Posts Tagged ‘VE7CNF’
|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|
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."
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!
It seems that all of my blogspots of late have focused on 630m propagation ... but what has been happening down there recently has been both amazing and somewhat unexpected. With the growing number of active stations listening and transmitting, the band's propagation capabilities and mysteries are quickly revealing themselves.
Last night was a great example but perhaps the WSPRnet prop map illustrates this best.
Particularly striking was the long haul propagation from VK to North America, with northernmost VK4YB leading the pack. His 90 watt signal made it all the way to VE3IQB, near Ottawa as well as to NO3M, in Pennsylvania! To provide further hope to those that have little room for big receiving antennas, VE3IQB uses a typical small active e-probe antenna, 20' above ground!
I'm theorizing that Roger's signal was arriving today at much lower angles than normal, evidenced by its far-reaching east coast reception and the fact that it couldn't get over my 600' local obstruction to the west. I've always believed that it takes higher angled signal arrival for me to hear Roger and today's events seem to support this.
Exactly what would cause this to be the case, I'll leave to the experts but I imagine that the sudden surge in geomagnetic activity played a significant role in today's very different propagation paths.
Roger was not the only VK lighting-up the map today. A much more detailed account of all the action can be found on the KB5NJD's daily 630m report here ... all very inspirational and hopefully enough to spur even more new activity on the MF band.
Why not give a listen and see what you can hear?
As our sunsets start to come earlier and dawn arrives later and later, the sun's accelerated southerly excursion has brought sudden changes to 630m propagation.
This past weekend's CLE activity saw universally poor propagation as well as weather related QRN from lightning ... but as usual at this time of the year, things can change rapidly. Wednesday's overnight map of my own 630m WSPR activity illustrates why September propagation on LF and MF can often be spectacular and this is with just 65 watts total power output:
Among other things, the map indicates the growing interest among U.S. amateurs in the 630m band. Hopefully they won't have to wait too much longer, although I seem to be saying this more often than I would like to. It is of interest to note that even though these were WSPR reports, signal levels at most reporting stations were either into the 'audible CW' levels or at 'JT9 workable' levels ... all stations should be workable once the 630m ham band becomes a reality for all North Americans. Midwinter conditions over the next several years should see an abundance of transcontinental contacts on both CW and on JT9!
The east-west path is the bread and butter direction for interesting possibilities, when it comes to those of us in VE7 land. Normally it only really sets in when geomagnetic conditions are quiet but, as a result of coronal hole streaming, this week's geomagnetic field has been anything but quiet. As John Langridge, KB5NJD / WG2XIQ reported today in his invaluable '630m daily reports':
The geomagnetic field was extremely active, with many reporting periods at storm levels. The Bz is pointing to the South and solar wind velocities are very high, peaking at 700 km/s. This event is significant and I am just glad to see that it is helping and not hurting propagation. When will the bottom drop out? Clearly there is a lot going on here that we do not understand.
With stormy conditions continuing throughout the week, Friday's path to down-under enjoyed some enhancement as well, not unusual when the east-west path is disturbed. VK4YB's 90 watt signal was widely heard by several VE7's (VE7CNF, VA7MM and VE7BDQ) in the predawn hour, as Roger's signal peaked up briefly for several WSPR decodes.
As the coronal hole streaming continues, this morning's path to VK seemed even better along with a new antenna at VK4YB favoring the northwest:
12:24 VK4YB 0.475622 -21 VE7BDQ 11844 km
12:12 VK4YB 0.475621 -22 VE7BDQ 11844 km
12:08 VK4YB 0.475622 -17 VE7BDQ 11844 km
11:04 VK4YB 0.475622 -24 VE7BDQ 11844 km
11:02 VK4YB 0.475623 -22 VE7BDQ 11844 km
10:54 VK4YB 0.475623 -22 VE7BDQ 11844 km
12:28 VK4YB 0.475626 -21 VE7SL 11820 km
12:24 VK4YB 0.475625 -23 VE7SL 11820 km
11:54 VK4YB 0.475623 -25 VE7SL 11820 km
11:04 VK4YB 0.475623 -23 VE7SL 11820 km
11:02 VK4YB 0.475625 -26 VE7SL 11820 km
10:54 VK4YB 0.475626 -21 VE7SL 11820 km
11:22 VK4YB 0.475614 -28 VA7MM 11872 km
11:04 VK4YB 0.475614 -28 VA7MM 11872 km
11:02 VK4YB 0.475615 -33 VA7MM 11872 km
10:54 VK4YB 0.475615 -26 VA7MM 11872 km
I should mention that the other VE7 stations are all operating from noisy suburbs near Vancouver ... clearly fine examples of what can be done on 630m under less than ideal operating conditions and by paying close attention to system optimization. Please don't let living in the city stop you from enjoying the mysteries and challenges that our latest ham band has to offer ... as mentioned earlier, there is still much to be learned about using this band at amateur radio power levels and small backyard antennas. How exciting is that!
