After many months, even years, I finally got up the courage to give a CQ using Morse Code. Much to my terror, David Nadel - KD2OY, returned my call and we had a short QSO. It was short, mostly because I was so nervous that I didn't know what to say!
I would really like to thank a couple of guys who have provided a LOT of encouragement and support: Dave Meier (N4MW) and Armand Hamel (WA1UQO). I would have abandoned CW long ago if it weren't for these 2 guys!
The 1st contact has been logged - onward and onward!!!
73 de KJ4WLH
Saturday, November 24, 2012
Monday, November 19, 2012
Antenna Modeling – The Practical Use
What do these software products all have in common: EZNec, cocoaNEC, NEC 2, and NEC-Win?
No, the answer is not "3"; the correct answer is "2"! Yes, really - I'm not kidding…
One of my favorite things to do in Amateur Radio is trying to model the "perfect" antenna. I've "invested" (or wasted depending upon whom you ask!) a lot of time with EZNec (on Windows) and cocoaNEC (on Mac) and I really enjoy them a lot. I've often asked myself questions like:
I had to opportunity to "design" my own dipole. How tricky can that be you ask? As tricky as you want to make it. Since I knew how to use EZNec and cocoaNEC, I didn't just want a flattop dipole with it's 70+ Ohm feedpoint and 1.8+ SWR across the frequency band for 40m (see Figure 1). I used cocoaNEC to model a dipole, sized for 40m, about 45’ above the ground – which was very close to my QTH’s backyard setup – to see what a regular dipole would look like.
Since the 40m antenna is lower to the ground than the optimal height, I started changing my model by changing the legs of the dipole. I started off by slightly raising the legs by 10 degrees at the insulator and saw the feedpoint resistance drop a little. Eventually, I managed to find a nice combination of dipole leg “angle”, based upon the height over ground. I was also able to adjust the length of the legs to get the lowest SWR across the lower part of the 40m band. The SWR model is show in Figure 2.
During November of 2012, I managed to find some time to hang my 40m dipole based upon the calculations. I hung the wires and balun, trimmed, re-hung, trimmed, re-hung, etc. for a few hours. When I was finished, I used my analyzer to see just how close I was. Figure 3 shows the graph based upon the numbers my analyzer showed. The curve is about as close to a match (compare Figure 3 to Figure 2) as I could ever expect! I was so pleased – it has been a while since a project that I’m working on has turned out so well!
As I’m writing this, I still can’t believe just how accurate the EZNec and cocoaNEC programs are. I know it’s not rocket science, but I was able to design an antenna based on my requirements, build the antenna, and finally, measure to see that it matches the antenna design.
Once all the measurements were complete, I got right on the air. The ARRL was having a Sweepstakes competition and the contacts were rolling in! Perhaps band conditions were great or my antenna worked even better than I’d dreamed ☺ Either way, there were many contacts to be made! It was a great way to end a weekend!
If you think that you’d be interested in trying to model your own antenna, RARC will be offering a 3 or 4 week “Introduction to EZNec Antenna Modeling” class in the late winter/early spring.
73 de KJ4WLH
- They are intimidating, obscure, and un-intelligible software programs somehow related to Amateur Radio.
- They each provide a means to use mathematical sets of formulas to simulate antennas in the "real world."
- Electrical Engineers, PhD's, Nerds, and the socially unacceptable are the only humans who know the "secret and arcane" art of antenna modeling using these software tools.
- These are very expensive software products, well out of the reach of a typical Ham.
No, the answer is not "3"; the correct answer is "2"! Yes, really - I'm not kidding…
One of my favorite things to do in Amateur Radio is trying to model the "perfect" antenna. I've "invested" (or wasted depending upon whom you ask!) a lot of time with EZNec (on Windows) and cocoaNEC (on Mac) and I really enjoy them a lot. I've often asked myself questions like:
- I wonder what that dipole would look like in my back yard?
- What does a 3 element, 2-meter yagi do at 8' above the ground?
- How does a j-pole really radiate?
- Can I make my own Buckmaster (and save a TON of $$)?
