Date: Thu, 6 May 93 15:05:39 -0500
From: adams@chuck.dallas.sgi.com (Charles Adams)
Message-Id: <9305062005.AA10470@chuck.dallas.sgi.com>
To: qrp@Think.COM
Subject: Oak Hills Research QRP Kits
Gang,
i have built the following from OHR: (i'm just a crazy kit builder trying
to adjust to the lack of a heath supply....)
1. the 20 mtr old qrp kit ($149.95)
2. the OHR 40 mtr Spirit ($198.95)
3. the OHR 30 mtr Sprint ($109.95)
4. the OHR WM-1 wattmeter ($79.95)
5. the OHR Audio Filter ($69.95) not quite sure about this one
also a 20 mtr Spirit, but it's not ready yet........ ;-) thought i'd
try the visible part of the spectrum above 40 meters......
all the kits are super. the original rig, advertised by Ocean
State Electronics and others, is being replaced with a new kit
(soon to be announced and sold) called the Explorer.
all the kits have double sided, silk screened, green solder masked,
plated through holes, etc. circuit boards. good density and compact
boards. reminds of the better heath boards. parts are first rate
quality.
a. the Spirit is my favorite and my full time rig on 40 meters.
of course, the antenna is most important here. i use a 80 meter
long wire up 10 meters. my hit ratio is over 98%, and this is no
exaggaration on my part it has very little to do with my operating
skills. i mean, 2 watts is 2 watts is .... if i hear them, and the
receiver is HOT, i can work them. i may get beat periodically by
someone with more power, but hey, that's what qrp is all about.
i don't mind.
anyway, i digress again. the qsk solid state switching is just
beautiful. [i ran heath hw-16 (a long time ago at 25 watts) for
many many years just because it was the first rig to have solid
state switching, even though the rest was tubes.] everybody i talk
to says the keying is super in the Spirit.
talked to a w2 in february. i started the rig cold turkey in a room
where ambient temp was 60 degrees. the guy was running a kenwood that
had been on for 30 minutes plus. i talked to him for an hour at 40 wpm.
neither one of us touched the dial. the temp compensation in all of
Dick's, KE8KL, rigs is super. he spends extra time at this. Dick
bought OHR from Doug DeMaw some time back. i don't know the dates.
anyway, if you can spring the bucks, get this one. 2-5 watts out.
i set mine for 2. i thought 2 would be a challenge over 5. ;-)
b. the Sprint is a very small version of the W7EL DC rig. output is 1.5
watts. this one is going with me next week to houston for week long
business trip. also taking hw-9 to play with.
the sprint is on 30 meters and it works rather well. i have some
difficulty on my long wire due to rf ground, but i'm working this
problem out when i can get some time to play. when at home i'd
rather work 40 anyway. the rig is light, sorry i don't have the
exact size and weight, but ping me and i'll measure all of the above.
no ads on this rig that i've seen. maybe someone from Dayton saw
one at the meet.
i had Tejas' Backpacker I and never got it to work. the OHR board
is the size of one of the three boards in the Tejas. anyone gotten
a Tejas rig to work? i talked to a BP II in St. Louis months ago,
but the 40 beam the guy had was pointed to the east and stuck there.
kinda interesting story. guy was a qrp meeting and he had handed out
a copy of a newsletter that i had done to the group that he had gotten
from someone i had given it to in San Antonio..... small world.
BTW, that doesn't make me famous..... ;-)
c. the wattmeter and the audio filter are great. i would not part with
the wattmeter for anything other than a brandnew one. in case someone
doesn't want to bother with the assembly process. no qrp shack should
be without one of these critters. three scales, 10 mW, 1 W, and 10 W
full scale readings. 9V powered and i've left the thing on for days
at a time and still the battery is going.....
the audio filter is the best one around that i've seen. i gave my
Autek QF-1A away!! the audio filter is based on the one in a QST
article in Oct of 1992. i think that's right.... yeh, that's it.
ok, phd dissertation ended. if you want more details, send SASE,
830 Waite Drive, Copper Canyon, TX 75067-8581. i'll try to get
ASCII copy to think.com for ftp, but don't hold me to the fire on
this one guys. i'm against the wall already on my time line.
the explorer is gonna be in the $159-169 dollar class. can't wait
to get one. be the first kid on the block to own the whole set.
i am just a peachy keen happy customer. i am not paid by OHR or
employeed by them in any form or fashion.
