I have replaced the orginial bandswitch in my Swan Mark 1 amplifier with a Radio Switch Model 86S. Understandably this new bandswitch is much larger than the orginial switch so there is little room f
Author: carlseye at tampabay.rr.com (carl seyersdahl)
Date: Wed Feb 26 19:07:06 2003
The core may be fibreglass and resin "encased," but what is the core material.???? Iron or ferrite ?? -- Original Message -- From: "Radio WC6W" <wc6w@juno.com> To: <amps@contesting.com> Sent: Wednesd
Author: MorgusMagnificen at aol.com (MorgusMagnificen@aol.com)
Date: Thu Feb 27 10:58:49 2003
Bill: I am still trying to come up with a feasible design for you, for a toroidal replacement 80M coil. Meanwhile, you probably noticed the posting RE: a coil advertised for sale by WC6W, that was ad
Toroids do not require a ferrite or iron powder core at all. The necessary characteristics of a toroid are simply that it is in the shape we call a toroid. The self-shielding characteristics of toroi
Hi Eric, a posting T400-2 That's a T200-2A core.... note the A on the end. This unit has twice the cross-sectional area of a T200-2 core; Therefore, the balance of your analysis is in error. I observ
I have one of Bob's (W6YUY) original coils as described in the above article. The core is fiberglass & resin encased. It is currently wound with 20 turns of #12 wire. There are notches in the form fo
Author: MorgusMagnificen at aol.com (MorgusMagnificen@aol.com)
Date: Thu Feb 27 11:44:51 2003
Don: I will not debate the price issue, because it is highly variable. My figures are for very high-performance cores, which this is not. You are missing an extremely important point.The power losses
Hi Carl, Per Bob's article there is a T-400-2A Amidon/Micrometals iron powder core inside... not visible as packaged. It may not have been clear in my earlier posting, but this very part was assemble
If the winding has taps for 80 and 40 and the taps get shorted with the band switch, then that is the problem. You should use separate cores for each band. If you were to leave the taps open then you
The blue type ( -1) would give you more inductance with fewer turns on 160 and 80. I suspect it would run cooler. I don't know how, or if, it would work on 40. You might try a stack of one of each (O
My 2 x 3-500Z amp uses a two-stack T-225A-2 red mix iron powder toroid for 160-80-40. It gets hot, especially on 160, changing the loading and causing the grid current to drift up on extended transmi
It doesn't surprise me it falls apart on the upper end with a tapped toroid. The closed core is almost covered with a big shorted winding on the upper end. Unloaded Q has to be terrible. I've seen m
With some patience and extrapolation you *might* be able to divine the number of turns from this: http://www.rfconcepts.com/ETO-Alpha-PA-77-160m-Addition I'll apologize for not opening mine; one of t
Thanks Carl... I will use the 80m core design as the baseline. What I need is a target inductance for the 160m core. I think a turns count from the 160m core on an early model 70 or 77 series amp fro
Hi Tom, I could see really killing it if the turns were shorted but this amp uses taps on the toroidcoil it does not short the turns. The core is about 2 1/2 inches in diameter and about 3 inches i
I would think the toroids and the coil is the same since the 3 tubes are similar and on 160 nothing is that critical. The toroid itself is likely a Micrometals #2 mix. Go to Amidon and get one of the
Yes you are right Tom. It gets taped from the antenna side as a normal tankcoil would. No progressive shorting. So on 20 meters most of the coil is shorted. It seems to work very well on 160 and 80
I have an old TMC (LPA-1k) amplifier that I am getting going. It has a toroidtankcoil for all bands 1.6 MHz to 18 MHz. It has a pair of 3-500Z in it with 3000 volts at 700 mills. On 160 the efficie