W6IFE Newsletter

President: Doug Millar,
K6JEY 2791 Cedar Ave Long Beach, CA 90806 562-424-3737
[email-masked]

Vice President: Dick
Bremer, WB6DNX 1664 Holly St. Brea, CA 92621 714-529-2800
[email-masked]

Recording Sec:Mel Swanberg, WA6JBD 231 E
Alessandro Blvd Riverside, CA 92508 909-369-6515 [email-masked]

Corresponding Sec: Kurt
Geitner, K6RRA 213 Main St. #5 Seal Beach, CA 90740 310-718-4910
[email-masked]

Treasurer: Dick Kolbly,
K6HIJ 26335 Community Barstow, CA 92311 760-253-2477
[email-masked]

Editor: Bill Burns, WA6QYR 247 Rebel Rd
Ridgecrest, CA 93555 760-375-8566 [email-masked]

Webmaster Chip Angle, N6CA

ARRL Interface Frank Kelly, WB6CWN 1111 Rancho Conejo Blvd. #501 Newbury
Park, CA 91320

805-499-8047 [email-masked]

FCC Interface Dave Laag, K6OW 11614 Indian St. Moreno Valley, CA 92557
909-924-1517

W6IFE License Trustee Ed Munn, W6OYJ 6255 Radcliffe Dr. San Diego, CA 92122
619-453-4563

[email-masked]

The 3 January 2002 meeting of the SBMS
will have a talk by Chip N6CA on Dish Evaluation with a Laser Pointer. The SBMS
meets at the American Legion Hall 1024 Main Street (south of the 91 freeway) in
Corona, CA at 1900 hours local time on the first Thursday of each month. Check
out the SBMS web site at http://www.ham-radio.com/sbms/.

Prez Sez- Happy 2002! This should be an
outstanding year for microwave activity of all sorts. The Japanese have just
announced a new record on 75 GHz, there was a new record for 241 and 322 GHz,
which all point to a lot more equipment available and activity taking place on
millimeter bands. In addition, there is a large amount of activity on 10GHz.
24GHz that will soon accelerate thanks to the work our club members are doing on
the surplus equipment. (Check out Dave and Sam's report in this issue) I am
amazed at the level of activity all around our own club. We are mostly a
building club anyway but it seems like we are at a fever pitch with members
getting test equipment and building on several bands. I'm encouraging a friend
to put his 30 foot dish and 500w TWT on 3.5 GHz so our members can do EME with
horn antennas. As impossible as that may sound the numbers are good and all the
guy needs is some elliptical waveguide; he has the experience and equipment. We
may also see a significant number of our own club members above the 30 watt
output level on 10GHz this year.

This is an exciting time and we can either watch it happen or be part of the
action. What I mean is, that since so many people are working- get involved.
With lots going on, there is lots to share and be part of. Now is the chance to
become part of what we will look back on as a wonderful time. Remember that the
effort each of us puts into projects, sharing work, results and operating will
become synergistic to the whole club and the effect will be more than the sum of
the parts. Get parts, get help, shoot the engineer and get on; then perfect
it.

January Activity Day- We are planning to get out for the Jan VHF Sweepstakes
contest and get on the air on Microwaves during the contest. Send an email on
the reflector if you have definite plans or call me or Dave WA6CGR if you want
to get on and work us. We will also take a poll at the Jan meeting to see who is
going where and put it on the reflector. Should be a good time to check out our
rigs and progress on how they are doing.

Here is a Thought for the September 10GHz and Up Contest: Especially for all
the new operators on 24 GHz. We could have a party in the Mojave. With stations
on Heap's, Blueridge, Walt's point, a group of rovers and others we could have a
wonderful time operating. In September the Mojave is very dry and not too hot.
It is a fairly confined area with good views in many directions. With the rigs
we have for 10 and 24 GHz and using a special liaison frequency we could have a
ball operating. From my experience there is almost no spot you could go to on a
good day and not work stations easily. It will be a good time and place to
operate on 24 GHz especially. In addition the stopping places to operate in the
Mojave are well documented by Chuck and Bill, so the effort will be worth it. I
suggest this as opposed to using Signal Hill and the LA basin because it is too
easy to get wiped out by moisture on 24 GHz. In the last four years I have had
much better results in the Mojave. In addition, it will give new operators a
cinch operating environment to test out their new 24 GHz narrow band rigs. Any
thoughts?

