I've finally finished the tile work and most of the rest of my home
projects and I've been able to spend the last few days on Ultralight
construction projects.
The first effort was to create the final dial for the National SRF-39
Table Model. I spent about a day on this using a signal generator for
both the Western Hemisphere and Eastern dials. I spotted individual
frequencies below 1000 and did each 50 kHz or so above... then
interpolating. The FM dial was strictly listening, recording known
frequencies and then SWAGing the dots on that dial. I'm really
pleased with the results. I can read the dial to the 9/10 KHz below 1000
with full confidence and can usually guess correctly above. I'm not sure
just how much I'll even use this set to DX, but I've always wanted to
make something like this. It was even more fun than I expected. The
radiating station names are on there just for decoration, tho' they also
represent a decent hit list for me from the Northwest. Most of us have
always loved the old radios with city or country names on the dial. I'm
certainly no exception.
I also put together two identical cabinets from specimen wood. One, from
60 year old recycled Arkansas walnut, houses the radio. A second of
identical dimensions is a speaker enclosure. I was originally going to
house a small stereo amp and speakers cannibalized from an Ipod dock...
to provide speaker-level volume for the SRF-39 and for my mp3 player,
etc. However, despite Nick's good technical counsel, I managed to burn
that little amp out immediately. Since the unit cost me almost
nothing and I managed to salvage the four little speakers, it wasn't a
total disaster. I eventually did a search on line and found Canakit
in suburban Vancouver that makes a wonderful line of kits and assembled
units. A "Walkman" stereo amp, 5 watts per channel, is on its
way to me now. The speaker unit cabinet, out of salvaged tropical
hardwood similar to ebony, will have the four little speakers in the
front panel along with stereo controls, a power switch and a switch to
throw the stereo output either to those four little speakers or out the
back to a pair of outboard larger stereo speakers. As soon as I get
the stereo amp (late next week) installed, I'll post photos of both
units.... I'm really pleased with how they both look and what testing
I've done with the National SRF-39 hooked up to serious antennas, it
looks to be an excellent DX receiver.
I had completed modifying my Sangean DT-200VX to accept an outside
antenna a couple of weeks ago, but I'd delayed writing the article until
I had the time and found the nerve to tackle the Eton E100 for a
similar mod. You might remember that I'd gotten the back case off the
e100 and been unable to go further in disassembling the radio.... I lost
my nerve and tiptoed back out of the radio. Well, after a lot of thought
and some more study of the interior photos posted on line by
HongKongRadioer, I restarted the E100 project this morning. I had guessed
correctly and things went reasonably well. If you know how, taking the
radio apart is really not bad at all. Its a shame that Eton does not make
Technical Manuals available. I took good pictures and will write up the
disassembly instructions in the next day or two.
Installing an external antenna port
inside the e100 case
proved impossible with this tightly packed radio, but I was able to
install a "PC board-type" phone jack mounted on the upper edge
of the outside of the case. This leads inside to the typical
pick-up coil wrapped around the stock ferrite bar antenna. I've not had a
chance to test this unit much, but it seems to work well on an outside
antenna on at least the upper half of the dial. There seemed to be less
sensitivity than I expected below 600 KHz. Also, when I briefly tried it
late this afternoon, I noticed some overloading from my local daytimer (1
mile away), so I'm only cautiously optimistic about performance of
the e100 with an outside antenna.
I did notice, though, that the e100 is PERFECT for a transplant of a
larger rod. The coil on the stock ferrite bar is a simple single coil
with connections only to each end of the coil (no center tap, etc.) The
two solder points for the antenna coil are right in front of you as you
open the back of the case. It would be simplicity itself to
unsolder the two wires from the board and solder in cabling to an
appropriately sized coil on a much larger bar, outboard to the case...
the Transplant strategy that Gary DeBock is pioneering.
Well, as you can see, I've been having loads of fun getting ready to
return to the DX beaches of the NW. I'll upload that e100 disassembly
information Monday.
Hope Gary DeB does only moderately well in his Grayland visit
:>)
John B.
Stillwater, Oklahoma, USA
Rcvrs: WiNRADiO 313e, Eton e1, NRD-535(kiwa-mods)
Antennas: 700' NE/SW mini-Bev, Wellbrook Phased Array (pre-production
version)