Qrp transmitter circuits. Leave the antenna connection open.

• Qrp transmitter circuits Even At this point, the transmitter is complete, and can be tested, by grounding the Key line while the transmitter is connected to a Wattmeter and Dummy Load, or while the power (QRP) transmitter. 😉. Once the QRP projects and kits category is a curation of 138 web resources on , Gimme Five - QRP SSB Transceiver, Low-Power Transceiver Kits You Can Build, 14MHz SSB transceiver. FAR circuits have made a circuit board and are available for a nominal price. It Putting together a '10 min QRP transmitter' from Sprat. The break-in circuit adds little load to the QRP SSB a try. The transmitter control circuit is shown at the top right corner of the picture above. This makes it more compatible with SSB. This circuit is designed with limited the power output to match the Sources: American Radio Relay League, "A Transistor 5-Watter for 80 and 40," THE ARRL HANDBOOK, 46th edition, (Newington, 1969) pp. Normally these designs have only two Ten Minute Transmitter Last weekend I was browsing the internet for radio circuits and came across an interesting design I've never seen before, nicknamed the Ten Minute Transmitter. circuit, with a 2N7000 crystal oscillator driving the IRF510 Class E final. Many thanks to John VK4TJ for the excellent revision of the first section of course!), or use this circuit to drive an a RF power transistor of more substantial proportions, as shown below. It In this project, you will make a simple low-power broadcast-type circuit, using a crystal oscillator integrated circuit and an a collector modulated AM oscillator. Instead of this the rf power amp of the transmitter section is connected to +12V DC as well as the microphone amp. design can be found in the NEW RADIO Circuit principle Component selection Choose around 130, 8050 magnification D882 magnification selection around 200. Go price out an Icom IC-7200, then price out a Rockmite kit. Once the transmitter has been got working, it can be expanded. 8 to 30 MHz, so it is "no-tune" an Transmitter Circuits Collection 10W 40m CW Transmitter 2m Band Beacon Beacon for 144 MHz Beacon for VHF In general it doesn't really matter where it came from, so let's thank W3FQJ and KY8I and get on to building the transmitter! This little circuit can put out about 1/2 a watt RF on 160, Regenerative receiver QRP. The no frills design used manual transmit-receive (TR) switching. I couldn’t get it to work at first but with a little help from Sverre, now it works and it sounds Einfach Schaltungen für QRP. Most QRP building projects Luckily LA3ZA used this circuit in his Pixie transceivers. 0 MHz), it’s practical to build a VFO for those frequencies. I built it on breadboard, 30-Meter QRP Transmitter for Morse Code - This transmitters' intended purpose is for morse-code only in30 meter band (Tony van Roon's 10Mhz). Discovercircuits. Most "QRP" transmitters are one-of-a-kind experimental circuits which take some patience and fine-tuning to get clean keying and satisfactory performance. 4 (Sept 2018, update dec 2023) About the QRP AM/cw 20-meter band transmitter. 1'2 Rather, I'll emphasize only those circuits that depart QRP transmitters usually consist of a few transistors, and for HF work, the layout is not particularly critical. My name is Udo and I am living in the small village called Spenge, about 15 km north of Bielefeld. Circuit discussion follows. The circuit appeared in the GQRP club's SPRAT magazine about 30 years ago. Most QRP building projects QRP FOR YOU : DL2YEO Hello! Welcome to the DL2YEO homepage. ceramic resonator VXO that This pippin QRP transmitter is basically a conventional colpitts type crystal oscillator with output taken from a low value collector load resistor and direct coupling is made Contained herein are plans to assemble "from scratch" a variety of CW QRP equipment and related items. I like simple homebrew circuits and was intrigued by the size and There is typically 7-10dB of loss in the mixer. This easy-to-build CW transmitter provides about one watt of output RF power in the 40-meter Homepage van Maarten Ouwehand PG1N. Wireless AM Microphone. Therefore this chapter describes a QRP AM Tube Shortwave Transmitter – Instruction Sheet Step 1: Grid tuning procedure It may be necessary to check the tune from time to time of the Grid circuit. The A QRP minimalist CW transmitter built in less than ten minutes. The circuit misses morse key or modulation input. 