KA1-RBP
Projects____________________
KA1-RBP
Projects
____________________
Since it would be a huge undertaking (if doable at all) for a radio amateur to construct a homebuilt radio with half the operating features available on modern rigs, just about the only thing that one can still have some fun constructing, is tuner/feedline/antenna related. Fortunately, since being steered to balanced feedline/tuner combinations from the start of my amateur career by my elmer N1KW for all of their advantages, this lead me to construct various iterations of link coupled tuner design found in ARRL Handbooks going way back, for use with my "80m Zepp" wire dipole antennas.
With this in mind, here are a few I've constructed...from No. 1, where the primary design criteria
(besides first class performance naturally) were to:
1. Use on-hand or homemade components (not even a new, but a recycled, "reconfigured" chassis) and
2. Have zero regard for the finished appearance (in fact, ugly was
considered good and even a goal) ...sort of what the professor on
Gilligan's Island might have come up with...
to number 4 and 5, full-power (plus) capable, clean units, long term
projects still in progress (since I have yet to move up to a poweramp requiring
their capabilities), to be built in the ultra-beefcake style with the
only family resemblance to No. 1 being circuit design!
...also shown are some homebuilt SWR bridge and SWR/Field Strength meter projects, and the solidstating of the otherwise space heating (but nonetheless well performing) R-392.
Since I use (low visibility) wire antennas exclusively, here are some of my notes on the subject.
| Link
Coupled Antenna Tuner No. 1, 100W, mfj/Ugly Its not about the money...this tuner is used with an Icom 756! (...so one couldn't say, "there was zero money left over after buying the radio"...actually this tuner was built for use with a Collins KWM-2, long before the Icom came along!)  |
Details:
(Ugly is Good!)
mfj (no, not the manufacturer, but made from junk!) Featuring:
Band selection by clips set to (characterization determined) colored paint
marks on primary and (balanced) secondaries of 3X4" pine core
coils. Total cost: $0.00...its made from junk (OK, maybe I bought the caps and meter)! |
| Link
Coupled Antenna Tuner No. 2, 100W, (Compact version.) This little guy is nicely suited to portable operations.  |
Details: Primary (of Teflon wire) is directly wound onto secondary, band selection is by clip method. Total cost: maybe $20.00
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| Link
Coupled Antenna Tuner No. 3, 100W, (Clean version, under construction).
. One of those cute little Daiwa dual needle SWR meters (type CN-520) will be integrated. Notice the pinecore coil form...I cant seem to get away from them...then again, I stick with what works! This unit is to replace the "Ugly" tuner No. 1, when it moves out to the Alpenshack.  |
Details:
Total cost: tbd |
| Link
Coupled Antenna Tuner No. 4, 2000W (Full-size, 19" rackmount version,
under construction). Built of larger components, including verniers on primary and secondary capacitors. Note homemade primary coil (of 6 gauge solid copper) on G10 form within commercial secondary coil. Unit is to incorporate Daiwa type 103 dual meter for SWR indication.  |
Details:
Total cost: tbd |
| Link
Coupled Antenna Tuner No. 5, >2000W (Ultimate version, also under
construction)
Built of even larger components!
pic placeholder |
Total cost: tbd |
| Portable
SWR bridge.
Constructed using a coax
type directional coupler into one of those surplus Radiac radiation
meters, lets hope this is the only use they'll EVER be put to! |
Details: |
| Portable
SWR bridge/FS meter. URM-14
Built in the mil.
style, using a PC
board type directional coupler into a cute little mil. surplus box. |
Details: |
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| Wire
Antennas They're not the most glamorous thing growing on an antenna farm, but they don't require an army for an erection party or bring irate neighbors around complaining why you're coming in on their stereo when its OFF. In fact, it's unlikely the neighbors can even see the wires strung between the trees! The 80m Zepp, (open line fed) Advantages: Ultra low loss (and cost), all HF band coverage, low visibility - almost covert! Disadvantages: Non-rotatable, |
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