This produces a 250 Watt amplifier and has a strip line inductor to match the output. RECOMMENDED POWER SUPPLY 35-40 AMPS. There are also unbranded units available. COM 205-572-6922 , 445-245-0562 CallText. As long as you have a massive power supply capable of around 700 amps to run it, some pretty mean coax and a very solidly built antenna with low SWR then youre in for one heck of a time. Amplifiers are 500 each will DEMO on pickup Chihuahua puppies 400 each. 1-30MHz BROADBAND MOSFETS 2xSD2933 CLASS AB TEST. 500 Watts. AM linear amplifiers are often operated incorrectly. 500 in. Texas Star DX-667V Transmitter. Or fastest delivery Tomorrow, Feb 9. Pre-amp yes. COM Due to the COVID-19 Pandemic, Parts and suppliers have been really slow. Tube Eimac 3cpx1500A78877 used test full power output TransmitReceive switching 30 Amps open frame relay Power-line requirements 220240 Vac 5060 HZ 25 or - Amps at 240 Vac Power Supply Heavy duty 1. 00 >2000 watt 700. Looks ok, works good (400 to 450 peak watts). com or call (301)870-6085 Check out our new antennas from noname products. for sale > antiques - by owner. ICOM IC-PW2 Linear Amplifier (DEPOSIT) (PRICE TBA) &163; 10. , 1 x 3 6LF6 Tuber, 120 Volts, Ugly, but works great. A CB radio comes set up for four watts of power, which is a level regulated by the Federal Communications Commission. 95 Ameritron HF Power Amplifiers Amplifier, Mobile, No-Tune, Solid State, 500 W Output PEP, 160-15 meters, 14 Vdc, 80 A Maximum Line Current See More Specifications Estimated Ship Date Today Would you rather pick it up Select Location Free Shipping Add To Cart Wish List Compare DX Engineering Super Card View Details See if you Prequalify. Add to Compare. For sale HF LINEAR AMPLIFIER 500W AUTO BIAS RF INPUT 10W RF OUTPUT 500W POWER SUPPLY 48-55V20A FREQ. KPA500 Features 500W, Compact, Solid State FET amplifier for 160-6 m. com Cb Amplifier 1-16 of 602 results for "cb amplifier" RESULTS HYS TC-300 CB Band HF AMP for CB Band Handheld Radio Transceiver 34 19999 FREE delivery Feb 28 - Mar 23 Only 19 left in stock - order soon. CB linear Amplifiers 500 Watts & Chihuahuas - 500. RF Linear Power Amplifier 1-1050MHz for DTMB Amplified Emission. 90 35. 00 Free shipping or Best Offer 28 watching Varmint Xl-100 cb ham radio linear amplifier 56. 42,000 views Nov 30, 2018 453 Dislike Steve Stevens 3. Reviews more BEST ANTENNA AROUND. Equipped with Adjustable High-PassLow-Pass Crossover Filter, Auto Turn ON Facility, Can Connect Speakers, Tube Subwoofer, Subwoofer. COM Due to the COVID-19 Pandemic, Parts and suppliers have been really slow. -30dB 3IMD) power transistors in push-pullparallel. Fatboy 1x2290 drive 2x2879 mobile 500 watt Radio Linear Amplifier. 50 Amps. -30dB 3IMD) power transistors in push-pullparallel. INPUT POWER 2-12W SSBCW. Sirio Tornado 27 27 - 30 Mhz Tunable 10m & CB Base Antenna. Tube Eimac 3cpx1500A78877 used test full power output TransmitReceive switching 30 Amps open frame relay Power-line requirements 220240 Vac 5060 HZ 25 or - Amps at 240 Vac Power Supply Heavy duty 1. Most small units will have 2-3 week lead time. The black knob selects the various metering positions. 00 Export &163; 8. I purchased this amp at an estate sale . Internal low noise linear power supply 100-120, 200-240 VAC, 5060 Hz operation. This compact little amplifier is the brain-child of Pat Murdoch, ZL1AXB, in Auckland, New Zealand. Linear amplifier for sale Vintage linear conchord 21. 5 amp steel core transformer and high capacitance grade filter capacitor, also features time. Of the brand texas star in addition to a power equivalent to 350 w A color silver and also for instance amateur, linear. MFJ-264 Best Highly Adaptable Dummy Load 4. The item "Vintage Elkins CB Radio Linear Amplifier 4 Tubes FOR PARTS ONLY" is in sale since Monday, October 25, 2021. This post is for a LA. Texas Star DX-667V Transmitter. 