Posts Tagged ‘WSPR’
VE7CNF / 630m Mobile … almost.
September 4th, 2017 | 
Author:  |
| If you think 160m mobile is a challenge... |
Hot on the heels of his recent 630m maritime adventure, Toby (VE7CNF), continued to demonstrate the flexibility of his small 20W 630m portable system with an afternoon of fixed 'mobile' activity from his vehicle.
Local 630m op's in-boxes received a surprise alert on Tuesday:
"Are any of you available on Tuedsay for a 630m land mobile test with VE7CNF/7?"
Toby set things up at Sea Island's Iona Regional Park, situated on the ocean's edge just north of Vancouver International Airport. This gave him a good shot to several of the local 630m ops around the local region.
When Canadian amateurs first approached RAC and Industry Canada for a slice of spectrum near 500KHz, the main goal was to secure a frequency range that would support excellent groundwave propagation for a possible future emergency data network. Whether this will ever happen or not remains to be seen, but Toby's afternoon outing, along with the recent 630 marine mobile activity certainly helps to demonstrate the potential for the band to provide reliable signals with relatively small antennas and low erp.
Toby's basic transverter is rather unique in that the transmitter's FET power mixer also passes signals backwards to function in the receive mode:
"I’ve developed a 630m band linear transverter that produces 30W of transmitter power. It has no power amplifier and draws only 175 mA from a 12V power supply. It works for both transmit and receive with no T/R antenna relays or switching circuits.
I’ve used a bidirectional high-power mixer circuit to directly take 100W of power from a 160m band transceiver and produce useful output power on 630m. For receive, 630m signals can pass backwards through the circuit and are up-converted to 160m.
My transverter is actually the small box on the dash above the steering wheel. The gear in the back near the variometer is used only during setup to resonate the antenna. It's a signal generator and oscilloscope. The AC transformers are just an isolation transformer that I need to make the test equipment work with my 12V-to-AC inverter."
 |
| Toby VE7CNF/7 at Iona |
"VE7CNF/7 Operation was from the Iona Beach area near Vancouver, grid CN89jf. The location is right beside salt water. There are no nearby power lines so rx noise was S0. Operation was in daylight, around 4 pm local time. Signals were excellent and all CW was easy copy.
On 475.0 kHz CW I managed to work Roger VE7VV (CN88il, him 529, me 579) and Jack VA7JX (CN79kv, him 569, me 579). I heard Steve VE7SL (CN88iu) at 599 briefly, then he had a problem and we didn't complete a QSO. He gave me 599 later by email.
The antenna is about 24 ft high and the fishing-rod-and-wire top load is pulled forward about 8 ft. The matching circuit is a loading coil, variometer, and autotransformer. My Tx power was 20W TPO and estimated EIRP 75 mW. The rig was my home brew transverter with an IC-7410."
"After CW I ran WSPR for a while, 23:42 to 00:08 UTC (4:42 to 5:08 pm local). WSPRnet lists my spots as my home QTH CN89ng, but I did have CN89jf entered in WSJT-X. I got spots from WI2XJQ -17, VE7BDQ +14, VE7AB +6, VE7VV +1, W7IUV -26, WH2XGP -30 dB. I also decoded WSPR from VE7VV +7 and VA7JX +9 dB."
On 475.0 kHz CW I managed to work Roger VE7VV (CN88il, him 529, me 579) and Jack VA7JX (CN79kv, him 569, me 579). I heard Steve VE7SL (CN88iu) at 599 briefly, then he had a problem and we didn't complete a QSO. He gave me 599 later by email.
The antenna is about 24 ft high and the fishing-rod-and-wire top load is pulled forward about 8 ft. The matching circuit is a loading coil, variometer, and autotransformer. My Tx power was 20W TPO and estimated EIRP 75 mW. The rig was my home brew transverter with an IC-7410."
"After CW I ran WSPR for a while, 23:42 to 00:08 UTC (4:42 to 5:08 pm local). WSPRnet lists my spots as my home QTH CN89ng, but I did have CN89jf entered in WSJT-X. I got spots from WI2XJQ -17, VE7BDQ +14, VE7AB +6, VE7VV +1, W7IUV -26, WH2XGP -30 dB. I also decoded WSPR from VE7VV +7 and VA7JX +9 dB."
