Hi All, Having been caught on more than one occasion with fakes, particularly fake SD memory cards, I now only buy semiconductor components from reputable sources - more costly, yes, but you are guar
Hi Ulf, No need to go to the States - try RS Components - their Swedish Website https://se.rs-online.com/web/ or Farnell - their Swedish Website https://se.farnell.com/ Both are reputable suppliers D
Hi All Sometime ago someone on this reflector compiled a list of manufacturers who were willing to produce custom wound HT transformers for amateurs in the UK. I also recall that it included comments
As you mention screen voltage, I assume you are talking of tetrode amplifiers. In a conventional grounded cathode/filament 4CX tetrode linear amplifier biased for class AB1 operation, the control gri
Hi Robert, I have an RF104. AFAIK the RF deck is the same as the RF103. It is the channel programme board behind the front door that is different. Please email me off list and I'll try to answer any
Hi Byron, My approach to producing dedicated meter scales is as follows. You will need flatbed scanner and a laser printer. 1 - Remove the meter scale, place on flatbed scanner and obtain jpg or bmp
Hi Byron, I have a homebrewed 2m W6PO amp built to the dimensions given in the original W6PO article. I run it with an HT of about 3700V under load. The grid current and efficiency is very dependent
I guess you haven't heard of Russ Andrews. https://www.russandrews.com/select-ks6068-speaker-cable-with-wbt0610ag-bananas-33739993131/ A mere £17,800 ($23,000) for a single 1.5 metre speaker cable. 1
Hi Alek, I have a 70cm GS35b amp which exhibits most of the characteristics which you describe. My amp is based upon the design of PA3CSG https://pa3csg.nl/?page_id=17 . Also see VK3NX's comments htt
Hi Paul, You could be lucky with your tube. Googling "GS35b tuning drift" will yield many examples. David G4FTC For whatever it may be worth, my 2m GS35b amp doesn't show any tuning drift at all runn
Hi Jim, I use them extensively - in particular these https://uk.rs-online.com/web/p/clinch-nuts/0827647 Infinitely better than self tapping screws. Would be lost without them. 73 David G4FTC ________
Hi Kouichi, I have two SB220s and they both work well on the WARC bands. The input circuit of the SB220 is a low Q PI network which is effectively a low pass filter, so, if you want to operate on 12m
Hi Kouichi, Correct. Correct. Don't expect it to tune control to be near the expected frequency legend on the front panel. It will be very helpful to have power meters/SWR meters in both the input an
Hi Kouichi I consider the SB220 amplifier to be one of the best workhorses available. But it does require some respect to ensure satisfactory performance. Metering is basic but more than adequate. Ab
Hi Kouichi, $470 is a very good price - as long as it works! You really need to see it in person and, if possible, in operation. The 3-500Z tubes are available but other spare parts such as the meter
Hi Victor, Please enlighten me. David G4FTC ________________________________ From: Victor Rosenthal <k2vco.vic@gmail.com> Sent: 09 October 2024 10:31 To: David G4FTC <g4ftc@hotmail.com> Cc: Kouichi U
Thanks - I can see the logic in that. You just need to ensure that the voltage across the shunt resistor in normal operation never exceeds, say, 0.5V, and that the diodes used can handle the fault cu
I would be cautious about using zeners - from my experience their failure mode is to go short circuit which necessitates taking the amp apart to replace them. Sometime ago I wanted to ensure that a t
Hi Kouichi The SB220 was normally available as a kit for home construction and the assembly manual and schematic are available here http://www.radiomanual.info/schemi/ACC_PA/Heathkit_SB-220_serv_user
I agree with Don's comments that the cost of rewinding the transformer may exceed the cost of a new one. I would suggest getting quotes for both a re-wind and a new transformer. David G4FTC _________