Upload
others
View
8
Download
2
Embed Size (px)
Citation preview
1
A simple soundcard interface for digital modes By J.B.Randall, W1ZE
If you are new to the HF bands or a seasoned veteran thinking of trying your hand at TTY, PSK, MFSK and the other digital modes you may already know you need a way to connect your PC or laptop to your HF transceiver. The device needed is called a soundcard interface and there are a lot on them in the Ham Radio marketplace with names like Signa-Link, MFJ, Little Rascal, West Mountain, etc. They are all good and will do the job. Some have a lot of bells and whistles but they all do the same thing.
As you may know I am a DIY person and like to build things. Over the past dozen years I have assembled several types on soundcard interface devices, from very simple to complex. All worked as designed and help me enjoy the digital modes. In fact I think I have put article into past Squelch Tales newsletters describing several types I have built and used. These days, I appreciate building things using the KISS (Keep It Simple Stupid) design method.
Since I own several YAESU and ICOM transceivers I wanted a simple interface that would work with both makes and most models without disrupting the rigs microphone and speaker circuits. So I went to the Internet and started to see what others had built. Most of the designs used rig keying functions from data provided by the computers serial output connection. Problem one, my PC and laptop(s) no longer provide a serial port, only USB and printer outputs. Technology marches on, I guess. If you have one of these computers and want to use an interface device that needs serial port data to do your PTT keying, you need to buy a serial to USB interface adaptor. I didn’t want to spend the money for one, so back to the Internet I went looking for more ideas.
2
What I came up with was a tone keying circuit that used the data (audio) voltage from the computers audio output (or line out) to drive a keying circuit. Using that found information I bread-boarded a audio rectifier circuit using two 1N914 switching diodes to produce a small DC voltage to drive a single NPN transistor (like a 2N2222) and it in turn would take the transceivers + key-line voltage to ground keying the transceiver. The little circuit worked well.
Now to build a hard copy. With two very small 600/600-ohm audio isolation transformers, salvaged from a few junk PC soundcard boards I started to assemble the small circuit board. I highly recommend using the transformers to isolate the electrical system in the PC from the electrical and audio circuits in the transceiver to keep hum and hash out of your transmitted signal.
As you can see in the above diagram, audio signal is sampled from the secondary of the isolation transformer on the incoming PC audio/data line through a resistor and coupling capacitor feeding the rectifying diodes. After some experimenting I found out that a 1 uF electrolytic capacitor at the base input of the 2N2222 giving me about a second and a half keying hang-time, good for PSK and RTTY. If you want more hang time increase the capacitor value to 10 to 22uF. For less hang time try a .47 uF cap. I housed the entire circuit board into a 1x2x5 inch black plastic project box.
This circuit will work with most all HF transceivers. My ICOM & Yaesu rigs have a rear apron 6-pin mini-DIN data jack that can be used for digital modes. Fortunately the pin-out on the DIN jack was the same for both manufacturers. Data-in, Data-out, PTT and ground pin-out connections are the same configuration..
I salvaged a 6-pin Mini Din plug & cable off an old busted computer keyboard and wired it to the interface circuit. I can plug the interface into the ICOM or Yaesu transceivers and it functions well and no need to unplug the transceivers microphone or external speaker to do digital modes.
As a final note: Some Yaesu rigs like the FT-450D, FT-897D, FT-857D and others with the rear apron Mini-DIN data ports, also have a programmable “Digital VOX” command setting that when the rig sees audio/data on the data input circuit the Digital VOX keys up the rig, thus eliminating the need for an external audio/data keying circuit. All that is needed for these rigs is an interface assembly consisting of two small Isolation transformers a few resistors, a capacitor and a 1K
linear taper mic/data-line level pot. 73 W1ZE
3
The Cordermans,W3ZD/W2ZD & K2CML Members of the MARA
Roy’s Corderman, W3ZD’s two sons followed in their father’s footsteps by becoming ham radio
operators. During WWII Roy helped develop radio and recording devices for the War Department.
Oldest brother Sidney ‘Sid’ K2CML became one of the founding engineers for McIntosh Corp, the Audio
recording, HiFi and Stereo developers. Sid now in his early 90s and until last year lived in Five Islands,
Georgetown, Maine during the summer and wintered in Scottsdale, Arizona, where he now resides full
time. The Youngest son Allan ‘Al’ now holds his father’s call of W3ZD. Al is a Naval Academy
Graduate and Navy Pilot. He went on to earn a MBA from Harvard Business School. Al was also with
RCA Communications in Palo Alto, California. Later in life he and his wife started a publishing
company here in Maine. Al now lives at the Highlands in Topsham but still attends MARA meetings and
activities when he can. Both Sid and Al are long time members of the MARA.
