1996 Jul 30 3 NXP Semiconductors Product specification N-channel silicon field-effect transistors BF245A; BF245B; BF245C LIMITING VALUES In accordance with the. A succession of FET-like devices was patented by Julius Lilienfeld in the 1920s and 1930s. However, materials science and fabrication technology would require. BFW10 Datasheet(HTML) 2 Page - Motorola, Inc: zoom in zoom out. BFW10 is high frequency n-channel MOSFET recommended for use in VHF-UHF band high frequency amplifier circuits. Detailed Technical data sheet of the device. BFW 10 - Brace For War 10 pits Dan Da Riot Hyatt vs Jon Lethal Leven fight in National Convention Centre Canberra, Canberra, Australian Capital Territory, Australia on Aug 27, 2011.
GDO and BFW 10
Bfw10 Fet Terminals
#17739 Can anyone suggest the following: 1. A simple GDO circuit whose components are cheap and available in India. The GDO is much needed to tune coils for NR60. Are commercial GDO available in India? KIndly suggest where and how to get it in India. 2. A cheap but a good substitute of BFW 10 that is available in India. BFW 10 that are currently available in the market are priced very high. Rs.150 per piece in Delhi. 3. A cheap substitute for BC 178. 4. What care/precautions one needs to take while handling, soldering, and desoldering BFW 10? Thanks VU2TPR | |||
#17740 yes,vu2tpr. simplest is on 50FET projects booklet the booklet is linked here http://www.talkingelectronics.com/projects/TheTransistorAmplifier/50FETProjects.pdf Please look at pages 45 and 46. you may use any JFET all the best | |||
#17741 1. you can use J310 or BF245C you get them at Rs15 approx each 3 I suppose you are seeking metal can version pnp. Instead you can well use BC558 in TO92 package or even 2N3906 with pins reversed. (3906 is EBC while BC557 is CBE) 4.Firstly completer the other parts marking pins for the FET.later insert the j FET just plug out your soldering rod from mains after it is hot, solder the device before it is cold. my concentration went to Grid dip only, later i realized you sought more queries. | |||
#17742 NR60 project is very good project ,very long back i have home brewed ,VFO is rock steady ,there wont be any drift at all. I used BC 148 plastic package but Hfe is mach ed . Please let me know PCB are available. VU2RJW On Fri, Mar 11, 2016 at 10:12 AM, TP SINHA tp_sinha@... [BITX20] <BITX20@...> wrote:
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#17743 GDO was a quick and dirty instrument of the past. Now we understand and do things differently and more accurately. Instead of a GDO, I urge you to consider a vfo as a signal generator and a power meter made like an rf probe. they are just as simple as a GDO but far more accurate. - f ------ Original message------ From: TP SINHA tp_sinha@... [BITX20] Date: Fri, 11 Mar 2016 10:12 To: BITX20@...; Subject:[BITX20] GDO and BFW 10 Can anyone suggest the following: | |||
#17744 Soundararajan jee, you might well consider HF-1 latest design by Ashhar Farhan, The design is superior with dual conversion and stable 1st local oscillator. I would say it is state of art design. soon you might get a pcb for that . | |||
#17745 Does Farhan already published an article about HF1 transceiver with also the arduino code? Because I have seen only the schematic for now attached in one email, Il giorno 11/mar/2016, alle ore 08:32, mvs_sarma@... [BITX20] <BITX20@...> ha scritto:
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#17746 Hello friends I build a simple system to measure ressonance basead in : Grid-dip-meters Item 11.3 here in Brasil my friend PYMG Gomes also made an equipment like this http://www.py2mg.qsl.br/Arquivos_PDF/GRIDDI~1.pdf It is not a dip meter but increase the signal when the ressonance pointis reachead. I use with a DDS VFO or signal generator. I build the sensor coils in 20mm(diameter) and 10cm long PVC tube... 5turns in each side... For to check a ressonance use one coil of the sensor.... 73 from py2ohh miguel | |||
#17747 Sorry to disagree, but to discribe GDOs as a 'quick and dirty instrument of toggle quoted messageShow quoted textthe past', IMHO rather misses the point. I agree that for accuracy, a proper calibrated signal generator is much better, or for even better accuracy an Arduino/Si5351 based device -- which I have built. GDOs were not named as Grid Dip Meters for nothing. These were portable (?) thermionic valve based devices that were primarily intended as a convenient means of determining the resonant frequency of tuned circuits -- a 'dip' in grid current occured at resonance. I recall building and using a GDO approx 60 years ago -- based on a 6C4 triode valve. More recently, I built a solid state equivalent of a GDO, based on a dual gate FET and bipolar transistor. With nine or so plug-in coils, this covers frequencies from 1.7MHz right through to over 100MHZ. I spent some time calibrating the device so it can be and has been very useful to get a quick checks on resonant circuits, including when setting up/tuning resonant antennas. In the latter case a short loop of wire is connected across the feed point of the antenna and loosely coupled to the GDO. GDOs are very compact and portable, and IMHO can still a be useful instruments. Regards Ken Hough (M0KOH) On Thursday 10 March 2016 22:40:39 you wrote: GDO was a quick and dirty instrument of the past. Now we understand and | |||