I had to opportunity to "design" my own dipole. How tricky can that be you ask? As tricky as you want to make it. Since I knew how to use EZNec and cocoaNEC, I didn't just want a flattop dipole with it's 70+ Ohm feedpoint and 1.8+ SWR across the frequency band for 40m (see Figure 1). I used cocoaNEC to model a dipole, sized for 40m, about 45’ above the ground – which was very close to my QTH’s backyard setup – to see what a regular dipole would look like.
 |
| Figure 1 - 40m Dipole "Flat Top" |
Since the 40m antenna is lower to the ground than the optimal height, I started changing my model by changing the legs of the dipole. I started off by slightly raising the legs by 10 degrees at the insulator and saw the feedpoint resistance drop a little. Eventually, I managed to find a nice combination of dipole leg “angle”, based upon the height over ground. I was also able to adjust the length of the legs to get the lowest SWR across the lower part of the 40m band. The SWR model is show in Figure 2.
 |
| Figure 2 - 40m "V" Dipole |
During November of 2012, I managed to find some time to hang my 40m dipole based upon the calculations. I hung the wires and balun, trimmed, re-hung, trimmed, re-hung, etc. for a few hours. When I was finished, I used my analyzer to see just how close I was. Figure 3 shows the graph based upon the numbers my analyzer showed. The curve is about as close to a match (compare Figure 3 to Figure 2) as I could ever expect! I was so pleased – it has been a while since a project that I’m working on has turned out so well!
| Figure 3 - Actual Analyzer Measurements at my QTH |
As I’m writing this, I still can’t believe just how accurate the EZNec and cocoaNEC programs are. I know it’s not rocket science, but I was able to design an antenna based on my requirements, build the antenna, and finally, measure to see that it matches the antenna design.
Once all the measurements were complete, I got right on the air. The ARRL was having a Sweepstakes competition and the contacts were rolling in! Perhaps band conditions were great or my antenna worked even better than I’d dreamed ☺ Either way, there were many contacts to be made! It was a great way to end a weekend!
If you think that you’d be interested in trying to model your own antenna, RARC will be offering a 3 or 4 week “Introduction to EZNec Antenna Modeling” class in the late winter/early spring.
73 de KJ4WLH
Sunday, November 18, 2012
40m V Dipole - It's up and awesome!
Well, it sure has taken me a while, but I decided that I needed to remove my doublet. I was doing some antenna modeling with EZNec and CocoaNec and saw just how horrible the actual antenna resonance was and realized that even though I could get my tuner to match; the doublet was still not exactly working very efficiently :(
So, those thoughts as well as the desire to run a little bit of power in the future and CW, caused me to re-think my antenna situation. After much fun, deliberation, and consternation, I decided that I'd bite the bullet and build 1 - 40m dipole and 2 - 20m dipoles. I went to Balun Designs and picked up a couple of baluns: the 1116de (for 40m) and the 1115e (for 20m). Wireman got the call for some more #531 wire and I was in business.
I'd be doing quite a bit of antenna modeling and decided that I did not want a flat-top dipole, I wanted a V that I could "control" the angles a little bit. So, I came up with something of a compromise - I tied a 50' piece of rope between the insulators, hung the wire from the insulators, and the antenna balun hung down in the air between the wires. It sounds more complicated than it really is - the rope just let me accurately define the length of the legs of the dipole. It also meant that I could get the Impedance down to around 48 - 52 ohms or so :)
This afternoon I got to go outside and work on my latest adventure. I think I dropped and raised the balun and wires about 7 or 8 times, but at the end, it was certainly worth it! I was trying to get my lowest SWR around the 7.150 mark and was only just a little bit off. I guess I could have kept cutting, but after a while you're just in the right ball park and it's time to call it a day :)
I wired it up, connected to some LMR 400 and listened around for a little while. Perhaps conditions were just excellent today, but I had MANY, MANY stations around that were S9+40. I listened to a contest running and gave a shout out, immediate response with a "Hey, your 60+ over here in Annapolis" - I replied with a "Thanks for the station report, new dipole and I'm very pleased!" I'm also very pleased that my rig was pulling more amps than I'd ever seen - FINALLY, an antenna that is NOT a compromise - just works!
73 de KJ4WLH
So, those thoughts as well as the desire to run a little bit of power in the future and CW, caused me to re-think my antenna situation. After much fun, deliberation, and consternation, I decided that I'd bite the bullet and build 1 - 40m dipole and 2 - 20m dipoles. I went to Balun Designs and picked up a couple of baluns: the 1116de (for 40m) and the 1115e (for 20m). Wireman got the call for some more #531 wire and I was in business.
