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Reviews For: Oak Hills Research 100A

Category: QRP Radios (5 watts or less)

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Review Summary For : Oak Hills Research 100A
Reviews: 51MSRP: 129.95
Description:
The Oak Hills Research OHR 100A single band CW transceiver kit
Product is in production
More Info: http://www.ohr.com/ohr100a.htm
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00514.9
KC0EM Rating: 1999-09-30
Oak Hills Research 100A Time Owned: unknown months.
I wanted a 30 meter QRP kit and after looking at several kits I chose the Oak Hills kit. My first impressions of the kit were excellent. It comes with a heavy duty PC board that is silk screened and masked with plated through holes. The layout is not crowded making assembly a breeze. I used a 20 year old Weller soldering station with a small tip. I should say that I am not the usual kit builder. I designed and built equipment electronic equipment for almost 30 years before leaving the field.
There was one missing transistor that an e-mail message brought through the mail even before I needed it in the assembly. There was also an extra hardware kit I return to Oak Hills. The only other problem I had checking the parts were the 100k resistors that last yellow band blended in so well with the color of the body of the resistor I never did see it and had to resort to the ohm meter, but that is the resistor manufacture's poor choice of body color and not Oak Hills' fault. I was impressed by the fact they package items that might be confused separately. They did with caps that were N150, N330, and so on. It very nice touch to the kit. These kits are for the 80, 40, and 30 meter bands, so there was a little bag with the components needed to make my kit into a 30 meter rig -- that made for a bit of worry and more about that later.
Stuffing the board went quickly. I enjoyed the building so much I went slowly, but I would expect you could complete the kit in a weekend or two at most. I had to steal time from a growing business which also slowed me down.
There seemed to be a missing resistor, R107. It proved to be in the 30 meter package of parts. I had expected caps and coils to be part of the band package kit but not a resistor -- my fault and not Oak Hills. Anyway all this is to say when you build yours, don't panic when you come up with an empty hole for a resistor on the the board.
There are nine toroid coils to wind, but the most turns on any coil is only 26 turns. This means the coils are no real chore. The wire used is some on which the insulation melts away as you tin the wire, so there is no sandpapering the enamel off the wire.
A very nice touch is all the controls are wired to the PC board through six Molex connectors. It means you can remove the PC board by pulling off the connectors, unsoldering the one wire to the antenna and removing the four screws that hold the board in place.
Other touches I liked were the detent on the RIT pot, the large precision pot used for tuning control, and the good overall quality of the cabinet.
The kit passed the smoke test and worked the first time I turned it on. It requires alignment. You need a frequency counter, a digital voltmeter, dummy load, QRP wattmeter, and a transceiver with 30 meter coverage.
Off the cuff alignment
All I had that met the above conditions was a Radio Shack digital voltmeter, but I was able to get it "almost" aligned. I used a general coverage receiver to get the VFO on frequency. It would have been a lot easier with a frequency counter. Peaking the various caps went well with my DVM. I didn't have a means of setting the BFO to the correct side of the zero beat, until I tried using one of the digital stations on 30m. It went well. My antenna tuner has sort of a wattmeter and dummy load in it -- it has trouble reading power levels as low as 5 watts -- and I used it to set the power levels. I would think you could also set the power levels by monitoring the current flow during transmit into a dummy load. You could set the output level to 700 ma and be sure you were in the safe power limits. One alignment procedure I could never figure a way to do was the transmit offset. All said and done the rig has produced many contacts with good signal reports even with this crude off the cuff alignment technique. There were even a few DX contacts, but this morning I put the rig in the mail along with $45 for Oak Hills Research to do a professional alignment job. It was working so well for me I almost didn't bother, but I had never used the needed finger nail polish/coil dope on the VFO coil to hold the turns in place. You could get frequency jumps if you tapped the case, and I want to throw it in my luggage and keep the dial accurate.
I recommend this rig. It tunes smoothly. There are no thumps or clicks as you key it. The bandwidth adjustment on the crystal filter is smooth and the loss does not seem large to my ears. It drives an external speaker to more volume than I would ever want with good quality sound. You can also get a digital display for it, but I plan to travel with it and a power supply and the rig are all I would want to carry in addition to my Heathkit HFT-9A antenna tuner.