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Home / Avionics / Antennas / Comant /Comant VHF Communication Antenna CI-121
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Comant VHF Communication Antenna CI-121

23 Reviews 9 Answered Questions
$265.00/Each
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Part# 11-17921
MFR Model# CI-121

Overview

Frequencies Covered: 118-137 MHz

Similar to the CI 109, the CI 121 is smaller in diameter and lighter at only 0.5 pounds. Features a tapered glass laminate housing and die-cast aluminum base. Offers standard mounting and appearance to many Cessna communication antennas. The CI 121 has been re-tested and upgraded to the new RTCA DO-160D environmental requirements and offers the 118 to 137 MHz frequency associated with DO-186A MOPS.

Note: Gasket included.
   
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WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov.

Specifications

MODEL CI-121 VHF ANTENNA
Electrical
Frequency
118-137 MHz
VSWR
2.5:1 Maximum
Polarization
Vertical
Radiation Pattern
Omnidirectional
Impedance
50 Ohms
Power
50 Watts
Mechanical
Weight
0.5 lbs. Max.
Height
19 in
Material
Metal Housing / Fiberglass Whip
Finish
Glossy White
Connector
BNC (Female)
Gasket B12607-3
Cork Neoprene
Federal Specifications
RCTA Environmental
DO-160D
FAA TSO
C37d,C38d

Applications

  • Single engine piston aircraft for applications of this antenna design.
  • Consult your FBO or installation shop for best application information.

Documents

  • Frequently Purchased With
  • Customers Also Viewed
  • Related Items

Reviews

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Great antenna, added to our 7AC, reception is notably better and the build quality and forum factor is appreciated

North C Verified Purchase

Comant CI-121 VHF Comm Antenna BNC
June 17, 2025

All good works as expected.

Ray H Verified Purchase

Comant CI-121 VHF Comm Antenna BNC
June 7, 2025

Quick and easy replacement for the stock antenna that had split open in my 172M.

Chip C Verified Purchase

Comant CI-121 VHF Comm Antenna BNC
March 9, 2025

This antenna is a great improvement over the one I had on my Aeronca!

Gary P Verified Purchase

Comant CI-121 VHF Comm Antenna BNC
October 25, 2024

Shipped quickly.

Steven S Verified Purchase

Comant CI-121 VHF Comm Antenna BNC
April 30, 2024

Like the other Comant antenna I have, this one is well built, finish is perfect. I’m still building the plane so will report results when it is installed and operational.

Donald W Verified Purchase

Comant CI-121 VHF Comm Antenna BNC
November 1, 2023

Woodaero Verified Purchase

Comant CI-121 VHF Comm Antenna BNC
August 1, 2023

My mechanic told me to buy this one for the 182p after the previous one had cracked through the middle. He put it on in 5 minutes and its great. Does the job.

Naos J Verified Purchase

Comant CI-121 VHF Comm Antenna BNC
May 5, 2023

COM1 transmission was very weak. Replace both antennas (COM1 &2), much improved performance on my C172N. The antennas were an exact fit as the originals.

Jack Verified Purchase

Comant CI-121 VHF Comm Antenna BNC
February 18, 2023

Easy install and seems to be well-made

Paul R Verified Purchase

Comant CI-121 VHF Comm Antenna BNC
October 16, 2022

Q&A

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Please note, Aircraft Spruce ®'s personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce ® assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Antenna CI-121 Reference is made to installation on single engine aircraft, can this antenna be installed on a twin Comanche (PA-30)?

Per the manufacturer: This antenna is designed for use on single engine aircraft. For twin engine aircraft a blade type antenna is recommended.

Q: Where can I find length and mounting information for the CI-121?

Please see the documents tab on this page for length and mounting information.

Q: Is the Comant VHF CI-121 antenna compatible with a Bendix King KX155 Nav / Comm? besides the comm will work with the nav?

Yes this is will work with the KX155 but only for the Comm part of the unit, for the Nav portion Nav please use part number 11-15700.

Q: Would this CI-121 antenna work with a Garmin 430WAAS com?

Yes, this antenna can be used only for the COM portion.

Q: Can this Comant CI-121 antenna be installed on a CIRRUS SR22

There is no application guide for this antenna showing which specific aircraft it fits. It is FAA TSO approved for use on certified aircraft. Please check with your A&P to detemrine if it can be legally installed.

Q: Does this Comant VHF communication CI-121 with FAA TSO paperwork?

No. This does not include those documents.

Q: Is the CI-121 antenna compatible with VHF NAV/COM MX107B and MX300B both installed on a C150M? Thanks

It will work for the COM portion of the radio.

Q: Does this CI-121 antenna come with required mounting hardware?

Hardware is not included.

Q: There is no documents tab on this page for the CI 121 antenna to show the footprint, mounting pattern, or length of the antenna

The data sheet has been added to the web page for download and review.

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