6-30MHz (300W) Linear Amplifier (With Pre-Amp. 500 Watts. Home Amplifiers Product Results Filters In Stock. Texas Star 350V CW Transmitter. Smile more. Repairs We do offer repair service on most makes and models of radios and amplifiers. Go back to the Amplifiers page. COM Due to the COVID-19 Pandemic, Parts and suppliers have been really slow. This compact little amplifier is the brain-child of Pat Murdoch, ZL1AXB, in Auckland, New Zealand. We have a great online selection at the lowest prices with Fast & Free shipping on many items. Class B biasing. for sale > antiques - by owner. Sub total. Find many great new & used options and get the best deals for Astron RS-20M 20 Amp 60 hz 500 watts DC Power Supply wMeters at the best online prices at eBay Free shipping for many products. Includes ALS-600 Amplifier and a 120220 VAC, 5060 Hz AC switching power supply for home operation. The 144MHz Gemini 2-500 incorporates the same, sequenced, front panel switchable 13. Condition Select a new, used, refurbished, or parts-only amplifier. AU 129. 00 20. Ham Radio FIREBIRD F-500 Linear RF Amplifier NOT FOR CB. Chokes are supplied for the RF In, RF Out, Relay Cable, and. 5 amp steel core transformer and high capacitance grade filter capacitor, also features time. 97 USD USA AMERITRON ALS-500M NO TUNE 500W PEP. The Varmit plastic meter face is missing. 9 (34) 19999 FREE delivery Mar 21 - Apr 13 Only 13 left in stock - order soon. The 144MHz Gemini 2-500 incorporates the same, sequenced, front panel switchable 13. 9 (35) 19999 FREE delivery Apr 6 - May 1 DC -160MHz Antenna Sharer,100W Antenna Sharer SDR Transceiver Switch TR Switch Box,Antenna Sharing Device Aluminum Alloy Box Device 3. Add To Cart. Due to the COVID-19 Pandemic, Parts and suppliers have been really slow. 99 Click & Collect &163;4. Gonset GSB-101 800 Watt linear amplifier for a base station, covers 80-10 meters , has 4 811A tubes. FREE delivery Mar 21 - Apr 13. 1-24 of 112 results for "cb linear amplifier" RESULTS HYS TC-300 CB Band HF AMP for CB Band Handheld Radio Transceiver 3. RECOMMENDED POWER SUPPLY 35-40 AMPS. Ameritron Amplifiers - Free Shipping on Most Orders Over 99 at DX Engineering Welcome My Account Order Status Wish List Hot Deals What&39;s New Brands Quick Order Gift Card Shop Departments Amplifiers Amplifiers See All Items In This Department Antennas Antennas See All Items In This Department Antenna Tuners Antenna Tuners. HF6m LINEAR AMPLIFIER 500W V2. Has 4 x Toshiba 2SC2879 (100W SSB output ea. These kits are designed to choke common mode currents going into or exiting from your rig. uk or call at 01922 414 796. Best CB linear amplifier Review MegaWatt S-700-12 CB Radio Linear Amp. DC -160MHz Antenna Sharer,100W Antenna Sharer SDR Transceiver Switch TR Switch Box,Antenna Sharing Device Aluminum Alloy Box Device 3. Go back to the Amplifiers page. Find used Cb Linear Amplifier for sale on eBay, Craigslist, Letgo, OfferUp, Amazon and others. Its intermodulation and harmonic distortion products are well below 40 dB down from its maximum power output, and its tendency toward parasitic oscillations is so low that a parasitic plate choke is unnecessary. , 1 x 3 6LF6 Tuber, 120 Volts, Ugly, but works great. Palomar 400 Linear Amplifier - 150 (CEDARTOWN) Ad id 807172211627688. 2 (13) 6470. CB or Ham radio. Amplifier Height 3. COM Due to the COVID-19 Pandemic, Parts and suppliers have been really slow. Opens in a new window or tab. 9 (34) 19999. 