Rf choke for cb radio. In other words, do not make a choke coil, then splice it in later with PL-259’s and couplers. B) IMPROVED COAX CHOKE: Wrap coax onto a PVC pipe, using nylon rope to space the turns. 525 inch I. If the external meter shows one SWR and your radio’s built in meter shows another then you might have a common mode current problem. Choke or vary the length of your coax until you get a decent SWR match. 22K views 1 year ago #hamradioantenna #amateurradio #hamradio. I'd like to put two on my setup, if they prove to be effective, which from what I've seen, they are. LED & HID lights can cause a tremendous amount of RF Interference. Time to reduce the annoying RF sources that are picked up in your radio, or cause havoc with interconnecting shack equipment. Most times an RF Choke is placed in series with the power lead with a capacitor placed across the power lead and ground to create a 2nd order low pass filter which creates clean DC. Rated 5000 Watts PEP from 1-61 MHz. Recurring Donations; Search; Ways To Donate; Bozo's Photo Gallery; Username Change Use this RF Choke for LED headlights or light barswith maximum 10 gauge wire. See full list on moonrakeronline. The RF choke on this antenna more likely will help prevent problems with RF local to your shack. Any value in between is probably close enough. Made in USA by small ham radio owned businesses. It just prevents RF from travelling back down the shield of your coax and causing EMI/RFI. Ferrite beads help eliminate interference in two directions: from a source to your radio. Solution #2: Instead of using a FSB-1/4 Snap on choke, use a FSB-1/2 Snap on choke and pass the Ethernet wire through twice thereby increasing the effective impedance 4X. CM can flow on multi-conductor cables, too, like on your rotator control cable. I saw a few filters on the net some are ferrite split core that go around the antenna cable and Dec 18, 2008 · A value if 22 uH is typical for the small choke on the input side. 2K. The plate choke is probably about the same 22 uH value, but it's built to take more current. RFC2 - 3. Has anyone used an RF Choke on the coax or the in-line antenna filters ? If so Jan 20, 2007 · An RF Choke blocks an AC signal while allowing DC to pass. Fuel your knowledge, unlock secrets, and engage in discussions. CB radio noise filter is simple to connect and effective. Those get to be very pricey, and I've bought high end chokes from Palomar for ham radio use. Jul 7, 2023 · Quick links. May 3, 2008 · radial capacitor inline with the pwr wires near the pump eliminate it too. Constructing an Effective CM Choke There are many ways to create a CM choke. I feed my yagis with coaxial chokes-they can do wonders- it actually is a 1-1 current choke to shield the inner conductor-to the outer shield in a magnetic field. If you're going to go with snap-on ferrite beads, at least use five, if not six of the right mix. A filter and/ or “braid-breaker” (see below) should be fitted in the coaxial cable at ‘X1’ but if this is not sufficient, another should be fitted at either ‘X2’ or at ‘X3’. 75 x 75 inches What is a choke? An RF (Radio Frequency) choke, also known as a choke coil or simply a choke, is an electrical component used to block or filter out high-frequency signals while allowing direct current (DC) or low-frequency signals to pass through. I get lots of noise from my fuel pump. The beads close and fit over cable sizes such Many of our RFI and Ferrite Core products are available at HAM RADIO OUTLET stores We are always looking for new products to sell or distribute under the Palomar Engineers name – if you have a product or idea, please send us an email at Sales@Palomar-Engineers. 8 uHy choke Cobra/Robyn/Uniden CB's HW-B2-20C ($3. 5mm Snap On Ferrite Core Noise Suppressor RF Choke For Wire Up To 10 Gauge. For CB radio, the cheap off the rack ones will work wonders. CHOKE-KIT! is a quality pre-assembled high power current balun* which provides approximately 24 microhenries of "common-mode" inductive reactance. You will be using the same piece of coax that is used for the feedline. a choke, retest to see if the current has declined to an acceptable value. This will lower the effectiveness of the choke. Feb 8, 2021 · In most cases its a waste of coax and does little to nothing. Essentially a choke is an inductor. Oct 10, 2023 · Inductors and RF chokes are basically the same type of electrical components. A capacitor from each line to ground can also be used. Workman CF-2 8-Amp Line Noise Filter RF Choke Power is designed to reduce or eliminate DC Power Line noise from