Oak Hills Research
20879 Madison St
Big Rapids, MI 49307
Dick Witzke KE8KL (ex KD7RT)
i'd put the phone number here, but then i'd be asking for trouble. ;-)
don't want to put him in overload. it's in the mags, except QST.
72 es gl de k5fo,
Chuck Adams, K5FO @ 70+ wpm cw
adams@sgi.com
======================================================================
Date: Mon, 31 May 1993 09:37:17 -0500 (CDT)
From: "Jeff M. Gold" <JMG@tntech.edu>
Subject: Oak Hills Spirit Review
To: qrp@Think.COM
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Here is my review (totally non-technical) of the
Oak Hills Research Spirit:
Description:
------------
Single Band kit for 80, 40,30,20,or 15
Curtis Chip keyer (8044ABM)
Superhet receiver with diode ring mixer and RF pre-amp
4 pole crystal ladder filter followed by an on board audio filter
Switchable HP AGC circuit with manual gain control
2 watts audio output
VFO with 8:1 vernier drive
Sinewave sidetone oscillator w/frequency and level controls
QSK
5 Watts output
12vDC
4"X6 1/4"X6 7/8" weighs 47 oz.
100% complete kit with pre-wound coils, PC boards are quality
double-sided and plated through and screened.
====================================================================
OK, that is what it says in the catalogue. I opened the box and checked
things out. There is a stack of stapled sheets that are the
instructions. There are large part overlays, a chart showing you how
to read the resistor codes, a detailed and well thought out parts list.
and the schematics.
This kit isn't the Heath step by step approach. The first page tells you
some general things about assembling the kit and soldering and be
careful type comments. The first step is to find all the parts and make
sure they have been sent to you. Next you find the Receiver board and
then it tells you to put in all the resistors followed by the
capacitors. The next steps do go through what you need to do. As the
process itself would get more unclear the directions get clearer.
After building a number of kits I find I like this approach best. I
first check off all the parts and label them on a piece of paper and
stick the wires through. This gives me a chance to make sure all the
parts have been included, familiarizes me with the parts and gives me a
double check about putting the correct parts in the right holes on the
board. I check them once while I am going through the parts check off
and then again before I place them on the board. I also find that
checking off the parts is my least favorite part, and when I do it this
way, when I start to build I don't have to go hunting for parts. Since
I have started to use this approach, my projects seem to work correctly
the first time (except for putting in an audio chip backwards and
smoking it.. well no one is perfect and I was able to get a replacement
for $2.00 at Radio Shack). I found the way the parts were listed on
the instructions made it very easy to identify them and check them off.
I found almost all steps in the final construction to be very clear and
unambiguous. I do a lot of documentation at my job. I find that most
instruction sets have places where the author meant one thing and the
words indicate something else.
OK, now for the kit. I think there were over 170 resistors in this kit.
It took me quite some time and energy to sort out the parts. I found ALL
the parts to be of top quality. The enclosure is excellent. I didn't see
any hint of cutting corners in any piece that was included with the kit.
After building kits from about all kit manufacturers, the quality of the
parts in this were the best. I have found that Ramsey uses some quality
parts and some real garbage..I think Ramsey's enclosures are real
ripoffs.