I'd be doing quite a bit of antenna modeling and decided that I did not want a flat-top dipole, I wanted a V that I could "control" the angles a little bit. So, I came up with something of a compromise - I tied a 50' piece of rope between the insulators, hung the wire from the insulators, and the antenna balun hung down in the air between the wires. It sounds more complicated than it really is - the rope just let me accurately define the length of the legs of the dipole. It also meant that I could get the Impedance down to around 48 - 52 ohms or so :)
This afternoon I got to go outside and work on my latest adventure. I think I dropped and raised the balun and wires about 7 or 8 times, but at the end, it was certainly worth it! I was trying to get my lowest SWR around the 7.150 mark and was only just a little bit off. I guess I could have kept cutting, but after a while you're just in the right ball park and it's time to call it a day :)
I wired it up, connected to some LMR 400 and listened around for a little while. Perhaps conditions were just excellent today, but I had MANY, MANY stations around that were S9+40. I listened to a contest running and gave a shout out, immediate response with a "Hey, your 60+ over here in Annapolis" - I replied with a "Thanks for the station report, new dipole and I'm very pleased!" I'm also very pleased that my rig was pulling more amps than I'd ever seen - FINALLY, an antenna that is NOT a compromise - just works!
73 de KJ4WLH
Wednesday, October 24, 2012
2012 BSA Jamboree on the Air
2012 Boy Scout Jamboree on the Air (BS-JOTA)
Link to Pictures:
The BS-JOTA was held on Saturday, October 20th from 8:30 a.m. until 5:15 p.m. at the Cub Adventure Camp, located in Maidens, VA. The BSA Heart of Virginia Council's Cardinal District held a Cub Scout "Cub Olympics" during the weekend of October 19th - 21st. Approximately 1,200 Cub Scouts and their families camped during the weekend.
I'd like to thank the following individuals and sponsors:
The BS-JOTA team set up an HF station, D-Star station, VHF/UHF station, and IRLP station over the day. Contacts on HF were made all over the United States, Canada, and even over to Europe! Austin Thomas (N4CVA), a Boy Scout was instrumental in showing the Cub Scouts how to make the "correct" contact - and MANY boys did make HF contacts throughout the day! Austin did a fantastic job!
When large numbers of Cub Scouts showed up at the BS-JOTA station, Win Grant (WA4SSG) and David Thomas (KB4IQT) would take small groups a few dozen yards away from each other and they would use HT's to make contacts with each other. Needless to say, a LOT of "local" contacts were made as well!
Armand Hamel (WA1UQO) brought one of the most fun instruments of the day - a key and code practice oscillator! I believe Armand's key was the MOST USED piece of equipment - at least 100 scouts touched the key and the just LOVED making it squeak and squeal. One "lesson" shared with the boys was teaching them how to say "HI" in Morse Code: ". . . . . ." The best part of having the boys learn to key "HI" was telling them that they could use their flashlights and do the SAME THING with the light - they could "talk" to each other in "secret code"!! Big smiles, you could almost see the wheels turning in their heads as they figured out what they were going to do later that night.
The D-Star station was connected to the BS-JOTA reflector (REF033A) and occasionally to the Atlanta reflector (REF030C). D-Star contacts were light as most of the operators were VERY busy helping the scouts talk either on HF or HT's in the small groups. There were a lot of stations making contacts throughout the world on the BS-JOTA reflector: Argentina, UK, New Zealand, and many others. It was great hearing all the different countries and the accents of the stations were really interesting to the scouts as well.
As the afternoon wore on, the Scouts (and the operators) were getting tired! The HF station was shut down and we linked the RATS UHF IRLP node to the BS-JOTA node (9091). Scout after Scout after Scout made contacts primarily with other scouts in Canada and Texas. At least 20 Scouts made contacts with other Scouts; and an occasional Ham as well - all over IRLP!
The day went great! At least 50 - 60 Scouts made contacts with someone, mostly with other Scouts. The day was beautiful. The volunteers made the day go smoothly and were so generous with their time. My final thoughts are these - I really enjoy ham radio and I also sharing my passion for this great hobby of ours with people who are open to new ideas! We are the ones who make the entrance to our hobby "friendly" and "welcoming". Get out there and "welcome" someone into your hobby today!
73 de KJ4WLH
Jim Bates, Troop 876, RARC Member, RATS Member
Link to Pictures:
The BS-JOTA was held on Saturday, October 20th from 8:30 a.m. until 5:15 p.m. at the Cub Adventure Camp, located in Maidens, VA. The BSA Heart of Virginia Council's Cardinal District held a Cub Scout "Cub Olympics" during the weekend of October 19th - 21st. Approximately 1,200 Cub Scouts and their families camped during the weekend.
