Hi all, I'm just thinking about transductors and find them them quite fascinating again. I read a bit Wikipedia and thought about the use as a steerable transformer. Imagine you have a hard switching
I believe something like that is used at SAQ (Grimeton Radio) on 17.2 kHz as a saturable reactor for keying the transmission. John F5VLF [email protected] Researching history of RABSON, BLACKSH
John is right. The transductors at SAQ can be seen in this photo in google street view: https://www.google.se/maps/@57.1139306,12.4045874,3a,75y,221.02h,87.43t/data=!3m7!1e1!3m5!1sA9thq95lEHf5u-4IrG4
Hello Johan, Very nice, thanks for the link! Here is another link which explains something, also with a historic background. https://de.wikipedia.org/wiki/Pungs-Drossel The site is only in German but
Thanks Stefan, yes, the Pungs-Drossel is an early transductor! I just love the sentence: "Das Mikrofon musste sich unmittelbar am Sender befinden und der Sprecher war ständig in Gefahr, sich an den v
They use a system like that on the US Navy's VLF transmitter at station NAA, Cutler, Maine. It keeps the high Q antenna resonant in step with the FSK modulation. 73, J.B., VE3EAR LowFER Beacon "EAR"
Stefan your idea of saturating the transformer is, I think, flawed. If you reduce mu-r of the core by saturating with DC, the primary winding will have vastly reduced inductance and appear as a n
Hi Andy, Yes yes, i agree, and that's what i don't fully understand yet. Last night i played a bit with the transductor that is laying arround here in a cupboard. It didn't take much time to build up
Hi Stefan, I think you'd have to do it the other way round, i.e. place the saturable reactor in series with the load. Without DC, the reactor will present high impedance, minimizing RF and supply cur
Hi Andy, Yes yes, i agree, and that's what i don't fully understand yet. Last night i played a bit with the transductor that is laying arround here in a cupboard. It didn't take much time to build u
Hi Markus, Am 19.04.2017 12:41, schrieb Markus Vester: Hi Stefan, I think you'd have to do it the other way round, i.e. place the saturable reactor in series with the load. Without DC, the reactor wi
Hi Stefan, you can find//simplified schematic diagrams of the SAQ TX here, including the "magnetic amplifier": http://retroradio47.blogspot.se/ http://www.nsarc.ca/hf/saq.pdf 73 de Johan SM6LKM
...i can confirm that the circuit from my hand drawing is working. I've just built up such a transformer, see attachment. The test was done on 475 kHz, into a dummy load. Now the power into the dummy
I measured SAQ's backwave as 17dB below key-down power, "only" 4kW leaks out when the key is up. You are on the right track. Just need another 12.5dB to reach SAQ performance! ;-) 73 Johan
Your circuit is a magnetic amplifier. This book is useful. https://archive.org/details/MagneticAmplifiers 73 Claudio ik2pii -- ZE-Light e ZE-Pro: servizi zimbra per caselle con dominio email.it, per
I used a much smaller circuit but identical as an input attenuator for an experimental vlf transceiver and it worked very well. The control was obtained from the agc line. Definitely worth pursuing!1
Thanks for all the interesting contributions. The old book is a very nice one :-) I expect using saturated coils rather than a saturated transformer can give better results when it is used for keying
Some idea for the transformer... May be that a small toroidal transformer core for mainline power supply can be useful for 2 and 6 kHz bands. But toroid are without transformer air gap. A core from
Hallo Stefan, definitely wrong, what You say. The stray field of the centre leg winding puts the yokes to saturation. Stray field closes throug the outer legs. This means the stray field of the centr