The board was the single item that impressed me the most. Like it says
it is high quality plated through. You heat the joint and the board
sucks up the solder. The result is that you will be proud to show either
side of this board to anyone.. my wife comments on how her needlework is
beautiful on the front side, but she won't show the back to anyone, well
many of my projects are like that. With this one, I felt like displaying
the board in an art show.. what a proud pop I am. The silk screening on
the receiver board was ok, but certainly not great.. I found I put one
piece in the wrong place because I couldn't read the part #. Well this
really isn't a problem, and it was my fault. There is a clear large part
overlay that makes it a breeze to build.
The receiver board is jam packed with parts.. but the back of the board
is layed out so that if you use a fine tipped soldering iron you really
shouldn't have any problems with solder bridges. The transmitter board
was a lot less dense.
The Keyer board isn't plated through and not near in quality to the
other 2 boards.. be careful with this one.. I found it not nearly as
much fun to solder to as the other boards.
Once I got the parts checked off and labeled, I found it very easy to
assemble. The first part of the instructions that tell you to put on
about 200 parts are a mere 2-3 steps. Then when you put in the rest of
the parts the instructions (like assembling the chassis, the final
wiring and alignment) are detailed and clear. There are no checks as to
whether you have built it right.. like Heath's resistance checks, when
you are done, you power up and pray.
I was real careful with this kit, but got a little too excited at the
final assembly and had put one teeny weeny audio chip in backwards.. boy
did I feel dumb.. and when I powered up.. the smoke came out.. it failed
the smoke test (or is it it passed the smoke test, but failed to work).
It was very easy to spot the mistake, and since the chip was on a
socket, it was a breeze to correct. I checked the resistors and other
parts that fed it, and no problem at all.
The final alignment suggests a frequency counter. I can't ever get the
frequency counter in my MFJ antenna analyzer to read such low levels, so
I use my 757GX as my alignment tool. You just need to set a coil and a
capacitor to set the full 100kc bandwidth for the VFO. I take a piece of
copper wire, stick it in the antenna jack of my 757 and hold the loose
end over the oscillator circuit. It works just fine. The rest of the
alignment had some aspects I have never encountered before. You tune the
pitch of your TX out signal and the sidetone pitch (I once again used
the 757, put both rigs on dummy load, transmitted and set the Spirit for
the same note as the 757. I figured the Yaesu people knew what they were
doing and had the proper equipment when they did it). The TX alignment I
used my Oak Hills QRP wattmeter and you simply adjust a variable
resistor for power level and then 2 coils for maximum output. I spoke
with Dick at Oak Hills who suggest you tune it for the full 5 watts out
to get the best quality TX signal. Over the weekend I took the case off
a few times and tweeked various things. A note about the keyer weighting
adjustment. I started at the suggested middle position. The keyer was
acting really funky... couldn't really set it right. I turned the
weighting adjustment and it is now perfect..one of the better keyers I
have used..guess that is why a lot of people use Curtis chips. One of
the adjustments that you peak .. be careful that you are on the right
sideband.. I didn't have much audio level to my speaker, when I went and
re-read the instructions, it had cautioned me about it.. went back and
re-adjusted and everything was fine.
Ok, now for the real stuff.... how did it work. Well let me tell you
that the weekend of the CQ WPX CW contest is quite some time to test out
a new QRP rig. The rig puts out a full 5 watts (I turned mine back from
a little over 6 watts.. may have to have a friend put the oscilloscope
on it to check the signal out). The keyer works real smooth.. full break
in.. but has a minor little click in it.. don't think the click is going
over the air.. I have listened on another receiver. The receiver at
first deceived me and I will need to do some more testing. The bands
were really crowded in my QTH. The big guns were using big ammo. The rig
doesn't have a narrow and wide CW filter switch. This worried me.
During contests it is real nice to have a narrow filter available. I
tuned around and noticed that when the receiver got a signal, you really
only heard that one signal. At first I thought that this was caused by
the receiver being too insensitive. After spending the entire weekend of
the contest testing the rig out, I found that if I could hear them on
the other rig, I could hear them on the Spirit without other station
interference. I am not as of yet a person who possesses enough
electronics knowledge to go in and analyze the circuit and do
comparisons. I can do extensive "real-life" tests.. which from my
experience sometimes had more truth than theory.