"This was great fun. I'll have to try more locations, and see if I can improve the equipment for easier setup. I had great copy on Roger 529 and Jack 569. Working Jack was a surprise, and his signal was excellent. Being beside salt water is magic. Rx noise was so low at that location, near Iona Beach CN89jf."
Our 'new' band continues to demonstrate its ability to offer exciting opportunities to experimenters, home-brewers and DXers alike and for those with the creative imagination to push new boundaries, who knows where one of the first frequency ranges to be used by amateurs back in the 20's might eventually take us.
I can visualize, at some point in the future, the usefulness of a province-wide 630m emergency comms network utilizing a basic 'grab and go' system based on much of Toby's demonstrated work.
If you are a Canadian amateur why not join the fun on 630m now? U.S. amateurs will be arriving shortly and when they do, things should be getting even more exciting on the new band!
Digital Revolution Or Evolution?
 |
| courtesy: KD0WTE |
A recent reflector posting tended to confirm a rather intriguing trend that I have also been noticing over the past few years.
The poster lamented the fact that he often found very few or even no CW / SSB signals on the HF bands while at the same time seeing lots of activity throughout the digital portion of the bands.
It does seem like there is far less CW and phone activity on the HF bands now, than there was a few years ago and there is no question that digital activity has soared. Whether it's RTTY, PSK31, JT65, WSPR, JT9 or others, these digital signals are always prominent and, band plan or not, are slowly migrating further in the band as activity increases ... but is this the reason for the decline of traditional modes?
The digital weak-signal modes make these extremely popular for a number of reasons. Nowadays, many amateurs are living in antenna-restricted communities and are forced to develop smaller, lower and less effective stealthy antenna systems if they wish to get on the air and make contacts. Most of these modes perform well with minimal amounts of power and are capable of hearing well into the noise ... and unless you live out in the country, with well-separated neighbours, we all know that noise is increasing at horrific levels almost everywhere. These two factors alone might well explain much of the growth in digital activity.
Licencing requirements have also been slowly evolving and today, getting a ticket is much easier than it was several decades ago ... and in many cases, without the requirements of knowing anything about CW. Every month, North Americans see a large number of new amateurs, many with no code skills and possibly not much interest in acquiring them. From my own local observations, most of these new amateurs usually head straight to FM on the VHF/UHF bands and have little knowledge of or interest in HF radio. These factors must also play into the demise of activity on the traditional HF modes as well.
We also shouldn't overlook the influence that Old Sol is having on our HF bands as well. Solar Cycle 24 (begun in 2008) has been one of the poorest on record and continues to generate month after month of terribly poor HF propagation. As a young SWL who listened in Cycle 19, (the largest on record), I can vouch for the relationship between HF activity and good propagation. Those were amazing days, when 20 and 15m would stay open all night long ... even 10m would often still be open with F2 propagation at midnight towards VK and ZL! Everyday, month after month, the bands were simply bulging with activity, from end to end ... high solar flux numbers bring high activity numbers and we are now experiencing the downside effects of what happens when the sun dreadfully underperforms. The only exception to band-bulging activity today seems to be limited to major contest weekends only. Where these people go the rest of the time is a mystery.
There are surely other reasons as well for the gradual decline of traditional-mode HF activity, including the fact that the general ham population is getting older. Large numbers of stations are simply 'going away' as interest or opportunity declines and as more of the aging traditional-mode ops go 'SK'. I know of several hams that have just given-up because of insurmountable increases in their local noise floors. Our new and usually younger hams, have largely grown up in the 'digital age' and for those that do find themselves exploring the HF bands without CW skills, might logically settle into the digital modes first.
Things are changing quickly, of that there is no doubt. Last summer, on 50mHz, I noticed a large increase in the number of dedicated CW operators moving to JT65 and JT9 during openings and this summer has already seen another huge migration from one mode to the other.
