Ham Radio
I always enjoyed building my own equipment as you can tell from my lead in.
Why build? Well it is certainly not to save money, that's for sure. You wind up with a bigger bill in the long run due to test equipment, and tools needed, boxes of parts that almost got used and antennas that almost worked. Not to mentioned the XYL who keeps asking when you are going to clean up all that junk in the basement. Probably like many hobbies where a do it yourself mentality is cherished, ham radio naturally lends itself to the builder enthusiast in all of us. But reality eventually sets in and we all settle for an acceptable level of mediocrity. I used to love to build transmitters. I built phasing rigs and filter rigs in the early days of SSB in 1955. By 1969 I learned how to sit in a darkened room and watch SSTV paint down the face of a Surplus P7 CRT. It was the crowning achievement when after only 8 seconds in the dark, you caught the decaying image of an American flag on the P7 screen sent by another crazy guy across the country also sitting in the dark!
Software Defined Radio So what's so new about this?
One of the more useful receiver enhancements in the early 50's was to use a BC-453 receiver, that tuned from 110 KC to 550 KC and featured very narrow pass band IF transformers that operated at 85KC with a sliding phenolic tuning rod attached to one of the coils inside each IF transformer. (In the bygone days it was CYCLEs not HERTZ; and AERIAL, not ANTENNA! I really am starting to feel downright ANCIENT some days!) Pushing and pulling these rods made the IFs have a wider or narrower pass band. Tuning the BC-453 around 455 KC and loosely coupling the aerial input of the BC-453 to the ham receiver's typically broad as a barn door 455 KC IF, you could separate the weak ones from the strong ones real easy. We used to call the BC-453, "the Q5er".
An Auto notching filter is a nice feature in the SDR-1000. But by carefully setting those phenol ic rods on the BC-453's three 85 KC IFs, I could notch out a carrier too. The SDR is very stable. True, but in 1960 when I used my Q5er on RTTY, the signal was 850 Hz wide not 31 Hz like PSK-31. In 1960 stability was nice, but if you left the radio on, the thing quit wandering so much after a while and warmth of the tubes had a certain charm of its own (called an electric bill!) Now cost, there is a difference. The BC-453s cost about 5 bucks at Aaron's Surplus Emporium; the SDR and computer, etc will take the heart out of a $3 kilo buck bill. Tuning is the biggest change of all. Ever try to make a nice circle with a mouse? After 50 some years of tuning the receiver frequency with a round flywheel weighted knob, Tuning with a mouse puts me among the tuning challenged class for sure. And instructions? About equal there. The BC-453 did not come with any; neither did the SDR. I had to down load 270 pages from the Internet top wind up with a theory of operation document with no operator's manual and no index. I could find the pin outs for the tubes in the ARRL Handbook which did at least have an index, so who needed a description?
It isn't 1960 any more. Things are crowded; things aren't done the old fashioned ways any more. You make a schedule with somebody and if you are 5 KHz off; he may not find you. The tuning knob went out with the Brontosaurus. You enter "14.230" on the keyboard and like magic, you are there. You want to work SSTV? Don't reach for the Rig blaster. You attach a "Virtual Audio Cable" from the SDR's software digital output audio port to the ChromaPIX's software digital input audio port". Whopsie! SSTV is not just video; it also uses a microphone to describe and comment on the pictures. Unfortunately the Software Designer was not an SSTVer. No way to do a Software microphone. Tilt. Flex Radio says "we goofed!" Interesting admission, but meanwhile I have to unplug the microphone and plug in a video cable as there ain 't no way to there from here! Maybe we should call it Unflex radio?