Above is a photo of Roy Corderman, the original W3ZD standing next to a prototype VHF transmitter with the brass tube
wave-meter. The meter is now in the possession of Bob Oxton, W1RSO. Roy was a mover and shaker in the early days of
Ham Radio and radio communications. During WWII Roy worked in the Washington Physics lab working on electronic
equipment to help in the war effort. He was given special recognition by President FDR shown in the following photo.
4
Roy W3ZD at his station in Roy with son Sidney having Field Day Al operating a solar power station
the early 30s in the 30s during Field Day 2009 in Topsham
A FAMILY OF ACCOMPLISHED HAMS
.
5
Field Day 2016, a ho-hum
event due to a blank sun
Again this year the MARA’s KS1R Field Day
team set up operations at the Topsham Red
Cross facility during Field Day weekend.
Weather was good but
the HF bands to say the
least were not
accomidating. The folks
who attended had fun
and some QSOs were
made with several folks got their first chance to
try out PSK and RTTY.
The major reason for the low QSO total was that
Old Sol had no spots, just a blank sun. Tad
Cook, K7RA who does the propagation forecasts
for the ARRL wrote:
There were no sunspots during all of
Field Day weekend.
The last time we saw a blank Sun
(before June 2016) was 2014. Just one
day, on July 17, 2014. Sunspot number
was 0, and only for one day. Prior to
that, there were just two days in
2011, on January 27,and on August 14.
Prior to that there were 51 days with
a blank Sun in 2010, with 12 periods
ranging from 1 to 13 days. The longest
periods were 11 days beginning on May
9, 2010 and 13 days beginning on April
1, 2010.
These recent periods of no sunspot
activity are a surprise to me, even
though we are in a declining half of
the solar cycle.
Rich, AB1YX & Norm, W1MKD doing PSK & RTTY
Jim McIrvin, N1IPA setting up the Sat-Comm antenna in hopes
of a contact
6
ARRL’s New England Divison Director Tom Frenay,
K1KI stopped by to show League interest in the MARA’s
Field Day effort
Rich, AB1YX holds a training session on the Raspberry-Pi
and its usefulness in Ham Radio
Here is our submitted report to the ARRL:
Call Used: KS1R
GOTA Station Call: none
ARRL/RAC Section: ME Class: 1F
Participants: 26 Club/Group Name: Merrymeeting Amateur
Radio Association (MARA)
Power Source(s): Commercial, Battery, Solar
Power Multiplier: 2X
Bonus Points:
100% Emergency power 100
Media Publicity 100
Public Location 100
Public Information Table 100
Formal message to ARRL SM/SEC 100
W1AW Field Day Message 100
Formal messages handled - No.=10 100
Natural power QSOs completed 100
Site Visit by invited elected official 100
Site Visit by invited served agency official 100
Submitted via the Web 50
Educational activity 100
Total Bonus Points 1,150
Score Summary:
CW Digital Phone Total
Total QSOs 5 40 8
Total Points 10 80 8 98 Claimed Score = 196
Submitted by:
Donald Wakeman, KA1WAL
Comments:
(blank)
Band/Mode QSO Breakdown:
CW Digital Phone
QSOs Pwr(W) QSOs Pwr(W) QSOs Pwr(W)
160m
80m
40m 5 100 7 50 5 100
20m 33 50 3 100
15m
10m
6m
2m
1.25
Other
Satellite
GOTA
TOTAL 5 40 8
As you can see by the above QSO tally the bands
did not cooperate for our 1F effort. But all in all,
7
those that came out to the KS1R Field Day had
fun and maybe learned something too.
DXWATCH a useful
tool in the shack
By W1ZE
Chasing DX , looking for that new grid on six
meters or a VHF/UHF weak signal station is a lot
of fun and every little advantage helps land a
good contact. To this end I rely heavily on the
Internet based DX spotting services. The one I
use the most is a direct connection to one of the
various Telnet DX spotting nodes. Check out
http://www.ng3k.com/misc/cluster.html for more
info on the Telnet system. With Telnet you have
to make your PC or laptop emulate a dumb
terminal using a free program such as PuTTY.
The spotting service works well and is fast and
interactive.
The other day the Telnet spotting system went
down for hours while I was looking for six meter
spots out of Europe. Bummer Dude! I quick
went on a Google search for DX spotting sites
and came across a free access site called
DXWATCH at http://www.dxwatch.com/ so I
logged onto the site and set up an account.
It appeared to have the same spotting listings as
the Telnet system and I think maybe it is getting
its feed from the worldwide DX spotting Telnet
system. The graphics are good and easy to read.
