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I need a 75' length of cable w/ PL259's. 2/3 of it will be an outside vertical run. HF only. I've been using cheap RG8 from decades ago that was stored. What is JEFA? I was set to shop for LMR400 when I found "LMR400/213 type" ads for a BR400 cable. Terminology is getting tricky.

Thank you all for the feedback on this. I've been using old tubes (300y's) to set voltage & current limits. Had to order a new current meter that I'm waiting on to do final adjustments before I put new tubes in it (300a's).

Found the Answer, I think. Re-read the 2004 Pride DX-300 Review/Manual originally published on CBTricks.com. Page 32, section 4.4, Item 7 states Screen voltage at tube pins can vary +/-10%. That’s a lot but good news for me as I’m bit low.

10-80 Tetrode amp project: Scrapped the T-match and made it an L-Network. Improved input SWR's went down 10-80. Reduced turns on torroid from 11 to 10. Other side of pass-through is 1:6 unun w/ 300ohm swamping resistor. Waiting for a low mA meter to set standing current. Have all voltages...

Thanks for your comment, I was oblivious to that.

I review Transformer listing on Ebay, bad habit I know. Listing error but label clarifies specs https://www.ebay.com/itm/181817645835?mkcid=1&mkrid=711-53200-19255-0&siteid=0&customid=link&campid=5336136228&toolid=20001&mkevt=1

Found this delightful article that has lots of pictures and recommend it to anyone who ever exchanged QSL cards. Priceless quote: "Before FT8 turned Ham Radio into an iPhone app". https://www.md0mdi.im/history-worth-remembering/ Happy New Year neil NYC

How much can the Screen Voltage vary? Is it like the Control Grid where it must be exactly what datasheet states? Or can it vary a bit like the other tube grids & filament? Everything I find online concerns Screen Current and that's addressed by the control boards. Datasheets state the same...

Had to revise grid-driven input by removing UNUN. SWR analyzer helps to set input SWR with different grid resistance layouts as I have what amounts to an L network preceding the swamping resistance to help compensate for the mismatch. My goal is to lower the drive requirements. My Screen...

I apparently installed the wrong bias Zener (56v) for the 300a tubes so I'm waiting on replacement (51v). I have 2 sets of new & used 4cx300a & 300y and placed a small toggle to switch Zener voltages (-55 & -70). Looking back it was silly idea. How often would I change tubes, right? This...

Thanks for solving that mystery but used to vaporize metal the tubes must take a beating. So much for parts value. I see that Seller dripped the price by half. neil

https://www.ebay.com/itm/153424580138?mkcid=1&mkrid=711-53200-19255-0&siteid=0&customid=link&campid=5336136228&toolid=20001&mkevt=1 "MRC A114265 Quad 1000 RF Deck Sputter Power Supply 3500 VDC Eimac SK-4063-500Z" Can't imagine what it does or why it's configured like that. Coils must be...

Yesterday I made the 1:2.5 unun (center screen picture below) and swr analyzer said it's OK for matching the 110 ohm swamping scheme for 30w max drive. I used another T-68-2 red core and 20Ga magnet wire. That 110 ohm grounding scheme came from a 1958 QST: A Compact 650-Watt Amplifier. Unun...

The portable setup scene is fun. Perfecting the fast deployment with remote location adds to the challenge. I loved operating from my 4x4 where no one else could go. On foot, focus on antenna sites of hilltops and cliffs (or trees if you're able). Despite lack of real power, a directional...

My 10-80 grid-driven 4cx300a x2 amp is proceeding. I had to order parts for input. Last I reported, I had almost 100w AM from an old CB using W8Ji’s Resistive Input circuit that splits the 50 ohm swamping resistance. It was first application of drive so I used old tubes I got for free so I...

Thanks for putting those download cites together like that. neil, NYC

What type of relay is it?

I stumbled on an Audio site that mentioned rebuilding large electrolytics for less than purchasing new (https://www.nmr.mgh.harvard.edu/~reese/electrolytics/). I never knew that was an option. I have a McIntosh that needs 2 large caps and the cost has kept me from doing it. Got a new-to-me...

I'm about to resume work on that project. Had to stop and rebuild my bench power supply that quit right after I got the 2x 4cx300a producing RF but could not complete the tune. Bad bench supply stops everything, ya know? More to come of the amp in few weeks. Thanks again neil NYC

Hi, I'm trying to cobble together a tuned input and need the value of a fixed inductor (Thumbnail pic) from the Tuned Input of a Collins 30L-1 HF amp. Every Collins diagram / manual I can find list is too blurry to read. Part L-19 I tried to decipher the color codes but I can't figure it...