The current genre of Software Defined Radios is more of an affliction than a reality in my opinion. Flex Radio's founder hates knobs, so you are stuck with tuning with a mouse! All of the other current upper tier radios have Digital Filters, Micro controllers, Programmability, etc. They also look like a radio and have real knobs. But you are also stuck with all the features that some Japanese Designers thought you should have. It all comes down to, "So who is the designer?" In any case it isn't me, for sure. Future generations of SDRs better take that into consideration or it will die an ugly death. I am firmly convinced that the old saying, "He who pays the fiddler, calls the tune." is just as applicable to who is doing the software defining. My idea of an ideal radio is different from another ham's idea. If the radio is really defined by the right person, easy customization should be the main feature.
All of the current radio designs are a mixture of software, firmware, and hardware. Software can provide design of flexibility but at the cost of taking longer to accomplish a given task. Hardware on the other hand is typically very fast, but not quite as flexible. Firmware shares both problems - slowness and inflexibility. Firmware is usually just a minimum part of the software to get something barely running. Like the boot software in a PC called the BIOS is Firmware. .
At the recent Dayton Hamvention, I attended a Flexradio infomercial by Gerald Youngblood, K5SDR, on Saturday night offsite at the University of Dayton. The cokes and the pretzels tasted good, and it was nice to sit down for a while after trekking the hamvention. The highlight of the night was when Gerald showed a version of his Flex-5000 box that had a big knob on the front panel! Unfortunately very little information was presented. Gerald likes to think that the SDR-1000 is the ultimate answer in flexibility as compared to the usual Japanese rigs. But I think it is just the opposite. I can modify the ICOM, YAESUs, and KENWOODs hardware, but unless I am a software giant, I am stuck with what can be downloaded from Flex.. Perhaps .01% of the hams can modify this big gob of software. The other 99.99% of us are stuck with what is delivered. Gerald pointed out that serial #1 runs the same as the latest unit. Well, that is quite correct, and neither one will do SSTV correctly! Gerald pointed out that SDR-1000 will maintain its state of the art leadership forever by merely doing software upgrades. If you believe that one, I've got a great bridge over the East River that I would like to sell you at a very good price! I want a rig that will run in full duplex. which is required when operating through satellites. Gerald's answer to that requirement is to buy the new Flex-5000A box for $2400. Maybe I can use the rubber feet off of my SDR-1000. Doesn't sound very flexible to me.
The concept of an SDR is great, but this first generation of SDR's by Flex isn't there yet. Click here to see what is entailed in Software Defined Radio.
Perhaps a better name for a rig like this is a "Software Define Ground Station", mirroring the current AMSAT "Software Defined Satellite" architecture. A Software Defined Ground Station is not the cheapest way to achieve a "good" ham station. It is hopefully a way to achieve a reasonable initial cost system with maximal operational features of the most important features to the individual operator with the least likelihood of obsolescence which may well prove to be the least cost solution with the most capabilities over the long run. But SDGS puts too much emphasis on Software. A "Define" is too passive for my liking. I think a better way to look at it is as a User based system, So I now call this process a User Designed Ground Station or UDGS.
UDS (User Designed Station)
Having led you along the above thoughts, let us do it a bit different. You are the one buying the radio, right? So why not buy ( or better, Build) one that is designed strictly for your needs, not some software weenie that tells you that you have to tune the radio with a mouse! Isn't that the dumbest way to run a radio you ever heard of?
Let's start by defining several types of ham operators, and looking at what kind of a radio that they would like.
Appliance Operator : Go hit the X in the upper Right corner. You don't want to read any more of this!
Rag Chewer Only: The first thing you tell the person after answering a CQ is your age. Go hit the X too.
You read the social columns of QST: Go away! You are probably a life member of the ARRL. I'll bet you are on the board of directors of your local ham club that thinks Field Day is the ultimate Ham Activity. You probably also believe that GOTA Bonus Field Day points are going to get the kids into ham radio.
Builder - Rag Chewer: Now we are getting somewhere! You live to talk to people about something they have done. You are able to reply with things you have done. It really get's going when you have each invented something. It might not be of major significance, but you did it yourself and by damn, it was fun to do it. If two stations answer your CQ, one a rare DX station who will be a "Hello my dearest friend, Robert, you are 5X9 into Nowheresville, Island. 73 and best of DX" type and the other one is someone in Kansas. You would go back to Kansas.
