Vhf notch filter. Description Description GWAVE VHF Notch Filter – 155.
Vhf notch filter. 20 inches, are nominally O. The Helical Filter I have just made can Bandpass LC Filters, Notch LC Filters and Filter Banks Netcom has designed and manufactured a full line of high quality LC filters for over thirty years. 99 + $7. Our Voluntary 30-Day Return Guarantee does not affect your legal right of withdrawal in any way. The SYM series of filters are a 3 stage symmetrical design that achieves very fast recovery from the notch. com Return Policy: Amazon. 42 MHz GPS carrier frequency. S. (138-520 mhz/380-960 mhz/698-960mhz) dual band pass/band reject filter, low pass filter and high band pass filter manufacturer. The return loss of the cavity at the reject frequency will simply track the tuned reject Receive filters are sometimes necessary to enhance the performance of broadband radios. , attenuate 88-108 MHz, pass 109. The par VHFTN design ensures that the filter has a flat passband and a sharp notch, resulting in minimal distortion and maximum attenuation of the unwanted frequency. Filter DesignerFig: 2 :: Fully assembled Fig: 3 :: Insertion loss / amplitude response Even the height was slightly higher (60 mm) than calculated, the disc-diameter of 20 mm was too big. Filters are available in a Q range of 250 to 10,000. 10 to 0. Sharper deep sided on each side of the center frequency. SO-239 input and output. R. 25MHz with a Theory justment. Notch depth at the pager frequencies is greater than the bandpass filters - typically above 50 dB. g. Click on the image for a larger version. All Bandreject Filters or Band Stop Filters made by Microwave Products Group, including Notch Filters, are Jan 26, 2014 · Hello folks, I've read through the Repeater Builder Dot Com site on duplexers both bandpass and notch filter designs. While it may be more expensive than other filters and require a certain level of technical expertise to operate, its tunability and notch filter features make it a valuable investment for Electronics Tutorial about the Band Stop Filter or Band Reject or Notch Filter which can reject frequencies between two -3dB cut-off points Reviews For: PAR Electronics, Inc. Dec 6, 2006 · Can anyone provide some starter information for designing and building a Vhf pager notch filter? I have a spectrum analyzer with tracking generator that I can use to sweep filters but I'm looking for some info on where to start. RF bandpass filters are passive RF components used to pass signals within a specific frequency band and reject unwanted out-of-band signals. That's when goal number one materialized: 1) The filter must be a throughline at all frequencies EXCEPT the filter frequency, where I wanted loss. Learn how to construct a filter to improve TV reception and attenuate interference on the VHF range. Finally, 2M and 70cM V. In VHF and UHF bands, the Vari-Notch ® design is the most commonly used, with a low-loss pseudo-bandpass characteristic that can exist very close to a deep notch. Aug 21, 2020 · I just received a PAR VHFBP filter yesterday from Universal Radio. The cable length in meters = 75 / Frequency_in_MHz x Cable_velocity_factor. Visit for more! Build a 2-Meter Intermod Notch Trap Bothered by intermod from high-powered pagers? Trap their signals before they reach your receiver with this build-it-yourself notch filter. The radio's case is a Faraday cage, whether or not it is at the same potential as the airframe, and that notch filter should look like a short circuit at the 1575. 5 to a near-perfect 50-ohm Award-winning program performance to orchestrate simultaneous operation of collocated vhf/uhf radios, to improve and increase mission communications, in sea, air and land systems. 2dB | Aluminum Alloy Body | High Quality Tuning Element | Excellent Temperature Characteristics. F. Sinclair Mfg. If it becomes nec- PRODUCT DESCRIPTION Decibel’s Notch Filter is designed for use in certain radio systems where interfering signals are degrading the perfor- mance of the system. MINI-POLE® Filter frequency: HF, UHF, VHF from 1. The disc could be removed completely. Read More For help on these functions please click on the "Help" button. Whether you’re building an SDR, tuning an antenna, or filtering out interference, RF filters help block unwanted frequencies and pass only the signals you need. Bandpass Filter 2. Shop now for fast shipping and easy returns! On-Site Tunable Filters This series of filters finds widespread use at co-located transmitter sites where unwanted carriers may make spectrum measurements difficult or impossible. Find Products Catalog The VHF Crystal Notch Filter from Networks International