3 de jan. So not a fixed power cable and no power cable included. It may be used for all narrow band . Add to Wish List Add to Compare 95. The 144MHz Gemini 2-500 incorporates the same, sequenced, front panel switchable 13. Zetagi B501P Power Amplifier 70-250W AMFM, 140-500W SSB Zetagi. Sirio SY 27-4 4 elements Yagi Beam CB Antenna. Years back I had helped build a couple of valve (tube in the US) amplifiers using a single 4CX250B on 2 meters. 500 Watts. Base Station Linear Amplifiers (tube type) 500 Watt p. We are working hard to resolve this issue. Add to Compare. Feed it with a power amplifier from DX Engineering. ALS-500M amplifiers operate at full power with continuous frequency coverage from 1. OUTPUT 60-250W (PEP) AMFM - 120-450W (PEP) SSBCW. The item Maco 750 Amateur Linear CB Tube Amplifier Ham Radio is in sale . 00 >2000 watt 700. 1400 Watts. Note These units are sold as CW Transmitters and not as linear amplifiers. 3 de jan. 1,200 Watt Base Station Linear Amplifier, 3 4X150 Ceramic Tubes, Dual Meters, Easy Tuning. Jun 08, 2019 The 45 watt version only takes 10 milliwatts of drive to get full power, so it can be connected directly to the BitX 40 TR relay with a 3 to 6 dB pad (bypassing the PA). knife blanks made in usa. OUTPUT 60-250W (PEP) AMFM - 120-450W (PEP) SSBCW. Texas Star DX-500V Transmitter. There are also unbranded units available. Home Contact Us Log In Shopping Cart - 0 item(s) - 0. CB linear Amplifiers 500 Watts & Chihuahuas - 500. We are working hard to resolve this issue. 59 shipping. Kenwood TS-990S - FREE SP-990M Speaker and MC-43 Mic. Texas Star DX-500V Transmitter. Amplifiers are 500 each will DEMO on pickup Chihuahua puppies 400 each. Heathkit SB-221 Linear amplifier kit unassembled 1,175. Learning how to hook up a CB linear amp (kicker box) is easy. Results 1 - 24 of 89. com Cb Amplifier 1-16 of 602 results for "cb amplifier" RESULTS HYS TC-300 CB Band HF AMP for CB Band Handheld Radio Transceiver 34 19999 FREE delivery Feb 28 - Mar 23 Only 19 left in stock - order soon. Smile more. , 1 x 3 6LF6 Tuber, 120 Volts, Ugly, but works great. This can be selected by the operator to be either an. 90 35. Here are some of the best CB Linear Amplifiers. Due to the COVID-19 Pandemic, Parts and suppliers have been really slow. TNT 600hd. 500 Watts. Texas Star DX-400V CW Transmitter. Find many great new & used options and get the best deals for Astron RS-20M 20 Amp 60 hz 500 watts DC Power Supply wMeters at the best online prices at eBay Free shipping for many products. Amplifiers are 500 each will DEMO on pickup Chihuahua puppies 400 each. This is because the CB application prioritizes low-noise over power efficiency, something which a linear amplifier offers. Chokes are supplied for the RF In, RF Out, Relay Cable, and. 3000 Watt CB Linear Amplifier mrwizard33 302 subscribers Subscribe 271K views 14 years ago This home brew amp put out 3KW the first time it was fired up. We reserve the right to refuse sales and service to anyone. DC -160MHz Antenna Sharer,100W Antenna Sharer SDR Transceiver Switch TR Switch Box,Antenna Sharing Device Aluminum Alloy Box Device 3. Find the best Amplifier 500 price Amplifier 500 for sale in India. 90 35. Jun 08, 2019 The 45 watt version only takes 10 milliwatts of drive to get full power, so it can be connected directly to the BitX 40 TR relay with a 3 to 6 dB pad (bypassing the PA). We reserve the right to refuse sales and service to anyone. Tube Eimac 3cpx1500A78877 used test full power output TransmitReceive switching 30 Amps open frame relay Power-line requirements 220240 Vac 5060 HZ 25 or - Amps at 240 Vac Power Supply Heavy duty 1. Its intermodulation and harmonic distortion products are well below 40 dB down from its maximum power output, and its tendency toward parasitic oscillations is so low that a parasitic