entering a CB Mobile Radio Information and specifications page coiled coax choke balun, connected to the output of the tuner, takes care of both the balance issue and keeping common-mode RF off of the coax run from my rig to the tuner. Includes two PL-259 Connectors soldered in place. Choosing a Feed Line Choke Feed Line Common Mode Chokes Get the best deal for rf choke from the largest online selection at eBay. An RF choke uses frequency selectivity to allow the passage of low-frequency DC signals while blocking high-frequency AC signals such as radio frequency. the trick is that the ground to the frame needs to be shorter, and of lower resistance than the power wire ( this is why i specified Try putting the choke at the feedpoint, not at the radio, in lieu of the ugly balun you have now. 8-30 MHz, 1500W PEP, SO-239: Fixed-mount CB Radios - Amazon. 1. Use as dipole antenna to coax interface, and a common mode choke to keep RF on the antenna and off the outside of the coax braid. com RF Chokes and RF IF Tuning Coils for CB Radios are available from Ken's Electronics, (Wholesale & Retail Electronic Parts) Kalamazoo, Michigan at reasonable prices. Sep 13, 2012 · Buy MFJ Enterprises Original MFJ-915 RF Isolator 1. My mag mount is located in the middle of the roof. 2 uhy Q=55 750Ma DC: $2,07: PH86-1421 epoxy molded RF choke 4. Either that or get a couple of clip on 31 Mix ferrites and wind the coax through one of them as near to the antenna a few times and likewise with the power cable for the CB and amp. D. May 3, 2008 · I have the truck grounded pretty well. That inductance slows or stops electrical signals from flowing on the 'outside' of that cable. 57″ (over 1/2″, 14. Knowing what is on the market we target our designs for 'best of breed' for each antenna system. Quick links. 1K subscribers. Now the swr is around 1. 8MHz to 30MHz 50ohm-balun is easy. Purpose. (Typically < 5% of the RF current depending on the choking impedance). May 13, 2024 · The ground pin of the bus is connected to the internal solid ground plane through a 27 nH, 2 A, 70 mohm RF choke with a self-resonant frequency of 2. The difference in design is related to the function the device will perform in a circuit. Commonly used on CB radio base stations. None of the conductors needs to be grounded for RF to pick up and/or radiate RF common-mode signals. It eliminates unwanted RF on the shield Figure 2: The minimum 160m and Add this RF choke where your coax cable. RF Chokes are typically used on the DC supply of the device affected by noise. 8-61 MHz) The simplest, most cost effective feed line choke is a ferrite ring installed as shown in the picture (at the antenna feed point). Write or Call 435-200-4902 Check Out OnAllBands – Our Ham Radio Blog Packed with News, Tech Tips, Features & More RF Isolator, 1:1 Current Choke, Ferrite Bead Type, 50 Ohm, 1500 W PEP, 1. more. * For 1. 25 x . Join a vibrant community of like-minded individuals and explore the exciting realm of CB radios. 1. 2 shows a video recorder with its RF output connected to the aerial socket of a TV. The MFJ-915 RF Isolator is a 1:1 Current Balun, designed to be placed in An Inexpensive, High-Performance, Ugly 50 ohm Balun "Building a no-grief 1. Feb 2, 2011 · So, if you wind a coax cable into a coil you produce some inductance on the "OUTSIDE" of that coax. Cobra, Uniden, Midland CB Anyone use these on their coax to reduce the reflect caused by the coax radiating as part of the antenna? What are the pros and cons? Please explain. Nov 8, 2018 · Figure 2: An example that works well is this "balun", or RF Choke more appropriately, by Palomar Engineers called the BA-2 ferrite sleeve, 1:1 current choke balun, with 5 Mix 31 Ferrite Beads in series, installed on a short coax pigtail. Another standard size CB mobile radio that includes RF gain and mic gain is the Cobra 29 LTD Classic. An example is shown in the picture below. Making your own RF choke is an easy project, even if you are a novice and have never done anything like this before. Connect with CB radio enthusiasts at CB Radio Talk Forum. Improves antenna pattern by preventing your dipole from becoming a tripole Prevents pesky coax braid radiation and RFI for best results use multiple turns through center Use one choke for each antenna feed Great deals on Radio Communication Baluns & Chokes. Power line filter used to remove unwanted RF (engine noise, inverter noise, other electronic interference) from your CB radio or stereo. You should be able to find such choke in most hardware stores these kinds of days and they come at relatively affordable