Coax loss charts (from W3LPL)

Frank, W3LPL posted helpful coax loss charts to the CQ-Contest email list some time ago. I’ve used them extensively, particularly in deciding if it was necessary to use LDF4-50a hardline over RG-8. I’m reprinting this here, with credit to Frank, so it is not buried in the email list archives.

Note: charts may not format properly on a mobile device.

From: Frank Donovan W3LPL
 
Subject: CONTESTER's coax cable attenuation charts
 
 
 
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
 
 
 
                       
 
                            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

Also see my article: Proper feeding of non-resonant antennas

2018 ARRL 160

Call: N1TA
Operator(s): N1TA
Station: N1TA

Class: Single Op LP
QTH: WMA
Operating Time (hrs): 

Summary:
Total:  QSOs = 328  Sections = 41  Countries = 7  Total Score = 32,064

Club: 

Comments:

TX: 150' Inverted-L (90' vertical) against 40,000sqft groundscreen
RX: 450' switchable beverage NE/SW
Inside: FT-1000MP

Thanks for the Q's.

Inverted-L replaces Inverted-V

The venerable inverted-V has served me well for the summer, but as winter has fallen here, I took it down and replaced it with an Inverted-L for 160m. I intend to tune it elsewhere as well, but this too will (hopefully) be a temporary antenna until house work subsides and real antennas can be added.

The radial field is very basic, about twelve radials on the ground (which is about 90 too few). I have it resonated with a series doorknob cap, and a static bleed choke across the feedpoint.

More to come!

2018 WPX CW

Call: N1TA
Operator(s): N1TA
Station: N1TA

Class: SO(A)SB40 LP
QTH: MA
Operating Time (hrs): 

Summary:
 Band  QSOs
------------
  160:    0
   80:    1
   40:  189
   20:    4
   15:   14
   10:    0
------------
Total:  208  Prefixes = 170  Total Score = 130,390

Club: Yankee Clipper Contest Club

Comments:

New station still not totally assembled; just played around. Only 40m dipole at
90' and FT-1000MP. No 220V in shack yet, so low power entry. Thanks for the fun.

2018 New England QSO Party

Call: N1TA
Operator(s): N1TA
Station: N1TA

Class: Single Op LP
QTH: 
Operating Time (hrs): 

Summary:
 Band  CW-Dig Qs  Ph Qs
------------------------
   80:               
   40:    234       1
   20:     87       5
   15:      7        
   10:               
------------------------
Total:    328       6  Mults = 47  Total Score = 31,114

Club: Yankee Clipper Contest Club

Comments:

Just moved into a new home and hadn't really started putting the shack together
until Thursday. Decided at the last minute to hand out some points. I had a
social engagement for the Kentucky Derby, so managed only an hour or so on
Saturday night, but spent all of Sunday in front of the radio.

Thankfully, K1YO came by last week to shoot a rope over a tall pine. The bad
news: the only antenna I had ready to go was a 40m dipole. The good news: it was
90+ feet high. Had no DVK, so kept away from phone, and on CW I was occasionally
dogged by RF in the shack. The wire wouldn't tune nice on 80, so I just stuck to
40 and 20. I caught the tail-end of the Sunday 15m opening, but just didn't have
the antenna to really take advantage of it! Now that the "new house"
work is winding down, I look forward to spending more time on radio projects.

Thanks to the chasers for following my yellowy signal from band-to-band.

Antenna: 40m inverted-V at 90'
Rig: 30 year-old FT-1000MP
MVP: Heathkit SA-2060 tuner
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