plate choke is unnecessary. The 144MHz Gemini 2-500 incorporates the same, sequenced, front panel switchable 13. The black knob selects the various metering positions. Ready to useATU-500 Antenna Tuner with Shell,no need to assemble,developed by N7DDC. This home brew amp put out 3KW the first time it was fired up. 00 Checkout. Power-line requirements 200240 Vac 5060 HZ 30 or - Amps at 240 Vac Power Supply Heavy duty 1. COMMANDER 150A LINEAR AMPLIFIER 150. Internal low noise linear power supply 100-120, 200-240 VAC, 5060 Hz operation. Search 50 Watt Hf Linear Amplifier. The KL703 is a new 500W linear Amplifer for operation between 25 and 30 MHz, (developed for the 10m amateur radio band). Screen voltage is 600, and the anode idle current is 80 MA. Pyramid PS9KX Universal Compact Bench Power Supply-5 Amp Linear Regulated Home Lab Benchtop Converter w 13. Report Last Updated on February 20, 2023 with Eagle 500 Linear Amp Cb Radio&92; Ham Radio (Southern Indiana ,Brandenburg KY Area). 00 >2000 watt 700. uk or call at 01922 414 796. Amplifiers are 500 each will DEMO on pickup Chihuahua puppies 400 each. 20 postage 17h. So a 100 watt amplifier to an export CBRadio without adjustable power provides more than 10 watts, does not work. To prevent damage to your installation, make sure to use power leads from. 1 Off. 000 in. 95 74. Palomar 400 Linear Amplifier - 150 (CEDARTOWN) Ad id 807172211627688. 8v preamplifier supply on receive. Find many great new & used options and get the best deals for Astron RS-20M 20 Amp 60 hz 500 watts DC Power Supply wMeters at the best online prices at eBay Free shipping for many products. INPUT POWER 2-12W SSBCW. Amplifier Height 3. Power Output (RMS) 300 Watts. Amplifiers are a favourite homebrew project. SSB Delay yes. 8v preamplifier supply on receive. Visit the link below for current inventory Texas Star Mod V Plus CW Transmitter Texas Star 250V CW Transmitter Texas Star 350V CW Transmitter Texas Star DX-400V CW Transmitter Texas Star DX-500V Transmitter Texas Star DX-667V Transmitter Go back to the Amplifiers page. Linear Amp Gemini 2-500 144MHz 500W Solid State Linear Amplifier Solid state 144MHz 500W Linear Amplifier 500W output Ampleon ART700FH LDMOS Integral 50V Linear Power supply Drive requirements 4-25W (specified at purchase) Cooling for data mode operation Full protection for overdriveswrtemperature. View All CB Radio Amplifiers For Sale. 14 amps times 12 volts equal approx 168 watts of input. COM 205-572-6922 , 445-245-0562 CallText Featured Products 102" Whip Adjuster 7" Long Version 37. Rocketbox amps for radio communication (cb radio) cb linear, palomar, 9530, rocketbox 250, rocketbox 500hd, and other electronics supplies. Ameritron Amplifiers - Free Shipping on Most Orders Over 99 at DX Engineering Welcome My Account Order Status Wish List Hot Deals What&39;s New Brands Quick Order Gift Card Shop Departments Amplifiers Amplifiers See All Items In This Department Antennas Antennas See All Items In This Department Antenna Tuners Antenna Tuners. cutoff value calculator. 00 >600 watt 300. Exactly the same size as the K3S transceiver, the KPA500 fills out our K3S-P3-KPA500 &x27;K-Line&x27;. As long as you have a massive power supply capable of around 700 amps to run it, some pretty mean coax and a very solidly built antenna with low SWR then youre in for one heck of a time. - Showing 1 to 14 of 14. Years back I had helped build a couple of valve (tube in the US) amplifiers using a single 4CX250B on 2 meters. ATU-100 Upgraded ATU-500W ATU500 Automatic Antenna Tuner (ATU-500W by N7DDC) Tuning Range 10W-500W. Add to Wish List Add to Compare 358. Due to the COVID-19 Pandemic, Parts and suppliers have been really slow. The Gemini 2-500 is a complete turnkey solution incorporating a 50V linear power supply. In addition, specific models mentioned in the CB Radio forum Like AMPS for cobra cb radios, tti,. 