> Ignoring tech specs I think an even more impressive test room
> is that one reserved for employees to set up their personal rigs and
> operate during lunch hours. When the Orion arrives I'd like to drive it up
> there during W1AW code practice on 20M...point the headquarters beam at
> the Maxim Station beam and vice versa and see how close to W1AW I can hear my
> Argonaut running 5W from home.... Now THERE's a real world test!
Most of the time, we leave one of the W1AW castoff rigs in there. Staff can
bring their own rigs
in if they want. We also use that station as a test bed if we need to do any
on-the-air testing, on "off"
hours, of course.
There is a LOT of signal coming down that antenna line. One time, we set up a
bird and a dummy
load and measured the power coming back down the feed line while W1AW was
operating. We
measured 4 watts! I don't think that any rig could not block at that level. :-)
But I remember one year I was mobile with my Ten Tec Omni D during the ARRL
Phone Sweepstakes. I parked right under the W1AW antenna array and was able to
work 'em on phone while they were blasting away on CW, at least on 20 meters.
That rig is still my main rig at home, btw. :-)
73,
Ed Hare, W1RFI
ARRL Lab
225 Main St
Newington, CT 06111
Tel: 860-594-0318
Internet: w1rfi@arrl.org
Web: http://www.arrl.org/tis
> -----Original Message-----
> From: Tom A [mailto:althofft@concentric.net]
> Sent: Thursday, March 06, 2003 4:37 PM
> To: tentec@contesting.com
> Subject: Re: ARRL Lab Test Equipment (was RE: [TenTec] Ed Hare)
>
>
> Ed... Bob-K2TK and I enjoyed some New England hospitality
> during our tour of
> ARRL headquarters last November and saw for ourselves your
> setup and the
> room where "You are shielded from government spies and alien
> mind readers".
>
> Ignoring tech specs I think an even more impressive test room
> is that one
> reserved for employees to set up their personal rigs and
> operate during
> lunch hours. When the Orion arrives I'd like to drive it up
> there during
> W1AW code practice on 20M...point the headquarters beam at
> the Maxim Station
> beam and vice versa and see how close to W1AW I can hear my
> Argonaut running
> 5W from home.... Now THERE's a real world test!
>
> ----- Original Message -----
> From: "Hare,Ed, W1RFI" <w1rfi@arrl.org>
> To: <tentec@contesting.com>
> Sent: Thursday, March 06, 2003 3:10 PM
> Subject: ARRL Lab Test Equipment (was RE: [TenTec] Ed Hare)
>
>
> > > Thanks every so much for you very informative post to
> > > me and to the Ten Tec reflector. That, coupled with your
> > > willingness to discuss your techniques with Jim, the techniques
> > > and the process/procedures you and your staff use for generating
> > > your results, certainly produces a heretofore
> nonexistent, positive
> > > impression of what really is going on within the ARRL.
> >
> > Thanks, Tom. That is why I join in these discussions. I
> agree that ARRL
> can and should
> > do as thorough a job as possible telling members how we do
> things. Of
> course, in one
> > sense, we did, because the test procedures manual and
> several articles
> available at:
> >
> > http://www.arrl.org/tis/info/rigbuy.html
> >
> > Explain a lot of it. Unfortunately, the world has become diverse and
> something put in
> > one venue may not be seen by someone who looks in another
> venue. The flip
> side,
> > of course, is that assumptions are even more dangerous than
> the lack of
> information.
> > Hopefully, the three posts I will make, and the expected followup
> discussion, will
> > help on all counts.
> >
> > The ARRL Lab has a reasonable suite of test
> instrumentation. The newer
> stuff is
> > not quite top of the line, but is right up there, chosen to
> help ARRL
> extend its test
> > capabilities into the future. The older equipment is quite
> servicable and
> is very much
> > up to the task at hand, with better specifications than
> needed for the
> performance of
> > the equipment being tested. The Lab's ability to easily
> test microwave
> equipment is
> > somewhat limited, although Zack Lau is quite skilled at
> microwave design
> and has been
> > able to design nearly any test fixturing needed. Most of
> ARRL's Product
> Review testing
> > has been for equipment operating at 1.2 GHz and below.
> >
> > All equipment used for major Lab Product Review testing is
> calibrated per
> the cycle
> > recommended by the equipment manufacturer. We use an
> external calibration
> service,
> > Essco, near Boston, MA. Every November, Mike Tracy drives
> the equipment to
> cal,
> > and picks it up a week later, with the cal usually
> sandwiched in between
> Product
> > Review testing. Other, less-critical, Lab-owned equipment is self
> calibrated, using the
> > calibrated equipment and the good judgement of the Lab
> engineering staff.