Although this year's Sporadic-E season is just getting started, I have already heard many more countries on JT65 than I have on the traditional modes (Japan, Philippines, China, Formosa, Alaska, Venezuela, Cuba, Brazil). Yesterday I listened to a PY calling CQ on CW for some length, with no takers, while it seemed most of the usual west coast ops were watching the digital band. I fear that many good QSO possibilities will be lost as more stations switch to the much slower digital modes ... on 6m, many of the openings last for a very short time making CW or SSB the quickest way to complete a contact. The other problem I notice this summer is that there are several JT sub-modes and it is often difficult or impossible to figure out which mode is being used let alone having the time to switch to the other mode before signals are gone ... perhaps a case of having too much of a 'good thing'? Hopefully one mode will emerge as the '6m standard' so all are on the same page.
What will be the long-term outcome of these changes remains to be seen but I suspect we'll see more and more of our HF CW and SSB spectrum space gradually shrinking to make room for more digital activity, likely to become the dominant modes eventually.
As a life-time, almost exclusive CW operator since age 15, I find this somewhat disheartening but must admit that over the past few years, I have found my own level of weak-signal digital activity increasing by leaps and bounds. These are powerful, capable modes and offer amateurs new and exciting challenges from VLF to nanowaves. Are they as exciting as my much-loved CW? Ask me in a couple of years!
Digital Revolution Or Evolution?
|
| courtesy: KD0WTE |
A recent reflector posting tended to confirm a rather intriguing trend that I have also been noticing over the past few years.
The poster lamented the fact that he often found very few or even no CW / SSB signals on the HF bands while at the same time seeing lots of activity throughout the digital portion of the bands.
It does seem like there is far less CW and phone activity on the HF bands now, than there was a few years ago and there is no question that digital activity has soared. Whether it's RTTY, PSK31, JT65, WSPR, JT9 or others, these digital signals are always prominent and, band plan or not, are slowly migrating further in the band as activity increases ... but is this the reason for the decline of traditional modes?
The digital weak-signal modes make these extremely popular for a number of reasons. Nowadays, many amateurs are living in antenna-restricted communities and are forced to develop smaller, lower and less effective stealthy antenna systems if they wish to get on the air and make contacts. Most of these modes perform well with minimal amounts of power and are capable of hearing well into the noise ... and unless you live out in the country, with well-separated neighbours, we all know that noise is increasing at horrific levels almost everywhere. These two factors alone might well explain much of the growth in digital activity.
Licencing requirements have also been slowly evolving and today, getting a ticket is much easier than it was several decades ago ... and in many cases, without the requirements of knowing anything about CW. Every month, North Americans see a large number of new amateurs, many with no code skills and possibly not much interest in acquiring them. From my own local observations, most of these new amateurs usually head straight to FM on the VHF/UHF bands and have little knowledge of or interest in HF radio. These factors must also play into the demise of activity on the traditional HF modes as well.
We also shouldn't overlook the influence that Old Sol is having on our HF bands as well. Solar Cycle 24 (begun in 2008) has been one of the poorest on record and continues to generate month after month of terribly poor HF propagation. As a young SWL who listened in Cycle 19, (the largest on record), I can vouch for the relationship between HF activity and good propagation. Those were amazing days, when 20 and 15m would stay open all night long ... even 10m would often still be open with F2 propagation at midnight towards VK and ZL! Everyday, month after month, the bands were simply bulging with activity, from end to end ... high solar flux numbers bring high activity numbers and we are now experiencing the downside effects of what happens when the sun dreadfully underperforms. The only exception to band-bulging activity today seems to be limited to major contest weekends only. Where these people go the rest of the time is a mystery.
There are surely other reasons as well for the gradual decline of traditional-mode HF activity, including the fact that the general ham population is getting older. Large numbers of stations are simply 'going away' as interest or opportunity declines and as more of the aging traditional-mode ops go 'SK'. I know of several hams that have just given-up because of insurmountable increases in their local noise floors. Our new and usually younger hams, have largely grown up in the 'digital age' and for those that do find themselves exploring the HF bands without CW skills, might logically settle into the digital modes first.
Things are changing quickly, of that there is no doubt. Last summer, on 50MHz, I noticed a large increase in the number of dedicated CW operators moving to JT65 and JT9 during openings and this summer has already seen another huge migration from one mode to the other.
