....  oh the bad numbers... lets make it a 1 meter length
since thats a bit easier to compute.  pick a coax with a velocity factor of
.66 (standard rg-8 solid poly), this gives a speed of light in the coax of
.66*300x10^6 m/s or about 200x10^6 m/s.  so a pulse short enough to fill 
only 1m of coax would be 1/200x10^6 or about .005 micro seconds long, or
200,000 times shorter than the 1msec pulse considered above.
 
another way to look at it... a piece of coax long enough to hold that whole
1msec pulse would be 200km long.  its kind of like trying to pump water from
bosten to nyc in a garden hose.  keep things in scale, rg-8 for hf from your
shack to the antenna in your yard is just as good as a garden hose for going
from your faucet to your garden... you'll never notice the pressure drop.
but try to use rg-8 or your garden hose to get from boston to nyc and it all
falls apart, or try to use rg-8 for microwaves or your garden hose for a
pulsed high pressure washer and see what happens.
 
> 
> Of course, eventually, all the water may drain out of the pipe. But that
> isn't what you really wanted.
> 
> Repeat this phrase until you believe it: Mismatch loss is REAL loss.
> 
 
repeat after me... 
 
Mismatch loss is REAL loss, but I'm going to ignore it anyway and have
fun.
 
-- 
David Robbins K1TTT (ex KY1H)

 




David Robbins, K1TTT K1TTT@arrl.net