prices as well. https://www. Description Use this adapter to help suppress the noise on your LED headlights. The CB noise filter includes a 3-pin female power connector and is usable with radios that require less than 10 amps (i. 0 out of 5 stars 533 The CB-1-5000EB current balun is useful as common mode feed line chokes or unbalanced coax to balanced antenna interface. Specs Model / SKU: RFC2 Product Details: For LED Headlights with up to 10 gauge wire Compatible with: LED Headlights Details Help me choose PRODUCT OPTIONS COLOR Lorem ipsum dolor sit amet I read about RF chokes that may reduce the swr a little, so I fitted one about 16" below the base of the antenna. What are your thoughts? May 3, 2020 · An RF choke can save the day for field radio operations where you do not necessarily control all aspects of your antenna sy For just a few Dollars to boot An RF choke can save the day for Connect with CB radio enthusiasts at CB Radio Talk Forum. This Radio Frequency Chokes category is a curation of 28 web resources on , High Performance common-mode chokes, How Common Mode Chokes Work, Homebrew RF chocke - Magnetic Longwire Balun. com FREE DELIVERY possible on eligible purchases Amazon. Mar 20, 2012 · The RF choke you're using isn't good enough. Fast & Free shipping on many items! 12-Foot Length: Ideal for various CB radio setups, providing flexibility and reach. Chokes that have a high Q can create unwanted resonance in power isolation circuits. This common mode noise current gets on the coax braid from neighborhood noise sources Useful for small cables or one pass with RG8 size coax (43, 31, and 61 beads). The objective with the balun is to eliminate common-mode current on the feedline Operating a radio without an RF choke puts the set's electronics at risk and can impact tuning and reception quality. It's pretty much a universal plate choke for up to 2 or 3 tubes. Dec 1, 2023 · Tips for ham radio antennas in an attic March 18, 2024; Replacing the 1:1 balun for a better performing Cobweb antenna March 9, 2024; Chosing ham radio equipment as a newbie December 30, 2023; Understanding PEP power and Duty Cycle in amateur radio December 1, 2023; PA9X’ broadband choke Radio Frequency coils (RF coils) are also called inductors. The impedance of a FSB-1/4 choke at 28 mHz is about 160 ohms. This antenna maintained a SWR below 1. * 1:1 , 50 Ohms; Accepts Coax cables with PL-259 Connectors. Oct 4, 2012 · RF Isolator Balun MFJ-915 Choke For Ham & CB Radio HF Antennas * Eliminate Stray RF from Amateur & Cb Radio Antenna Feedlines. New Listing 1000UH 1MH RF CHOKE SUMITUBE NOS / HAM RADIO / AMPLIFIER / DIY ELECTRONICS. If your RFI problem is on the low frequencies like 160-80-40 meters, than more than likely, RF is getting into your AC lines and the chokes mentioned above will help suppress the problem. Both the battery and the frame have good clean connections. !" "No costly ferrite-cores are needed, just a short length of 3 to 5 inch size plastic pipe, about 25 feet of 50ohm coax plus some nylon cable ties. Jun 12, 2017 · Amateur Radio (G3TXQ) - Common-mode chokes. The RFI kit is designed to be installed on your radio transceiver to reduce Radio Frequency Interference (RFI) caused by common mode current on the outside of the coax braid at the output of your radio and on the DC power supply Jul 7, 2022 · Because ferrite collars are inductive and capacitive, circuit designs must also account for “Q” or the reactance of the inductor divided by the AC or RF resistance plus any DC resistance found in the choke windings. The indoor choke did not make a difference for me, but everyone's setup is different. com/Jabinco-20pcs-Ferrite-Suppr Jul 23, 2015 · In order to keep that RF energy off the braid, we also need to raise the impedance of the outer braid, so we’ll use a variation of the balun called an RF choke. Varmint used 56 uH. Be prepared and able to communicate in case of emergency with the largest selection at eBay. A common-mode choke with an ideal infinite impedance essentially "disconnects" the common-mode of the feedline, but common-mode currents can still find their way onto the feedline through mutual coupling through the electromagnetic field. 5 from 25. 