Although this year's Sporadic-E season is just getting started, I have already heard many more countries on JT65 than I have on the traditional modes (Japan, Philippines, China, Formosa, Alaska, Venezuela, Cuba, Brazil). Yesterday I listened to a PY calling CQ on CW for some length, with no takers, while it seemed most of the usual west coast ops were watching the digital band. I fear that many good QSO possibilities will be lost as more stations switch to the much slower digital modes ... on 6m, many of the openings last for a very short time making CW or SSB the quickest way to complete a contact. The other problem I notice this summer is that there are several JT sub-modes and it is often difficult or impossible to figure out which mode is being used let alone having the time to switch to the other mode before signals are gone ... perhaps a case of having too much of a 'good thing'? Hopefully one mode will emerge as the '6m standard' so all are on the same page.
What will be the long-term outcome of these changes remains to be seen but I suspect we'll see more and more of our HF CW and SSB spectrum space gradually shrinking to make room for more digital activity, likely to become the dominant modes eventually.
As a life-time, almost exclusive CW operator since age 15, I find this somewhat disheartening but must admit that over the past few years, I have found my own level of weak-signal digital activity increasing by leaps and bounds. These are powerful, capable modes and offer amateurs new and exciting challenges from VLF to nanowaves. Are they as exciting as my much-loved CW? Ask me in a couple of years!
Amateur Radio …. sort of
Today was a busy day with a lot of commitments and a lot of chores and not much time for Amateur Radio. So what does an intrepid Amateur Radio op do? Put his tail between his legs and slink off into the distance? No, he does the next best thing - he engages in related activities.
I had a class this morning that meets one Saturday a month. It started last September and ends next month, and it runs from 9:00 AM to 1:00 PM. You can see that that's a good chunk of the day. So it was SOTABEAMS WSPRLite to the rescue! It's kind of like a Ronco counter top oven - "set it and forget it". So I hooked up my WSPRLite to my W3EDP, set it up for 200 milliWatts on 20 Meters and let it go to town!
I figured that I'd let it run, see how the W3EDP gets out and still do the things I had to do today.
This WSPRLite is so cool! It's a software defined WSPR beacon in a package about half the size of an Altoids tin. It's powered by the USB port of your computer. You pick the band and power output and hook it up to your antenna. You wait until 2 seconds past any even minute and you press the little black button on the right to kick things off. The beacon transmits for 110 seconds and then waits for the next opportunity when the frequency is clear. I set it so that it would randomly transmit about 20% of the time; and you can let it run for up to three days if you want.
In the meantime, yesterday, while checking my e-mail, I saw that Joe Everhart N2CX co-founder of the NJQRP Club was going to be activating Edison State Park for Parks on the Air. It's designator is KFF-1615 and it's all of about 15 minutes from my house. So I e-mailed Joe back with my cell phone number and told him to text me when he got there; and I would come out and meet him.
After class I came home and broke out the lawnmower and got the front yard done. As I was walking to the backyard, I felt my pocket buzz. I whipped out my phone and read a text that Joe was on site and setting up. I dropped the lawnmower like a hot potato and high tailed it to the park. After all, what QRPer in his right mind would miss the opportunity to talk with a QRP Legend, right? When I got there, I saw Joe had finished setting up and was operating from his car.
It was getting out all right! Into the midwest USA and into Europe on 200 milliWatts! The W3EDP seems to be doing OK!
It turned out to be a good day, after all. I got to attend my class, got my chores done and got to hob-nob with a QRP giant - while giving my wire antenna a check out at the same time!
And here I thought the day would be a bust, Amateur Radio-wise!
72 de Larry W2LJ
QRP - When you care to send the very least!
I had a class this morning that meets one Saturday a month. It started last September and ends next month, and it runs from 9:00 AM to 1:00 PM. You can see that that's a good chunk of the day. So it was SOTABEAMS WSPRLite to the rescue! It's kind of like a Ronco counter top oven - "set it and forget it". So I hooked up my WSPRLite to my W3EDP, set it up for 200 milliWatts on 20 Meters and let it go to town!
I figured that I'd let it run, see how the W3EDP gets out and still do the things I had to do today.
