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Title: Oh Am Forum brain trust, I beseech thee. many ?'s.... Post by: N3DRB The Derb on July 18, 2008, 01:29:35 AM no reference books here. Did a google search but came back with thousands of near misses. Need brains like zombie.
On the Gonset Maul, the B+ wire from the bleeder passes within 2 inches of the cathode chokes and runs inside the main wiring harness to boot. 1700 volts. stock, went to a grommet to pass through to the upper chassis where it tied off to the bottom end of the plate choke. Does not impress me. Once again, it was Slab that pointed this out as substandard. Since I have more of the stuff than I can use for 10 stations, I'm planning on using RGS 400 coax and adding a small ceramic feedthru instead of the grommet so I can keep the B+ line shielded and bypassed for rf on both ends, the bleeder end which is above chassis, and the other end which can be bypassed on both sides of the chassis right at the chassis end of the plate choke both above and below the steel. the choke is 120 uh @ 1 amp CCS. I presume the RGS 400 being teflon and silver double shielded it will take 2KV from center to shield safely and keep the DC and whatever RF remains at the choke bypass inside the shield until it gets back to the bleeder/ B+ source? I also want to isolate the input/output better once it gets below the main chassis. What value of bypass cap at the bottom of that choke above and below the steel will keep RF off that B+ line, and will the coax handle the DC safely? I presume so since the rather ordinary PVC did, but I wanna know fer sure. I have about 250 ferrite beads made of number 43 material which start working at 25 mhz and goes up to 250 Mhz. 40 ohms @ 25 mhz and goes up from there. Where to best use some of these? Some of these may be dumb questions, but my radio mental depth perception ability has gone down a bit. kinda like I feel I should know all this stuff and I know I used to, but I don't trust myself anymore. Title: Re: Oh Am Forum brain trust, I beseech thee. many ?'s.... Post by: The Slab Bacon on July 18, 2008, 05:45:27 AM Timmy,
If you put something around .01 @2kv or better on both ends of the coax and ground the shield, you should be good for whatever. Use a 2kv or higher cap for a little safety margin. .001s should prolly do it, But i always like to go to the "overkill" side of values to insure more than enough adequacey. With the "new and improved" plate choke, bypass values shouldnt be anywhere near as critical. the Slab Bacon Title: Re: Oh Am Forum brain trust, I beseech thee. many ?'s.... Post by: N3DRB The Derb on July 18, 2008, 09:47:38 AM I got 25 or 35 .003's @ 3kv begging to get used. I'll grab em and sprinkle them around. tnx om. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
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