Anything that creates a voltage spike or arc or short is likely to take one or more small signal transistors on the Input Bias Board. On two occasions, I've had to replace a half dozen of them at a t
I strongly agree, and have had some discussions with GM3SEK on the topic. The consolidated schematic is one step in the direction of possibly incorporating his board into the Titan 425. Ian also sugg
Hi Guys, I'm troubleshooting a "stuttering" keying problem on one of my 425s. I suspect a relay problem -- K3, K4, or K6. Vacuum relay is fairly new Gigavac, replaced last summer, and it's been throu
Power amps have input and interstage circuitry that may handle relatively low power. I've studied ferrites a LOT with respect to RFI suppression and common mode chokes, but I'm not an expert on their
All of this data has been in Fair-Rite's printed catalog for many years, and that catalog has been on Fair-Rite's website as a pdf for at least 5 years. 73, Jim ______________________________________
Were you building a TRANSFORMER (commonly called a voltage balun) or a CHOKE (commonly called a current balun)? They are VERY different. a choke. See http://audiosystemsgroup.com/RFI-Ham.pdf 73, Jim
I understand your quandry. Here's the single page htm with data for #61. http://www.fair-rite.com/newfair/materials61.htm and the page with links to all materials http://www.fair-rite.com/newfair/mat
Lots of good advice in this post. See comments interspersed, lots of snips to save space in the digest. YES! The good news is that this can be predicted from mfr data sheets. The bad news is that you
Of course -- there are many different ferrite mixes from the same and different manufacturers, and sizes and shapes of cores made from those mixes, just as there are many different kinds of capacitor
NO! This is a major misunderstanding of the maximum power transfer theorem, which says that if a generator has a fixed value of resistance (that is, we can change ONLY the load resistance) AND IS LI
Totally inappropriate use of "SWR." SWR is a characteristic of a transmission line, not a passive network. 73, Jim Brown K9YC _______________________________________________ Amps mailing list Amps@co
DIN connectors are available from the usual suspects -- Newark, Allied, etc. One VERY important caution. The usual ham sources, as well as Mouser, etc. sell cheapo imitation DIN connectors that it is
Thanks Joe. I've seen catalog listings for the correct FT1000 part at the sources I mentioned. I don't own a 7000. 73, Jim K9YC _______________________________________________ Amps mailing list Amps@
As I'm sure you're aware, a 240V load has no connection to neutral -- it draws its power from +120 and - 120. The green wire (equipment safety ground) is not permitted to carry current (except in the
Contesters love amps and antenna tuners that auto-tune so that we can QSY and switch bands quickly, but good auto-tune isn't cheap. For less than what I would pay for one decent used auto-tune legal
I strongly agree that connecting these transformers in series is a bad idea. The INPUT voltage WILL divide between them, but there is no satisfactory neutral, and no satisfactory way to create a neut
See my attempt to combine the schematics into a more coherent form. No guarantees about accuracy, but several dozen sets of eyes have reviewed them, and I've made a few corrections. As near as I can
First, I have no idea what an AADE unit is. Second, I don't know what a B&W 852 is either, but since you're measuring inductance, I'm guessing its a switched tapped inductor. Third, all of your measu
Several months ago, we had a discussion about what was a proper way to connect a 120V load to a 240V source. Since about 1975, it has been illegal to connect a load between either side of the 240V li
So study a book on antennas! It is very well known (not far from the beginning of the discussion in almost any text) that the physical length of a resonant conductor depends on its cross section. The