9 (34) 19999. 9 (34) 19999 FREE delivery Mar 15 - Apr 7. Get the best deals for cb radio base linear amplifier at eBay. 8Vdc supply voltage. Amplifiers are 500 each will DEMO on pickup Chihuahua puppies 400 each. COMMANDER 150A LINEAR AMPLIFIER 150. COM Due to the COVID-19 Pandemic, Parts and suppliers have been really slow. Best CB linear amplifier Review MegaWatt S-700-12 CB Radio Linear Amp. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs. Compare 30 million ads Find Cb . 000 in. Brand new CB linear amps in box & warrenty. COM Due to the COVID-19 Pandemic, Parts and suppliers have been really slow. maloof brothers net worth, las cruces jobs
FREE delivery Feb 13 - 14. . 500 watt cb linear amplifier for sale
This post is for a LA. Screen voltage is 600, and the anode idle current is 80 MA. 00 USD USA Alcatel Eagle 250 Linear Tube. The FCC rules state. Show results from. for sale > antiques - by owner. Watt stranger 4k. Fatboy 1x2290 drive 2x2879 mobile 500 watt Radio Linear Amplifier Red Ranger Oct 6, 2011 R Red Ranger Active Member Aug 16, 2008 150 2. Minimum power 10 watt Below 10W cannot be tuned,please notice. , 1 x 3 6LF6 Tuber, 120 Volts, Ugly, but works great. - Showing 1 to 14 of 14 (1 Pages). com Cb Amplifier 1-16 of 602 results for "cb amplifier" RESULTS HYS TC-300 CB Band HF AMP for CB Band Handheld Radio Transceiver 34 19999 FREE delivery Feb 28 - Mar 23 Only 19 left in stock - order soon. Note These units are sold as CW Transmitters and not as linear amplifiers. 5 amp steel core transformer and high capacitance grade filter capacitor, also features time. Or fastest delivery Tomorrow, Feb 9. Only 13 left in stock - order soon. Transistors 4 x 2SC2879. MFJ Enterprises Inc,Ameritron,Hy-Gain,Hygain,Cushcraft,Vectronics,Mirage,MFJ,MFJ Enterprises,Antenna,Radio,Ham Radio,Amateur Radio,Tuner,Analyzer,Starkville,Amplifier. Tube Eimac 3cpx1500A78877 used test full power output TransmitReceive switching 30 Amps open frame relay Power-line requirements 220240 Vac 5060 HZ 25 or - Amps at 240 Vac Power Supply Heavy duty 1. Exactly the same size as the K3S transceiver, the KPA500 fills out our K3S-P3-KPA500 &x27;K-Line&x27;. 500 Watts. RM Italy HLA 305 Professional Linear Amplifier. , 1 x 3 6LF6 Tuber, 120 Volts, Ugly, but works great. 95 RM KL 703 500 watt input up to 35 watt 2 vents 679. The CB comes with 4 watts of power as regulated by the FCC. FREE delivery Feb 13 - 14. Available for immediate shipping Hardrock-500 features Completely self-contained - built-in power supply for 100-250 VAC. Palomar 400 Linear Amplifier - 150 (CEDARTOWN) Ad id 807172211627688. 50 lbs. The FCC rules state. 5 amp steel core transformer and high capacitance grade filter capacitor, also features time. com Cb Amplifier 1-16 of 602 results for "cb amplifier" RESULTS HYS TC-300 CB Band HF AMP for CB Band Handheld Radio Transceiver 34 19999 FREE delivery Feb 28 - Mar 23 Only 19 left in stock - order soon. Sirio FT-2 Fixing bracket. Find used Cb Linear Amplifier for sale on eBay, Craigslist, Letgo, OfferUp, Amazon and others. Texas Star DX-667V Transmitter. 500 Watts. 8v preamplifier supply on receive. 9 (34) 19999 FREE delivery Mar 15 - Apr 7. The 144MHz Gemini 2-500 incorporates the same, sequenced, front panel switchable 13. This produces a 250 Watt amplifier and has a strip line inductor to match the output. Opens in a new window or tab. COM Due to the COVID-19 Pandemic, Parts and suppliers have been really slow. Solid state 144MHz 500W Linear Amplifier; 500W output; Ampleon ART700FH LDMOS; Integral 50V Linear Power supply; Drive requirements 4-25W (specified at purchase) Cooling for data mode operation; Full protection for overdriveswrtemperature; Switchable preamp output voltage on RX with bias tee option; N Type connectors on input and output; All. Pre-amp available. Vintage CB Ham Radio Firebird F-500 Tube Linear Amplifier. 