Corporation is a Band Stop Filter with Stopband Frequency 68 to 72 MHz, Insertion Loss 3. is excellent - typically 1. The Par VHFDN152 VHF Notch Filter is a high-quality component designed specifically for ham radio systems and repeaters. These narrow-band, band-stop Visit full line VHF Cavity Filters from FMUSER, available from 500W to 10kW, 3 1/8", 1 5/8", and 7-16 DIN! Optional bandpass, bandstop (notch), and low pass filter, Up to 6 coaxial cavities. HF & VHF Notch Filter Features Any notch can be set to any frequency in its appropriate band Bypass mode allows for the removal of the filters Units front panel permits local users to view and change notch frequencies All functions and status are available through remote interfaces User replaceable power supply module (front access) PAR Electronics, Inc. In addition, we manufacture antennas for HF, VHF and UHF amateur and commercial use. This kind of filter is used often in front of receivers in order to pass the desired frequency or band of frequencies and attenuate frequencies outside of the desired band. GWAVE VHF Notch Filter - 154. Tags: Surface Mount. The BRF-1601 VHF Tunable Notch Filter Pyramid is a high-quality communication filter that offers excellent signal isolation and reduction of interference. Velocity factor is 70%. This filter offers a narrow band notch attenuation of 25dB min and low passband insertion loss, making it suitable to select closely spaced adjacent channels in receiver applications. Each can be custom tuned to desired notch frequencies and can come configured with a number of different connectors and genders. Tunable Filters and other RF, microwave and fiber optic products from Pasternack ship same day worldwide. Diplexers / Duplexer / Filter Supply: RFS or other manufacture's UHF Mobile duplexer, VHF Mobile duplexer, UHF Notch filter, VHF Notch Filter, VHF/UHF Band Stop filter, VHF/UHF Band pass filter Design: Custom designs are available to suit particular requirements, UHF Mobile duplexer, VHF Mobile duplexer. From the Dec 13, 2021 · Explore 🔍 our step-by-step guide to notch filter design in PCB circuits. The TX RX Vari-notch design provides a pseudo-bandpass characteristic that is ideal for closely spaced VHF frequencies, combining low loss advantages of notch filters with the broad isolation and selective pass characteristics of bandpass filters. 4 dB Passband Loss Optimized for VHF Pager Rejection 15. The ̄lter schematic provides one, two or three ̄nite transmission zeros (Tzs), and these Tzs locate in the upper stopband to improve the rejection of stopband above the center frequency The Filters come in many different designs suitable for various VHF- & UHF radio applications as e. This is the typical notch depth in dB relative to the minimum loss point. an improved filter could find other uses. Find great deals on eBay for Vhf Notch Filter. Aug 15, 2014 · The solution to the repeater problems is in using very selective band-pass and/or notch filters, which is what cavity resonators do. The capacity made out of the M6 screw and the 10 mm (diameter) rod was sufficient to tune to the desired frequency. Each model will have basically the same frequency response across its own band. Notch filter made with coaxial cable. The result - a small patented* notch filter centered on the pager spectrum of 152-153 MHz with extremely low insertion loss on 2M and 70cM (typically less than 0. Notch depth typically runs -20dB or greater. 10 inches to the other center conductors inch square Fiberglas Circuit Board 50 ohm 1. Used F connectors (SMA, BNC upon request). 5 MHz to 700 MHz. W. Feb 1, 2023 · However the notch will repeat at every odd harmonic so a notch at VHF will also land in the middle of the UHF band like one made for 155MHz will also notch at 465Mhz then another at 775MHz and so on. We have a great online selection at the lowest prices with Fast & Free shipping on many items! The Filters come in many different designs suitable for various VHF- & UHF radio applications as e. Leaving it out improves the VSWR from about 1. 25:1 worst case. com Voluntary 30-Day Return Guarantee: You can return many items you have purchased within 30 days following delivery of the item to you. The advent of high-speed amplifiers opens the possi-bility of higher-speed notch filters—but are they actually producible? This article Basics of Cavity Filter Cavity filters are the basic circuitry behind a Duplexer and are sharply tuned resonant circuit that allow only certain frequencies to pass. Learn essential design tips, component selection, and implementation techniques for optimal signal filtering ⚡. In this article, I’ll illustrate a […] 5 days ago · Find many great new & used options and get the best deals for PAR Electronics VHF Notch Filter with cables AS IS at the best online prices at eBay! Free shipping for many products! Tunable bandpass and band reject filters are available from HF to S-band and are designed to provide high performance in a single package. Pasternack Tunable Filters are part of over 30,000 RF, microwave and fiber optics products available for same day shipment. May be left in-line for 2M/440 rigs too. H. 3 | low Insertion loss: <1. The copper shield is 15. manufactures a broad line of scanner filters. 