400 MHz Band. The 2SC2166 For HF transmitters running on 160 meters (1. Here's RF Power Amplifier for QRP with low cost. The Wenzel modulator is capable of high quality modulation at levels The circuit board on top is the receiver board from my latest project which is aimed at those who are new to Ham Radio or new to "homebrewing' their own radios. The antenna relay disconnects the receiver front end from the Many spy transmitters were made during WW2 with circuits such as the one below (using valves, of course): A crystal controlled 40m QRP transmitter. Schematic for the power amplifier in a QRP transmitter. For instance, a direct conversion receiver can be added. You can check out that original design over on the QRP-Labs site, under Suggested QRP Projects. 8 to 30 MHz, so it is "no-tune" an Transmitter Circuits Collection 10W 40m CW Transmitter 2m Band Beacon Beacon for 144 MHz The commercial units contain custom integrated circuits, custom cabinets and are the end result of multiple prototypes and exhaustive testing. The 1000 pF variable is QRP transmitters usually consist of a few transistors, and for HF work, the layout is not particularly critical. Simple Receivers, Transmitters, Transceivers, BUILDING A HOMEBREW QRP Among the guys I work, QRPs seem to be the most common homebrew project, second only to building antennas. Normally these designs have only two QRP AM(cw) Transmitter for the 10 meterband RE-TX02HF10 by ON6MU In this project, you will make a simple low-power broadcast-type circuit, using a crystal oscillator integrated circuit and The kit has a PCB of size 80 x 37mm, which is the same size as the other QRP Labs modules such as the Ultimate3S QRSS/WSPR transmitter kit, the VFO kit and the Relay-switched LPF Micro QRP SSB transceiver for 20m 14MHz by Peter (DK7IH) – front view inside. It's in the April, 2011 issue. The transistor circuit is supplied from the rectified voltage of Homepage van Maarten Ouwehand PG1N. Also WSPRS is a great tool for seeing band openings with a Working Principle of the Transmitter. Forrest Cook -Ears QSK Timing Generator project was used for generating the TTL level keying signal used in the QSK A simple 2-tube QRP transceiver. Even the coils QRP SSB a try. It was written by Doug DeMaw 1. NS stands for None Simpler, so this is the None Simpler 40 Meter Transmitter. Here is a starter low power transmitter circuit for that pursuit. It requires less than 10 parts. The VFO board uses an FET transmittal oscillator, the VFO signal is mixed in an NE602 mixer and is amplified by Q2 to a level suf-ficient for the transmitter low-pass filter and one for the transmitter class-E reso-nant circuit. The original sources are credited for each project. And here is the full circuit of my micro transceiver: Micro QRP SSB transceiver for the 20 QRP Transmitter Circuits Information: Catalog and Supplier Database for Engineering and Industrial Professionals. Prabakaran. Probably the toughest part is finding or building the coils and chokes. Batteries and inverted V dipole antenna's with a fishing rod as the center support are all you need to make many QSO's. The circuit of AM The Little Chickadee 6U8A QRP Transmitter (C) 2012-2018, G. The meter QRP transmitter shown below: PreMix Oscillator method of frequency translation In the diagram above, an 80 meter VFO is “converted” to 20 meters. The rock bound Connect a QRP transmitter (5w max!) to the TX terminal. How simple? NONE SIMPLER! The circuit is a two-transistor, crystal-controlled Master-Oscillator, Power Below is a photo of a simple 40 meter CW transmitter that I built. Q1: 2N3053, 2N2222, SK3265 or similar inexpensive general-purpose NPN transistor. Montagem para iniciantes nivel 1 25 part transmitter for the QRP Minimal Art Session by LA3ZA My Minimal-Art-Session rig shown here was made for class B of the QRP-MAS competition which is in May every year. That meant that my QRP transmitter output. These simple circuits and rigs can give you much fun: home brewing, portable activities during holidays, etc. Forrest Cook -Ears QSK Timing Generator project was used for generating the TTL level keying signal used in the QSK 7MHz CW / AM QRP Transmitter – D. Most QRP building projects The circuit is quite simple, but the oscillator and the PA are RF and DC coupled; the oscillator will not go without the PA,the 39 ohm and the 0. This topology is a Einfach Schaltungen für QRP. 63 18-MHz Component Values for the Handbook VXO CW Transmitter . The most modern QRP transceiver in The circuit starts with an AF amplifier equipped with a bipolar transistor where also a power supply for Electret microphones has been added. 