Hello Marco, Sunday, April 16, 2017 A very happy Easter to you too, Marco. From myself and my FET's alive and switching, and from those in the great recycling bin in the sky! I hope your FET's surviv
Hello Stefan, Tuesday, April 18, 2017 Thanks Stefan, I am toying with having a crack at VLF. I am wondering where I can find suitable 12 inch plus diameter tube to wind on, polycarbonate tube is ludi
Hello Dave, Thanks for that, with a bit of luck a forum lurker who contacted me by e-mail may be able to help me out with some pipe, but if not that's an option for me, appreciated! -- Best regards,
Hello LF'ers Over the last few days a new signal has appeared, I link to a couple of screen shots showing how it changes from a steady signal to a strange pattern. I don't recall any new electrical g
Hello Mike, 24 April 2017 I use 52V at 57 Amp HP SMPS units, they can be put in series or parallel with no mods, and i believe addin a negative voltage bias to the internal voltage trimmer pot will a
Hello Jay, Thanks for your and the other replies. Testing shows this is exactly the case and I have learnt something else with this, appreciated! -- Best regards, Chris mailto:[email protected]
Hello LF'ers, In the hope it may help or be of interest my experiments with containing the level of spikes seen at the end of a TX on the drains of push pull FET's has shown that the conventional, wi
28th May 2017 Hi Stefan, remarkable work on VLF, congratulations!! I see these with all FET's but I acquired very cheaply some Wolfspeed FETs with a lot of overhead. These spikes sometimes kill lesse
Hello Stefan, 28 April 2017 They go bang when run as 2 amps in parallel with the W1VD combiner. They then even blow the Varistors to kingdom come. I will try with the combiner into my big water coole
Hello Markus, Friday, April 28, 2017, 2:32:50 PM Another mail from me should appear in a minute, with a typo saying I have 1500pF and 10 ohms low inductance resistor "Drain to Gate". It is of course
Hello DK7FC, Friday, April 28, 2017, 2:40:41 PM Amp circuit and info here: http://www.w1vd.com/137-500-KWTX.html I use the W1VD LPF set up too, a total copy of Jay's design http://www.w1vd.com/LPF.ht
Hello Dr.Wolf, 24 April 2017 Thanks for the reply Wolf, I tested with no LPF and the output transformer got pretty hot. With the rebuilt LPF all was fine. So I now have two reliable, identical amps.
Hello Jay, Yes, this is what I found, I'm learning, slowly and appreciate the explanation, all the best. -- Best regards, Chris mailto:[email protected]
Hello Andy, 09 May 2017 I would like to try the transformer coupling, what turns ratio should I use please? I will not try and be too clever and impedance match there as well, i will leave the impeda
Hello rsgb, I finally had the right combination of time and assistance to get my huge Farnell linear variable voltage and current power supply upstairs into my shack in the last 3 days. I have always
Hello Clemens, Thanks for the reply, the 3 stacked cores will rise to 70 degrees C plus even with a small computer processor fan blowing through them. I am investigating ways of reducing this, the co
Hello Marco, 16 May 2017 Good to hear from you, thanks for the reply. I have remade the combiner's output transformer using 3 stacked 78 material toroids of the same size, and wound it with 180 stran
Hello Andy, Thanks, I seem to have had some success using 3 X the number of turns and changing from 77 compound to 79 compound. I think I follow your formulae, as I say, maths is my very weakest poin
Hello Clemens, Thanks for the corrections, I did struggle a bit to get sensible results, but put it down to user error :) No worries! I have built a new combiner transformer on 3 off 78 material stac
22nd May 2017 Hello Marco, I would be very interested to read / see your endeavours with this new amp, if you have the time and inclination to document what you are up to? Interest seems to have shif