I worked over 125 stations with my 5 watts and Gap vertical during the
contest. I worked to Russian stations, a S50S I think it was, an
Italian, a French, Alaska, a bunch of islands, and from the West Coast
to the East Coast and some other places in between. After I got the hang
of it, I got many returns on my first call.. not bad for 5 watts and a
vertical.. used the built in keyer, not my contest keyer and my Bencher
paddles.
Other impressions: I would have left out the AGC on and off, the RF
control and made the keyer an option. I use a straight key most of the
time. The rig is BIG and HEAVY. A little smaller than my HW9, but not
much smaller. The chassis is solid... lots of metal. I think Oak Hills
can keep the best parts of this kit, get rid of the extras, and maybe
add a narrow filter and a S meter. I think they are coming out with
something like this in the near future. For a station QRP rig, it would
be pretty hard to beat this though.. and for portable operation it would
also be excellent, a little too big for backpacking.
Jeff, AC4HF
======================================================================
Date: Tue, 08 Jun 1993 10:44:31 -0500 (CDT)
From: "Jeff M. Gold" <JMG@tntech.edu>
Subject: kits
To: qrp@Think.COM
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Well, I finished my Oak Hills Sprint Friday night and have been testing
it out. It was a very quick and easy kit to build. I built in a
speaker.. not really worth it.. you need headphones for it (Dick says
that is the way it is designed). I tried every power supply I own (very
well filtered and regulated) and couldn't use a power supply with it (a
problem with Direct Conversion Receivers). I finally gave in and use
headphones and a 4AH gell cell. The battery hasn't been charged in some
time.. but the little rig doesn't seem to eat much.
It took a little getting use to.. my first DC receiver. But I have found
that the 1 watt (due to low battery) seems to get out pretty good. If
the bands are busy.. forget it... all the information I have read about
DC receivers has proven to be correct.. noise and stations are
doubled... still have been able to make contacts as long as the band was
decent enough.. My Sprint is on 30 meters, and the bands seem to have
pretty bad since the weekend.
OK.. now for more news:
Just got the 624 Kits version of the Gary Breed transceiver that was in
the Handbook. It is a parts kit boards. You add your own enclosure and
jacks. It sell for $109. Thought it was going to be a bare bones type
deal. The circuit board is real good quality and nicely silk screened.
The instructions are step by step (good for a beginner), the schematics
are computer generated and all pretty and there is a nice parts overlay.
Going to build the receiver tonight, I hope. You build then test the
receiver before going onto the transmitter. I like this approach. One
thing I didn't like about the Spirit was you got all the way to the end,
no power off tests, and then you just power it on.
73
Jeff,AC4HF
======================================================================
Date: Thu, 10 Jun 1993 08:26:36 -0500 (CDT)
From: "Jeff M. Gold" <JMG@tntech.edu>
Subject: Oak HIlls Sprint
To: qrp@Think.COM
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Sorry about the last message.. I am trying a new editor and the key
sequence is different.
I will give this another try:
Oak Hills Sprint:
Oak Hills Research
20879 Madison St.
Big Rapids, MI 49307
1-800-842-3748 (Orders)
Sprint is W7EL Optimized QRP CW Transceiver
Single band for 80,40,30
High performance DC receiver
Diode ring mixer
VFO tuning 8:1 vernier ..covers any 100KHz of band
RIT, center dtent
Peaked audio filter
Sidetone oscillator
Smooth QSK
1.5 watts
all coils prewound
12vdc
100% complete kit
$109.95
-----------------------------
OK, that's what the catalogue says.. I am in no way
contected with the company, other then sending them a great
deal of my pay check.
