Radiofan_01
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That original HiFi-amplifier loudspeaker protection may delay about 2 seconds. https://forum.kiwisdr.com/uploads/577/JQ99WZZBH7I2.jpg
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No problem. Took 2 transistors as a Darlington in order to need no too much capacity. Relay not shown in picture. https://forum.kiwisdr.com/uploads/043/20DVOGSUC9TW.jpg
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Hello, interested on a 5V crowbar. Whilst using here an oldschool power supply . 9V/ 4A transformer 120 VA, 2-way-rectifier. 10000µF als load capacitor, power regulator IC UA78H05SC TO3 and mounted on heatsink 0.5 K/Watt with actual delivering 5.13V…
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Loud and clear to receive German Weather Service for Maritimes: Have a look on schedule intiteled So called RTTY. https://www.dwd.de/DE/fachnutzer/schifffahrt/funkausstrahlung/_functions/DownloadBox/Download_Box.html Some errors, but relatively good…
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The maior problem is the availability of original parts. Got a LM338T in a TO-220 housing. This part is heating up too much, even proper mounting on heat sink. The housing TO-3 should be preferred used. However me did not find any trusted vendor. T…
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Now working fine 24/7 with an 5V-IC featuring maximum 5 A in a TO-3 housing. https://forum.kiwisdr.com/uploads/430/MDIR0FHIJD6E.jpg Unfortunately there are some fakes on the road, which disguise themselves in TO-3 housing, but never deliver the high…
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As G8JNJ mentioned above, here a very remarkable experiene, what could happen, if snubber has not been calculated out properly. Approximately half a tenthousand (or more - I do not know) of powersupplies of very recommended popular manufacturer were…
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As you know, not all kind of so called "Schottky"-diodes are best for that mentioned rectifier purposes. Some developments have had took place in the meantime. SiC (Silicium Carbid) Schottky seeming to be suitable, despite a look on diagra…
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By the way: Most of the DC-stages do not strictly follow the datasheet recommendations for mounting rectifier diodes at least 9.5 mm lead length to prevent overheating. You may see the result of such mounting to tough to the printed board in changin…
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https://forum.kiwisdr.com/uploads/430/MDIR0FHIJD6E.jpg Sometimes the transformer inbuilt temperature fuse (120°C) burned. And the whole transformer had to be replaced. Prefer using tansformers with ambient temperature range TE40 and not TE60. Or not…
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Using center tap secondaries saves 2 diodes ( and condensors) and lowers ground impedance. That kind of PSU worked fine since a couple of years. I even tested it with CB-handheld-radio pushing the transmit button in order to see, what happens. Only …
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No, it is not a mistake, the T3 is a PNP and correctly wired. That sophisticated circuit allowes shorting on output, and after two seconds shorting output's voltage will be totally cut off, in order to avoid damage due to overheating and so on. You …
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The main reasons for using switching power supplies in my country are the EU regulations. For example ErP Directive (2009/125/EC) A Kiwi with a linear power supply would run the risk of not getting a CE mark and would therefore probably not go throu…
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OK, little bit off topic. But I tried find out the difference in noise produced by the internet router itself. Surprisingly the delivery contained switching PSU causes a noise between approx. 7 and 14 MHz. Just for fun connected a conventional trans…
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Tried out on "Local" connected to notebook via 1m CAT7e cable using the same PE as the power supply of the notebook nearby, causing that shown interference. You may recognize the little bit better SNR, at the time,when outer screen of the …
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https://forum.kiwisdr.com/uploads/047/RDBCACFAIK7X.jpg Lets having an example here. The isulation resistor beween protection earth of chassis of my linear PSU here in use and the KiWi minus DC lead should read as stated in picture. Even better as lo…
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The way to see that problem is important. Schematic above shows the configuration for an electric assy, which could catch up interferences on "polluted" mains PE lead, not in opposit way connecting leads marked with "load" to a s…
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https://forum.kiwisdr.com/uploads/875/V9WC303G6AHT.png In order to prevent noise on PE one can fit in a choke, withstand a shorting current.
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Thanks for insight, but basically I do not know, wether I am "landed" on "root" correctly. How does the prompt looks like correctly. I presume the procedure will be similar to some router configuration. And of course, some comman…
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As I tried out on security tab set to enable restrictions on console on local to "no" and restart server should work. https://forum.kiwisdr.com/uploads/760/DW7RMBJR7MHO.jpg However I am not familar with the specific syntax yet. Where to le…
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https://forum.kiwisdr.com/uploads/786/1GPH911E22ZE.jpg Sorry for posting some advertising like. Nevertheless I would like to discuss the advantage or disadvantage of so called LAN-Isolators. Tried out one of the special transformers directly connect…
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And the remaining noise spectrum is caused by the internet access router itself, LAN cable and so on. If router is switched off, the QRM between approx. 7 and 14 MHz disappears instantly. (On local operation mode that interference is no more there e…
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https://forum.kiwisdr.com/uploads/356/A5C54VX7LZP0.jpg Adding some pictures. Main problem was, to get an appropriate metal case, which does not produce an extra acoustic hum by magnetizing caused of housing sheet iron
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Hello, My homebrewed PSU seems a little bit oldschool and oversized. Transformer 120 VA and a regulator IC µA78H05SC, in a TO-3 housing and mounted on a 0.5°/Watt heatsink. The heatsink temperature reaches 35° Celsius on an ambient temperature of 27…
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Hi, maybe quite off topic, but could probably help explaining some mysterious failure. Some consideration in where RF power actually takes effect. Not even on transmitter's antenna, as it should be. Me performed a testing on CB radio, and after 5 se…
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https://forum.kiwisdr.com/index.php?p=/discussion/comment/17305#Comment_17305 what a coincidence. I have bought two of this linear PSU in which one for KIWI1 and another one ready for KIWI 2(order has been placed). DC output carries very low ripple …