This month's meeting: Chip will review his dish accuracy measurement
technique. Bring a dish and get it tested! (You will need to be able to remove
the feed.)

Let me know if you have any requests for programs for our meetings or have
any resources.

Doug Millar K6JEY

2002 Scheduling.

January 3, 1650Z - Quadrantids meteor shower

January 19-21, 1900Z-0400Z - ARRL January VHF Sweepstakes

7 February-- 24 GHz status review. Presentation by various members on the
status of their 24 GHz stations. Frequency and power measurement test set-ups
will be available for member's radios.

Banquet at the Guasti Cafe. With white elephant exchange and door prizes!
(And good food)

7 March-- Noise Figure seminar- review of techniques with testing available
through 24 GHz.

April-May, dates TBA, Spring Sprints

April 22, 1030Z - Lyrids meteor shower

May 17-19 - Dayton Hamfest

June 8-10, 1800Z - 0300Z - ARRL June VHF QSO Party

August 3-4, 1800Z - 1800Z - ARRL UHF Contest

August 12, 1720Z - Perseids meteor shower

August 17-18, 8 AM - 8 PM - ARRL 10-GHz Cumulative Contest

September 14-16, 1800Z - 0300Z - ARRL September VHF QSO Party

September 21-22, 8 AM-8 PM - ARRL 10-GHz Cumulative Contest

Sept-Oct, dates TBA, Fall Sprints

October 24-27 - Microwave Update 2002/Eastern VHF-UHF combined Conference
sponsored by N.E.W.S.

November 19, 0040Z - Leonids meteor shower

December 14, 1000Z - Geminids meteor shower

More on the P-Comm unit conversion project. Photos
added by WA6QYR from the December SBMS meeting.

To all SBMS, As promised, here is some background and the latest update for
the 24 GHz P-Com conversion project:

1. The Project - The goal of this project is to modify P-Com 23 GHz Tel-Link
Out Door Units (ODU's) to Amateur 24 GHz SSB transverters while maintaining the
original case and antenna mounting configuration.

2. The ODU - The P-Com Out Door Unit consists of an IF Processor, a Power
Supply which receives -48 volts from the IF Processor, a Synthesizer, a Receive
Module, a Transmit Module (rated at either +16 dBm or +21 dBm at 23 GHz) and an
antenna Diplexer. The P-Com ODU is approximately 12" in diameter and about 12"
high. These particular units were manufactured by REMEC in San Diego, CA.

It has two coax connectors, a type 'N' connector which normally connects the
ODU to any of a series of P-Com InDoor Units (IDU's) through up to 150' of 9913
50 Ohm coax. The IDU's generate a transmit IF of about 300 MHz, have a receive
IF of 140 MHz and provide -48 volts to the ODU all through the 9913 coax. This
coax cable is called an IFL or Inter Facility Link cable. The other coax
connector on the ODU is a 'BNC' connector which serves as the 'RSSI' or Receive
Signal Strength Indicator (S-Meter) connector.

The antenna attaches to the ODU via 4 'latches' on the ODU.

The ODU has an antenna 'port' which is a 3/8" circular waveguide port that
mates to the antenna's circular waveguide connector. The (optional) matching 2
foot P-Com dish antennas contain the feed and radome and come with a mounting
bracket that will mount to 2" to 4" pipes.

The power supply converts the -48 volts (referenced to the ODU chassis) to
+12, +5 and -5 volts. The output of the power supply connects back to the IF
processor module which provides a central connector bank that feeds all of the
other modules.

The synthesizer modules have variations among the units we have seen (about
25) in that some are high side local oscillators in the 21 GHz units and low
side local oscillators in the 23 GHz units. The low frequency units are in the
range of 9.6 GHz and the high frequency units are in the 12 GHz range. The units
are originally designed to operate in 84 channels spaced at 7 MHz between
channels.