Builder - Contester: Now we have the real extrovert amongst us. Winning is the only thing that means anything. The only reason God made weekdays is to separate the weekend contests. Your rig is the ultimate tool, your weapon of choice, you live and die along with it. You are a definitely a type A personality. You won't live a long life as a type A, but you pray to God that you die on a weekday instead of during a contest! You concentrate on a better antenna, a redundant station that would NEVER Fail during a contest, great sounding and tailored audio. Computers are another tool in your arsenal to the top of the standings because they save you .5 seconds per contact. Antennas stroke your fire. Bigger, Better, More Gain, Better F/B. Heaven is a 200 foot rotating tower with stacked bazilion element monobanders at various levels. Hell is the same thing,except the coax is shorted.
Builder - DXer: Not many of these, most are Assembler - DXers at most, but don't leave yet. Might be some promise here. You are usually the seeker, not the seekee, but on occasion you have been known to go to some God forsaken pile of rocks for a week. You are easy to spot at the ham club meeting. You always look sleepy from staying up all night to work that rare one. Your Call is a first line consideration. It's one of those new fangled 1X2 or 2X1 calls that always get me confused. Your receiver is the primary tool of choice. You can't work 'em if you can't hear 'em, right? Powerful is the game, and antenna gain is the name. Heaven is a new 4 element StepIR beam. Hell is a new 4 element StepIR still on Backorder.
Builder - Experimenter: Your main worry is that you will finish your project. You might have to use the thing. Oh No! My Elmers, like W8QEJ, 50 years ago were like this. I really liked these guys, but I couldn't ever do anything for them to help them complete it and use it - this would be, well, punishing them in a way. But I could listen for hours to their tales of how "10 Meters when the propagation was so good you could work the world on 50 watts to a dummy load."
Satelliter: Sometimes confused with an appliance operator. But I think there is hope here. At least he has to really work to put all those xx#$$% components together and make them work properly in the correct elevation and azimuth direction for the right 15 minutes on a frequency constantly changing due to Doppler. Visitors grovel in awe at his feet. Other hams think that he is, well, weird. His XYL does not think he is weird,; she has no doubts about this. They talk in strange languages, like, "the grid is DM79." Say what? A long time ago I learned that a grid is a part of a vacuum tube. What the Hell kind of a tube had 79 grids? Then somebody clued me in that he was talking about his QTH. So where the Hell is DM79? "It's Denver, Colorado." His XYL is right; he is weird!
QRPer: I dunno if he is just a hard up guy that can't afford a real radio, or is out for a challenge. Unfortunately if it is for a challenge, I wind being the challengee. I have to pull out his crummy weak signal out of the QRM mud. He enjoys himself in his easy chair because I have a nice clear sounding signal due to POWER..But I am here to tell you, that the future of ham radio may be in the QRPers. They build the stuff. The appliance of choice is frequently a K2 radio that comes as a kit .The new K3 is not in the same league; with surface mount, cost s ~$2K... face it, the Do It Yourself QRPer becomes just another appliance operator. Sad. The QRPers are generally lean and mean, youthful operating machines. THe QRP forum at Dayton was packed to the gills. They had real experimenters talking up there about neat DIY projects. In fact the QRPers arrive at Dayton a day early every year so they could have a day of more talks about their favorite thingies. "Amplifier" is a wordy dirty to them, of course, not to be spoken in polite society. Well, maybe "preamplifier" is an OK word.
