Gang, here is my review of the Oak Hills Research OHR100 transceiver kit.
Review of Oak Hills Research OHR100 40M CW Transceiver Kit
Review Version 1.00
Chuck Adams, K5FO
February 18, 1997
MFR: Oak Hills Research
Address of MFR: 20879 Madison Street
Big Rapids, MI 49307
616.796.0920 phone number
Designer: Dick Witzke, KE8KL
Model: OHR100
Size: 14.4cm x 12.3cm board
Weight: 23.4 ounces for assembled kit with case
PC board: Double sided plated-through, solder-masked
and silk-screened PC board
Manual: 19 pages 8.5x11" double sided manual + 10 pages
parts listings and schematics and illustrations
Power : 12 to 15VDC
RX Drain: 65mA
TX Drain: ~800mA on transmit for 5W output
Ant Connection: SO-239 connector
Pwr Connection: Coaxial DC Power Jack
Key Connection: 1/4" Mono Phone Jack
Ear Phones: 1/4" Mono Phone Jack
Modes: CW only
Kit: Yes. Complete with case and internal parts
Bands: 40M with other bands (30M and 20M available)
LO/VFO: Osc with 3.712-3.782MHz out (7.000-7.070MHz tuning)
Drift: Less than 500Hz in 20 minutes from a cold start with
cover removed at 65 degrees F.
Dial Range: Marked 0 to 70
RX: SuperHet
XMT: Yes. Rated 5W. Measured 5W into dummy and 5W into
antenna at 12.88V.
Filter: Four crystal filter at 9.000MHz
Selectivity: About 1100Hz-400Hz variable
RIT: Yes.
Gain: Audio.
AGC: Yes
Preamp: No
Atten: No
Builtin SPKR: No
Meter: No
S Tone: Sine wave generated at audio levels. Adjustable level.
VFO: Yes. Covers 70KHz or a little more of the 40M band.
Output: 5.0W adjustable with external knob to lower levels
Internal Keyer: No.
QSK: Yes
Price: $129.95 US (see web page http://www.ohr.com/)
Availability: From Oak Hills Research at above address.
Options: None known at this time
Date of Review: February 18, 1997
Author: Chuck Adams, K5FO
Comments: Another super rig from Oak Hills Research.
With the qrp-l group buy going on at Oak Hills Research, see early postings
to this group over the past few weeks, I couldn't just stand around and not
get in on the fun, so called Oak Hills Research and sure enough in a week
comes the little brown box on the little Brown truck. I didn't see the UPS
guy/gal show up at the doorstep but there is was when I got home from work.
This was on Wednesday evening but I held off opening the box until Friday
night. Such discipline. Did I mention that OHR takes plastic? It helps.
MasterCard and Visa cards spoken there. He also takes personal checks and
the old Money Order.
I thought that I'd build this one with pictures, so visit the web page and
see the results up close and personal. Also visit OHR's web page at
http://www.ohr.com/ (that was simple enough)
The PC board shop that Oak Hills Research uses has got to be one of the top
10 in the world. The quality is outstanding. Green solder masked and with
the white silkscreen is a joy to work with and doesn't cause a great deal of
strain on the eyes. The registration and alignment of the silkscreen along
with the crisp fine print makes the assembly process a joy. The top kits
with great boards are OHR, Small Wonder Labs, Wilderness Radio, NorCal, and
S&S Engineering just to name the leaders of the pack.
One of the first things that I do is to get a plastic school box and put the
parts in it. This does a couple of things for me. Keeps all the parts in
one place so that I don't lose anything. Also allows me to stop at any point
and continue later without having to scramble around putting things up and
later unpacking to start back up on the project. Another thing, don't break
open any bags until you need something in them. Resistors are in a separate
bag and the bandpack is also in a separate bag. I haven't had OHR short me
on anything except one socket in all these years and although OHR and others
have you open the bags and do an inventory first thing, I never have. I do
it as I go along. I find it easier in the long run. Now it can get scarey
sometimes as it did for me in this kit, as R105 (15 ohms) is in the bandpack
and not in the resistor bag. This is not mentioned in the manual (yet) and
R105 is missing from the parts list but magically appears later in the manual
when you get to putting the bandpack parts on the board. So just relax.
