Re: Disassembly of E100
Hi John and Others,
Thanks to John for the detailed disassembly instructions for the Eton E100, in the dxer.ca Ultralight File area. These instructions would have proven useful, when alignments on two E100's were performed here recently.
My first experience with E100 disassembly was back in February, shortly after the 2008 Shootout file was written (and the E100 barely missed the cutoff). Kevin Schanilec sent me a unit to align, and right away I could see that the E100 was something really special. Kevin had already used his E100 to make some phenomenal X-band receptions, and his unit had the highest upper-band sensitivity (and selectivity) that I had ever heard in a stock Ultralight. Low-band performance, however, was an embarrassment.
Upon disassembly, I discovered that the loopstick in Kevin's E100 was a type without a movable coil, i.e. individual windings wrapped around an immovable form. This was the first time I had ever seen this configuration in a portable, although I later discovered that the ICF-2010 has the same type of loopstick. Anyway, I had to admit to Kevin that I could not align the low band, because of the loopstick design.
One month later, Rob Ross and I together bid on two E100's on eBay from Durham Radio, and got them for $27.01 apiece. When I disassembled these, I discovered a different type of loopstick, with a moveable form. Accordingly, both Rob and I now have E100's which are fully aligned, making the units the most sensitive and selective stock Ultralights around, with the exception of the SRF-T615's low-band sensitivity.
The alignment procedure involves peaking the loopstick coil on a 600 kHz weak signal (thank goodness for CKBD-600!) by sliding it along the ferrite bar, after removing all wax. High band is peaked by adjusting the red-bordered square- shaped trimmer capacitor located at the extreme left center position on John's photos. A weak 1400 kHz (or thereabouts) signal is tuned in, and peaked for maximum signal. I discovered that it is not necessary to completely disassemble the radio to get at this trimmer cap, but you do need to pull out some slack in the large bundle of wires under the center clamp, in order to flip the circuit board over enough to adjust the trimmer. It worked well for Rob's (and my) unit.
It's a tossup which stock Ultralight I would most like to have on a DXpedition-- the E100 or an SRF-T615. The E100 has better selectivity and better high-band sensitivity, while the SRF-T615 has a lower noise lfloor, and better low-band sensitivity. The E100 has far more memories, but the SRF-T615 has better nulling ability. I guess the choice comes down to an intangible decision.. which radio is the most thrilling to use? For me, it's the SRF-T615, a tiny overachiever.
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