OK, now. I have defined 6 Blue guy ( and gal ) groups that I would like to design a real "User Defined Radio" for. But I really think that the situation is much bigger than just the radio; it should include the Antenna selecting as well, and it should include the application to which the station will be put to use; e.g. a CW station has much different needs than a an AM nostalgia rig. A contester station is much different than a DXer station. An SSTV station is different from a PSK-31station because though both use the sound card for demodulation, the PSK-31 has no microphone jack, but the SSTV station will be running voice the majority of the time. SO instead of a UDR, I prefer to call this effort a
User Designed Station or UDS
Click here to find out more about my ideas about User Designed Station
I want your help , dear reader. Input your thoughts on what you would want in an ideal radio or station. Don't think that anything is too outlandish. Don't be bashful. It's your radio, you might build or at least have it built by someone for you; you call the tune. Send your comments to me by manually entering the address below:
Reader inputs here
PSK-31
This is one of the most interesting groups I have seen in a long time. All the stations run very low power and most of them can carry on quite a ragchew from a keyboard. It is similar to the old RTTY stations, except instead of an old greaser like a Model 15 or 19 occupying 850 Hz shift FSK (2125 to 2975), it is now a computer with a soundcard running some free software and occupying only 31 Hz bandwidth if properly adjusted. It's the only mode I have ever been accused of being too powerful when I was only running 9 watts on 20M! Goggle Search on "PSK-31" and find out all about it, and then download and install some great free software. I personally prefer Digipan 2.0, but other pieces of software are great too.
This used to be the most exciting mode of all, but now it seems to full of appliance operators who think they are the state of the art when they down load some stale picture from the Internet and put a CW ID at the end of each transmission. The leadership was unable to convey the idea that the images sent should be a personal reflection of the person and his or her station. Any rig can send out SSTV and most hams have a computer as part of the ham station. 90% or more hams should be running SSTV to show the station they are contacting what they look like and what their station looks like. Kinda sad that this has not happened. And the FCC eliminated the need for a separate ID 25 years ago.
Satellites
Visit AMASAT.org to learn everything you ever wanted to know about satellites and download some good sotfware to find out where the satellites are and how to track them..The current top contenders are NOVA and PCSAT32. Each one is $50 to $60 Buyware with a Demo period. Nova is prettier and buggie, but PCSAT32 also includes automatic doppler correction that semi works.
Amateur Satellite operation can be quite a challenge. It is equipment intensive so don't enter the mode if on a tight budget. If you have your WAS and DXCC, and are searching for new forms of ham radio excitement, this would be the place to look into. The mode is typically on the VHF and UHF bands and requires a rig that can be operated Full Duplex. (you will be Transmittting and Receiving simultaneously). It is the Ultimate mode for those that like to hear themselves talk!
You will start off with about a $1.5 Kilobuck full duplex capable rig like the ICOM 910 H , the Kenwood TS-2000(X) or the Yaesu 847 (I think I heard that it has just beeen discontinued).
The next item is a pair of antennas that have some significant gain and are right circularly polarized. Top of the line used to be a KLM 435 MHz Cross Yagi with a total of 40 elements that were remotely switchable between left and right polarization along with a KLM 145 MHz Cross Yagi with a total of 22 elements that were remotely swichaable between left and right polarization. To turn this combo a Yaesu G-5500 dual axis rotator is used on top of a tower that put the antenna in the clear, horizon to horizon, if possible. The KLMs are out of business but I see them all the time at hamfests so a bit of prudent shopping will get a nice system but the polarity switching relays will usually need a bit of burnishing. M2 now produces similar cross yagis but without the remote switching dual circularity feature, which is too bad. Even the high gain of these antennas into hardline leaves the signal from the satellites very weak so it is wise to get a pair (2M and 70 CM) of antenna mounted preamps. The Yagis will run about $500, or less from the flea market ($200 is typical for the pair), say $1K for the tower, $600 for the rotator, $500 for top of the line preamps, and around $500 for low loss coax and 12 conductor rotator cable. So plan on around $3 Kilbucks for the antenna, but it will really impress the neighborhood hams, and piss off the local CC&R Gestapo.
