I had a gs31b laying around waiting for my urge to build another amp. The gs35bgs35b tubes is used for wideband power amplification at frequencies up to mhz in rf equipment. How do we calculate the input impedance of a patch antenna from. Second, the cathode input impedance is very dynamic and the tuned. The ten meter circuit is closest to the tube and the 160 is nearest the input. If you want to add or optimise a fixed input circuits for each band, it is best to use the cvalues giving in the table.
It is also commonly described as the opposition against the flow of a given signal current at the input of a circuit or load. I was originally not too happy with the load presented to my ts440 driver in the first place even with the 8877. After optimization, we got improved resu lts at patch. When the soviet union fell apart, different tubes began appearing for sale. From there several ideas have been reused and also new electronics. The amplifier now runs almost exactly the way it did when it had the 8877. Do not use this amplifier without a proper lowpass filter. However, this time i want to try a little different approach. This link is listed in our web site directory since thursday aug 24 2006, and till today gs35bamplifier has been followed for a total of 1491 times. There are lots of web documents and pages about amateur amplifier projects. New tubes and my ptfe chimneys were installed, a w4zt bias board was installed replacing the zener and the air opening into the rear chassis was widened. Bencher dust cover another simple rainyday project. The gs35b tube socket is made from 316 aluminum plate. The gs35b is a russian triode that is relatively cheap and easy to get hold of.
F 5 m a g smeter killer linear power for 6m basetd gs35b 4000 v. I have a large 240 volt input variac, which i can use to adjust the dc output voltage up or down a bit. The pi net used 2 x small air trimmer caps and just one coil between em. It virtually eliminates the stray inductance in the grid circuit. About gs35bamplifier the resource is currently listed in in a single category. How do we calculate the input impedance of a patch antenna from its dimension. W4zt tuned input circuit gs35b gs35b russian triode. Design of a microstriplinefed inset patch antenna for. How to calculate input impedance edge for this microstrip patch. Replacing cx with a piece of coax cable terminated with a variable capacitor ct. The secondaries are in parallel full wave bridge rectification and about 30uf of filter capacity no choke input. F 5 m a g smeter killer linear power for 6m basetd gs35b 4000 v pwr 2 kw hf not bulshit p. Previously, the patch antenna was fed at the end as shown here. Bias is created by a bias circuit board and is adjustable from 1735 vdc producing an idle current of 40 ma for ssb operation at 3000 vdc.
Click on the picture to see the details of the construction. Gs35b gs35b russian triode tube,socket and teflon chimney. While reasonable impedance matching can be important for proper exciter operation, the tuned input circuit of a groundedgrid or cathode driven radio frequency power amplifier provides multiple important functions for the amplifier. The microstrip patch antenna calculator determines the length l and width w of a rectangular microstrip patch antenna for a given resonant frequency or vice versa. With zero power input turn your transceiver off, ground the key input signal line, and adjust the variable bias resistor for a resting plate current reading of 100 ma.
This home brewed amplifier uses a single russian gs35b power tube and has an output power of 1. This amplifier was designed to run 247 key down for heavy contesting and high duty cycle wsjt modes. The switching could be done with a rotary swich too. Sep 03, 2014 his small wire radial system covers a 16 x 25 patch.
We sale of brand new gs35b 2,5kw tubes at the best price in the world. The input impedance at the radiation edge is also computed. Computation of input impedance of rectangular, circular and. An 8877 can be specified as an extra cost option if required. Jan 30, 2011 f 5 m a g smeter killer linear power for 6m basetd gs35b 4000 v pwr 2 kw hf not bulshit p. The variable bias circuit is adjusted with all normal tube voltages applied. Mains voltmeter a very simple yet handy project for a wet afternoon. The socket to the right has my teflon chimney in place. This amplifier is similar to the rest of them, this page is a quick overview of my project. The impedance variation with feed position of a microstrip linefed. The main category is amateur linear amplifiers that is about vhf linear amplifiers. The power supply is capable of producing 3900 vdc output plate voltage.
The gs36b tetrode is generally considered to be similar to the 4cx400a. The gs35b was chosen for its ruggedness and it low cost. This link is listed in our web site directory since tuesday apr 28 2009, and till today gs35b hf power amplifier has been followed for a total of 2468 times. The so called specification sheet for the gs31bgs35b was provided for the tubes as they were produced in the soyus unionengl. An rf power amplifiers tuned input circuit is more than just impedance matching. The voltage into the dut is composed of 2 parts, an incident wave e i1 and a reflected one e r1 characterized by voltage and current. I have question about the rectangular microstrip antenna input impedance at edge.
The first step you must do is to know what your plate load impedance is. The design is not original although i have included a few ideas of my own. The gs36b tetrode is designed for power amplification in distributedgain amplifiers and singlesideband signal amplifiers at frequencies up to 75 mhz, and for power amplification at up to 500 mhz in rf equipment. I am using a ft2000d which has an internal automatic tuner which i do not use because the amplifier has an input pi network for tuning the input. Gs35b 35 the cost of new tubes available for amateur radio applications has gone through the roof. Their low profile design, often square or rectangular, allows them to be mounted to flat surfaces. Microstrip antennas have wide implementation in many applications. With my ft277 and the 150w input the linear makes 2000w output. After optimization, we got improved resu lts at patch length. The radiation edge input impedance is also calculated and is based on w. Just input the value of s11 or the reflection coefficient and read the impedance at that pointthe example below converts a s11 magnitude of 0. Computation of input impedance of rectangular, circular and hexagonal patch microstrip antennas in s and xband. Rf driving power from the transceiver is applied to the tubes cathode using an input matching circuit. How do we calculate the input impedance of a patch antenna.