The transmit and receive modules use surface mount devices which allows for
easier modification. The original high IF frequency in the first modified unit
was 3,775 MHz and the original output frequency was in the range of 23.012 GHz
transmit and 22.004 GHz receive. The L.O. frequency applied to the transmit and
receive module is 1/2 the actual operational L.O. frequency. The L.O. frequency
is doubled in the transmit and receive modules.

The diplexer has a transmit/receive split of 1 GHz with circular waveguide
antenna port and WR-42 waveguide input and output for the transmit and receive
modules. There is a circulator between the diplexer and the transmit module as
well as between the diplexer and the receive module.

The transmit and receive modules have WR-42 antenna ports and SMA connectors
for the L.O. and I.F. ports.

3. The Plan - The agreed upon frequency configuration is as follows:

a) The operating frequency is 24.192 GHz

b) The Amateur I.F. frequency is 432.000 MHz

c) The internal high I.F. frequency is 3.072 GHz

d) The L.O. frequency is

The high I.F. frequency of 3.072 GHz was chosen so as not to have to move the
transmit and receive module filters too far (from 3.775 GHz).

4. Progress to Date 11/16/2001 - Synthesizers -

The synthesizers in their original form have several problems that needed to
be resolved. Specifically:

a) The frequency stability of the synthesizer reference oscillator is rated
at +/- 8 ppm! Not adequate for SSB use requiring less than 0.5 ppm. An external
QualComm 10 MHz TCXO was chosen to replace the original TCXO.

b) There was significant digital noise generated by communication between the
I.F. processor and the synthesizer (exchanging channel information). This
communication was disabled.

c) The synthesizer loop filter is too slow causing slow lock-up and
in-sufficient sideband suppression. This has been resolved by changing the loop
component values.

d) The synthesizer V.C.O. requires modification to increase the frequency to
lock at the required output frequency of 10.560 GHz (24.192 GHz - 3.072 GHz =
21.120 GHz divided by 2 = 10.560 GHz divided by 5 = the actual V.C.O. frequency
of 2.112 GHz). Two capacitors were changed to bring the V.C.O. into range.

e) There is a proprietary protocol that the I.F. processor uses to
communicate to the processor, so a standard MicroChip PIC 16F84A-04/P
micro-controller was chosen to program the Motorola MC14515 synthesizer chip on
power up. The loader program was written by Sam - K6VLM and provided to SBMS for
this project. The new PIC 16F84A-04/P micro-controller board is now installed in
the synthesizer box in the space vacated by the old TCXO.

f) The output amplifiers were re-tuned to produce an output power of 60+ mW,
down about 10 mW from the original 70 mW L.O. output.

Transmit Module -

The transmit module required several modifications. The I.F. input circuit
was modified to add a MAR-4 MMIC amplifier instead of the '420' programmable
attenuator and biased appropriately. The I.F. filter was re-tuned to 3.072 GHz
from 3.775 GHz. The L.O. doubler was re-tuned for a 10.560 GHz input/21.120 GHz
output to the mixer. No re-tuning of the output filter was necessary. It was
determined that the optimum voltage to the output GaAsFET's was +5 volts.

Success!! - With +7 dBm I.F. input at 3.072 GHz, the power output at 24.192
GHz was over 100 mW! The saturated power output was measured at 145 mW!

I.F. Processor Module -

This module is removed and is not used. Instead, a second converter module is
built using a QualComm 3036/3236 Rectangular Synthesizer board (located at
http://www.ham-radio.com/sbms/sd/rplldoc1.htm.)

programmed to 2.640 GHz, and a Mini-Circuits SKY-5G mixer to convert the
3.072 GHz I.F. to 432 MHz. The converter board (designed by K6VLM) uses a Pin
Diode switch go between transmit and receive (no relays!). The QualComm 10 MHz
TCXO is shared between the 2.640 GHz QualComm Synthesizer and the 10.560 GHz
Synthesizer.