#17748 Ken, toggle quoted messageShow quoted textI was hoping someone would stand up for the good ol GDO. The GDO was useful, I still have one in the box of test jigs, but I haven't touched it for years. Let me illustrate why, let's take the example of using it to build the BITX. 1. The bandpass filter. Some of us use toroids. The toroids won't respond to the GDO as they have no discernible field outside (they are self-shielding). The GDO will be useless against them. Now, about Sunil Lakhani's BIT X(v3 versions), they use coils inside shields : this won't work either. The GDOs are good with open coils, we see very few of them these days. Even if we do manage to get the GDO going (let's say by using air core coils), the bandpass of the BITX is triple tuned, we need to see what happens to the signal that enters at teh antenna jack and comes out at the RF amplifier end. The GDO will not be able to inject into the first coil and detect the energy from the last one. Tweaking each coil separately will be misleading. 2. Crystal filter. The crystal filter needs a signal that remains within 100 hz at least until we can take a reading. There is no way the GDO will do that. The GDO will not be able to measure the output at the other end either. So, aligning the crystal filters is not possible either. 3. Setting the frequencies. The GDO's frequency is unstable as the coil is exposed to the open for it to stay at a definite frequency. The tuning is too coarse to be set at any particular frequency within 100 hz (a requirement for proper alignment of the BFO and the VFO). Now, moving away from the BITX, let's look at measuring an antenna's performance. The usual way is to add a loop to the antenna's connector and dip with the GDO. This provides us with a rough indication, but don't we want to know how good or bad the mismatch is ? The way to do it is feed an RF generator through an RF impedance bridge and connect the RF detector to the measure the return loss. This will allow you to calculate the VSWR easily. Measuring the gain of an amplifier, loss of a filter, all these are possible with a signal generator and a power meter. My early attempts were entirely analog like this: http://www.phonestack.com/farhan/siggen.html but now, I use something a little more digital but far more accurate and useful, the sweeperino (http://hfsignals.blogspot.in/p/sweeperino.html). I can carry the sweeperino to a field, it nicely fits in my pocket! - f On Fri, Mar 11, 2016 at 7:24 PM, Ken Hough kenhough@... [BITX20] <BITX20@...> wrote:
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#17749 I built a simple Scalar Network Analyzer using an Arduino Nano, small TFT display, and a AD9850 module. I used 2 simple diode detectors to measure output and input voltages and used to arduino to calculate gain or loss..I included applications to use it for checking filter responses, and as a signal generator With a return loss bridge, I could measure antenna responses. With a simple add on coil it is possible to use it as a GDO. Information on this application and other uses are on my blog DuWayne's Place: SNA Jr as Grid Dip Meter
DuWayne | |||
#17750 DuWayne, Hey, there's lot's of interesting stuff on your blogspot! I'll take a closer look ASAP. Regards Ken Hough (M0KOH) On Friday 11 March 2016 15:20:34 you wrote: I built a simple Scalar Network Analyzer using an Arduino Nano, small TFTI used 2 simple diode detectors to measure output and input voltages and used to arduino to calculate gain or loss..I Preview by YahooDuWayne
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#17751 Ashar, toggle quoted messageShow quoted textOf course there are lot's of applications where a GDO would not be the best choice, but where precision in frequency is not too critical, the good old GDO can still be useful. I used mine just two days ago! A GDO can be linked to a toroid via a closed loop of wire through the toroid. I know that this works because I've done it. Screened coils are more of a problem. Perhaps not the best way to tune a band pass filter, but I initially set up my BITX20 by connecting a short antenna and then tuning for maximum audio noise output over the required band width. I guess that I could have used my GDO by using a coupling coil into the antenna socket. Agreed that the GDO would not be of much use for checking Xtal filter response, but then neither would many so called signal generators. I used my Arduino/Si5351/LCD sig gen after calibrating this by zero beating against WWV on 10MHz. I can select the incremental frequency step down to +/- 1Hz. WRT checking antennas: A GDO will only detect resonance and it can do this well for resonant antennas. It will not report on impedance. However, I have used my GDO successfully to tune a 40m/20m loaded dipole and a 15m/10m/6m fan dipole arrangement. Both of these antennas are fixed in the roof space of my house, so it was very easy to get to the feeds points. After tuning, both of these antennas gave low SWR on all bands. No further adjustment was needed. I use choke baluns on the coax feeders to these antennas. I wouldn't consider using a GDO for measuring gain, or for other quantitative work, but all of this misses the point. My own GDO uses nine coils to cover it's whole frequency range so I was able to calibrate it fairly accurately. GDOs are very portable, convenient, adaptable, and for some jobs can be adequate -- and IMHO even preferable. Regards Ken Hough (M0KOH) On Friday 11 March 2016 20:41:38 you wrote: Ken, | |||
Fet Bfw10
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