The boards are plated thru.. the best quality I have
soldered.. I am currently building a kit with good boards that aren't
plated thru, and boy do I notice the difference. Apply heat
and solder and the board sucks up the solder..looks great
and makes a real good connection.
The directions aren't step by step. More like check the
parts off and put them in. The board is silk screened and
there is a very nice large parts overlay, so putting the
parts in is a breeze. When you have to do more than just put
resistors or capacitors in, the directions become more
detailed and are very clear. With some help a beginner
should be able to do this fairly easily. I like to put the
lowest lying parts in first.. not the resistors and then
caps as directions suggest.. this way the IC sockets sit
flatter to the board.
The cabinet is very nice and all plugs and jacks are
included. The rig is VERY small. It draws very little
current. I have been trying to drain a 12v 4ah gel cell
before vacation. I leave the receiver on from when I get
home till I go to sleep and have done a lot of operating
with it.. the battery didn't have a real good charge to
start with.. the rig is still taken a licken and it keeps on
tickin.
The receiver works nicely. This is my first Direct
Conversion Receiver.. quite and experience. I have read all
the down sides to them like.. you hear twice as much noise,
you must tune to the correct sideband, and it is more likely
to get inteference from AM stations.. all this is true.
I put the rig on the air last weekend and it took a few
minutes to learn how to tune quickly.. the directions
clearly tell you the procedure..simply start at the "0" end
of the scale and when you get the signal to the "0" side it
is the correct side. While tuning around I usually tune past
the signal till it is right in the middle of the wave.. the
signal disappears.. then make sure by tuning up a little
past and then down again to the correct side. It only takes
a few seconds and it really seems to be working. I have been
getting most people the first shot on about 1 watt.
This last week the 30 meter band around here has been real
bad. Lots of noise sounding like storms inside the rig. I
have still been able to get thru the noise and make
contacts. I have had a problem with signals coming over my
QSO in the middle so I couldn't hear the other person.. but
they could hear me. They were on a superhet.. and only
hearing one side of the wave..
I have enjoyed the rig.. it will make a nice backpacking
rig.. can use my small gell cell and going to make a new
top piece and radials for my portable PVC vertical for the
30 meter band this weekend and take it with me to a
conference.
I have tested it against a couple of Superhets.. I still
like a superhet better.. find them easier to operate and
easier to carry on a longer QSO without inteference that
really isn't even on your freq. This doesn't mean I don't
like the Sprint... I was on it this morning and the bands
were behaving a little better and I had a real nice and
clear QSO with no problem.. always surprised how well the 1
watt is getting out with the way the 30 meter band has been.
73
Jeff, AC4HF
======================================================================
Date: 07 Sep 93 00:14:29 EDT
From: Stan Cooper <71154.331@CompuServe.COM>
To: Doug Hendricks <qrp@Think.COM>
Subject: Oak Hills Research QRP 20 Review
Message-Id: <930907041429_71154.331_DHQ59-1@CompuServe.COM>
Product Review - Oak Hills Research 20 Meter QRP CW Transceiver Kit
By Stan Cooper, K4DRD
Although I've enjoyed working QRP for the past twenty years using a Ten-Tec
Argonaut model 505, there are occasions - vacations and business trips - when
I want to take along a small HF rig, but the Argonaut is just too big and
takes up too much luggage space. Early last year, with a ten day Hawaiian
vacation coming up, a small ad in QST for the Oak Hills Research QRP
transceiver caught my eye. The ad offered a 7.5" x 6.25" x 2.5" CW
transceiver kit in either 40 Meter or 20 Meter versions for $149.95.