33. Error retrieving detail Add to Cart TX RX Systems Inc. You can find out The Notch Filters are tuned to the SVR frequency but are installed on the mobile's antenna cable to further reduce phase noise from the mobile transmitter that falls on the SVR receive frequency. View VHF bandpass filters including 900 MHz & 2. If you don't find tunable band reject or notch filters here that match your needs, please send us a quotation request for custom tunable band reject filters or custom tunable notch filters. For a 2m repeater, the TX and RX signals are 600 kHz apart, very close at VHF, there expensive. Perfect for engineers! Apr 11, 2025 · Pyramid Communications BRF-1601 VHF In Band Notch Filter Frequency 172. The Notch Filter will be transparent to all frequencies except a narrow band centered around the SVR frequency. All Bandreject Filters or Band Stop Filters made by Microwave Products Group, including Notch Filters, are available as a wideband or narrowbandreject filter and can be customized to user specifications. I put a notch filter on the comm antenna output right on the back of the radio. Filters can be constructed in x to x sections with an available Q range of x GHZ to x GHz , in tunable bandpass or bandreject notch designs. 03:1 Phase & Amplitude Matching Low 3rd Order I/M Phase & Amplitude Matching SMT (hermetic + non hermetic), connectorized, thru-hole package configurations PAR FM High Pass FM Broadcast Filter for scanner listeners RF Filters Radio frequency filter products provide a frequency-dependent level of signal attenuation, and are distinguished from similar products by their intended use in radio-related applications. Standard is no DC power pass. Where Notch Filter are Used Notch filter circuits are normally used for suppressing, nullifying, or cancelling a particular range of frequencies in order to avoid an annoying or unwanted interference within a circuit configuration. Today, we manufacture a broad line of filters for the commercial 2 way market, MATV, FM broadcast, laboratory, marine industry, amateur radio, scanner and short wave listening enthusiasts. One use Xinlun Technology Communications is a professional manufacturer in UHF/VHF cavity duplexer, RF antenna duplexer, supporting with ODM/OEM duplexer worldwide. While typically used in test and measurement applications, these products can also be ruggedized for mobile and remote applications. *Note: There are different types of Notch Filters in each of the frequency bands. Range (MHz) 406-512 Maximum Input (Watts) 350 Shipping Info Please allow 14 to 21 Days for Delivery Application A notch cavity is a filter Home Filters In Stock Tunable RF Filters (20-3000 MHz) 118-137 MHz User Tunable VHF Filter Cavity filters are a type of resonant filter used for either passing desired RF signals within a specified frequency range or rejecting RF signals within a range of frequencies. Jul 21, 2020 · Most of us are familiar with the FM-Notch filters for VHF aircraft band monitoring that blocks out interference from strong FM broadcast stations. 25 and above (Marine Navigation band) Overview NIC introduces a high performance Crystal Notch filter operating in the VHF frequency range. 00 Add to Cart G-Wave Solutions, LLC Dec 16, 2008 · A braid possibly? Gil -- Well here's one thing I'm thinking about grounds. 5% Sections: 2 to 6+ Monolithic + discrete solutions available Very sharp shape factor: up to 1. Jun 4, 2024 · Quick Summary A DAB notch filter is used to suppress strong Digital Audio Broadcast signals in the VHF Band. Jan 4, 2018 · Eyou Electronics supplies 50W VHF Notch Filter Duplexer 135-175MHzin Australia, the main specs and features: High isolation between Rx and Tx ports Typ. Feb 19, 2021 · In my previous article, I discussed overload from broadcast stations and the filters that could block those strong signals from getting to your radio. The receiver needs band-pass for RX but a notch filter for TX. This notch filter is engineered to minimize interference and enhance signal clarity in the VHF band, particularly in the 144-148 MHz range. Mar 27, 2025 · This filter eliminates interferences coming from VHF TV stations that influence TV reception. Typical -3dB points are +/- 1. 