THE VOICE OF SUNNY COLORADO
BALLOON LAUNCH UP IT GOES SUNDAY FEBRUARY 24, 2001 AT 10:00 AM M.S.T.
HAMFEAST YES HAMFEAST! THAT'S WHAT IS SAYS IN THE SWIARC DICTIONARY. I QUOTE FROM PAGE 1 "HAMFEAST" LARGE VARIETY OF NEW, HAM RADIOS, ANTENNAS, & ACCESSORIES, PLUS FLEA MARKET TABLES GALORE!
WHO IS SWIARC?
IT'S A CLUB BACK
EAST IN IOWA.
THE HAVE ART BELL , KIM KOMANDO, GORDON WEST, AND A SIMPLEX BALLOON REPEATER.
I GAVE N0UQZ 4 OF OUR OLD SIMPLEX REPEATERS
THEY GOT BURGHARDT AMATEUR CENTER SHOWING AT THEIR BIG EVENT
MARCH 3, 2001 IN COUNCIL BLUFFS, IA.
CHECK IT OUT HERE
COLORADO TROUT STILL
ART BELL HAS A COLD AND MAY CONTINUE TO HAVE A SUBSTITUTE THE NEXT FEW DAYS.
WESTERN NEBRASKA RADIO CLUB MAY CHALLENGE THE IOWA CORNBORE CLUBS TO OUT DO THE NEBRASKA AMATEUR REST STOP.
Rocky Mountain Radio League's
Cross Band Repeater
The Rocky Mountain Radio League's cross band repeater was built by Bob Schellhorn [NØTI], Glenn Casino [WNØEHE] and Bob Ragain [WB4ETT]. For some close up pictures of the interior of the machine
The repeater identifies itself with a Morse Code beacon every 8 minutes. Periodically a robot voice announces the identification and also notes the input and output frequencies of the repeater.
The cross band repeater has a GPS/APRS system on board.
Every 60 seconds during normal flight an APRS position packet will be transmitted. During descent, when the payload approaches the ground, the APRS beacons increase in frequency to approximately once every 10 seconds.
Please, turn off any beacons you may have running on packet if you are listening to the receive frequency. They will only interfere with other stations in your area attempting to log the APRS data.
Do NOT attempt to DIGI through the cross band repeater. It is not a true packet station. There is NO mailbox, no digi, no gate associated with the callsign of the APRS packet data.
Often the signal from this payload is received by a station in the Denver area and retransmitted into the National APRS system. If that is the case, we may appear nationwide either via 30 meter gates (10.151 MHz LSB)
The Repeater uses vertically polarized antennae for both receive and transmit. However, the payload string is usually swinging back and forth, thus altering the polarity significantly. The balloon also tends to rotate spinning the antennae about their vertical axis. All this motion tends to create a signal that fluctuates quite a bit on both input and output. This fluctuation is most pronounced while the balloon is transitioning between "layers" of the atmosphere where different wind conditions exist.
A circularly polarized antenna would offer the best opportunity for strong signal reception and transmission from a ground station. However, we have noted that most stations can make good contacts through this type of disturbance with standard vertically polarized antennae.
When the balloon bursts, or a payload is cut away from the balloon, the payloads tumble around quite a bit and the signal quality becomes extremely erratic. If you hear a relatively constant signal with periodic variations in strength and suddenly the signal starts fluctuating wildly, you are probably "witnessing" a burst or cut down event. Within a minute or two, the parachute will begin to provide enough drag to force the payload train into a more orderly vertical orientation. Signals will then more closely resemble those received during ascent. However, there is always much more fluctuation during descent.
There are no CTCSS tone blocks on the repeater. Just transmit on 445.975 MHz and you should hear yourself coming back down on the output frequency of 147.555 MHz. Remember to use headphones or control the receive volume in order to eliminate feedback on your transmission.
Depending on conditions, the repeater may be operated under various limitations set by a net control operator.
The most common operating mode is a directed net where all stations are invited and encouraged to check in and participate.
When you hear a break in the net, call net control and give your callsign, name, city and state of your location. If you live in a small town that the net control station might not recognize, you might instead check in and state your location as 25 miles south west of a well known city in your area. That way net control will be aware of your location. The net control operator will acknowledge stations checking in. He or she will attempt to facilitate long distance QSOs by making suggestions on who should try and contact whom.
If you hear a very distant station and wish to make a contact with them, do not hesitate to ask net control for permission to make the call. While net control will attempt to put together long distance QSOs, he or she may miss an excellent possibility that you are aware of.
Try and defer to stations out on the border of the footprint. Granted, if you live in Denver and hear someone in Pierre, SD it's a long contact for you. But, someone else (say in Albuquerque, New Mexico) would be in a better position for a really long range QSO. See the Window of Opportunity section below for more info on how the footprint expands over time.
If traffic is minimal, a net control operator might open things up a bit allowing stations to freely use the repeater. However there is ALWAYS a net control station who may at any time step in and assume control of the frequency.