I've been exchanging e-mails lately with Roger, VK4YB, in Queensland, Australia.
Roger is located about 30 miles from the ocean and has been the only VK signal that I have been able to hear on 630m WSPR mode. He seems to have the strongest signal out of Australia on 630m with his 90 watts and 120' tree supported wire vertical. John, VE7BDQ, has been heard twice down under with his modest station running at the allowable 5W EIRP limit, being reported in the fall of 2015 and again this spring. As well, John has heard Roger, the only signal from VK that either of us has copied.
I would like to be able to run some schedules with Roger in the fall, when transpacific paths should peak again. With that in mind, construction has begun on a new 630m transverter that will allow me to drive my present FET amplifier at full EIRP. Our schedules will utilize the JT9 weak signal mode, similar to JT65 but designed for the noisier LF and MF bands. It uses about 10% of the bandwidth that a JT65 signal requires, about 15Hz, and gains about 2db more sensitivity. A two-way QSO, under the best conditions, would take four minutes if all went well. A typical exchange of the required information, if initiated at my end, would look something like this:
VE7SL VK4YB -20
73 73 (not really needed but indicates RR received)
The path from my end is difficult as I am on the east side of Mayne Island and in Roger's direction, about one mile from a 600' hill directly in line with VK. Any RF heading Roger's way will need to leave here at a fairly high angle, which is likely the case anyway considering the low and short (in terms of wavelength) inverted-L antenna.
The path profile from here to the open Pacific Ocean is shown below, with my end being on the right edge, just behind those two hills. The rest of the obstructions are on Saltspring Island and then Vancouver Island, before hitting open water.
|VE7SL To VK4YB courtesy: Hey What's That Path Profiler|
|W7IUV To VK4YB courtesy: Hey What's That Path Profiler|
|To VK4YB courtesy: Hey What's That Path Profiler|
The path from John, VE7BDQ, already heard in VK, is also easier than from here. Not far from the water, John has a pretty clear shot across Georgia Strait, giving his signal lots of time to gain altitude and clear those pesky Vancouver Island peaks.
|VE7BDQ To VK4YB courtesy: Hey What's That Path Profiler|
|VE7CNF To VK4YB courtesy: Hey What's That Path Profiler|
|VA7MM To VK4YB courtesy: Hey What's That Path Profiler|
|VE7CA To VK4YB courtesy: Hey What's That Path Profiler|
|VK4YB Path To Pacific courtesy: Hey What's That Path Profiler|
As the solar activity slowly abates (but not this week!), propagation on 630m will slowly get better and better ... hopefully along with increased levels of Canadians transmitting on the band, and lots of stations in the USA. It is hoped that our enthusiastic neighbours to the south aren't too far away from getting the band fairly soon. Better get those soldering irons warmed-up so you are all ready to go!
After our recent lightwave CW QSO, described here, Toby (VE7CNF) has been re-focusing on refining his lightwave system for weak signal non-line-of-sight (NLOS) cloudbounce and scatter mode experiments.
His testing to date has been limited to within his own suburban yard, with the transmitter being set up on the south side of the house and the receiver set up on the north, while basically pointing things straight up.
Several tests have already been done with exciting results, including audible CW being returned from a low (5,000') cloud ceiling and weaker returns noted on clear air scatter but readily detected in the CW QRSS mode. Toby has also interfaced his PC audio, via amplifier and FET driver, to enable him to use WSPR and JT9 modes, resulting in positive signal returns using these two digital modes of modulation.