This kit, as the other OHR kits over the years has step by step check 'em off
as you go instructions. For the inexperienced builder there is a pictorial
on winding toroids (there are 9 in this kit) in the additional 10 pages and
there are two pages of 'parts pictorials' showing drawings of each part. This
is like the old Heathkit manuals and in fact Dick W. uses an illustrator that
used to do the Heath manuals if I remember correctly. I found that for an
hour or so after winding a number of toroids that the thumb and first finger
on the left hand are sore. I think that Dr Rick in VE3-land has a special
term for this like 'toroid-tendinitis'. :-)
I went through the assembly process without a single hitch. The instruction
manual is complete and fairly detailed so shouldn't be any trouble for the
builder. Just use a good 25W soldering iron with 63/37 or 60/40 0.031"
diameter solder suitable for electronic assembly. Don't use any larger iron
and use the best small tip you can find. I wish Ungar still made the PL-823
iron clad tip. I have been using the one that I have on the Weller for all
the kits but the S&S digital VFO that had SMT parts that I have built the last
five years and the tip is still as good as new (well almost). No pitting and
no visible wear that I can tell. A $2 investment that has paid off all after
all these years many times over. If you run across one or more of these at a
surplus place or at a swapmeet by all means latch onto it. Maybe we outta
start a writein campaign to Ungar to bring them back.
The parts are first class. The tuning pot is a sealed 100K part made by
Precision in Canada. A real nice pot and I like the feel. It is wirewound
and will last longer than the carbon deposit type pots that I have used on
other rigs.
One thing that I still do and did even back in the Heathkit days, but this is
recommended only for the experienced builder. Most kits will have you precut
a wire that goes between two points. I don't. I strip the covering from one
end of the wire, solder it and then place the wire along the desired path
until I get to the final point. Then very carefully (remember the other end
is already soldered) cut the wire with enough margin to allow stripping and
soldering. This gives me an exact length that is usually different from the
one in the manual. I think it comes out neater and you can judge this from
the photos showing the wiring harnesses on the web page. Again, experience
and care is needed here and do this only if you feel that you can do this
without error or have some spare wire available in case of error.
So if you are going to spend $130 for a 40M transceiver you have several
choices. This OHR100 transceiver is I think a good one and will last the
builder a long time. It will do the full 5W for those that have just got to
get the last watt out to the antenna allowed by QRP levels. Other rigs are
in the 1W to 2W level. And of course, with the adjustable output and when
conditions are more favorable, you can crank the power down to the milliWatt
level. I haven't seen how low it will go but it should be under 10mW and at
that level getting on the air will indeed be a challange.
I fired the OHR100 up and aligned it in short order and nothing was installed
incorrectly and no problems encountered. Having a scope and a frequency
counter will help in the alignment.
I put it on the air late Sunday at 2W and worked a couple of stations stateside.
Early Monday morning I was hearing a lot of DX in Europe, Japan, Australia,
and the receiver is very good. The selectivity is excellent and will help dig
out the weak ones. The QSK and AGC are excellent as OHR has always been good
at doing these things. Sidetone is generated with an audio sine wave generator
and has adjustable level and adjustable tone frequency internal to the rig.
This reviewer has invested a lot of time and money is a lot of kits including
a lot of OHR stuff. It may seem that I work for OHR, but I don't. I have a
full time job already. I do this stuff for fun.
See web page below in signature for pictures after noon CST Tuesday, February
18th.
SIG
Chuck Adams K5FO adams@sgi.com DXCC=9
http://reality.sgi.com/employees/adams_dallas/
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