This WSPRLite is so cool! It's a software defined WSPR beacon in a package about half the size of an Altoids tin. It's powered by the USB port of your computer. You pick the band and power output and hook it up to your antenna. You wait until 2 seconds past any even minute and you press the little black button on the right to kick things off. The beacon transmits for 110 seconds and then waits for the next opportunity when the frequency is clear. I set it so that it would randomly transmit about 20% of the time; and you can let it run for up to three days if you want.
In the meantime, yesterday, while checking my e-mail, I saw that Joe Everhart N2CX co-founder of the NJQRP Club was going to be activating Edison State Park for Parks on the Air. It's designator is KFF-1615 and it's all of about 15 minutes from my house. So I e-mailed Joe back with my cell phone number and told him to text me when he got there; and I would come out and meet him.
After class I came home and broke out the lawnmower and got the front yard done. As I was walking to the backyard, I felt my pocket buzz. I whipped out my phone and read a text that Joe was on site and setting up. I dropped the lawnmower like a hot potato and high tailed it to the park. After all, what QRPer in his right mind would miss the opportunity to talk with a QRP Legend, right? When I got there, I saw Joe had finished setting up and was operating from his car.
If you click on the picture to get a better view, you will notice that mounted at the rear of the car was Joe's 16 foot crappie pole. He had a loading coil attached and ran wire to the top. He told me that this arrangement seems to work for him as well as a full blown 31 foot mast secured via a drive on mast support. And who am I not to take him at his word? Joe is quite the QRP innovator. It seems that not an issue of "QRP Quarterly" goes by without some kind of juicy tidbit from Joe. And if N2CX says it works, then by golly, you can be assured that it works!
When I got there, Joe was making contacts on 40 Meters with his KX3. He noticed the same thing that I think we're all keenly aware of, that 20 Meters seems to stink, lately. Anyway, we kibbitzed for a few minutes and then I took my leave after Joe's son Kevin took a few photos of us together. After all, he came all the way to Edison from his home to make QSOs and put KFF-1615 on the air, not shoot the breeze with W2LJ!
When I got home, before I started on the back yard, I raced downstairs to the shack and hooked up the KX3 to the HF9V and went looking for Joe. I listened on 7.034 MHz, where I saw him operating from during our visit, only to hear not a peep. Figuring that he changed bands, I checked both 30 Meters and then 20 Meters, Bingo on 14.062 MHz (goundwave)! I got Joe in my log and helped him towards making the minimum number of contacts he needed to qualify for an activation.
Before resuming lawn duty, I decided to check WSPRNet, to see how the WSPRLite was getting out.
It was getting out all right! Into the midwest USA and into Europe on 200 milliWatts! The W3EDP seems to be doing OK!
It turned out to be a good day, after all. I got to attend my class, got my chores done and got to hob-nob with a QRP giant - while giving my wire antenna a check out at the same time!
And here I thought the day would be a bust, Amateur Radio-wise!
72 de Larry W2LJ
QRP - When you care to send the very least!
Amateur Radio …. sort of
Today was a busy day with a lot of commitments and a lot of chores and not much time for Amateur Radio. So what does an intrepid Amateur Radio op do? Put his tail between his legs and slink off into the distance? No, he does the next best thing - he engages in related activities.
I had a class this morning that meets one Saturday a month. It started last September and ends next month, and it runs from 9:00 AM to 1:00 PM. You can see that that's a good chunk of the day. So it was SOTABEAMS WSPRLite to the rescue! It's kind of like a Ronco counter top oven - "set it and forget it". So I hooked up my WSPRLite to my W3EDP, set it up for 200 milliWatts on 20 Meters and let it go to town!
I figured that I'd let it run, see how the W3EDP gets out and still do the things I had to do today.
This WSPRLite is so cool! It's a software defined WSPR beacon in a package about half the size of an Altoids tin. It's powered by the USB port of your computer. You pick the band and power output and hook it up to your antenna. You wait until 2 seconds past any even minute and you press the little black button on the right to kick things off. The beacon transmits for 110 seconds and then waits for the next opportunity when the frequency is clear. I set it so that it would randomly transmit about 20% of the time; and you can let it run for up to three days if you want.