Receive Module -

The Receive Module has been finalized, the modification required was to
modify the receive I.F. filter to 3.072 GHz and tune the multiplier.

Power Supply -

The original Power Supply is removed and will be replaced by a 12 volt input
supply delivering all necessary voltages (+12, +5 and -5 volts).

5. Next Steps -

First, to build the second prototype (the synthesizer is finished and the
transmitter is about 50% complete) and complete the documentation and web site.
Secondly, to put together kits and documentation to have a first run at building
three systems by Doug - K6JEY, John - KJ6HZ, Kurt - K6RRA, Ken - WB6DTA and Bob
- W6SYA. Thirdly, to be able to provide kits (in a quantity buy to get better
prices) to SBMS members who have already purchased P-Com units and want to get
on 24 GHz SSB as soon as possible and to others later.

Sam - K6VLM has provided the engineering modifications, micro-controller
programming and will be providing the final tuning modifications for the Receive
Module as well as P.C. Board designs

for the micro-controller, second converter and transmit and receive power
supply bias boards.

Dave - WA6CGR has provided the P-Com units (ODU's and Antennas) and will be
providing the 2nd prototype and design verification, parts kits (including
pre-programmed micro-controllers), SMD components (resistors, capacitors,
micro-controller chips, SMD crystals, mixers, etc.), documentation (photos,
conversion instructions, web site), etc.

6. Acknowledgements -

I would like to thank Sam - K6VLM for all of his continuous efforts, Hiro -
KE6IDA, Doug, K6JEY, John - KJ6HZ, Kurt - K6RRA, Chuck - WB6IGP, Kerry - N6IZW
(and I'm sure others) for their input, suggestions and putting up with us on the
radio. This has been and will continue to be an exciting and intense SBMS
project that everyone will be able to participate in!

Thanks, Dave - WA6CGR

Photos by WA6QYR at the December meeting.

At the pile of boxes center is Dave WA6CGR and Sam K6VLM during the December
meeting where Dave had more P-Comm 23 GHz "land mine" boxes to sell and the
indoor units. Both talked about the modifications to make the unit into a useful
24 GHz transverter. See the above document of status as of the end of November.
Dave can be reached at WA6CGR@ ham-radio.com. WA6QYR photo.

Last meeting- John Hoot's (N6NHP) talk on "Practical Radio Astronomy at
Microwave Frequencies" was super! Lots of viewgraphs and photographs showing
what he is doing at the Benton, Az site along with some stuff that any SBMS
member could do in listening to the universe. Thanks John. In addition to John
there were more visitors: Chuck W7VX of Redondo Beach; John, KD6IOX of Pomona;
and Gary, WA7BIP of Duarte. Welcome!

29 people attended the December SBMS meeting. There were lots of things to
report on activites by everyone, but little space left in this newsletter to
cover that. The Wants and Gots for sale sheet was misplaced at the meeting so
that information isn't available to report.

As this goes to press (the Xerox machine at a local business) I would like to
wish everyone a Merry Christmas and a Happy New Year.

73's Bill

Some of the older members of the Society had a good chat during the December
2001 meeting. Here from the left Ed, W6OYJ, George, K6MBL and Dick, K6HIJ
discuss activities and what they have been doing. Photo by WA6QYR

The San Bernardino Microwave Society is a technical amateur radio club
affiliated with the ARRL having a membership of over 90 amateurs from Hawaii and
Alaska to the east coast. Dues are $15 per year, which includes a badge and
monthly newsletter. Your mail label indicates your call followed by when your
dues are due. Dues can be sent to the treasurer as listed under the banner on
the front page. If you have material you would like in the newsletter please
send it to Bill WA6QYR at 247 Rebel Road Ridgecrest, CA 93555,
[email-masked], or phone 760-375-8566. The newsletter is generated
about the 15th of the month and put into the mail at least the week prior to the
meeting. This is your newsletter. SBMS Newsletter material can be copied as long
as SBMS is identified as source.

San Bernardino Microwave Society newsletter

247 Rebel Road

Ridgecrest, CA

93555

USA