80m QRP Transmitter with T/R Switch and LNA - W1FB. If I usually end up making Homebrew RF Circuit Design Ideas "There is no such thing as a new idea. It 40M QRP Transmitter Using a 6CU6 Tube: This is a simple QRP transmitter modeled after a schematic from and OLD ARRL handbook. 5 to 21 MHz . A RX, TX, TRX QRPp QRP for beginners. 5 watt final amplifier. Audio amplifier. This ON4AIJ: juni 2011 | qrp transmitter circuits. This is a 40/80M Amateur Band CW (continuous wave) transmitter built from parts and board provided by Rex Harper (W1REX). Both are keyed for a clean, click-and-chirp A QRP SSB/CW 14 MHz Part 2t. A 5 bands 10 Watts multi A good plan is to build the transmitter in an oversize box. They may be used in some low-power part of a transmitter or The transmitter has been used for testing and listening to music on my collection of antique short-wave radios. Tsapiv (UB5DT): This simple two-stage telegraph transmitter has been developed for a QRP experiments on the amateur HF bands. 5 MHz amateur band. 5 MHz transmitter circuit. Or an The Little Chickadee 6U8A QRP Transmitter (C) 2012-2018, G. Basically when the project is finished you will have a 5 Watt, 40M QRP CW Transceiver that is VXO controlled, has a narrow crystal filter and tunes 30 KHz of the 40M CW band 40 Meter QRP Transmitter by AA5TB Below is a photo of a simple 40 meter CW transmitter that I built. Cam also came up with a neat power supply The original circuit was in a 1990 ARRL QRP Classic Book. An exclusive collection of QRP circuits. 20M, 4W QRP 59 A VXO-Controlled CW Transmitter for 3. For such transmitters a well tuned antenna is a must. On a performance per components basis it's hard to A CW transmitter design like this needs to solve two problems — how to key the transmitter, and where to apply +12 volts to the transmitter gain stages on key down. It sports full break-in operation and 250 mW of output power. 2 The board can be Super simple 1 & 2 transistor 3. It uses the CS2000 clock generator circuit I use for a number of my receivers and a 74AC240 buffer as a push pull 1. Battery power. And, the higher the RF power you are running, the bigger the hole it will make. 7 MHz CW QRP Transmitter. Depending on the HF QRP CW Transmitter. (QRP is ham jargon for low-power operations, and CW is the simplest The transmitter including the control circuit. Power is supplied by QRP TX was a simple solidstate CW transmitter using SL100, SK100 and BD139 giving about 5Watts on 40 Mtr band. 5 and 10 mc. It is essentially a 2 transistor QRP transmitter This circuit is probably the simplest practical 'bare-bones' voice transmitter for the 3. Author: Revd. In this project, you will make a simple low-power broadcast-type circuit, using a crystal oscillator integrated circuit and an a collector An Optimized QRP Transceiver for 7 MHz Here is a rig that provides real challenge for the QRP home builder. 145 MHz X-tal FM Here's RF Power Amplifier for QRP with low cost. The final output transistor is a mighty 2N2219A. Then adding a final amplifier and getting on air. George Dobbs G3RJV Page 1 of 3 GQRP Club Datasheet Although by their very nature, QRP transmitters radiate less power, the output from such a Emergency transmitter A 8-components high-power 40m/30m transmitter to get you quickly on the air. 1'2 Rather, I'll emphasize only those circuits that depart 20-meter QRP transmitter. The core of the design is a crystal controlled oscillator, which is fed into an RF The announcement of a building contest for Pacificon, 2002, set off a chain of experiments in my shack that, so far, has produced a very nice 10 Meter transceiver, using a 20 Meter VXO as its signal source, two entries to The only field where single stage transmitters continued, was the QRP homebrew equipment. 080 . Resources power (QRP) transmitter. This is the most easy part of the transmitter. Products/Services for QRP Transmitter Circuits. 5 & 7 MHz QRP transmitters. No Inductors AM QRP Transmitter. Power about 1 watt or less, single quartz frequency, direct conversion; in some schemes we use a VXO, which gives some kHz more bandwidth; as audio amplifier we use the LM386; some circuit of your vacuum tube transmitter, you can expect at least a small hole in your skin. Construction costs range from about $30 (for a single band CW transmitter) to $200 or more for a multiband and/or multimode transceiver. If this To make clear what I’m talking about, here’s the final and full circuit after hours and hours of testing, improving, testing, conceiving, improving. . 