It is also interactive and you can post spots and
set your own spotting filters. It is not as fast as
the direct Telnet system which has instant input
postings. DXWATCH updates new postings
about every 60 seconds but I can live with that,
plus I don’t have to use a dumb terminal
program to access it. Another thing it does do,
when you put your curser on the spotted call sign
the DX stations data appears on the screen like
country, zone, etc. a nice added feature.
Try it, you may like it, and it is FREE.
JULY 2016, A GOOD MONTH
FOR SIX METERS
The first part of July found some increased
sporadic-E and enhanced F layer DX activity on
the old six meter band. Even those of us up here
in Maine were experiencing some good band
openings across the pond into Europe, North
Africa with an occasional signal out of the near
east (i.e., Israel & Jorden). In addition there was
some double hop propagation to the west with
stations from the Pacific northwest making it out
to the northeast. Mid month evening openings
would last into the late hours with midwest and
Rocky Mountain region stations pounding into
Maine and Atlantic Canada.
The evening of the July 13th had wall to wall
signals throughout the SSB portion of the band
and a lot of CW activity between 50.075 and
50.105 MHz. Stations with high power and big
beams as would be expected were easy to work
but even stations running 100 watts or less into
dipoles and halos could be worked with ease.
If you have not tried your hand at six meter SSB
and/or CW, string up a dipole (9 ¼ feet long) and
give the band a try. You may enjoy it.
8
BOXBORO By Bob DeMattia, K1IW
Boxboro! is less than two months away, so our
event planning is in full swing. We are close to
publishing our forum schedule - look for another
announcement in a few weeks.
In the meantime, take a look at our Friday and
Saturday evening programs. At our Friday
DXCC/Contesting dinner, David Collingham,
K3LP, will brief us on the recently completed
VP8S DXepdition. On Saturday, noted radio
historian Donna Halper will treat us to "Heroes
of Amateur Radio: Past, Present, and Future".
Visit our website for more info. While you are
there, you can sign up a friend for a license class
or VE Exam. You can also reserve yourself
an operating slot at our W1A special event
station.
We still have opportunities for those that would
like to volunteer a few hours of them time at the
convention. Volunteers will receive a voucher
for a free lunch.
Finally, we've published a "Guide to Quick
Entry" on our website to learn how to avoid
those entry lines.
Visit our website today to find more and
purchase tickets!
http://www.boxboro.org
73,
Bob DeMattia
Chairman, Boxboro Convention 2016 Committee
P.S. Even if you've already ordered tickets, please
be sure to check our website for program updates.
ARE YOU UP TO DATE?
If you can not remember the last time you
plunked down $10 for your MARA yearly
membership, most likely you need to get in touch
with Marjorie Turner, KX1I [email protected]
and bring your membership up to date.
If you are not a member and would like to
become a member of the Merrymeeting Amateur
Radio Association (MARA) you can get all the
membership information needed from the
Association’s website at www.ks1r.org. We
would love to have you join us.
Rockwell Collins to
End Mechanical Filter
Production
As more and more communications equipment
designs have adopted digital signal processing
techniques, Rockwell Collins has announced that
it will stop manufacturing its renowned
mechanical filters. It did not provide a specific
date.
“Over the past several years, we have seen a
dramatic reduction in demand for narrowband
analog filters,” the company said on its website.
“Due to this and other economic reasons,
[Rockwell Collins] Filter Products will be
9
discontinuing its mechanical filter products in
the near
future.”
Rockwell Collins makes two different types of
mechanical filters, many of which have found
their way into Amateur Radio products and
applications. In a mechanical filter, input and
output transducers convert the electrical signal
to and from resonant mechanical vibrations,
respectively.
“For frequencies between 100 kHz and 700 kHz,
we create filters made from rods resonating in a
torsion mode,” the company explained on its
website. “For frequencies below 100 kHz, we use
flexure code bar resonators.”
Collins has made mechanical filters for more han
6 decades, and their initial application was in
telephone circuits. The filters gained favor for
Amateur Radio use because of their excellent
selectivity, especially in IF applications. It is said
to take about 12 weeks to manufacture a single
unit.
Art Collins, W0CXX (SK), founded Collins
Radio Company in 1933 in Cedar Rapids, Iowa.
That same year Collins supplied the equipment
to establish communication with the Byrd South
Pole expedition. Over the years, Collins
produced a line of Amateur Radio equipment,
and its products remain popular among radio
amateurs and collectors. Rockwell International
purchased the company in 1973, and Rockwell
Collins was spun off in 2001. Today, the
company has focused its market on electronic
communications, avionics, and in-flight
entertainment systems.
Thanks to Mike Morris, WA6ILQ;
Rockwell Collins