Hugh those fets are faster than a fuse! Dave GW8GLO 136khz it is then. I will be listening and transmitting Opera and QRSS (speed dependent on PA dissipation), input 220 to 300W from a 300W audio amp
Very sad to hear he was a great inspiration and always willing to help. He will be missed by all. --Original Message-- From: Roman <[email protected]> To: rsgb_lf_group <[email protected]>
Does anybody know what ferrite grade is used on the fet driver transformer. I have had one burn out and have rebuilt it but would like to redesign it with better isolation between windings. Have trie
Thanks for the reply the transformer failed because of a small cut in the rubber sleeving where it entered the ferrite. As the ferrite is earthed the insulation on the litz was not good enough. I hav
Andy I have used an ENI amp, the 1140L. These work well at 136 with up to 1.5kw on my amp. They are very inefficient as would be expected. They are also very expensive unless you are lucky, mine came
Andy thanks for that I am looking to find a scrap amplifier module to play around with with a view to rebuild the PCB and drive circuits. Looking on a scope the switching is very symmetrical but that
OK thanks Andy I do have the circuit diagrams but I understood that the clamp only operated if the drive was lost. The description was not that clear to me but a probe with the scope may clear that u
Chris should be able to hear any signal from you, already have electrodes in place about 50m apart and over 4m deep into the water table. Lot of noise on them with several volts from a local mw tx! N
OK Chris I have built some time ago a elf transceiver that is sound card based using a usb card. It works from about 10hz to 20khz, needs finishing but it is working. All I need is a good high power
Just south of welshpool in the severn valley, good earth! 73 Dave --Original Message-- From: Chris Wilson <[email protected]> To: Chris Wilson <[email protected]> Sent: Wed, 1 Jun 2016
Has anybody tried using the Russian teflon doorknob capacitors for tuned circuits on 137 khz? I have seen some rated at 2000pf at 16kv which will give me the 8000pf I require to tune the loop. So far
OK Andy they are the normal doorknob types, the ones I am looking at are made of a white ceramic case and are nitrogen filled with bolts at either end. There are 2 types available in 2000pf 2kv and 1
Lubos these were used on submarines and some surface ships in various navy's. We used one as a monitor but it was not very sensitive due to it being designed for use with an active antenna usually wi
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
Does anybody have diagrams for the ENI 1140L linear amplifier. I have some parts of the manual but no diags! It covers from 10khz to 250khz with an OP of about 1.2 kw and is linear. The psu is very i
Paul would be interested in one please advise when you have more info. It would have to be sent so can this be done. Many thanks Having a clear out at work. There are some hefty studio grade audio am
Hugh will look out for you on sunday, we can use PW for talkback Can try any mode you like as it is all linear here.73 Dave GW8GLO Hello rsgb_lf_group. I hope to be QRP & QRSS this Saturday & Sunda
Try using a synchronous keying circuit, only uses a few ics and is reliable. I have used it on a modified Decca 5501 on 136 and a similar tx on 475 with no blown fets even to a short circuit, guard c
Paul still interested in 2 if possible, terry can pick up for me when you have them. Many thanks Now after some delay these amplifiers are starting to come through. The first two arrived today at our
