End Fed Feed Line Choke for Non-Resonant and End Fed Half Wave AntennasProduct DetailsType: 8-10 turns of RG-8X with Pl259 Connector, 3 turns of RG-213 cableRFI Range (MHz): 1-300 MHzID-B (in/mm): 1.4"OD-A (in/mm): 2.4"Height-C (in/mm): 1/2"Feed Line Choke
Each end fed antenna needs a feed line
choke at the radio end of the coax to stop the antenna common mode
current (on the coax braid) from getting into the radio when
transmitting and also to stop RFI common mode noise when receiving. The
simplest, most cost effective choke is a ferrite ring (F240 size)
installed as shown in the picture (at the transceiver end of the coax)
Add the Feed line choke (part # EFFLC-240) for $10 to your end fed
today and stop the pesky RFI from getting into your radio and causing
audio distortion or unexpected operation!
NOTE: Coax shown in picture is NOT INCLUDED and is shown as an installation example only. If you want a pre-wound choke check part# JC-1-1500-3 or JC-1-1500-6.
For non-resonant end fed antennas placement of the choke from 16-95 feet away from the antenna feed point to use the coax braid as the counterpoise (since these antennas are really off center fed dipoles with the short side using the coax braid as the counterpoise. Wind 8-10 turns thru center for an effective 3-30 MHz choke. See Bullet Antenna configurations for exact choke placement depending upon wire length.
For End fed Half Wave antennas place 1-3 feet from antenna feed point to act as short counterpoise for these voltage fed antennas. Use 8-10 turns.
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Feed Line Choke
Each end fed antenna needs a feed line
choke at the radio end of the coax to stop the antenna common mode
current (on the coax braid) from getting into the radio when
transmitting and also to stop RFI common mode noise when receiving. The
simplest, most cost effective choke is a ferrite ring (F240 size)
installed as shown in the picture (at the transceiver end of the coax)
Add the Feed line choke (part # EFFLC-240) for $10 to your end fed
today and stop the pesky RFI from getting into your radio and causing
audio distortion or unexpected operation!
NOTE: Coax shown in picture is NOT INCLUDED and is shown as an installation example only. If you want a pre-wound choke check part# JC-1-1500-3 or JC-1-1500-6.
For non-resonant end fed antennas placement of the choke from 16-95 feet away from the antenna feed point to use the coax braid as the counterpoise (since these antennas are really off center fed dipoles with the short side using the coax braid as the counterpoise. Wind 8-10 turns thru center for an effective 3-30 MHz choke. See Bullet Antenna configurations for exact choke placement depending upon wire length.
For End fed Half Wave antennas place 1-3 feet from antenna feed point to act as short counterpoise for these voltage fed antennas. Use 8-10 turns.
Christmas lights or yard lights with switching DC power supplies are often the RFI source and a clamp on ferrite bead on the AC AND the DC side feeding the lights is needed to help suppress the switching power supply RFI noise. Suitable snap on beads are FSB31-1/2 for the 1-250 MHz range.
We have also had reported wireless HDTV boxes, and FOSCAM and AMCREST security camera systems causing RFI to garage door remote openers. Use our Garage Door Opener RFI kit to suppress the interference to the opener (VICTIM) – you need one kit for each opener. Maximize the distance from the camera to the openers may also help. Additionally shield cable to the garage door sensors may be needed depending on severity of the camera RFI.
Obvious Tech Note: make sure your remote batteries have enough energy to activate the GDO or the signal they transmit may not be large enough to over ride the RFI signal, but a fresh battery may be able to overcome the weak RFI source and allow the GDO to operate correctly.