rod Cutting Charts
Measuring the Rod Length - UHF Antennas
The dimensions shown on the cutting chart are for
sections of rod below the phasing coil. The rod above
this coil comes preset from the factory. Do not cut
this upper rod. The rod length indicated on the chart
refers to the length of the rod from the bottom of
the phasing coil to the end of the rod. Be sure to be
precise for best results.
Cutting the Rod
The whip is constructed of the highest grade
17-7PH stainless steel, to provide all-weather
protection and maximum radiation efficiency. Use
sharp corner of file or edge of grinding wheel to
cut the rod. Use file to score the rod and snap off
with a pair of pliers.
Cleaning the Rod
To clean the open coil antenna rod, use a damp sponge and soap.
800 MHz Band
Larsen®
LM 800 antennas are cut to be resonant at 806-866 MHz,
825 at 825-896 MHz and 900 at 890-960 MHz. No further cutting is necessary
Shock Spring Option
Some cutting charts apply to LM antennas designed
for a shock spring. Those antennas come with a
metal cone that screws either directly on the base
or on the shock spring (see adjacent drawing). The
cutting lengths are based on inserting the rod as far
as possible into the spring of base loading coil. This
gives the user approximately 3/4” of adjustment in
case the rod was inadvertently cut too short.
Upper Rod
Do NOT Cut
Phasing Coil
Measure
to end of
rod and cut
per chart
DO NOT CUT
ROD ABOVE COIL!
Measure correct length
per chart and cut bottom
end of rod
Cone
Shock
Spring
Antenna
base
LM quArter wAve
OPer. Freq.
rOd Length
(inCheS)
(CM.)
Q
136 Mhz
20-3/4
52.7
138 Mhz
20-1/2
52.1
140 Mhz
20-1/4
51.4
142 Mhz
20
50.8
144 Mhz
19-3/4
50.2
146 Mhz
19-7/16
49.4
148 Mhz
19-3/16
48.7
150 Mhz
19
48.3
152 Mhz
18-11/16
47.5
154 Mhz
18-1/2
47.0
156 Mhz
18-1/4
46.4
158 Mhz
18
45.7
160 Mhz
17-13/16
45.2
162 Mhz
17-9/16
44.6
164 Mhz
17-5/16
44.0
166 Mhz
17-1/8
43.5
168 Mhz
16-7/8
42.9
172 Mhz
16-7/16
41.8
220 Mhz
12-1/2
31.8
225 Mhz
12-3/8
31.4
225 Mhz
12-3/16
31.0
400 Mhz
6-15/16
17.6
410 Mhz
6-13/16
17.3
420 Mhz
6-5/8
16.8
430 Mhz
6-7/16
16.4
440 Mhz
6-5/16
16.0
450 Mhz
6-3/16
15.7
460 Mhz
6
15.2
470 Mhz
5-7/8
14.9
480 Mhz
5-3/4
14.6
490 Mhz
5-5/8
14.3
500 Mhz
5-9/6
16.5
510 Mhz
5-7/16
13.8
LM vhF BAnd
OPer. Freq. w/O SPring
w/SPring
(inCheS) (CM.)
(inCheS) (CM.)
lm150c / lm150B
144 Mhz
49
124.5
46-7/8 119.1
146 Mhz
48-1/4 122.6
45-3/4 116.2
148 Mhz
47-3/4 121.3
45
114.3
150 Mhz
46-7/8 119.1
44
111.8
152 Mhz
46-1/4 117.5
43-1/4 109.9
154 Mhz
45-3/8 115.3
42-3/8 107.6
156 Mhz
44-5/8 113.4
41-5/8 105.7
158 Mhz
43-7/8 111.4
40-3/4 103.5
160 Mhz
43-1/8 109.5
40
101.6
162 Mhz
42-1/4 107.3
39-1/4 97.7
164 Mhz
41-5/8 105.7
38-5/8 98.1
166 Mhz
41-1/8 104.5
37-7/8 96.2
168 Mhz
40-3/8 102.6
37-1/8 94.3
170 Mhz
39-3/4 101.0
36-3/4 93.4
172 Mhz
39-1/4 99.7
36-1/8 91.8
174 Mhz
38-5/8 98.1
35-5/8 90.5
LLM uhF BAnd
OPer. Freq. w/O SPring
w/SPring
(inCheS) (CM.)
(inCheS) (CM.)
lm406c
405
Mhz 11-7/8 30.2 10-1/2 26.7
410 Mhz
11-5/16 28.7
9-7/8 25.1
415
Mhz 10-1/2 26.7 9-1/16 23.0
420 Mhz
10-1/4 26.0
8-3/4 22.2
lm420c
420
Mhz 12-1/6 30.6 10-1/2 26.7
425
Mhz 11-5/8 29.5 10-1/8 25.7
430 Mhz
11
27.9
9-3/4 24.8
435 Mhz
10-9/16 26.8
9-1/4 23.5
440 Mhz
10-1/8 25.7
8-3/4 22.2
lm440c
440 Mhz
11-1/4 28.6
9-3/4 24.8
445
Mhz 10-3/4 27.3 9-7/16 24.0
450 Mhz
10-3/8 26.4
9
22.9
455 Mhz
9-3/4 24.8
8-1/4 21.0
460 Mhz
9-5/8 24.5
8
20.3
lm450c
450 Mhz
11
27.9
9-7/16 24.0
455 Mhz
10-3/8 26.4
8-3/4 22.2
460 Mhz
10-1/8 25.7
8-5/8 21.9
465 Mhz
9-13/16 24.9
8-1/2 21.6
470 Mhz
9-3/8 23.8
8-1/16 20.5
lm470c
470 Mhz
10-1/16 25.6
8-5/8 21.9
475 Mhz
9-5/8 24.5
7-7/78 18.0
480
Mhz 9-1/4 23.5 7-3/4 19.7
485 Mhz
9
22.9
7-5/8 19.4
490
Mhz 8-5/8 21.9 7-1/2 19.1
lm490c
490
Mhz 9-5/8 24.5 8-1/8 20.6
495
Mhz 9-1/8 23.2 7-1/2 19.1
500
Mhz 8-7/8 22.5 7-1/4 18.4
505 Mhz
8-9/16 21.8
7
17.8
512
Mhz 8-1/8 20.6 6-5/8 16.8
T
LP SERIES
1. Install the two #10 set screws with the allen wrench. Set screws and allen
wrench are supplied.
2. If antenna coax cable and mount must
be installed, be sure to route the cable
as shown.
3. On newer cars the TLP will need to be
mounted along the side of the trunk
lid or hood. On older models the TLP
may be mounted on the lip of the
trunk lid nearest the rear window of
the auto.
Tighten the set screws
sufficiently to break through the
paint and establish a good ground connection.
4. Route coax cable from the trunk area to the radio. Install the connector.
Connect antenna cable to radio.
5. Install antenna on TLP mount.
Antenna Mount
Set Screws (2)
Coaxial Cable
