W6IFE Newsletter

President Jeff Fort, KN6VR 2019 Hunter Rd
Chino Hills, CA 91709 714-577-0045 [email-masked]

VP 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]

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 2 March 2000 meeting of the SBMS will
have Gordon Huff, WA6FMX, talk on solid-state T/R circuits. 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/.

REMINDER Nominations for SBMS 2000-2001 officers will take place in March and
the election in April.

Last meeting John Stephensen, KD6OZH had a great tech talk about the design
of low noise oscillators. His 38-page handout was overwhelming. Thanks for the
super talk. . Visitors were Merritt Martin, KD6WKS of Adelanto and George
Schrock, KF6NVO of Hesperia. Welcome! John, KE6JVV; Bill, WA6QYR; and Doug,
K6JEY had equipment for sale and some giveaways. 26 present.

Scheduling-

4 Mar. SBMS Dinner at the Cask and Cleaver in Victorville, CA with a social
at 6 pm and dinner at 7 pm.

6 Apr. TBD

4 May TBD

May sometime, a joint measurement party with San Diego Microwave Group?

10-12 June VHF QSO Party

President Jeff Fort is planning the annual SBMS Dinner on 4 March at Cask and
Cleaver Restaurant 13885 Park Ave. in Victorville, CA 760-241-7318. A social
will start at 6 p.m. followed by dinner at 7 p.m. See enclosed map. Please note
the restaurant is next to and can be seen from the I-15 freeway, but is some 100
yards off of the street. There is a big sign on Park Avenue showing where to
turn in to the parking lot. Jeff will be taking a head count at the 2 March
meeting.

Wants and Gots for Sale

Want two 4CX400A 's Bob Gardner W6SYA 818-248-3683

Want WR-42 90-degree twist and waveguide switch Dave WA6CGR 909-318-5154.

Want a heavy-duty tripod for new dish, Mel WA6JBD 909-369-6515

Activity reported at the February 1999 SBMS meeting- Dick, WB6DNX had cleaned
up his shack; Chuck, WA6EXV is finishing up modifications to his 10 ft EME dish
and making schematic of the "TV tuners" from last months visit by Kerry, N6IZW;
Bill, WA6QYR worked on an older motorhome TVRO az/el mount and the TV tuners;
Mel, WA6JBD finished his 24 GHz gunnplexer temperature controller box; Doug,
K6JEY, worked on a new Shepard crook feed; Jim, K6ML is having cable TVI
problems at his new QTH; Ken, WB6DTA is collecting 3.4 and 5.6 GHz gear; Kurt,
K6RRA has been drilling holes in circuit boards; Alicia, KF6WMX has been hitting
the books; Jeff, KN6VR attended a meeting of the San Diego Microwave Group and
was impressed at the stuff Kerry, N6IZW has; John, KJ6HZ tuned up a
gunnplexer.

Larry, K6HLH reported a phone number change 661-264-3126.

. "TV tuners". At the January 2000 SBMS meeting Kerry, N6IZW, brought in some
surplus "TV tuners", Toshiba model CVA-151 (RCA connectors) and CVA-113 (F
connectors). These have a number of surface mount parts inside and everyone was
encouraged to take several home. The now defunct "Ham Radio Magazine" had a
series of articles on various spectrum analyzers, electronically tuned receivers
and things that could be done with excess TV tuners. Ham Radio September 1986
page 82, March 1987 page 99, September 1987 page 49, September 1988 page 84, and
Communications Quarterly premier issue fall 1990 all had something to do with
the basic TV tuner. The older tuners had a VHF and a UHF section that allowed
receiving signals from 50 to 300 MHz and 500 to 800 MHz. IF outputs were in the
45 MHz range. This set of articles added the 3089 FM receiver on a chip plus an
audio amp to make a panadaptor, spectrum analyzer, or tunable receiver from the
basic circuits in the first article to the addition of computer control and
spectrum analysis in the last modifications article. More recently "73 Amateur
Radio Today" magazine had a 3 part series by Hugh Wells, W6WTU, on "TV/ VCR
Tuner Applications" in the April 1997 page 18, May 1997 page 36, and June 1997
page 30 issues. Wells indicates the newer "cable ready" tuners cover 45 MHz to
900 MHz with an IF of 47 MHz for the TV units and 63 MHz for the VCR units.
Again with the marriage of either some chips or another IF receiver and sweep
circuits or a pot, one could build some interesting receivers from junk box
parts. The tuners from the SBMS meeting appear to only cover 30 to 400 MHz. But
there are some interesting circuits inside. They seem to have an input filter, a
VCO, a prescaler, and mixer in the first module. A 600 MHz filter, narrow
tunable VCO, mixer and some filtered output amplifiers in the second module. See
Chuck's drawings.

The first module VCO tunes 500 to 1100 MHz. The prescaler divides the VCO by
64 in the CVA-151 and by 256 in the CVA-113 and provides a TTL output. The mixer
provides a 600 MHz output to the second module from the combination of the input
signal and the VCO. Applying +12v to pins B1 and B3 power up the devices. B2 for
the prescaler wants to be +5v. . The prescaler TTL output is on pin PS. The
first VCO tuning voltage is applied to pin VT and can range from zero volts (500
MHz VCO frequency) to about 25v for 1100 MHz. The VCO is quite stable for the
amount of circuitry inside.

The second module has a VCO that operates 560 to 570 MHz with application of
zero to 25v on pin AFC. The output circuit bandwidth is close to 20 MHz to
accommodate the full TV signal spectrum. These tuners appear to be built for
cable or similar operations where high-level signals are present so if one wants
to use it for a receiver, some preamplification needs to be added in front of
the tuner.

Another use of the tuner might be as a signal generator. If one were to strip
out the front-end filters and replace them with an MMIC, one could couple the
strong VCO signals to the "input" connector via a buffer amplifier. Using the
prescaler and a HF counter one could display the signal generators frequency
(divided by which scale factor tuner you have). Another signal generator version
could take the AFC VCO signal into the first module mixer. This way the mixer
output would be near DC to 500 MHz. Thus you could have a voltage tunable signal
generator covering from DC to 1100 MHz with two tuner units. Have fun. Bill,
WA6QYR

73's Bill

Bryan, W6BY on Mount Diablo in 1997. Photo via George, K6MBL files

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 Your mail label indicates your call
followed by when it is time to renew your dues. 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

back to SBMS
homepage