That original HiFi-amplifier loudspeaker protection may delay about 2 seconds.
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BTW: Tried a linear regualtor IC 78H05SC and reduced the output electrolytic capacitor value from 470 µF to 47 µF => and starting power on self reset works as desired.
Tried some NE555- circuits. However those ones triggered with a short glitch directly on Mains power on. This was not intended, basically.
Now working with delay circuit for proper start posted below in attachment. Transistors BC 337-16. Relay OMRON G5L-117p-ps 5V. Cover can be dismantled for contact cleaning purposes (if necessary).
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The delay time is on first start after a longer period of "power off" approximately 5 seconds. If power switched "off" and directly consecutively again "on", delay time is at least 1 second. Reason: C1 will be discharged over BE-path of Q1, mainly. And then only from approx. 0.4V towards 0.7V and not 0V to 0.7V charging. All transistors are saturated, show UEC approx. 0,1V. Current 1.3 mA on start, 70 mA in state "on" according current via relay's coil. In order to make switching off contacts a liitle bit faster, the Zener diode D2 added antiserial to D1, together resulting only approx. 4V in "negative" direction.
As part of cleaning up the RF environment at my QTH, I ran a quick Apples-vs-Apples comparison on two switchmode power supplies.
At least down at the VLF part of the spectrum, the newer Apple A1444 power supply (the compact little brick without the ability to change the 230V pins) is significantly quieter than the older Apple A1205 SMPS (the one that allows you to swap out the 230V connector when you're roaming to another country, etc).
The image below shows the cleaner spectrum of the A1444 below, versus the slightly noisier performance when powered from the A1205. Nothing else was changed, and the comparison was made just a few minutes apart, and then re-confirmed back the other way a few minutes later.
At a subjective level, it was much easier to copy the Pearce NDB on 340kHz when using the A1444 SMPS, versus the NDB being detectable but virtually unreadable on the older unit.
[ 281kHz and 340kHz are the YPJT and YPEA NDBs, whereas 158, 238, 316, 397, 476kHz are noise coming from source(s) that I'm yet to find and mitigate. I suspect they are coming from other SMPS ]
Of course, this is just from a sample size of one, but I thought I'd share this observation in case it helps anyone else.
The switching power supply of the internet router itself produces "spurs". The linear power supply 12V works instead properly. However use of some TVs and other consumer equipment might cause interferences, which me cannot influence at all. Generally speaking the situation on my QTH is able to decode telecontrol transmitters as DCF39 (139 kHz) and DCF49 (129.1 kHz) if me changes antenna to LF range. (ferrit rod) Even TDF timesignal can be decoded (Allouis 162 kHz). Those frequencies are protected by authorities and BNetzA (Federal Network Agenca similar to FCC in USA) is able to prosecute in certain cases. By the way BBC on 198 kHz transmits telecontrol signals, too. This is the main reason not to stop transmitting on long wave in the UK.
Comments
Linear versus switch-mode is an ongoing quest and debate.
I have tried both over the years on the Kiwi and other SDR
I have found these to be quiet and with a DIN rail, easily mounted
Other users have used Meanwell in other chassis types.
https://www.amazon.com/MDR-60-5-meanwell-Industrial-Supply-MDR-60/dp/B01N58K3S4
That original HiFi-amplifier loudspeaker protection may delay about 2 seconds.
BTW: Tried a linear regualtor IC 78H05SC and reduced the output electrolytic capacitor value from 470 µF to 47 µF => and starting power on self reset works as desired.
My realization all entrusted ... it seems to be fine. Classic power supply, trafo+78h05 ..
Tried some NE555- circuits. However those ones triggered with a short glitch directly on Mains power on. This was not intended, basically.
Now working with delay circuit for proper start posted below in attachment. Transistors BC 337-16. Relay OMRON G5L-117p-ps 5V. Cover can be dismantled for contact cleaning purposes (if necessary).
The delay time is on first start after a longer period of "power off" approximately 5 seconds. If power switched "off" and directly consecutively again "on", delay time is at least 1 second. Reason: C1 will be discharged over BE-path of Q1, mainly. And then only from approx. 0.4V towards 0.7V and not 0V to 0.7V charging. All transistors are saturated, show UEC approx. 0,1V. Current 1.3 mA on start, 70 mA in state "on" according current via relay's coil. In order to make switching off contacts a liitle bit faster, the Zener diode D2 added antiserial to D1, together resulting only approx. 4V in "negative" direction.
As part of cleaning up the RF environment at my QTH, I ran a quick Apples-vs-Apples comparison on two switchmode power supplies.
At least down at the VLF part of the spectrum, the newer Apple A1444 power supply (the compact little brick without the ability to change the 230V pins) is significantly quieter than the older Apple A1205 SMPS (the one that allows you to swap out the 230V connector when you're roaming to another country, etc).
The image below shows the cleaner spectrum of the A1444 below, versus the slightly noisier performance when powered from the A1205. Nothing else was changed, and the comparison was made just a few minutes apart, and then re-confirmed back the other way a few minutes later.
At a subjective level, it was much easier to copy the Pearce NDB on 340kHz when using the A1444 SMPS, versus the NDB being detectable but virtually unreadable on the older unit.
[ 281kHz and 340kHz are the YPJT and YPEA NDBs, whereas 158, 238, 316, 397, 476kHz are noise coming from source(s) that I'm yet to find and mitigate. I suspect they are coming from other SMPS ]
Of course, this is just from a sample size of one, but I thought I'd share this observation in case it helps anyone else.
73, Chris VK6KCH
The switching power supply of the internet router itself produces "spurs". The linear power supply 12V works instead properly. However use of some TVs and other consumer equipment might cause interferences, which me cannot influence at all. Generally speaking the situation on my QTH is able to decode telecontrol transmitters as DCF39 (139 kHz) and DCF49 (129.1 kHz) if me changes antenna to LF range. (ferrit rod) Even TDF timesignal can be decoded (Allouis 162 kHz). Those frequencies are protected by authorities and BNetzA (Federal Network Agenca similar to FCC in USA) is able to prosecute in certain cases. By the way BBC on 198 kHz transmits telecontrol signals, too. This is the main reason not to stop transmitting on long wave in the UK.
I didn't know BBC R4 transmitted telecontrol. But there it is! (two-point phase modulation in the IQ display)
If you zoom all the way in on the waterfall, you can see that signal on 198.
Just FYI:
Yep. Till June 2025 and later on, probably.
https://www.bbc.co.uk/reception/questions/everything-else/radioteleswitching