Why not just let the repeater be open at all times?
Occasionally, the only repeater coverage a recovery team has is the cross band repeater. In that event, the frequency is turned over to them to coordinate the recovery operation. This happens infrequently, as most of our flight land somewhere within repeater coverage of the front range of Colorado. But, should the balloon dash out too far to the east and outrun repeater coverage, the balloon is the recovery team's best means of coordination.
Windows of Opportunity
A typical EOSS balloon will ascend at a rate of approximately 1100 feet per minute.
At this rate of ascent, 13 minutes into the flight the balloon will be at an altitude of 20,000 feet above sea level and the footprint will have a radius of 163 miles.
footprint at 20,000 ft. ASL
36 minutes into the flight the balloon will be at an altitude of 45,000 feet above sea level and the footprint will have a radius of 268 miles.
footprint at 45,000 ft. ASL
From this altitude it will take approximately 40 minutes
to reach an altitude of 90,000 feet above sea level (77 minutes into the
flight). Most of our flights will ascend to that height. At that
altitude the foot print of the crossband repeater will be approximately
392 miles in radius.
However, once the balloon rises above 80,000 feet the likelihood of a burst becomes significantly greater. Therefore, as good operating practice, we suggest that only really distant stations check into the net and request contacts at this point. Remember, the footprint is constantly growing. A station at the extreme edge of the footprint may not even hear the balloon until, literally, the last minute of ascent. Offering deference to those distant stations would be appreciated.
Here is an example of how a net control station can be very helpful. In the above map, Pierre, SD would check in sometime within the last few minutes of the flight. Then at the very last minute, Albuquerque, NM would check in. Net control would, hopefully, recognize this excellent opportunity for a really long distance QSO and tell Albuquerque to call Pierre. It takes Net Control to put this together because Albuquerque never heard the repeater or Pierre's check in since that event happened just prior to Albuquerque's reception of the repeater's signal. Of course, if Net Control misses this opportunity, hopefully Pierre will see the possibilities and request the QSO. If closer in stations are keeping clear of the repeater during the last few minutes of ascent this contact is much more likely to happen.
Try and be aware of your distance to all the stations checking into the net. In the above example, Albuquerque might not check in. Perhaps you are located in Pueblo, CO. You might be the station with the best chance for the maximum distance QSO during a flight by calling Pierre. But, with a lot of Colorado stations checked in, the Net Control might not pick up on this fact. In that case, you should try to get permission to make the contact. Just be sure to allow air time for more distant stations to check in. It's all a judgment call on your part. If you can make a contact of over 400 miles, you should elevate your own priority in your calculations and go for it.
Once the balloon bursts and falls below 80,000 feet net control will once again accept any contact requests. We've had our chance at long distance QSOs and now it's time to just have some fun.
The rate of ascent is a relatively constant factor. However, descent is entirely different. The only brake on descent speed is the parachute. And the parachute works against the surrounding air. And, obviously, the atmosphere is much less dense at high altitude. Therefore, the balloon begins its descent at a very high rate of speed. As the balloon moves into denser and denser air, it continually slows its descent rate.
And so, stations on the fringes of the footprint will rapidly lose the signal.
Also, since the Tracking and Recovery teams usually don't need the repeater until the last stages of the flight (below 45,000 feet) they may not need to commandeer the system until most of the distant stations have already fallen out of coverage anyway.
QSL Cards Exchanged between Contact Stations:
Balloon borne repeaters are an excellent opportunity to do some "DX" work in the VHF/UHF realm of amateur radio.
You should try and exchange QSL cards with really distant stations. Who knows, you might even make it into the record books. The current record (as of 08/Feb/2001) as posted on the is 526 miles.
It should be still be possible to beat this one. In the example above regarding a hypothetical contact between Pierre, SD and Albuquerque, NM the distance between stations is approximately 725 statute miles.
DO NOT exchange address information during a QSO made through the repeater. Time may be short and a lengthily exchange of addresses might cause others to miss their opportunity to make a contact.
Try and determine if either or both stations have their address information current with the FCC database. That way, you can just confirm that info and know you have a good address. You can easily get their address by going to one of the call sign servers on the Web. I'd recommend the QRZ database.
If only one station is current with the FCC then, the other station should take it upon themselves to initiate the QSL card exchange by sending their card to the station with the good address, including their current address for the reply QSL card.
ONE EXCEPTION, you can exchange an email address ONLY if it is one that goes through a REALLY WELL KNOWN reflector such as the ARRL.NET or AMSAT.ORG sites. Those exchanges should go quickly as all the individual need know about you is your call sign and which reflector you use. Don't try and send a unique email address though as that will undoubtedly require lots of phonetics and bog down the net.
It has been suggested that EOSS act as a QSL bureau for future flights. If we do take on that responsibility, the exchange of cards may be facilitated. Look for announcements here (on this page) or on the flight announcement page for the availability of a Bureau service on future flights. This will depend on recruitment of a Bureau manager.