Published specifications for the rigs are pretty impressive:
SPECIFICATIONS:
General:
Frequency Range: 14,000 to 14,100 kHz (20 Meter Version)
7,000 to 7,100 kHz (40 Meter Version)
Transmit Offset: 700 Hz
Mode: CW
Power Requirement: 13.6 VDC (Negative Ground)
Power Consumption: 700 ma at 2.5 Watts Transmit
60 ma Receive (no signal)
Antenna Impedance: 50 ohms
T/R Switching: Semi-Break in
Sidetone Frequency: 700 Hz
Active Components: 7 ICs, 14 Transistors, 13 Diodes
Transmitter:
Final Power Output: 2 - 3 Watts
Final Output Stage: 2SC1909 or 2SC2092
Receiver:
Circuitry: Single Conversion Superheterodyne, IF: 9 MHz
Sensitivity: .25 V
Selectivity: + 1 kHz @ (-6 dB) 4 Pole Crystal Ladder
IF Filter Integral, Switchable Active
Audio Filter: 1 kHz With 700 Hz Center
Frequency
RIT: + 1.5 kHz
Audio Output: 500 Mw
I chose to order the twenty meter version, partly because of the DX potential
on twenty and partly because of antenna restrictions. Also, my recollection
of QRM from high powered broadcast transmitters on forty meters when I was a
novice is still vivid in my memory.
Assembly -
The kit arrived several days after I'd placed my order. After inventorying
all of the parts, I began assembly. The kit is built around a single printed
circuit board, and all coils are prewound. Although the instructions are not
detailed "step-by-step" procedures with profuse illustrations like the old
Heathkit manuals, they are adequate, and I managed to get all of the parts
properly mounted and soldered to the PC board.
One complaint I have is the number of jumpers on the PC board. There are
twenty six jumpers, and they are not clearly shown on the parts overlay
illustration; the two ends of each jumper are labeled, but one must locate the
label for one end, then look at a very "busy" drawing for the label
identifying the other end. Finding the locations of each of the jumpers was
very time consuming, and this task could have been made much easier had the
jumpers themselves been drawn on the parts overlay illustration. By contrast,
the NorCal 40 QRP transceiver has only four or five jumpers - a sure sign that
Wayne Burdick, N6KR, put a lot of thought into the board layout.
Assembly took place non-stop over a Saturday afternoon and evening, and I
decided to wait until Sunday morning to apply power. The checkout and
alignment instructions call for the use of a voltmeter, frequency counter and
an oscilloscope, so if these aren't part of your tool box, you should probably
arrange to borrow them from a neighbor before attempting alignment.
The VFO coil, L1, is the only coil not "doped" from the factory, and the
reason for this is that the winding of L1 is compressed or expanded on the
toroid core to obtain the proper VFO frequency before doping by the builder.
I spent about an hour tweaking the L1 winding trying to "bring in" the VFO
frequency to the required 5 MHz with the tuning capacitor plates fully meshed.
I finally gave up, wrote a brief note to the folks at Oak Hills Research
explaining my predicament, and shipped the unit back to the factory for check
out and alignment.
The OHR people called me to let me know that after they had adjusted L1
(admittedly a tricky procedure), the rest of the alignment was uneventful.
They even complimented me on my work (nice soldering, no wiring errors, etc.).
The cost for their efforts was a very reasonable $28.00, including return
shipping charges.
Operating -
The rig arrived by UPS several days later, and I fired it up minutes after
opening the box. I live in a twentieth story apartment, so my antenna options
are pretty limited. I'm currently using a pair of "Hustler" mobile whips with
20 meter resonators, configured as a dipole. Using this antenna, I worked
several states in the first few hours on the air with the OHR rig. It was
(and still is) a real thrill to use this tiny rig, powered by a twelve volt
gell cell, to work DX as far away as Latvia. I've found the rig very easy to
use, and on-the-air reports of the signal quality have been gratifying. I'm
consistently told that the signal is steady as a rock, without any sign of
chirp, and - when powered with an AC supply - hum free. QSK characteristics
are excellent.
Receiver audio is adequate when used with a quality eight ohm impedance
headset, but I bought a Radio Shack eight ohm speaker with a 12 VDC powered
eight watt internal amplifier (part number 21-541) for use with the rig, and
have come to prefer the speaker.