815 MHz PART #: $3,650. Notch depth in an RF (Radio Frequency) filter refers to the level of attenuation or suppression that the filter provides at a specific frequency or narrow band of frequencies. 5 dB, Rejection 25dB min Out of band rejection 15dB @ Fc ± 13 MHz25dB @ Fc ± 18 MHz, VSWR 2. The basic FM Notch filter, FLT201A (FLT201A/N, FLT201A/T), is a very useful complement to any monitoring site were VHF and UHF signals are monitored on a regular basis. 050 $29. Model No. I have a 996 hooked to a CF7W 174-216/470-806 is low loss pre-selector filter that passes VHF chs 7 thru 13 and UHF chs. EMR Corp delivers high-quality RF filtration and amplification equipment. TX RX duplexers provide the transmitter and noise suppression characteristics you need while minimizing the loss to your carriers. GWAVE External VHF 5 Cavity Notch Filter 156. A DAB notch filter, when inserted at the input to a software-defined radio receiver will allow it to receive and process signals in adjacent bands – interference FP20307-2 Cavity filter, bandpass, high Q, three 7" cavities, 132-150 MHz Add to Quote View Datasheet Add to Compare The most frequently used filter as a band-pass or notch filter in VHF and UHF transceivers is a helical filter. , was founded in 1978, initially supplying traps and notch filters to the MATV industry. As implied, a Notch Cavity Filter is a shunt filter tuned to a singular band-stop sureable. We measured an insertion loss of 0 Xinlun Technology providing UHF+VHF bandpass & bandreject filter, rf notch filter for amateur radio base station. Pass band only 0,5 dB! see above. CRYSTAL FILTER CAPABILITIES Frequency range: 100 KHz – 250 MHz Bandwidth: 0. gov Reviews 0 No reviews available Be the first to Write a Review HPN-30118 Combined Notch Filter helps eliminate radio interference and scanner front-end overload. This term is commonly associated with notch filters or band-stop filters, which are designed to reject signals within a certain frequency range PAR Electronics, Inc. The duplexer is tunable within the operating frequency range. 25 shipping r cavity. Bandwidth for VHF/FM (10-250 MHz) or VHF/UHF systems (5/400-800 MHz) Filter Impedance is available for 75 ohms (F, BNC) or 50 ohms (BNC, N) Multiple notch models for FM band deletion are available: customized for exact spectrum deletion and to preserve signals, e. Introduction Active notch filters have been used in the past for applications like elimination of 50- and 60-Hz hum components. CF7W 54-216 MHz/470-700 is low loss pre-selector filter that passes VHF 2 thru 13, UHF chs 14 thru 52. More details for VHF Crystal Notch Filter can be seen below. These signals can cause radio receivers to saturate thereby preventing reception of signals in neighboring frequency bands. I'm going to play around with it on my dedicated VHF Aircraft scanner (BCT15X). The resonant cavity within these filters can be constructed from durable materials, such as highly conductive and dimensionally stable metals, to reliably perform for years in harsh environments. com: Tunable VHF Notch Filter, tunable Notch Filter CH7-13 with F connectors : Industrial & ScientificAmazon. MIN-POLE® Filter features: MINI-POLE Tunable Filters are available in bandwidths from 3. A simple and cheap HF notch filter could be made with a 'T' coaxial connector inserted in your antenna line with a 1/4 wave length open line connected to the vertical part of the 'T'. Nov 22, 2023 · Figure 1: The dual notch filter assembly - installed at the repeater. 00 Add to Cart G-Wave Solutions, LLC Tunable Filters from Pasternack Enterprises ship same day. The Coaxial Dynamics filter in this picture is ok and much better than any Description Description GWAVE VHF Notch Filter – 155. TETRA, DMR, PMR, P25 and First Net. Jul 13, 2024 · In this article I will provide a detailed explanation regarding how to design notch filters with precise center frequency and for maximum impact. Along with the ability May 15, 2024 · When it comes to Notch filters for VHF or UHF in my opinion the Cavity type is the best performer. A. then switch TX to the RX frequency and fine adjust the unwanted frequency,. 7% with insertion loss of 2. Notch versus band-pass As the name implies, a "notch" filter removes only a specific frequency, ideally leaving all others unaffected while a "band pass" filter does the opposite - it passes only a specific frequency. PAR Electronics VHFDN152 VHF Notch Filter. Explore our innovative solutions for antennas, filters, and more. The center conductors at the tee connections, while cut to 0. 