About gs35b hf power amplifier the resource is currently listed in in a single category. Input impedance, microstrip line feed, microstrip patch antenna. Why not build a monitoring system that can be viewed from a laptop and the band switch could also be controlled from the gui. May 26, 2011 the input impedance, load impedance, or external impedance of a circuit or electronic device is the thevenin equivalent impedance looking into its input. Microstrip patch antennas or simply patch antenna are increasingly useful because the antenna is printed directly onto a circuit board. First licenced in 1978, my primary interest in ham radio has always been home brewing and 160 meters. Since this typically yields a high input impedance, we would like to modify the feed. If no voltage is applied, the input is connected straight through. With 800w tube works 68 months and then died completely. Oct 26, 2009 first tuning of the new homemade gs35b amplifier. Since the current is low at the ends of a halfwave patch and increases in magnitude toward the center, the input impedance zvi could be reduced if the patch was fed closer to the center.
This unit is not the current linear amp uk amplifier available from paul g4ktz. The eastern europeans were quick to establish marketing for these tubes. Cutting this jumper and adding 15v 12 watt zener diode, d1, and the. Us8536950b2 us12641,228 us64122809a us8536950b2 us 8536950 b2 us8536950 b2 us 8536950b2 us 64122809 a us64122809 a us 64122809a us 8536950 b2 us8536950 b2 us 8536950b2 authority. The output network is a pil to suppress the second harmonic and a tnetwork is used for the input. Enter values for l and w for the microstrip patch to. The 5 kva pole pig transformer has multiple primary and secondary taps. I make and sell sockets, ptfe chimneys and bias boards. If the ratio lw is close to unity, the radiation pattern will be symmetric but may not provide a resonable input impedance. In march 20 i start to build a big linear with linear with the russian gs35b triode tube.
The gs35b gs35b tubes is used for wideband power amplification at frequencies up to mhz in rf equipment. The following information covers the 2005 model of the commercially made linear amp uk gs35b amplifier for the 50mhz band. High voltage used here is too high,gs35 should not be operated with more 2500v if you wish long life tube. Additional benefits of patch antennas is that they are easily fabricated making them cost effective. In theory, the output is more than enough for amateur service. Df6na datasheets gs35b also gs7b metalceramic transmitting power triode at frequencies up to mhz. I recently got the opportunity to put together this desk top amplifier using the gs35b triode. Homebrew pcbs tips on making oneoff or smallrun printed circuit boards. My newest selfmade linear with one gs35b dc2wk blog. Listed under the technical referenceamplifiershf amplifiers category that is about amateur linear amplifiers. It is built to last and provide many years of reliable service. Jul 26, 2016 i used gs35 few decades ago,mainly in bc applications.
Replacing cx with a piece of coax cable terminated with a variable capacitor ct makes for and easy to reach adjustment. This is a short antenna with a very high input impedance fet amplifier. How to calculate input impedance edge for this microstrip patch antenna. I find the following formula referenced to balanis antenna theory and design.
In theory, 75 watts of input power should produce legal limit output. Seems that most folks think the actual effective input impedance is somewhere between 25 and 90 ohms. I use a pinet tuner to trim the drive swr and keep the ts440 from folding back output power. I drew this schematic showing variable capacitors at the input and output. W4zt tuned input gs35b gs35b russian triode tube,socket. Considering a voltage source feeding into the dut with a source impedance of z 0. This link is listed in our web site directory since thursday aug 24 2006, and till today gs35b amplifier has been followed for a total of 1491 times. The main category is amateur linear amplifiers that is about hf amplifiers for ham radio use.
When a tube manufacturer specifies an input impedance for a particular tube that is the effective impedance that you should use to design a network to interface to. The voltage into the dut is composed of 2 parts, an incident wave e i1 and a reflected one e r1. I have first build one and soon after that a second one. Datasheet search engine for electronic components and semiconductors. Pdf impedance matching techniques for microstrip patch. W4zt socket this is my gs35b tube socket or mounting fixture design. Design of a microstriplinefed inset patch antenna for rfid. The psus are build after some study of other designs. I am now at the stage of designing my tuned input for the dual gs35b amp that is in process here. Gs35b hf linear amplifier having been successful with my 8 amplifier i have now decided to take things up a gear and build something even more powerful. Various design formulae to calculate the input impedance of patch antenna and techniques to design a matching network should be known to rf designer. Our carefully designed and individually optimised input matching board ensures low vswr on all bands from 160 to 10 including warc. Although the input impedance of the groundedgrid gs35b is close to 50 ohms and would provide a good match for a driver with fixedimpedance output.
The jumper j on the board should be cut only if you need to increase the bias voltage over 39 volts. Running high plate voltage will increase bias and increase input impedance. For example,with 2000v of ua,as broadcast transmitter,in nonstop service,gs35 survive for tree years with 1kw out,and after that power drops 800w. Numero accessi a questa pagina dal 10101 totale inviate i vostri commenti e le vostre richieste a. I like to show you here the steps from this project.
Starting with the fixed input value, experiment with lx and cx to get the lowest swr. About gs35b amplifier the resource is currently listed in in a single category. Gs35b 6m amplifier here are some pictures of my gs35b amplifier for 6 meters i built back in 2005. Another way to do the conversion is to use the smith chart. This amplifier is designed around the low cost russian gs35b triode, and features. Also good for other grid bias applications with gs35b or other ham linear amplifier applications requiring grid bias. Perfect for gi7b t retrofit in a dentron mla2500, allows you to eliminate the need for a 2n3055 or similar grid bias circuit.
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