Oak Hills Research also offers a keyer kit which may be built into the
transceiver. I opted to build the keyer into a separate minibox since I
wanted to use it with the Argonaut as well as the OHR rig. The keyer is built
around the Curtis 8044ABM keyer chip and costs $29.95.
Control Layout-
The OHR QRP rig controls are nicely laid out, with the vernier VFO frequency
dial located in the center of the front panel. The audio volume control with
On/Off switch is in the lower left corner of the front panel, and the
headphone jack is mounted directly above it in the upper left corner. The
receiver incremental tuning (RIT) knob is in the lower right corner, and the
audio filter "narrow/wide" switch is located in the upper right corner. The
antenna connector, an SO-239 type, is located on the rear apron along with the
key jack and 12 VDC power jack.
Summary-
The OHR QRP rig is well designed and a real ball to operate! In spite of my
complaints, I believe anyone could assemble the kit and get it on the air.
Although I haven't tested the unit's specifications, I have no reason to
believe the manufacturer's published specifications aren't accurate. The
receiver is hotter than a pistol, and the transmitted signal gets glowing
reports.
Manufacturer-
Oak Hills Research Phone: (616) 796-0920
20879 Madison Street
Big Rapids, MI 49307
======================================================================
PRODUCT REVIEW -- OAK HILLS RESEARCH "QRP SPRINT"
by KR8L, MI QRP #M-98, NW QRP #127
The Oak Hills Research (OHR) "QRP Sprint" is a single band CW
transceiver kit based on the W7EL Optimized QRP Transceiver. The
W7EL design, which features 1.5 watt output, full break-in,
sidetone, RIT, and a direct conversion receiver, was first
presented in the August 1980 issue of QST. The design has been
updated since that time and was republished by the ARRL in QRP
Classics (1990) and the ARRL Handbook (1993). The kit is available
from OHR in 80, 40 and 30 meter versions at a cost of about
$110.00, plus shipping. I recently purchased and constructed the
30 meter version of the QRP Sprint.
First Impressions
I was very pleased with the kit from the moment I opened the box.
The cabinet is a rugged affair made from heavy gauge aluminum and
finished with an attractive, durable paint job. The circuit board
shows similar quality with a silk-screened component side and
plated-through holes. The parts layout is well thought out, and no
wire jumpers are required on the board. Individual components are
well marked with small parts packaged in plastic bags or on tape
strips. Despite the small size of the cabinet (5x5x2+ inches), OHR
has chosen to use an SO-239 for the antenna connection and
one-quarter inch jacks for the headphones and key, rather than the
smaller, less robust RCA and one-eighth inch jacks. A full parts
inventory and parts layout diagram are included along with the
assembly instructions.
Construction
The QRP Sprint is a relatively easy kit to construct, although I
might hesitate to recommend it to someone with no electronics
building experience at all, primarily because of the compactness
and close component spacing. Installation of resistors and
capacitors is accomplished in whatever sequence the builder chooses
using the parts list, schematic, and parts layout as guides.
Installation of inductors, semiconductors, cabinet mounted
components, and interconnecting wires is directed in a step-by-step
fashion. All toroids are prewound. Most builders will find a
magnifying glass helpful to read component values (particularly on
the monolithic capacitors) and to make inspections for poor solder
joints and solder bridges. Alignment is simple and
straightforward, requiring only a frequency counter, wattmeter, and
the appropriate non-metallic tools for adjusting slugs in the tuned
transformers.
Operation
My QRP Sprint worked just fine the first time I turned it on, and
I managed to make a contact with my first call. I attribute this
at least in part to my practice of making frequent checks, double
checks, and triple checks as components are installed on the board
and both before and after soldering them in place. I have made
solid contacts all over the country and as far away as eastern
Europe using nothing more than a six-band vertical. The small
size, light weight (18 ounces), and low current requirements
(40 milliamps on receive and 240 milliamps on transmit) make this
an ideal camping or backpacking rig. A pair of 6 volt lantern
batteries will provide for many hours of portable operation.