> (By "less
> > critical" I generally mean equipment that will not be used
> for Product
> Review, publication
> > or advertising acceptance.)
> >
> > The majority of the Product Review testing takes place in
> ARRL's shielded
> screen room.
> > The room is well grounded and the power-lines going into
> the room are
> voltage
> > conditioned with a Stabiline BCR3205U voltage regulator,
> 5.5 kVa. The
> output voltage
> > will stay at 234 V +- a couple of volts over a wide range of input
> voltages. The power
> > is then run through an EMI filter, to help keep the RF
> gremlins out. With
> the door closed,
> > the room has about 100 dB of isolation.
> >
> > The room is not temperature or humidity controlled, other
> than by the
> building heating
> > and air conditioning. Normally, about 75 F or so, and the building
> humidity ranges from
> > about 10% in the winter to up to about 40% in the summer.
> For some of our
> testing,
> > we use a small Tenney, Jr temperature chamber, typically
> testing that
> equipment still
> > functions at the low and high temperatures we expect the
> human users could
> tolerate.
> >
> > I won't go over every single piece of equipment the ARRL
> Lab owns, but
> will give
> > the highlights of the more important and heavily used equipment. It
> should give a good
> > overview of the test capabilities of the Lab. In addition to the
> equipment I will describe,
> > the Lab has the usual collection of cables, connectors, adapters,
> attenuators and the like.
> > Only cables that have been tested by the test engineer can
> be used for
> Product Review
> > testing, and at the least sign of trouble, they are discarded, or
> relegated to the other Lab
> > uses.
> >
> > For receiver testing, the centerpiece are the two IFR 2041 signal
> generators, +13 dBm,
> > LF-2.4 GHz. These are used in conjunction with calibrated
> step attenuators
> and a few
> > hand selected MiniCircuits two-port combiners. This fixture has been
> tested to at least
> > +40 dBm IP2 and +85 dBm IP2, with an independent
> verification using the
> Lab's 2nd
> > receive test fixture, which uses 1 W ultra-linear
> amplifiers donated by
> Ulrich Rohde
> > and attenuators and the like. For miscellaneous bench use,
> we also have a
> pair of
> > HP8640B generators. They are currently "self-cal" but in
> good working
> order, used
> > for miscellaneous tasks around the ARRL Lab.
> >
> > The receiver output is measured with an HP-339A distortion
> test set. This
> is an older
> > instrument, but in excellent working order and perfectly
> suited to RMS
> readings of the
> > receiver output, distortion measurements for SINAD
> sensitivity and the
> like. Its analog
> > meter actually makes it more useful in many cases than would a more
> modern, digital
> > readout. If a measurement is not affected by noise, it
> will give the same
> results as one
> > might get making the receiver output measurements on a
> spectrum analyzer,
> but, as
> > I had said in an earlier post, with a much better absolute accuracy.
> >
> > If needed, our HP-8563E spectrum analyzer (DC-26.5 GHz)
> does handle audio
> analysis
> > well. We also own a couple of National Instrument A/D cards and can
> digitize any signal
> > at up to a 500 kHz rate and use the accompanying Lab
> Windows CVI software.
> We use
> > CVI to control all of our test equipment and have written
> routines to
> program the spectrum
> > analyzer for various measurements. This package is the
> top-of-the line
> industry standard
> > test software, one step up from LabView.
> >
> > We also occasionally use the HP8970A noise-figure meter to measure
> preamplifiers and
> > the like.
> >
> > For transmitter testing, the HP8563E spectrum analyzer is
> the pride and
> joy of the ARRL
> > Lab! It is good from DC to 26.5 GHz. We ordered the
> high-stability option
> and its
> > minimum resolution bandwidth is 10 Hz. It can be used, with care, to
> measure harmonics
> > and intermod down to about 90 dB below the reference level.
> If needed, we
> do have some
> > VHF and UHF notch filters that could be used to attenuate
> the fundamental,
> to make
> > measurements well below that. The analyzer is used
> primarily for transmit
> spurious
> > emission and transmitter IMD measurements. We kept our old HP-141T
> analyzer frame
> > and plug ins and sometimes use it for various Lab tasks.
> >
> > For "gross" power measurements, we have a number of Bird
> wattmeters, with
> elements,
> > all in current calibration. We self-cal the elements
> because the times we
> have sent them out,
> > even to Bird, we were not happy with the results. For accurate power
> measurements, we use
> > an HP-437B microwattmeter with various power sensors (all
> calibrated by
> HP). To make
> > power measurements, the Lab connects a transmitter to a
> power attenuator
> whose exact
> > attenuation has been previously measured. We measure the
> power at the
> output of the
> > attenuator, then add back the value of the attenuator. This
> gets us power
> readings to within
> > about 4% or so, better than the Bird in most cases.