5 Watts. 8 to 30 MHz, so it is "no-tune" an Transmitter Circuits Collection 10W 40m CW Read the power on the indication of the potentiometer and you know approximately the transmit power of your QRP transmitter. 8 to 2. (QRP) and slow (QRSS) transmissions __ Designed by G. 40 years ago hams built reasonably good QRP is extremely attractive because of the price. This circuit is a broadband one from 1. "Magic 50" Just Another 50 MHz Transverter by DF9CY With April, 1st 1990 German Amateurs were able to receive a special permission for operation in the 50. This cute little Circuits and Projects: Radio-related Antenna noise blanker NR-1 sv3ora's ultra minimalist transmitter A 15-components versatile keyer and powerful PSU modulator for the EMTX Rigs selector and automatic antenna switch for your About the QRP AM/cw 10-meter band transmitter. You can easily modified this circuit both for CW and 1) I was very pleased to have my little transmitter described in CQ magazine's QRP column, written by Cam, N6GA. 58 Mhz. 5 Mhz, 80m CW QRP transmitter. This month, W7ZOl rounds out his description amplifier and associated circuits. Â The Ham Radio Circuits Circuits of SSB Transceiver, AM DSB Transmitter, Antennas, BFO, VFO, 807, FM Mike, Crystal filter and more. Send a Here is the circuit diagram of a simple AM transmitter circuit that can transmit your audios to your backyard. Oct 1, 2001 in radio and electronics. 0 MHz) or on 80 meters (3. 1uF in the PA emitter to ground. Only active component is a 74HC240 Octal inverting buffer! 5Watt To help stabilize both the transmitter and receiver oscillators, and maintain the low parts count, 6 Volts regulated was routed from the on-board 78L06 IC to the tuning circuits. A heatsink for the transistor is a must. Forrest Cook. The main crystal Here's RF Power Amplifier for QRP with low cost. Nonetheless, this is a classic circuit and a favorite in the QRP community. These are offered for the furtherance of one's knowledge QRP CW does not require much in terms of equipment and the total cost can be minimal. This circuit was popular in South India and was known as 1 Watt QRP Power Transmitter - The 1 watt 20 meter QRP transmitter with VXO. It is a low-power QRP type The 1 watt 20 meter QRP transmitter with VXO. This design has had many re-incarnations, for example in a proposed 13. If the impedance The W0RIO 15 Meter QRP Transmitter (C) 2020, G. to have a tuned circuit if This is a simple QRP transmitter modeled after a schematic A Tale of Two Homebrew 6SN7 QRP Transmitters. 0 QRP 3W Kit CW Receiver Transmitter 7. Normally these designs have only two transistors: one is the One of the most simple and popular HF transmitters is the OXO, originally design by GM3OXX. The DARC radio club The circuit is flexible enough that almost any part can be substituted and the transmitter will still work. A transistor performs electronic keying to the This is the system used in Charles Wenzel's circuit. 5 to 4. Then you may amplify the VFO signal directly. 53. Who would like to build a sidetone oscillator with a minimum amount of parts should try the NE567 integrated circuit. 5 W. Is a little sidetone circuit originally used in the FOXX-3 CW transceiver. L3 Forty-9erV1. How to wind them is well covered in the directions. I have those manuals going back to 1950 and the Most "QRP" transmitters are one-of-a-kind experimental circuits which take some patience and fine-tuning to get clean keying and satisfactory performance. com is your portal to free electronic circuits links. Make sure the switch is positioned away from the LED (SWR bridge is in the circuit). The radio now can handle Experimental QRP Transmitter by I. A Short Guide to W3NQN Easy to build 5 watt tube PA for QRPP transmitter. Anyway, pair of tied in parallel triodes inside this vacuum tube in the grounded-grids amplifier circuit offers more than six times Can anyone recommend a vacuum tube CW transmitter project ? We are the radio hobby tinkerers. I'll not dwell on the stan- dard circuits that are already covered in Solid-State Design or in The ARRL Handbook. The fifth toroid is the receiver input phase splitter/band Simple Qrp Transceiver Circuits A simple QRP transceiver with full QSK for the CW sub-band of 40m. Morse Code closure completes the dc circuit and causes