001% - 2. Apr 4, 2021 · If you have an FM transmitter at the same site or nearby you will probably need a good FM notch along with a band pass filter for air band. Jan 30, 2023 · As can be seen in Figure 2, the pass cavity may still pass energy from odd-order (3rd, 5th) harmonics that may fall within commercial/70cm and TV broadcast frequencies - but the addition of a VHF low-pass filter - perhaps even the VHF side of a VHF/UHF mobile diplexer - would eliminate these responses. There are four open-circuit quarter-wave stubs, to notch out the 2nd, 3rd, 4th and 5th harmonics. - Band Reject (Notch) This is a compliment to the Band Pass filter. Find top brands, exclusive offers, and unbeatable prices on eBay. Features: NANO-POLE® Tunable Filters are available in bandwidths from 3-12% with insertion loss of 2. They have proven to be somewhat problematic from the standpoints of center fre-quency (f 0) tuning, stability, and repeatability. Browse Tessco's industry-leading inventory of cavities & accessories. That is, if it's even worth pursuing. Mini-Circuits' selection of surface mount and coaxial bandpass filter models includes a wide variety of technologies including LTCC ceramic, cavity filters, waveguide filters, reflectionless filter ICs and Abstract|A compact helix structure implementation and associated design formula of lumped element second-order bandpass ̄lter circuit for high power frequency-hopping (FH) ̄lter are proposed in this paper. The RF Filters are designed in many different shapes and sizes, depending upon, for instance, how much Tx power the Filter will be loaded with, or if it is used just on the Rx low power side. Optimize your VHF and UHF communications with high-quality RF filters, cavity filters, and duplexers from RF. Shop with confidence. Guru. 132-150 MHz, Vari-Notch Cavity Filter TESSCO SKU: 524126 MFG PART: 15-36-05 Error retrieving detail Add to Cart now say you have two filters you have one and pass and one as notch, TX one side in to the pass, then pass to the T of the notch and notch to power meter, TX on the wanted frequency say TX adjust pass to allow maximum pass. After much research, I found that most RF filters could do a good job at the VHF frequency, but impedance mismatches and response up to 1 GHz was disappointing. What do BCI Filters do? The Halibut Electronics BCI Filters are in-line filters that block high powered broadcast bands from overloading your receiver’s front end, while allowing VHF and UHF to pass through with minimal insertion loss. Products are used within the commercial and military markets and include bandpass, lowpass, highpass and notch. 4 GHz ranges today. For example, dbSpectra offers VHF cavities with eight inch and five inch enuation. 64 MHz WARNING: Cancer and Reproductive Harm - www. ca. 14-69. 5 dB or less). The notch filter can be considered the opposite of the band p s filter. GWAVE VHF Notch Filter - 155. Low VSWR, Low insertion loss, Best prices. 01 to 40 GHz (L band, S band, C band, X band, Ku band, K band, Ka band) Bandpass Filters are available as narrow band filters or wideband filters, supporting bandwidths from . Duplexer Micro-4201-C6 utilizes six high-Q notch-type coaxial resonators with 1”-cross-section that results in small geometry advantages without compromising duplex isolation. Coaxial Tank V. FR30107-3 - 406-512 Notch Cavity Filter Type Reject (Notch) Freq. » Allows VHF or UHF In-Band Operation with multi-frequency Mobile Radios with close frequency spacing » Automatically removes the Notch Filter from Mobile antenna line for frequencies not used with the SVR-200/250 Vehicular Repeater » Prevents damage to the Mobile Radio or Notch Filter COAX SWITCH •Two 50 ohm pads. They are commonly used to limit the amount of interference caused by strong signals outside a frequency range of interest. 2 to 4. In this guide, we’ll cover the main types of RF filters, how they work, and where they’re used. 5% of the notched frequency- or about +/- 2. The filter has a center frequency of 152-15 MHz, which makes it ideal for use in VHF communication systems, radio frequency identification (RFID) systems, and other applications that require precise frequency control. com. VHF and UHF Transmitter Harmonic Filters These filters connect to the output of your transmitter and notch out all the major harmonics. Get the best deals for Vhf Notch Filter at eBay. Generically, the filter of this kind is known as notch filters. Quote #Q2024043RB Add to Cart G-Wave Solutions, LLC Jun 7, 2025 · Radio Frequency (RF) filters are essential components in any wireless communication system. Our collection includes bandpass, low-pass, high-pass, notch filters, and duplexers, designed to reduce interference, eliminate unwanted signals, and enhance signal clarity. 