Revised 08/28/2022
General Notes
For antennas over 71 feet, use 100 feet coax minimum and place choke in a position as shown in table below. This choke position will
be a good starting point for tuning your antenna on the bands you want to operate. Here are some examples of actual antenna wire
length and choke placement for the antenna SWR plots shown (units are in feet and % of total antenna length including counterpoise):
Antenna Wire length (feet/%)
Antenna feed point to choke
length (feet) – fine tune for best
results for you configuration(*)
Total Antenna Wire +
coax length (feet)
41 (72%)
16 (28%)
57 (100%)
71 (63%)
42-50 (37%)
113-121 (100%)
111 (75%)
37 (25%)
148 (100%)
155 (62%)
95 (38%)
250 (100%)
(*) - Choke measurement is from antenna feed point at 9:1 unun coax connector to choke.
Feed line Choke Options
Use Feedline choke EFFLC or SOFLC for RG-8X size cable or choke MC-1-500 (500 watts PEP) or MC-1-3000 (3KW PEP) for larger
coax with UHF connectors.
EFFLC (RG-8X coax not included) –
easiest to adjust length from matching
unit– up to -30 dB suppression
Mini-Choker™ MC-1-500-50 (500 watts
PEP) – up to -38 dB suppression
Maxi-Choker™ MC-1-3000 (3KW PEP) –
up to -48dB suppression
CMNF-1500 (1.5KW) – wall mounting– up
to -38 dB suppression
CMNF-5000 (5KW) – wall mounting – up to
-38 dB suppression
SOFLC - Snap On Feed Line choke (works
on RG-8X (6 turns) or RG-8 (3 turns) up to
38 dB suppression
Wire Pulleys
Split wire pulleys are very useful for installing free running antenna
wire. Use a halyard hoist on first pulley carabiner and free run the
wire from the matching unit thru the first and any additional pulleys.
Support the wire every 50-75 feet thru a pulley (and separate
halyard hoist/support attachment to the carabiner part of the pulley)
and the antenna will be much easier to raise and maintain in the
future.
Part#: Pulley-1.75