In the meantime, yesterday, while checking my e-mail, I saw that Joe Everhart N2CX co-founder of the NJQRP Club was going to be activating Edison State Park for Parks on the Air. It's designator is KFF-1615 and it's all of about 15 minutes from my house. So I e-mailed Joe back with my cell phone number and told him to text me when he got there; and I would come out and meet him.
After class I came home and broke out the lawnmower and got the front yard done. As I was walking to the backyard, I felt my pocket buzz. I whipped out my phone and read a text that Joe was on site and setting up. I dropped the lawnmower like a hot potato and high tailed it to the park. After all, what QRPer in his right mind would miss the opportunity to talk with a QRP Legend, right? When I got there, I saw Joe had finished setting up and was operating from his car.
It was getting out all right! Into the midwest USA and into Europe on 200 milliWatts! The W3EDP seems to be doing OK!
It turned out to be a good day, after all. I got to attend my class, got my chores done and got to hob-nob with a QRP giant - while giving my wire antenna a check out at the same time!
And here I thought the day would be a bust, Amateur Radio-wise!
72 de Larry W2LJ
QRP - When you care to send the very least!
I had a class this morning that meets one Saturday a month. It started last September and ends next month, and it runs from 9:00 AM to 1:00 PM. You can see that that's a good chunk of the day. So it was SOTABEAMS WSPRLite to the rescue! It's kind of like a Ronco counter top oven - "set it and forget it". So I hooked up my WSPRLite to my W3EDP, set it up for 200 milliWatts on 20 Meters and let it go to town!
I figured that I'd let it run, see how the W3EDP gets out and still do the things I had to do today.
This WSPRLite is so cool! It's a software defined WSPR beacon in a package about half the size of an Altoids tin. It's powered by the USB port of your computer. You pick the band and power output and hook it up to your antenna. You wait until 2 seconds past any even minute and you press the little black button on the right to kick things off. The beacon transmits for 110 seconds and then waits for the next opportunity when the frequency is clear. I set it so that it would randomly transmit about 20% of the time; and you can let it run for up to three days if you want.
In the meantime, yesterday, while checking my e-mail, I saw that Joe Everhart N2CX co-founder of the NJQRP Club was going to be activating Edison State Park for Parks on the Air. It's designator is KFF-1615 and it's all of about 15 minutes from my house. So I e-mailed Joe back with my cell phone number and told him to text me when he got there; and I would come out and meet him.
After class I came home and broke out the lawnmower and got the front yard done. As I was walking to the backyard, I felt my pocket buzz. I whipped out my phone and read a text that Joe was on site and setting up. I dropped the lawnmower like a hot potato and high tailed it to the park. After all, what QRPer in his right mind would miss the opportunity to talk with a QRP Legend, right? When I got there, I saw Joe had finished setting up and was operating from his car.
If you click on the picture to get a better view, you will notice that mounted at the rear of the car was Joe's 16 foot crappie pole. He had a loading coil attached and ran wire to the top. He told me that this arrangement seems to work for him as well as a full blown 31 foot mast secured via a drive on mast support. And who am I not to take him at his word? Joe is quite the QRP innovator. It seems that not an issue of "QRP Quarterly" goes by without some kind of juicy tidbit from Joe. And if N2CX says it works, then by golly, you can be assured that it works!
When I got there, Joe was making contacts on 40 Meters with his KX3. He noticed the same thing that I think we're all keenly aware of, that 20 Meters seems to stink, lately. Anyway, we kibbitzed for a few minutes and then I took my leave after Joe's son Kevin took a few photos of us together. After all, he came all the way to Edison from his home to make QSOs and put KFF-1615 on the air, not shoot the breeze with W2LJ!
When I got home, before I started on the back yard, I raced downstairs to the shack and hooked up the KX3 to the HF9V and went looking for Joe. I listened on 7.034 MHz, where I saw him operating from during our visit, only to hear not a peep. Figuring that he changed bands, I checked both 30 Meters and then 20 Meters, Bingo on 14.062 MHz (goundwave)! I got Joe in my log and helped him towards making the minimum number of contacts he needed to qualify for an activation.
Before resuming lawn duty, I decided to check WSPRNet, to see how the WSPRLite was getting out.