I'd like to thank the following individuals and sponsors:
- Richmond Amateur Radio Club (RARC)
- Sponsored the BS-JOTA station
- Provided HF equipment
- D-Star repeater access
- Richmond Amateur Telecommunication Society (RATS)
- UHF IRLP repeater access
- Cardinal District, Heart of Virginia Council
- Provided facilities for the BS-JOTA station
- Allowed the station to be part of the "Cub Olympics"
- Volunteers (in callsign order)
- KB4IQT - David Thomas - Troop 832
- KK4DWX - Bob Kendig
- N4CVA - Austin Thomas - Troop 832
- WA1UQO - Armand Hamel
- WA4SSG - Win Grant
- Mac McNeer(K4YEF)
- Use of the RARC Club callsign: W4ZA
The BS-JOTA team set up an HF station, D-Star station, VHF/UHF station, and IRLP station over the day. Contacts on HF were made all over the United States, Canada, and even over to Europe! Austin Thomas (N4CVA), a Boy Scout was instrumental in showing the Cub Scouts how to make the "correct" contact - and MANY boys did make HF contacts throughout the day! Austin did a fantastic job!
When large numbers of Cub Scouts showed up at the BS-JOTA station, Win Grant (WA4SSG) and David Thomas (KB4IQT) would take small groups a few dozen yards away from each other and they would use HT's to make contacts with each other. Needless to say, a LOT of "local" contacts were made as well!
Armand Hamel (WA1UQO) brought one of the most fun instruments of the day - a key and code practice oscillator! I believe Armand's key was the MOST USED piece of equipment - at least 100 scouts touched the key and the just LOVED making it squeak and squeal. One "lesson" shared with the boys was teaching them how to say "HI" in Morse Code: ". . . . . ." The best part of having the boys learn to key "HI" was telling them that they could use their flashlights and do the SAME THING with the light - they could "talk" to each other in "secret code"!! Big smiles, you could almost see the wheels turning in their heads as they figured out what they were going to do later that night.
The D-Star station was connected to the BS-JOTA reflector (REF033A) and occasionally to the Atlanta reflector (REF030C). D-Star contacts were light as most of the operators were VERY busy helping the scouts talk either on HF or HT's in the small groups. There were a lot of stations making contacts throughout the world on the BS-JOTA reflector: Argentina, UK, New Zealand, and many others. It was great hearing all the different countries and the accents of the stations were really interesting to the scouts as well.
As the afternoon wore on, the Scouts (and the operators) were getting tired! The HF station was shut down and we linked the RATS UHF IRLP node to the BS-JOTA node (9091). Scout after Scout after Scout made contacts primarily with other scouts in Canada and Texas. At least 20 Scouts made contacts with other Scouts; and an occasional Ham as well - all over IRLP!
The day went great! At least 50 - 60 Scouts made contacts with someone, mostly with other Scouts. The day was beautiful. The volunteers made the day go smoothly and were so generous with their time. My final thoughts are these - I really enjoy ham radio and I also sharing my passion for this great hobby of ours with people who are open to new ideas! We are the ones who make the entrance to our hobby "friendly" and "welcoming". Get out there and "welcome" someone into your hobby today!
73 de KJ4WLH
Jim Bates, Troop 876, RARC Member, RATS Member
Tuesday, September 25, 2012
6m loop problem - BIOLOGICAL!!!
Wow, I guess I just live and learn...
I few weeks, perhaps months now I suppose, my 6m loop stopped being resonant on 50.125. Really weird - I mean, it looked fine and was hanging right where it had been for a while and I hadn't done ANYTHING with it except use it. I really didn't understand what was going on.
So, last weekend I dropped the antenna and tried to re-adjust it so that it would be resonant (again!) on 50.125 +/-. It was really strange; I'd tune/adjust it, raise it up 20' or so, think that I'd just about got it and then it would change on me. It was really frustrating. So, I adjusted it "one last time" and hauled it up into the air.
Wouldn't you know; it wouldn't tune on my 9100! My 7600 would tune it up, but that didn't make a whole lot of sense to me. I used my antenna analyzer and it was around 3:1 match!!! WHAT??!!?? ARGHH!!
