30-AMP (PEAK) IN-LINE TOROIDAL DC NOISE FILTER for 12 VOLTS, ALTERNATOR, PULSE NOISE SUPPRESSIONProduct DetailsMPN: RFI-N25Country/Region of Manufacture: USAPURPOSE:The N-25 is a passive noise suppressor that employs a high density, low loss toroid 0.25mH choke designed to eliminate in-line noise for Auto-sound, Avionics, and ham radio/CB/Two-Way communication systems including: Alternator Whine, Fan Hums, Dodge Ram Cummings Torque Converter Clutch Cycling Repair*, etc.The N-25 applications include Power Equalizers, Small Amplifiers, Cellular Phones, CB Radios, Two Way Communication Equipment, CD Players, and AM/FM Cassette Decks, etc.
FEATURES:The air-cooled design of the N-25 filter permits maximum efficiency and effectiveness.The ferrite toroid core of the choke component of the L configuration is responsible for a very high rate of attenuation with very low line losses.There are only three wires needed for the installation of the passive filter -Filter Input, Filter Output, and the Chassis Ground.
INSTALLATION:Make sure the noise is in-line before installing an in-line filter such as the N-25.A good confirmation would be to temporarily substitute a 120 VAC to a 12 VDC power supply, or a 12 Volt motorcycle battery, for the vehicle's electrical system.If the noise goes away when the alternate power supply is connected, then you have a case of in-line noise.
To get optimum results with the N-25, the following directions should be followed:
1.Cut the component's main power lead between the fuse and the component.
2. Connect the Green wire to the fuse side. (If there is no fuse, add one --- 10 Amps is recommended)
3.Connect the fused Red wire to the component side.
4.Connect the Black wire to a good chassis ground.
Practical and easy to install, the N-25 is one of the most versatile and effective filters on the market.
Note: The 30-Amp rating is instantaneous = peak… not constant. Fuse the Green lead with a 5 to 10-Amp fuse. Average current draw should be no larger than the fuse size of 10 amps.
PURPOSE:The N-25 is a passive noise suppressor that employs a high density, low loss toroid 0.25mH choke designed to eliminate in-line noise for Auto-sound, Avionics, and ham radio/CB/Two-Way communication systems including: Alternator Whine, Fan Hums, Dodge Ram Cummings Torque Converter Clutch Cycling Repair*, etc.The N-25 applications include Power Equalizers, Small Amplifiers, Cellular Phones, CB Radios, Two Way Communication Equipment, CD Players, and AM/FM Cassette Decks, etc.
FEATURES:The air-cooled design of the N-25 filter permits maximum efficiency and effectiveness.The ferrite toroid core of the choke component of the L configuration is responsible for a very high rate of attenuation with very low line losses.There are only three wires needed for the installation of the passive filter -Filter Input, Filter Output, and the Chassis Ground.
INSTALLATION:Make sure the noise is in-line before installing an in-line filter such as the N-25.A good confirmation would be to temporarily substitute a 120 VAC to a 12 VDC power supply, or a 12 Volt motorcycle battery, for the vehicle's electrical system.If the noise goes away when the alternate power supply is connected, then you have a case of in-line noise.
To get optimum results with the N-25, the following directions should be followed:
1.Cut the component's main power lead between the fuse and the component.
2. Connect the Green wire to the fuse side. (If there is no fuse, add one --- 10 Amps is recommended)
3.Connect the fused Red wire to the component side.
4.Connect the Black wire to a good chassis ground.
Practical and easy to install, the N-25 is one of the most versatile and effective filters on the market.
Note: The 30-Amp rating is instantaneous = peak… not constant. Fuse the Green lead with a 5 to 10-Amp fuse. Average current draw should be no larger than the fuse size of 10 amps.
TECH NOTE: We also stock RFI kits to protect effected devices such as garage door openers, computers (laptops, desktops), dsl/cable routers, ethernet hubs and many more devices. If you run a high powered RF amplifier in your ham station also consider a linear amp RFI kit which will cut down RFI transmitted by your station. Remember there is always a “transmitter” and a “receiver” of RFI and the quest is to find and choke the “path” the RFI has selected – you need to add ferrites to both the transmitting side and the receiving side to eliminate RFI problems. The RFI-HTS kit only helps suppress RFI on the receiving side.
Typical RFI Problem/Solution:
Hello, I am Larry, a ham operator and I am having interference issues with my Direct TV system. My station is a FT450D through an Ameritron ALS-600. From the amp through a coax switch to choose between an OCF dipole or an Hustler 5BTV vertical. Any power over 100 watts and my DTV goes off the air and must completly reboot/format. Coax is RG-8. The DTV dish is pointed away from the dipole and separated by about 25'. DTV was totally useless! They suggested I not talk on the radio while she is watching TV! Please help me with a reasonable, cost effective soultion. (The wife gets really pissed when I shutdown the tv!) Thank you, Larry
Hi Larry,
Your RFI problem is quite common and is usually a sign of either a radiating coax feed line or reception of your radiated signal (source) by the Direct TV (the victim) through either the AC power lines acting as “antennas” for your ham signal or the coax braid of the satellite antenna acting as an antenna for your signal.
The solutions are straight forward:
1. To make sure your feed line is not radiating you need a feed line choke at each antenna feed point (also makes your antenna work better since it is not using the coax as part of the antenna). You can use our simple Kit 110 with 5 snap on chokes on each antenna for this purpose. Part # Kit 110 at $27.50 each – one for each antenna. These chokes will keep your feed line from radiating and coupling into your ac power lines. INFO HERE
2. The radiation from your antennas themselves may also be getting into the ac power lines and coax braid of the Direct TV antenna so you need to protect the victim receiver. Depending upon the sophistication of your direct TV setup (e.g. home theater, dvd, tape player, sub woofer speakers, etc), the path of the RFI may be coming thru the AC power lines of any connected device to the video including the video monitor itself! To help solve this problem we have a home theater RFI kit for up to 5 devices (you need a minimum of two – one for the Direct TV receiver(AC and coax input) and another for the video monitor AC power lines and HDMI or video input cable. Our kit part # is RFI-HTS. INFO HERE
These items should help reduce the RFI and let you operate on the air while your wife watches TV.
Bob Brehm, AK6R
Chief Engineer