8v preamplifier supply on receive. 1400 Watts. Pyramid PS9KX Universal Compact Bench Power Supply-5 Amp Linear Regulated Home Lab Benchtop Converter w 13. 96 &163;499. Linear Amp Gemini 2-500 144MHz 500W Solid State Linear Amplifier Solid state 144MHz 500W Linear Amplifier 500W output Ampleon ART700FH LDMOS Integral 50V Linear Power supply Drive requirements 4-25W (specified at purchase) Cooling for data mode operation Full protection for overdriveswrtemperature. com Cb Amplifier 1-16 of 602 results for "cb amplifier" RESULTS HYS TC-300 CB Band HF AMP for CB Band Handheld Radio Transceiver 34 19999 FREE delivery Feb 28 - Mar 23 Only 19 left in stock - order soon. It has 7 tubes They are 20LF6 tubes. 8v preamplifier supply on receive. It may be used for all narrow band . 00 25 bids 89. Search 50 Watt Hf Linear Amplifier. The 144MHz Gemini 2-500 incorporates the same, sequenced, front panel switchable 13. 8-volt equipment, it is a great choice. Black Book of CB Linear Amplifiers Brand New C 39. 95 RM KL 703 500 watt input up to 35 watt 2 vents 679. Chokes are supplied for the RF In, RF Out, Relay Cable, and. 00 8 bids 125. Of the brand texas star in addition to a power equivalent to 350 w A color silver and also for instance amateur, linear. 14 amps times 12 volts equal approx 168 watts of input. - RM KL503HD input up to 35 watten 26 dBi receiving gain 300 watt AM Fm 450 watt SSB 345. 15 YRS Contact Supplier 1 4 100w HF 20-30mhz SSB AM CW FM Power Amplifier for CB Radio; KP990 100W HF Linear Amplifier Shortwave Power Amplifier For 850 KN-990 FT-817 818 KX3 HF Radio Transceiver Specifications - Working. SSB Delay available. 8v preamplifier supply on receive. 1 Off. for sale > antiques - by owner. Search Cb Linear Amplifier Schematics. 5 to 22 MHz; 1012 Meters with easy-to-install optional kit, 29. Texas Star DX-667V Transmitter. 33 Read more COMING SOON ACOM 1200S 1. SSB Delay yes. Amplifier Depth 15. Tube Eimac 3cpx1500A78877 used test full power output TransmitReceive switching 30 Amps open frame relay Power-line requirements 220240 Vac 5060 HZ 25 or - Amps at 240 Vac Power Supply Heavy duty 1. 500 Watts. 00 88. 00 88. Exactly the same size. 50 6 bids 22. It is only 11 wide, 4 high, and 9 deep. AU 80. Price excl VAT 1,082. After tuning and a few mods it. Amplifier Height 3. Hooking up. Vintage CB Ham Radio Firebird F-500 Tube Linear Amplifier. 95 74. Looks ok, works good (400 to 450 peak watts). Jun 08, 2019 The 45 watt version only takes 10 milliwatts of drive to get full power, so it can be connected directly to the BitX 40 TR relay with a 3 to 6 dB pad (bypassing the PA). 5 amp steel core transformer and high capacitance grade filter capacitor, also features time. or Best Offer 79. Ham Radio FIREBIRD F-500 Linear RF Amplifier NOT FOR CB. Very heavy and want local pick up. unique wood anniversary gifts. 00 20. Find the best Amplifier 500 price Amplifier 500 for sale in India. Sale Eagle 500 Linear Amp. The Gemini 2-500 is a complete turnkey solution incorporating a 50V linear power supply. All Elecraft linear a. Add to Compare. 1,200 Watt Base Station Linear Amplifier, 3 4X150 Ceramic Tubes, Dual Meters, Easy Tuning. Languages Currencies A Passion for Communication. I purchased this amp at an estate sale . Used here in. cutoff value calculator. Cb Linear Amplifier (1000) Price when purchased online. . does iehp cover gym membership