(In case you haven't followed my rants recently, I've have a bad run of radio luck...)
Time passes... And now it's this afternoon - beautiful day and I have about an hour to kill until my next activity kicks up; sounds like a good time to take a look at the 6m loop problem. So, I dropped the antenna again, got out the M2 6m loop PDF and adjusted all the parts to the specs in the PDF. HOWEVER, when I was banging on the metal trying to shift parts around, ants started crawling out of the aluminum tubing! A LOT of ANTS - I mean, tons!!! How strange? Anyway, I kept on making noise and gave them a little while to clear out.
I went back later and it seemed like they'd moved on - I guess most of them did anyway. So I hauled the antenna back up in the air and guess what - 1.2:1 match :)
My "moral of the story is this", there is always a reason - it just might be stranger than what you think it is!
73 de KJ4WLH
I few weeks, perhaps months now I suppose, my 6m loop stopped being resonant on 50.125. Really weird - I mean, it looked fine and was hanging right where it had been for a while and I hadn't done ANYTHING with it except use it. I really didn't understand what was going on.
So, last weekend I dropped the antenna and tried to re-adjust it so that it would be resonant (again!) on 50.125 +/-. It was really strange; I'd tune/adjust it, raise it up 20' or so, think that I'd just about got it and then it would change on me. It was really frustrating. So, I adjusted it "one last time" and hauled it up into the air.
Wouldn't you know; it wouldn't tune on my 9100! My 7600 would tune it up, but that didn't make a whole lot of sense to me. I used my antenna analyzer and it was around 3:1 match!!! WHAT??!!?? ARGHH!!
(In case you haven't followed my rants recently, I've have a bad run of radio luck...)
Time passes... And now it's this afternoon - beautiful day and I have about an hour to kill until my next activity kicks up; sounds like a good time to take a look at the 6m loop problem. So, I dropped the antenna again, got out the M2 6m loop PDF and adjusted all the parts to the specs in the PDF. HOWEVER, when I was banging on the metal trying to shift parts around, ants started crawling out of the aluminum tubing! A LOT of ANTS - I mean, tons!!! How strange? Anyway, I kept on making noise and gave them a little while to clear out.
I went back later and it seemed like they'd moved on - I guess most of them did anyway. So I hauled the antenna back up in the air and guess what - 1.2:1 match :)
My "moral of the story is this", there is always a reason - it just might be stranger than what you think it is!
73 de KJ4WLH
Sunday, September 16, 2012
2m Stack Complete - Results, Hmmm...
Well, the 2m stack is hanging the back yard and I guess it's ok. You know, I keep thinking that the effort will mean something substantial - though I know it isn't really. So, here's what I figure out:
- 3db gain for a pair of loops +/- is a LOT of trouble for half an S-Unit.
- I think my 2m pre-amp is broken :(
- My LMR-400 N connector pins don't fit my LMR-400 coax...
- ARGHHH...
Sometimes I wonder why I do these things! I'm super frustrated that the pre-amp isn't working. I'm pretty much ready to stop purchasing anything used from folks I don't know. I mean, it was working on the bench - so, one everything it cable'd up, tie wrapped in place, and hanging up in the air - it decides NOT to work? What's up with that?
So, all the gear is done and I still hear the faint signals of N4MW's 2m beacon on 144.280. Pre-amp doesn't help at all and I guess sometime I'll figure out what my "lesson learned" is.
All I know is that today, I'm really tired of failure...
73 de KJ4WLH
Thursday, September 13, 2012
2m HO Loop Rebuild Project
I had a really high SWR on my 6m loop which meant that I needed to drop it to see what was going on. Since the loop mounting system also holds my 2m and 70cm loops, I decided to rebuild my 2m stack.
I have a 2m pre-amp that I've wanted to get in action for a while. I also have a M2 2m cable phasing set, which would be really great if I had a 2nd loop. So, I placed my order with HEO and ordered the final piece.
My goal is to have a pair if M2 2m HO loops, with a pre-amp mounted and up in the air by the end of the weekend.
Wish me luck!
73de KJ4WLH
I have a 2m pre-amp that I've wanted to get in action for a while. I also have a M2 2m cable phasing set, which would be really great if I had a 2nd loop. So, I placed my order with HEO and ordered the final piece.
My goal is to have a pair if M2 2m HO loops, with a pre-amp mounted and up in the air by the end of the weekend.
Wish me luck!
73de KJ4WLH
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