Hello chaps more on the 3CX800 build. I just call my old mother in the UK and told her where to find my stash of silver plated copper strap and wire and drew a blank. So I still need a source. Maybe
I On it's way to me from a faraway land is a PCB that is designed to be part of a socket for a 3CX800. It has 2.5mm clearance plated through holes. I need some solder in pins to make it into a workin
Hello what is the rule of thumb for conservatively estimating the required ratings for a load capacitor when used with a mono band Pi-L tank circuit? Anode voltage 2750V Tube design RL = 2600 ohms Q
Hello all, power required is a lot less. The VSWR is excellent as it is a mono band low VHF yagi. However sometimes things can go wrong and I want the capacitor to survive my late night sleepy blunde
Yes exactly Pi L and the intermediate impedance is 350 ohms, so I think I am right to uncomfortable with this little load C. Regards Conrad PA5Y Vic 4X6GP Letīs say the SWR is 3 then the load might b
As I do not (yet) own a decent LCR meter does anyone have a decent ball park figure for the stray C to chassis for a 3CX800A7? The side walls are 1.25 inches away from the tube and the lid is 2.5 inc
Thanks Steve that is very useful. Regards Conrad On 22/08/2017 21:48, Steve Thompson wrote: Some years ago I measured some valves, including 3CX800. I don't think I have kept the results but the gene
Hello again, I have gathered almost everything that I need for my 3CX800A7 conversion from 2m to 6m. I have choice of materials for L1. I have some 6mm soft copper pipe, some 4mm soft copper pipe and
Wrong use of the word annealed, the copper is hardened somehow and is darker than normal copper. I don't like it so I will buy some thin pure cooper sheet and cut in in a guillotine. That way I get e
Hello all I have found 2 second hand grid dip meters. One is a Heathkit HD1250 price 80 Euros, the other is a Leader LDM-815 price 50 Euros, you tube videos show that they both seem to work. The Hea
Yes very nice, I have used one and I have various VNA's at work some of which are staggeringly expensive. However they are not mine and a large. The VNWA3 needs a PC to work which is also not conveni
Some weird email delays, OK then the leader it is. Regards Conrad So does anyone have any experience of the devices that I asked about? Regards Conrad PA5Y On 2017-09-04 23:42, Jim Brown wrote: On 9/
The only catch at all is the threads are metric. No Bill, that is a bonus, when I order some HT57s I will have to remember to order some weird American brass screws to go with them! 73 Conrad PA5Y __
Bloody hell I was attempting to pull your leg! Sheesh Conrad PA5Y --Original Message-- From: Conrad PA5Y Sent: Friday, September 08, 2017 6:13 AM To: Bill Turner Cc: Amps group Subject: Re: [Amps] Pl
I know how to cold test an anode circuit by connecting a resistor between anode and grid using a resistor with the value of the design plate RL. I presume that I can do the same cold test for the inp
Some time ago I made a 8877 amplifier for 6m. It was a little low on efficiency, it turned out that you cannot use brake pipe as it contains nickle. Ever since then I have used soft copper or silver
Hello all. I have a question on behalf of an Italian friend of mine. He has 8877 amplifier for 2m and what sounds like some tired tubes. His 'normal' tube is a 3CPX1500. Recently he has noticed that
Hello all. I have a question on behalf of an Italian friend of mine. He has 8877 amplifier for 2m and what sounds like some tired tubes. His 'normal' tube is a 3CPX1500. Recently he has noticed that
That is indeed a tragedy, his designs were excellent and the aesthetics of his amplifiers were second to none. I sent him an email this morning before I saw this. RIP Paul and thank you for everythin
If I were building a new HF amplifier I would be tempted to incorporate a meter and dual directional coupler based on the work of Lofthur TF3LJ. PD0LEW has done some work recently with Newhaven displ