98) PH86-1424 epoxy molded RF Choke 10 uHy Q=65 500Ma DC: $2,07: PH86-1423 epoxy molded RF Choke 22 uhy Q=50 410Ma DC: $2,07 Oct 7, 2021 · These chokes aren't the best for low band HF. . For CB band it should be 5 turns wrapped around a 4. If the RFI is at higher frequencies, look for shorter antennas like interconnect cables between equipment which act as antennas and use FSB-1/4 or use FSB-1/2 What do you think of a Mix 31 Ferrite ring radial choke to reduce common mode interference? I have seen fellow radio enthusiasts use a ferrite ring with 12 wraps of coax to create a supposedly effective common mode choke. Pre-cut quality RG8U coax cable for base radio installations. It is usually cheaper to buy better coax than it is to buy a bigger amplifier. Most engineers are more familiar with inductors – some think both devices can be used interchangeably – that are prevalent in frequency selective systems, such as a tuner for radio receivers or filters. 21. 8-30 MHz, 1500W PEP, SO-239 : Electronics Dec 4, 2020 · The DXE-CSB31-525-5 kit features five medium-size snap-on beads (0. e. Our choke kits provide the ferrite, the cable, and the know-how to stop or dramatically reduce RFI on coax, USB cables, and ethernet cables. For an 80 meter version, you put the RF choke 20 feet below the feedpoint. I get better SWR curves and improved radiation along the plane of the antennas elements(or wire/whip antenna)Their should be Our CB-1-5000 is an excellent balun for this purpose and easily inserts into the coax line going into the radio station. Mar 9, 2006 · Making a rf coaxial choke -Id say 8-10 turns of mini 8X. With the right amount of coax, and its critical, you might have a choke that will REFLECT RF (VSWR) on the outside of the coax back towards the antenna a bit where a good choke balun made with ferrite will ABSORB RF on the outside of the coax. They can be variable values or fixed values, so, some are adjustable while others always present the same characteristics to the circuit. Moneysmith, W4NFR ; w4nfr@earthlink. 8 MHz) might not work if the interference is on CB (27 MHz). 000 MHz which is no small feat. Most communications / RF equipment produces, and is sensitive to Common Mode interference RF Appears on the two signal lines simultaneously in the same direction and phase A common-mode choke, produces equal and opposite magnetic fields that cancel one another. * Helps Reduce Interference & TVI. May 19, 2017 · Lmr-400 for CB use with IMax 2000 Alright time to pick the minds of Hams that read the CB section or any CB'r for that matter. Oct 19, 2011 · From what I’ve read, you do this by placing an RF choke (sometimes called a “line isolator”) at some point in the feedline to clamp off the common mode current. com. com: MFJ Enterprises Original MFJ-915 RF Isolator 1. More Information Radios have different receivers, different filters, as well as different power cords all of which can impact noise interference. These currents can burn your fingers on the key or lips on your microphone […] Cost effective way to reduce RF background noise on your CB radio. Oct 9, 2017 · The RF Choke Coil Solution. 5" former. It is the easiest method to try. net SPECIAL DETAILS RFC-1 Plate Choke is a ferrite loaded RF Plate choke using a value of 275 uh and used Simple Dipole Feed Line Choke for 1/4" coax (1. Understanding RF Chokes for Antennas. Coax Common Mode Chokes Common Mode Current (CMC) carried on the outside of a coaxial cable braid from your antenna can cause unwanted RF in your radio shack and can radiate this unwanted RF into you and your neighbor’s electronic devices. The following chart presents the results of impedance measurements made on a variety of common-mode choke implementations across the frequency range 1MHz to 30MHz. Below is the link to purchase on Amazon. RF chokes are simple make, For VHF and UHF antennas, all you need is to take 5 turns of coax and loop it into a 4 inch diameter circle. One fix to improve this is using a ferrite choke, sometimes called an RF choke. Ohmite used to make a part called "Z28". A great resource is K9YC's site and specifically, this PDF there. 0mm] Anti-Interference High-Frequency Ferrite Core Choke Subwoofer,Speaker,Mixer,Home Audio Device Noise Suppressor (0. WORKS WITH ALL BRANDS (Cobra, DAS, Midland, Uniden etc. But, they kill RFI. If a coax sleeve balun is chosen, the Fig 10 – Chokes of Fig 7 with fewer turns, measured to 1 GHz (Fair-Rite #43) Note that there are two sets of resonances for the chokes wound around the #78 material (Fig 8), but only one set for the chokes of Fig 7 and 9. A 1:1 choke balun, whether in coax or as ferrite cores/beads, to me is the most useful form of the balun. Small beads (61 and 73) only fit small coax. Fig. Jan 9, 2022 · I make myself an experimental RF or Common-mode choke, with the parts totalling in at a lower cost than can be purchased from a store. I have seen these products fo Apr 17, 2023 · Consider Picking Up RF Chokes: Made from