The main tuning control is smooth and linear, and the CW beat note
is a pleasure to listen to. Selectivity is limited and, of course,
the direct conversion receiver provides an audio image, but the
quality of the CW note, combined with proper use of the RIT, make
it possible to copy under even relatively crowded band conditions.
The solid state QSK circuit has to be heard to be believed. OHR
describes it as "silky smooth" and this is no exaggeration. The
rig is very stable mechanically, with no hint of microphonics or
hum.
My only complaint has been a relatively large amount of thermal
drift in the VFO (about 700 Hz in the first 20 minutes), but the
rig settles down pretty well after it warms up. I think that a
certain amount of thermal drift is probably unavoidable in a VFO
running at 10 MHz, and I would not be surprised to find that the 80
and 40 meter versions are much more stable. During on the air use
I have not found the drift to be a problem.
Product Support
The QRP Sprint replaced another W7EL-based rig in the OHR product
line, and my kit was one of the first ones shipped. During the
initial alignment I was only able to achieve a tuning range of
about 10.050 to 10.150 MHz, rather than the specified range of
10.100 to 10.200 MHz. I called Dick at OHR and he agreed to review
the problem. The next day he faxed me the results of his analysis,
and indicated that he was sending me a replacement for one of the
fixed capacitors in the VFO. Within a few days I had the new part
installed, the alignment was completed successfully, and I was back
on the air.
Oak Hills Research sells a number of QRP kits and stocks a variety
of components for the QRP homebrew enthusiast. A catalog may be
obtained by writing to them at 20879 Madison Street, Big Rapids,
MI 49307, or by calling (800) 842-3748.
======================================================================
Date: Mon, 16 May 1994 13:07:26 -0500 (CDT)
From: "JEFF M. GOLD" <JMG@tntech.edu>
Subject: Oak Hills Classic
To: qrp@Think.COM
Well Sunday I got my Oak Hills Dual bander going.
The directions and actual building were a really relaxing and
enjoyable experience. There were NO ambigous directions including
the alignement. The alignment was a little tricky and I may have
one or two very minor readjusts to do. I found only one minor
error in a diagram (but text directions were completely correct)
and Dick is going to change that.
The whole kit was top grade. Needed to be built slowly.. not too
much fun to debug once you are done with the plated thru boards.
The bands were in bad shape yesterday, but had no problem on
either 20-40. Had a nice 40+ minute chat on each band, worked some
contests (not sure which ones, but they seemed content with 599
and a serial number). Worked Netherlands.
The receiver seems to work extremely well. The QSK is GREAT, the
Curtis keyer works .. well like a Curtis Keyer (no complaints).
The power is adjustable from the rear down to about nothing. Mine
putting out a nice clean 5+ on 40 and little under 5 (but right
about at it) on 20 meters. The rig has a very nice sidetone that
is adjustable (I like a very low sidetone level when I operate for
long periods of time). The rig has seperate jacks for straight key
and paddles (if you have keyer option).
The rig doesn't have a built in speaker.. after a long period with
the headphones (I am not a headphone person) I simple plugged my
amplified speakers into the headphone jack and it worked great).
The audio seems to be enough to drive a speaker (i wired one or
two into the jack and seemed ok).
Got very good reports on my signal and it sounded great listening
to it on my kenwood 850.
If you have built before .. this is one of the best/most fun kits
I have ever done.
The only minor downside is that although the directions were
extremely clear, there is no circuit descriptions...I am not a
whiz with schematics.. when trying to figure out what I was really
doing in the alignment and how the rig worked it took me a while..
but other may just be able to look at the schematic.
I talked to Dick at Oak Hills and told him to think about
including circuit descriptions.
73
Jeff, AC4HF