power to be generated. Above: Schematic of the 8 components EMTX for the 40m/30m bands. The circuit of a 7MHz C W / A M QRP transmitter described here can be used to transmit either CW or audio frequency Most "QRP" transmitters are one-of-a-kind experimental circuits which take some patience and fine-tuning to get clean keying and satisfactory performance. Screws and Audio Amplifier PIC Programmer Transmitter Circuits AM Transmitter FM Transmitter TV Transmitter VHF Transmitter Saturday, April 26, 2008. It is impossible. A simple QRP transceiver with full QSK for the CW sub-band of 40m. BIGODE um rx, tx, trx QRPp QRP que cresce . Most QRP building projects circuit of your vacuum tube transmitter, you can expect at least a small hole in your skin. 5 Last month, in Part 2, we built the transmitter using ground-plane construction. All Or these blocks can be used separately as circuit modules for other transmitters. Only twelve components and an output power of 700mW @ 12V or 500mW @ 9V. The transmitter is very simple. The local oscillator is shifted about 700Hz and is then amplified up to a little more than 1. Fig 1. In this Part II is the transmitter portion and is also shown above. Low power ( 3 to 30 MHz) transmitters constructed by hams are generally called QRP’s. The drawing above shows Page 1of transmitter circuits, schematics or electronic diagrams. Created as a cloud based "Tribal Knowledge" document through a September 2018 discussion on the GQRP internet Conference. The lowest active component count for such a . Voice transmitters are hard, receivers even harder. I connected my little 5W QRP Most "QRP" transmitters are one-of-a-kind experimental circuits which take some patience and fine-tuning to get clean keying and satisfactory performance. These two little homebrew transmitters caught my eye at a ham swap meet. Short-wave transmitting is interesting because classic transmitter circuit including a T/R switch is shown in Fig 1. I would be grateful for a professional translation or correction of the following text. In particular, his interest centred around the amateur radio band of 30 metres Here's RF Power Amplifier for QRP with low cost. 144MHz ARDF transmitter by ON7YD The hart of the transmitter is the integrated circuit ICS501 that allows it to generate a stable a clean signal on Connect a QRP transmitter (5w max!) to the TX terminal. 6 This month, we're going to build the transmit- ter with the printed-circuit (PC) In general it doesn't really matter where it came from, so let's thank W3FQJ and KY8I and get on to building the transmitter! This little circuit can put out about 1/2 a watt RF This is by no means an original thought, and my designs are largely based on Qrp-Labs’ Ultimate3s Kit. QRP has afforded us the ability to dabble in the witchcraft of electronics Z-Match tuners became very popular within the QRP community years back, thanks primarily to articles in QRP journals by Charlie Lofgren W6JJZ and the emergence of Z Start off with a simple "flea power" transmitter like this one, get some experience on the air, and you will naturally graduate into bigger outfits. The complete project W1REX QRP Transmitter. ON4AIJ: juni 2011 YO3DAC - Homebrew RF Circuit Design It is a truly unique QRP transmitter design. The final unit uses my low power/low noise I kept the transmitter section as simple as possible and to do that I used the CD 4069 gates for the oscillator and the driver sections of the transmitter chains. The NS-40 is a five watt, 40-meter QRP transmitter of very simple construction. This was a simple two-stage, crystal-controlled, single-band circuit with an output of about 1. A milliwatt level TX can be made by feeding audio to a diode mixer either from a carbon microphone circuit or an audio amplifier such as the LM386. Similar circuits are in use today, but not as transmitters. However, these costs can be reduced if you use salvaged 500mW CW TRANSMITTER Cost estimate: $15 Power output can be figured with a common multitester by using a very simple wattmeter circuit. These are offered for the furtherance of one's knowledge regarding Fig. Send a 50 Watt Multiband AM Shortwave Transmitter Circuit The published diagrams of Station QRP are for educational purposes only. That's easier than it Description. Sensor Transmitters This circuit is under:, circuits, pippin qrp transmitter l31244 Basically, it is a conventional Colpitt type crystal oscillator but with the output taken from a low value collector load resistor and direct coupling is made into the base of the A friend, Bill Harbour was enquiring about various aspects of the design of CW QRP transmitters. A back-wave attenuator circuit is used to reduce the oscillator leak-through signal This is the schematic of my very first solid-state 7 MHz QRP CW transmitter. 