various ferrite materials, RF chokes would proceed to choke off all invading radio signals without compromising audio signals. (Heat-shrink tubing is removed for viewing). Removable PL-259 Connector : Easy "EZ-Install" design for quick and hassle-free installation. It is less expensive than the Uniden BC 980, so if you don't need or want the SSB feature, but still want RF gain, you could take a closer look at this set. They can determine if there are any service bulletins that apply to your car. ) OF CB/HAM/COMMERCIAL RADIO RIGS in 20-60 MHz range. Very pricey for those ferrite mixes, and I've also bought some of their big pipe bomb looking 1;1 chokes which work very well. Out-of-stock. You can purchase CMC chokes ready-buillt, or better yet, make one yourself. . May 3, 2008 · From ARRL Web Site: If you have a fuel-pump noise problem, the place to start is with your dealer or automotive service person. Justme is right, you need a Low Pass filter to remove harmonics. A cable greater than 1/10 wavelength generally needs chokes at both end of the cable. May 3, 2008 · yes, i had mentioned the ground loop theory. Ferrite Chokes in the Antenna System PH86-1420 epoxy molded RF choke 2. Both names refer to the same device. High-Quality RG8X Coax : Durable and efficient, with 95% copper braid for excellent shielding. RF Chokes are important to get right. Read honest and unbiased product reviews from our users. SWR should be the same along the entire feed line. Resources listed under Choke category belongs to Feed Lines main collection, and get reviewed and rated by amateur radio operators. Here is the very simple way to make an RF choke coil that will remove your RF feedback troubles. Specify quantity after adding to cart. The most common choke type is a simple coil of coax at the antenna’s feed point. They are typically measured in fractions of a Henry. It's not difficult. These biasing techniques will still require an RF signal with high enough amplitude to overcome the reverse (or complete lack of) bias at the Class-C input. Sep 24, 2020 · Just to be clear - a RF choke (CMC) should not have any effect on your SWR. Oct 14, 2017 · What works on the 80 meter ham band (3. Sep 10, 2022 · This video discusses the purpose of an RF Choke used to bias a Bipolar or LDMOS Power Transistor. Feb 2, 2022 · An RF choke (radio frequency choke) is a type of inductor, but it differs in its application, function, and design. The ferrite core function resembles that of an inductor, but the ferrite core frequency response deviates from this functionality at high frequencies. if you have more then one ground to the frame, there is a ground loop. Amateur frequency allocations are indicated approximately by the vertical grey bands. CHOKE-KIT! is a simple and effective way to reduce or eliminate unwanted RF from being conducted back into the shack when installed either near the antenna feedpoint or near the rig, or both. And for all three materials, the upper resonance starts just below 1 GHz for a single turn and moves down in frequency as the Jun 23, 2019 · For a transmitting radio application, the consequences may not be so benign. ) that can be used to effectively decouple or choke unwanted RF and RF noise from automobile ignition systems, speaker wires, control cables, or other wires and cables suspected of absorbing or radiating RF interference. Air Choke (Ugly Balun) for Ham Radio: An air choke, also known as an ugly balun, is used to prevent RF current from flowing down the outer conductor (shield) of your coax and back into your shack. like a filter cap in a p'wr supply An Inexpensive, High-Performance, Ugly 50 ohm Balun "Building a no-grief 1. There is no better information on common-mode RF choke design anywhere, either online or in print. 7 uhy Q=70 620Ma DC: $2,07: LL0158 =6R8K radial lead 5x10mm 6. 500 MHz to 30. Individual Ferrites – Toroids, Slip On, Snap On – for 1/8″ wire to 3″ diameter cables available in convenient 10, 25 and 100 packs. Ferrite-core chokes almost always trump air-core chokes. A simple explanation of what a NR400 - ProComm Noise Clipper CB Radio Noise Suppressor. May 24, 2022 · Some people also use a choke indoors before the coax connects to the radio. Jul 6, 2021 · Remember that it is radiowaves with long lengths at shortwave frequencies, so if a small choke are placed on the coax it might be at a place where the radiowave have its minumum voltage and maximum current making it a low impedance and the chokes higher impedance will not be enough to stop the RFI. Dec 18, 2008 · From the Common-mode chokes page: "Amateur Radio (G3TXQ) - Common-mode chokes The following chart presents the results of impedance measurements made on a variety of common-mode choke implementations across the frequency range 1MHz to 30MHz. 75 GHz to block the noisy RF signals. This is useful both from a safety perspective, and a practical one. It focuses on the design requirements, construction, and va Clip-on Noise Filter,VSKEY [10pcs 9. SO-239 input to side terminal/eyebolt output. Which is good, and the whole idea of an RF 'choke'! It chokes off that stuff on the outside of the cable. Transistor sets typically use coils rated Connect with CB radio enthusiasts at CB Radio Talk Forum. And a directional antenna in a receive application fed with coax with poor isolation may pick up enough external noise to negate the benefits of the antenna directivity. COASTAL WAVES & WIRES. Jul 14, 2020 · Adding an RF choke at the receiver won't help with blocking any common mode current which exists on the outside of the coax as this current flows into the coax at the antenna end and adds to the current traveling towards the receiver on the inside of the shield of the coax. Power Requirements – A feed line choke passes the RF current through the choke and only has to choke the much lower common mode current that is present on the braid. These work, but they are not always good enough. A choke at the radio will do little since the coax shield, connector, and enclosure of the radio already form a continuous shield around all the receiving circuitry. It is a reactive choke, as it relies on the inductive reactance of the coil to pres-ent an impedance to the CM Greyline seeks the advice of expert RF engineers with reputations for ultra high quality and results. 35inch Inner Diameter) 4. low-Q choke, with a ferrite bead on the base lead’s grounded end. Jun 8, 2020 · You are right that common-mode currents can occur elsewhere. 50 Ohm Impedance, 95% Shielding. com and we will be glad to discuss it with you. HERE ARE 5 METHODS: A) COILED COAX CHOKE: Coax wrapped to form a coil. Here is a good option for your If you know the source of the noise, you may be able to utilize a Snap-On RF Choke such as the RFC2, RFC3, or RFC4 noise suppressors. So based upon significantly less DB loss I figured I could use 50' of LMR-400 for my IMax-2000 and it turns out there must be a mismatch somewhere in this configuration, since my normal 1. ca. Attaches to the stud/antenna mount to cut down on RF on the outside of the coax shield (common mode currents) and improve your antenna system This RFI choke from ABR is an effective tool for mitigating radio frequency interference that may be picked up by the coaxial cable. May 1, 2019 · That’s how your signal causes RFI (RF interference) when an audio or control cable picks up your signal. Secure the loops with electrical tape or zip In addition to the antenna feed point choke, it is prudent to add another choke at the radio station end to choke off the common mode noise current picked up by the outside braid of the coax between the feed point and the station receiver. You can also sometimes see this effect when using an external (to your radio) SWR bridge. BANDWIDTH. May 3, 2008 · I'm sure I have the same problems as most late model F150 owners. 5 mm) Small style designed to snap onto power input cable: RCT2 RFI Radio Frequency Interference Ferrite Chokes – Black measures approximately 1. 1:1 and raises to about 1. Wikipedia Reference. A conductive cable like the input power cord for the HID or LED Large style designed for looping wires around coil: RND-6 ( Wurtz number 7427151 ) snap-on chokes The inside hole size is 0. Jun 29, 2017 · Unfortunately, ferrite beads (also called a ferrite choke, ferrite clamp, ferrite collar, EMI filter bead, or even a ferrite ring filter) can be a bit of a mystery. 8-30Mhz HF. Installing a ferrite disk at the fuel pump can be a real pain. SWR is set by adjusting your antenna's radiator length and/or matching system. 5:1 at 1 MHz either side of the lowest reading. Ways To Donate; Bozo's Photo Gallery; Recurring Donations; Search; Username Change Page 5 STONE CREEK SPECIAL (2) 3-500Z HF AMPLIFIER By William G. Now I think most of the problem with her TV is related to overloading and proximity but I was still interested to see the results. 2 VSWR (SWR) has now shot to 2. Find helpful customer reviews and review ratings for 4 RFI EMI Snap Ferrite CB Ham Radio RF Choke Filter Phone TV PC speaker noise Coax at Amazon. amazon. It consists of 8 loops of coax with 8" diameter loops. jenui sbly rhlbh pdvkil gshwy wtbtkpdb jddvvv hpcmot orixfr rokjv