I am looking into how to get on the birds cheaper, so I leaned on Dave, W6OAL, who lives nearby in Parker, Colorado, owner of the OLDE ANTENNA LAB, to build me a reduced size set of yagis. Dave came up with an 18 element X yagi on 435 MHz on a 5' boom and an 8 element X yagi on 145 MHz.on another 5' boom. These things are really fabulous working antennas with the preamps mentioned above attached. And Dave's workmanship on these antennas is flawless. He said he could turn them out at about $195 each. Gain is a function of reducing an antenna's beamwidth. so the bottom line is that if you don't need the higher gain, you will have an easier time pointing the antenna manually at a moving and invisible target. Most Hams of any significance already have a Tribandeer on HF on a reasonably siezd tower. All they need to do is to find an old rotator for elevation. Yaesu makes a new one for $300 , but a little fleamarket shopping will uncover an old U100 Alliance rotator. If it doesnt run it will be cheaper, and all you have to do is to replace the AC capacitor insider the control box. Excpect to pay between Nothing and $50 for the U100 and matching control unit. Mount the U100 about 5' above the tribander, rotated 90 degrees so the.normally vertical mast is a horizontal boom going out to the X yagis on opposite ends of this 5 to 10 foot boom. Some people insist. that a fiberglass boom should be used to avoid distorting the circular patttern. This is true if the antenna is oriented in a + configuration with the coax lines drooping down from the end of each yagi going towards the center of the boom where the elevation rotator is. This also a great configuration to have a coax line snag on the elements below and burn out the elevation rotator's motor. After learning this the hard way a couple of times, I now run my coax forwrd to the point of attachment of the yagi to the boom and along the boom to the rotator and down. Each yagi is now rotated into an X pattern and there is very little impact on the pattern by a metal mast and the coax line.
Satellites and Dishes
AMSAT bet the farm on AO-40. But soon after launch it started to crap out. The 2M gear worked great during initial testing soon after launch into a high orbit in November, 2000 then started to die and quit completely in 2004. This satellite had an orbit that varied between 700 miles up and 36K miles up. When this bird was 36K up, it was weaker than when it was near the Earth, but it had a footprint that covered almost 1/2 the earth. A replacement is promised by both the Germans and the Americans, but right now the only show in town is the cheaper Low Earth Orbiting Satellites (LEOS) which are much cheaper to make and launch.
The Morrison Dish Farm (you'll love this one!)
A few months ago I got a call from some local ham operators asking whether I would like some big dishes. Of course, I wanted some big dishes. But this was more thatn I ever imagined in my wildest dreams.
These dishes are located at Morrison, Colorado, which is about 10 miles West of Denver where the Rocky Mountain Foothills begin. In fact many of the first dinosaurs were discovered in the hills behind the dishes in the picture above.
So why did I wind up with all these big puppies?
The Denver TV stations built this site around 1969 to receive Satellite TV broadcasts for retransmission around Denver. The satellites were Geosyncronous birds on the C band which is about 4 GHz. The TV stations also uplinked programming of their own too, on 6 GHz. As the C band filled up, the activity shifted to the KU band which is about 12 GHz receive and 14 GHz transmit. The dishes all look South to the Geosyncronous belt; all arefixed in place, but moveable. Some are also motorized.
One of the most interesting is this wide angle dish. It sat slightly forward of all the rest, and could pick up the whole Clarke Belt C Band at one gulp. It has gas heaters beneath the front surface so that when it snowed, the snow immediately melted and no signal strength was lost.
To make a long interesting story short, about 5 years ago, the Denver TV stations abandoned the site, and the rancher who own the property got stuck with the whole shebang. The local high speed internet provider, called Whispertel, was started by a number of Denver area Hams. These guys sold off 51% of the company recently, and started looking around for something else to do. They decided that they wanted too start a data service center, and looked around around for some low cost place to hosue the equiptment. They found this site, but they really only wanted the buildings to house servers, routers, etc. and facilities for a solar powered data service center. So that's where I entered the picture. They are paying the rent on the whole multi acre site and would like to get some income from the dishes to help defray the cost. They could sell the dishes for their scrap value, but to any real ham, that would be a heartbreaker.