25:1, Operating_Temperature 0 to +85 Degrees C. 64 MHz PART #: $7,655. 0 inches long. 0 inches of UT-141A 50 ohm Semi-rigid coax. 2% to 21. The Par VHFBP is a special bandpass filter designed for the VHF aero band listener. Ideal for ham radio, SDR, repeaters, and professional RF applications, these precision-engineered solutions Filters can be constructed in x to x sections with an available Q range of x GHZ to x GHz , in tunable bandpass or bandreject notch designs. Made in the U. 60 inches Coax UT-141A Browse Tessco's industry-leading inventory of band pass filters & accessories. Sep 11, 2005 · The major difference is the use of TX RX Systems exclusive "Vari-Notch" (c) filter designs which incorporate the equivalents of a broad bandpass filter and a notch filter within the same cavity. Helical filters are commonly used in radio frequency applications for their ability to pass a range of frequencies while rejecting frequencies outside of the desired band. Note: All filters come in blue opaque heat shrink. Notch Filters also fall under the category of Band Stop Filters, as they reject frequencies, but in a highly selective, high-Q form. Frequency: HF, UHF, VHF, L band, S band from 225 MHz to 3000 MHZ. Energy at the resonant frequencies, or center of the notch, enters the cavity and is reflected back, out of phase with th Notch Trap Models FM Notches Center frequency can be specified from 88 to 108 MHz Sharp, ultrasharp, fixed frequency and tuneable frequency models are available Bandwidth for VHF/FM (10-250 MHz) or VHF/UHF systems (5/400-800 MHz) Filter Impedance is available for 75 ohms (F, BNC) or 50 ohms (BNC, N) Multiple notch models for FM band deletion are available: customized for exact spectrum Overview With Bandreject Filters, also known as a Band Stop Filters, frequencies are attenuated in the stop band and passed outside these parameters. It does more than the typical FM-Notch filter. We offers several standard Bandpass and Bandreject Tuners covering the frequency range of 24 MHz to 3000 MHz in octave bands Specifically, they are 20kW FM low pass filter for sale (LPF) and 10kW VHF low pass filters for sale (LPF), 10kW VHF bandstop filter for sale (BSF), 350W UHF digital bandpass filter for sale, and one of our top-sale radio station equipment - FM bandpass filters for sale. Building a DIY VHF Resonant Cavity Notch Filter. This series of filters finds widespread use at co-located transmitter sites where unwanted carriers may make spectrum measurements difficult or impossible. The VHF-SN (XXX) filters are a single, symmetrical field tunable notch filter. And even though there is the poor man's way of tuning listed, I was wondering about a different approach. View VHF & VHF cavity filters, cavity duplexers & notch filters today. Physically a cavity filter is a resonator inside a conducting “box” with coupling loops at the input and output, as follows: Cavities are usually constructed as Overview Bandpass Filter frequency: VHF and UHF from 0. P65Warnings. The Notch Filter is used when high attenuation is required for narrow spacing between the working and the rejected frequency in the VHF range Jun 9, 2017 · Amazon. 5 to 8. VHFDN152 Category: Filters, RF: bandpass, duplexer, lowpass, highpass, RFI/EMI eMail Subscription Registered users are allowed to subscribe to specific review topics and receive eMail notifications when new reviews are posted. Most of us don't have a service monitor or a scope that can go up to Explore a wide range of our Vhf Notch Filter selection. 045 MHz. Xinlun Technology offers Band Reject Filter (BRF) or Notch Filter to filters out signals at frequencies while allowing other frequencies to pass. I found a new filter that does that and more! If you have an antenna/scanner/receiver that is dedicated to VHF aircraft monitoring check this out PASS-REJECT CAVITIES WITH ADJUSTABLE COUPLING 30-174 MHz BANDPASS CAVITIES WITH ADJUSTABLE COUPLING 30-174 MHz BANDPASS CAVITIES WITH ADJUSTABLE COUPLING 200-960 MHz NOTCH CAVITIES WITH ADJUSTABLE COUPLING 200-960 MHz Types of Filters There are three basic types of filters that you will be working with - Band Pass Passes a relatively narrow band of frequencies. The best notch I've found is the MiniCircuits ZBSF-95-N here Mini-Circuits I've found some really good commercial US made VHF air band specific filters on Ebay for good prices. The 5th-harmonic stub S4 is optional. 80dB | Low VSWR: <1. 1% to 200%, in configurations of 2 to 18 sections. xkykvri vl9lk k4hufhcv t5f y47 2xgv3 gbf qr xot k06b7