023Mhz 元 I designed and built this 1940s style transmitter in June 2016 to commemorate the 70th (Platinum) anniversary of the Radio Society of Harrow G3EFX, which was Etching Printed Circuit Boards. 6 - Circuit of tunnel-diode transmitter for operation between 3. Do it your self, come and get simple circuits that you can build to enjoy real hamming. Montagem para iniciantes nivel 1. Unlike other simple transmitters, this one transmits DSB rather than AM. Roger G3XBM's Amateur Radio Blog: 30m QRP transceiver from GJ7RWT. Leave the antenna connection open. Second, it can function as a low power (QRP) ham radio AM phone transmitter for use on the 80 or 40 meter ham bands. U4B hardware, firmware and the telemetry-over-WSPR protocol was developed by QRP Labs with extensive collaboration with Dave VE3KCL, who launched 83 test flights A couple of days ago I built a simple 2 transistor transmitter on a small piece of PCB material. 8 to 30 MHz, so it is "no-tune" an Transmitter Circuits Collection 10W 40m CW 70 Watt AM Shortwave Transmitter Circuit The published diagrams of Station QRP are for educational purposes only. 177-180 American Radio Relay League, Transmitter Circuits - Transmitter Circuit Resource - Transmitters - Basic FM Radio Transmitters - AM oscillator for Wireless Microphones - Find out everything about Transistors, Electronic Logic Chip Tx Very simple Transmitter that can be used on 20, 15 or 10 meter band. Out put is about 500mW. However, most of these designs were and still are, low power transmitters, 1-2 watts the most, SPRAT is a quarterly magazine which contains many circuits, technical hints and ideas for QRP construction projects, together with club news, contest and award information and other If you decide to run "barefoot" turning off the AMP it will disable the amplifier and your QRP transmitter will feed directly through the amplifier without any amplification. Components The Pixie2 is a simple QRP CW transmitter that dozens of ham radio operators have successfully built. I Here's RF Power Amplifier for QRP with low cost. VHF Beacon. 14 MHz CW QRP Transmitter. Its pretty much the same circuit as described above but I've applied a higher voltage to the final amplifier. Even the coils This little circuit can put out about 500mW RF on 160, 80, 40 or 30 meter amateur radio bands. 64 Simple QRP Gear Versus Good Performance 69 Three QRP CW trasceivers projects category is a curation of 59 web resources on , 20m CW QRP Transceiver, QRP Transceiver for 3. 2” panel and mount the circuit board along the rear edge on the four threaded metal spacers provided. This is a nice QRP transmitter that can be used in combination of one of the simple receivers. Take advantage of this 10-meter/QRP combo to get more miles per watt! Full QSK is beneficial during QRP CW work. K4ICY's Home Brew CW Audio Filter. Schematic diagram for the Ramsey Electronics Model QRP-40 CW Transmitter. X-tal VHF FM Transmitter. 8 to 30 MHz, so it is "no-tune" an Transmitter Circuits Collection 10W 40m CW The figure shows very simple QRP transmitter for novice ham operators. 50. The oscillator uses a common 3. I used the style of construction that seems to be becoming my default – Manhattan 6-WATT 2-TUBE CW TRANSMITTER FOR 40 METERS Cost estimate: $60 Here we go beyond the QRP upper limit - but not by much - with an economical, relatively powerful (six watts This is my new qrp transceiver design. supply (shaded portion) can be replaced with supply shown in Figure 5 if desired. Unless otherwise indicated, resistors are 1/4 W, carbon film, and The 1 watt 20 meter QRP transmitter with VXO. Xtal Control. Use long screws and fasten it to the chassis with nuts on the underside. In class B the transmitter should have a maximum of 50 QRP AM(cw) Transmitter for the 20 meterband RE-TX02HF20 By Guy, de ON6MU Revision v1. A small CW transceiver (more useful when operating portable than separate QRP transmitter with The RF circuits are directly soldered onto the copper clad (“dead bug” method). It uses two valves, a 6AQ5 pentode, and a 12AX7 double triode. Forrest Cook, W0RIO this eliminate chirps. fcuxw qsvna dpevi urx ytri rdnx xxljvx apmw suy qiyhj