Enter Robert, W0LMD (me). I looked over the site, and I was scared, and I am fearless! But after a little reflection on the Toilet, ideas started popping into my head. The dishes are rather worthless as is to any ham. They are pointing to the "stationary" Geosyncronous birds and both the High Earth Orbiting HAMbirds like AO-40 and the Low Earth Orbiting HAMbirds like AO-51 have one thing in common. THEY AIN'T GEOSYNCRONOUS; THEY MOVE ALL OVER THE SKY! Same for EME!
Idea 1
The wide angle dish must have really cost a bundle! So what application might be served by this big dollar gem? SETI. Search for little green men! Now this doesn't do anything for me, but some people really want to do this. The movie "Contact" with Jody Foster is a interesting fictionalized story about this. So how would this work? If you look closely at the picture above, and I have more close up pictures, this big puppy is on skids that move along a short track and have been locked in place for many years, looking South.
This track could be extended a bit more to the left (West) and this wide angle dish moved with a big winch to look straight West. Behind this dish are a three stout angle steel beams the set the angle. If these are adjusted so that the dish looks straight upwards, you will have a wide angle sky searching dish that is constantly receiving overhead signals over an ~ 90 degree wide path as the earth rotates each day and orbits the Sun each year, called drift scanning.. And if a new elevation pivot was added, the northern end could be raised and lowered occcasionally permitting this dish to scan the complete visible sky at this 39.5 degree latitude.
The convex feed system above the dish houses the C band LNAs, one for each satelllite being received. Just replace these feeds with a multitude of patches between 400 MHz and 6 GHz and port the data received to the high speed Internet at the colocated data service center! Radio Astronomy sky surveys would use the same data.
Idea 2
I was contacted recently about supplying a 10' dish system to a University to track student built $40K Microsats. Some more Toilet brainstorming, and I came up with this solution. There are four 16 foot dishes on the site. One is on a broken motorized Altazimuth mount, One is on a working motorized Altazimuth mount. The other two 16' dishes are on fixed but wrench moveable mounts. I could make four large versions of my famous clothesline mounts and removing the 16' dishes from their present limited motion mounts, attach each of them to a new full motion mount. But I have invented a new 3 axis mount that is far simpler than anything ever made, is more stable and has no blind spots like all the two axis mounts have.
Triband patches between 400 MHz and 6 GHz would be placed at the prime focus of each 16' dish and port the data received to the high speed Internet at the colocated data service center!
Idea 3
Any satellite traveling over the Denver area could have "transmit" commands sent to it and the stored telemetry data quad redundantly received and ported to the Internet. Even miltary and satellites carrying highly proprietary data could be handled if end to end encryption were employed. In a former life I led a small group of engineers developing a Type 2 encryptor for the National Security Agency (NSA).
Software Antenna Design
Building an antenna used to be a major project. And testing them was even more difficult; usually the antenna builder was confident of success if he got a high RST score consistently. But things are different now. You can input all the parameters of your antenna in one of several NEC-2 based software systems, and get the results almost immediately, then play some "what if" games to see how things really work. Some antenna designing software is reiterative and will actually take your basic antenna parameters and optimize them for you. You soon learn that a High RST is more an accident of location rather than a proof of antenna perfection. I generally model the antenna extensively before I ever cut the first wire or cut the aluminum tuibing. The ARRL Antenna Manuals give away some older antenna modeling software. Newer antenna modeling software ranges from free to $150 or more.
I am currently very interested in the software design of antenna arrays. With the selection of the proper values, I found an array of 3 horizontal 40M dipoles whose pattern I can not only steer in Azimuth but also in Elevation, making it go from a very low angle of radiation "DXers Dream" to a "Cloud Warmer", beaming the signal straight up and down for local ragchews on a DX band.