It was getting out all right! Into the midwest USA and into Europe on 200 milliWatts! The W3EDP seems to be doing OK!
It turned out to be a good day, after all. I got to attend my class, got my chores done and got to hob-nob with a QRP giant - while giving my wire antenna a check out at the same time!
And here I thought the day would be a bust, Amateur Radio-wise!
72 de Larry W2LJ
QRP - When you care to send the very least!
Comparing two antennas with WSPR
 |
| Ultimate 3S with 5-band relay module in front, variable LM2596 power supply (with voltmeter) for the power amplifier behind left, a variable LM2596 supply set for 5 Volts for the Ultimate 3S in the middle, and the antenna switch to the right in the back. |
WSPR – The system for Weak Signal Propagation Reporter makes it easy to compare antennas if your transmitter can easily switch antennas. The system shown here can send on antenna 1 for almost two minutes and then switch immediately to antenna 2 for the next transmission.
The Ultimate 3S already has software that supports that and application note 3 from QRPLabs (Controlling additional relays using the Ultimate3S “Aux”) describes how. I built mine following that note and the experience from EA1CDV.
The circuit is controlled from pin D7 and consists of a transistor, a relay, a resistor and an electrolytic capacitor. In addition I have two LEDs that indicate which antenna which is in use. In the first picture the green LED in the back right under the BNC antenna connector shows that antenna 1 is connected.
In the next picture, the whole layout is shown a little better. In this case LED 2 is lit, the faint yellow one. It sits right under the additional SMA antenna connector in the top left-hand corner that I had to fit.
I have used this setup for a few days now on 7, 10, 14, and 18 MHz with some crossed doublet antennas (somewhat like this setup, but not in the same location). I change the frequency between antennas, e.g. 50 Hz below the center frequency of the band for antenna 1 and 50 Hz above for antenna 2 in order to simplify discrimination between the transmissions.
The short 13 m antenna transmits best East-West, and the longer 26 m antenna North-South. The directivity is in general confirmed by the WSPR reports I see. Sometimes the difference can be more than 10 dB in SNR, but more often it is closer to 5 dB. But it also happens that only one of the transmissions is detected. This should make for some interesting analysis in the coming months.
The post “Comparing two antennas with WSPR” first appeared on the LA3ZA Radio & Electronics Blog.
Comparing two antennas with WSPR
|
| Ultimate 3S with 5-band relay module in front, variable LM2596 power supply (with voltmeter) for the power amplifier behind left, a variable LM2596 supply set for 5 Volts for the Ultimate 3S in the middle, and the antenna switch to the right in the back. |
WSPR – The system for Weak Signal Propagation Reporter makes it easy to compare antennas if your transmitter can instantly switch antennas. The system shown here can send on antenna 1 for almost two minutes and then switch immediately to antenna 2 for the next transmission.
The Ultimate 3S already has software that supports that and application note 3 from QRPLabs (Controlling additional relays using the Ultimate3S “Aux”) describes how. I built mine following that note and the experience from EA1CDV.
The circuit is controlled from pin D7 and consists of a transistor, a relay, a resistor and an electrolytic capacitor. In addition I have two LEDs that indicate which antenna which is in use. In the first picture the green LED in the back right under the BNC antenna connector shows that antenna 1 is connected.
In the next picture, the whole layout is shown a little better. In this case LED 2 is lit, the faint yellow one. It sits right under the additional SMA antenna connector in the top left-hand corner that I had to fit.
I have used this setup for a few days now on 7, 10, 14, and 18 MHz with some crossed doublet antennas (somewhat like this setup, but not in the same location). I change the frequency between antennas, e.g. 50 Hz below the center frequency of the band for antenna 1 and 50 Hz above for antenna 2 in order to simplify discrimination between the transmissions.
The short 13 m antenna transmits best East-West, and the longer 26 m antenna North-South. The directivity is in general confirmed by the WSPR reports I see. Sometimes the difference can be more than 10 dB in SNR, but more often it is closer to 5 dB. But it also happens that only one of the transmissions is detected. This should make for some interesting analysis in the coming months.
The post “Comparing two antennas with WSPR” first appeared on the LA3ZA Radio & Electronics Blog.