> >
> > For frequency measurements, we use a portable
> Optoelectronics counter,
> with the high-
> > stability TCXO option. We have recently acquired a pair of HPZ3801
> GPS-conditioned
> > 10 MHz frequency references that are now being integrated into the
> frequency counter,
> > to get accuracy down to a fraction of a Hz. We can also
> measure frequency
> into the
> > microwave range with the HP5351B counter, with 1 Hz resolution.
> >
> > This year, the Lab purchased a long-overdue digital storage scope, a
> Tektronix TDS3052B.
> > This will be used for our keying and T/R turnaround
> meaurements, replacing
> our older Tek
> > scopes.
> >
> > The Lab has some excellent "homebrew" equipment, too. For
> phase noise, we
> use a test
> > fixture designed and built in the mid 80s by Zack Lau. A
> few years back,
> we tested a rig and
> > then sent that rig to Ulrich Rohde, for testing on his
> $100K+ phase-noise
> set up. We found
> > correlation, +- about a couple of dB, across the entire range.
> >
> > A number of years back, Jon Bloom designed a 9600-baud
> bit-error-rate test
> fixture that is
> > used for some of the digital radios.
> >
> > Perhaps the most impressive homebrew fixture we have it the
> one that we
> use for amplifier
> > IMD testing. It uses a 100-w coaxial power combiner whose
> terminations
> have been carefully
> > controlled with matching networks to give at least 60 dB of
> port-to-port
> isolation on 14 MHz
> > for up to a 3:1 input SWR on an amplifier under test. With
> this fixture,
> we can measure
> > amplifier performance down to -60 dB PEP on third order and
> about -70 dB
> on the higher-order products. This is much better than
> amplifiers we have
> tested, and we have on at least one
> > occasion measured an amplifier 10 dB better than the
> manufacturer, who had
> tested the same
> > amp, indicating that the amplifier manufacturer had
> measured his test
> setup, not his amp!
> >
> > While not all of this equipment is brand new, it is all
> quite suitable for
> the task at hand. ARRL
> > has carefully characterized its test setup and knows its
> capabilities and
> always ensures that
> > its published data are that of the equipment under test,
> not the test
> equipment. The only
> > exception I know to that occured before my time, where the
> Lab used the
> spectrum analyzer
> > to measure a transmitter's phase noise, only to realize
> later that the Lab
> had measured the
> > phase noise of the analyzer local oscillator.
> >
> > Although newer equipment would improve the usability for the test
> engineer, and may gain a
> > dB or two of accuracy in some measurements, the differences
> would not be
> night and day.
> > Those reading our results can feel comfortable that they
> are accurate,
> human foibles
> > notwithstanding, within a reasonable and acceptable accuracy.
> >
> > I hope the Ten Tec list readers will find this description
> useful. My
> wish list for new equipment
> > is appended, if anyone wants a nice tax writeoff! :-)
> >
> > 73,
> > Ed Hare, W1RFI
> > ARRL Lab
> > 225 Main St
> > Newington, CT 06111
> > Tel: 860-594-0318
> > Internet: w1rfi@arrl.org
> > Web: http://www.arrl.org/tis
> >
> > 1. Agilent 8753ES Network Analyzer
> > 2. Agilent 35670A FFT Dynamic Signal Analyzer, DC-102.4 kHz
> > 3. Agilent 5504B Phase Noise Test Set
> > 4. Agilent 6542A power supply
> > 5. Agilent 85640A Tracking Generator
> > 6. Tektronix TDS-5052B (with Opt. "PS" - multiple option package)
> > 7. Tektronix TDS-3052B (with TDS3AAN, TDS3BAT and TDS3GV
> options) - qty 2
> > 8. Agilent E4407B Portable Spectrum Analyzer with E1779A
> battery pack
> > 9. Rohde & Schwarz FSH3 Portable Spectrum Analyzer
> > 10. Agilent 34401A Digital Multimeter - qty 5
> > 11. Radar Engineers Model 240 HF-UHF RFI Locator
> > 12. Radar Engineers Model 250 Parabolic Ultrasonic Pinpointer
> > 13. Radar Engineers Model 247B Hotstick Line Sniffer
> > 14. Simplex Inc. Watt-Muncher Jr. Portable Load Bank
> > 15. Rohde & Schwarz ESIB26 EMI Receiver
> >
> > _______________________________________________
> > TenTec mailing list
> > TenTec@contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
> >
>
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