It´s the same here. In our latest CQDL I could read on two pages how a balun probably should not be wound. I wonder how many now must learn it the hard way. 73 Peter All these years, I've been
I repaired the TL-922 of a friend in 2006. One of the tubes had a grid short and the heater transformer was meltet. After repair I ordered a matched pair of 3-500ZG from RFP. They did very good gain
It does not matter for the HV caps how fast they are loaded. The reason for a step-start circuit is to limit the supply current to a value below that of a typical household circuit breaker. As long t
That is one of the reasons that standard solid state relays will not soft start transformers as they won´t switch on the peak of the sine wave but at zero volts 73 Peter I have a 240V 15A varia
I did that when I got my copy of V.O.Stokes book many years ago, where I found his wideband transformer concept. Using the largest ferrit toroids I could get, they were similar to Amidon cooling, use
Manfred, total wire lenghts must have been 6-7m. I fully agree to all your comments. Powered iron core baluns are only suitable for tuned circuits, not for wideband use. A good example is the 1:4 bal
The better news is that it worked in many thousands of amps built by Rohde&Schwarz from about 1958 to 1990 for the military and other gouvernment use. The early version was 500W AM/CW/FSK with a sing
For maximum power transfer the output impedance and the load must be the same. Above and below that value power drops. The internal low impedance of a solid state amp is converted to 50 Ohms by a wid
Those mentioned R&S transmitting chokes (90ĩH) use 25 windings on a 2 1/4" ceramic former containing a 1.5" diameter ferrit rod 3.5" long. The wire is Original use in 1-30MHz amps running at 3KV anod
Hi Manfred and the group, I made a mistake in my writing, 5 windings are per cm, actually itīs 13tpi. So the ferrit is longer then the coil! It extends 1/2" above and 1" below the coil. The ferrite c
The amplifier is happiest when the load is equal to the typically designed Zout: 50 ohms resistive. That practical loads might be different is another story and designers have to take care of that by
Zero crossing SSRs are no good idea, better to switch on the peak voltage. Far better is controlled switching, Circuit diagram: http://www.emeko.de/uploads/media/01-block-schem-us_tsr02-e_01.PDF expl
What is the difference bewteen 811 RF tubes and 811 audio tubes? Where was the Svetlana 811 built? The Svetlana tube factory in St.Petersburg is still building the transmit tubes under their (winged
Itīs not top secret factory http://www.svetlanajsc.ru/en/contacts/add/ In Germany Svetlana tubes are sold by WWS-Tech 73 Peter transmitting tubes like 4CX800A are still manufactured in St.Petersburg
Hi Dave, I just went there. Everything is fine with your site, no password request or anything else unusual. 73 Peter Hi all. I'm Dave G8WRB and I own the domain g8wrb.org. There is certainly nothing
Zero grid dissipation is no problem. No grid current, no dissipation. The Chinese 3CX1500A7 seem to be very reliable. A company nearby uses 200 of them for about two years and so far no tube failure.
I have pretty good experience in cleaning equipment lik 51s1, Drake Twins, Johnson Matchbox etc. in the dish washer. Just took out all meters. 73 Peter I have just acquired a BTI LK-2000 amp that is
So far that never happened! Cleaned a big roller inductor from a Racal linear lately in the machine. All variable capacitors of the old Johnson KW matchbox looked like new afterwards and nothing happ
It depends on the antenna if a tuner is necessary at all. I never needed a tuner except on open wire feeders. My IC-2KL is happy with all my antennas. It cuts back a little bit of power at the band e
Hi Val, What is the output of the GI7b at 900V anode voltage? 73, Peter Hi David, There is a GLA-1000 conversion to GI7B. It keeps the most of the amp - tank etc., as it's for HF, but GI7B is perfect