Toby described some of his results and methodology in a recent e-mail updater:
I've done some lightwave backscatter experiments this last week. The transmitter is on my front deck, pointed straight up as verified using a level across the lens end of the box. The receiver is in the back yard and pointed up also. Between the two, the house is about 30ft high and blocks any direct light.
Last night May 8 UTC was clear and I was getting a QRSS10 level signal with the receiver pointed at elevations from 70 to 85 degrees, through the transmitter beam. There was nothing received from straight up, so the clouds were too high for cloud backscatter. At 80 degrees elevation I got the best signal. I've attached an Argo screen grab of QRSS10 (FSK CW with the 570 Hz tone as key-down).
|QRSS10 CW clear air scatter return signal|
WSPR2 was decoding consistently and JT9 was about 70%. I tried JT65, BPSK31, and MFSK8 but the SNR was too low for those to work.
|JT9 cloudbounce return signal 14,000 - 24,000 FT|
May 8, 2016 UTC CYVR clouds and temperature/dewpoint data:
0500 FEW CLOUDS (1/8 - 2/8) 14000 FT, SCATTERED CLOUDS (3/8 - 4/8) 24000 FT, 14 C / 11 C
0600 FEW CLOUDS (1/8 - 2/8) 14000 FT, SCATTERED CLOUDS (3/8 - 4/8) 24000 FT, 14 C / 9 C
0700 FEW CLOUDS (1/8 - 2/8) 12000 FT, FEW CLOUDS (1/8 - 2/8) 22000 FT, 13 C / 7 C
... I'll try CW and digital again when there's some lower cloud conditions. That’s tough to get without rain at the same time.
I did get dew on the receiver last night, so I'll be adding heating resistors inside the boxes to keep the lenses warm. Electric heating has worked great to keep dew off the optical surfaces of my telescope. I'll also look at adding shrouds to shield the lenses from the cold sky.
More from May 15th:
I've also attached a screen grab of WSPR2. Signals were up around 0dB this time.
|WSPR cloudbounce return signals 1300 - 1900 FT|
I played with a bunch of digital modes and FMHELL and SSTV. Everything was working pretty well off the clouds.
|SSTV cloudbounce return signal|
The nextstep is to move the rx farther from home, then to try sending signals over to John or Steve by cloud bounce.
Toby's nearest lightwave neighbour, VA7MM, is in mid-build and is working to complete a system capable of running overnight cloudbounce / scatter tests between their two respective backyards ... the NLOS distance is about 15 km. Although the path includes some bright commercial lighting QRM, with narrow-band modes such as QRSS or WSPR, it may not be a problem. I suspect one of the biggest problems will be getting suitable weather as, here on the west coast, dense clouds usually turn into rain very quickly, especially near the coastal mountains where Toby and Mark are located.
I find Toby's results to be both encouraging and exciting! It will be interesting to try some cloudbounce between their respective stations and my own and maybe hopping the NLOS path across cloudy Georgia Strait. It may well be possible to do this in one of the quicker QRSS CW modes such as QRSS3 or QRSS10, both of which can have fairly fast exchanges of the required information (calls, signal report and final confirmations). Failing that, slower QRSS30 or one of the weak signal digital modes such as JT9 / WSPR which have the ability to dig deep (-30db) into the background noise may be the answer ... there is much to learn yet!
|51km Path courtesy: https://www.google.ca/maps|
Toby, VE7CNF, successfully inaugurated his lightwave station earlier this week, on Monday night, completing a nice two-way CW contact between West Vancouver (CN89) and Mayne Island (CN88). The distance spanned was approximately 51km (32 miles), crossing atop the western edges of Vancouver and then across the Strait of Georgia, the body of water separating mainland BC from Vancouver Island.
The details of Toby's homebrew lightwave equipment are described on his web site here and are similar to the station at this end ... also described in earlier blogs. This was the same path covered in my two previous lightwave QSO's with Markus, VE7CA, described here.
Monday evening's weather was clear and calm but at this time of the year, true darkness is a long time coming. With a full-moon just a few nights away, the sky never did get very dark it seemed. I set up my end of the path late in the afternoon, just in front of the house.
VE7CNF/7 end showing the busy-looking site in operation.
Accompanying Toby to the mountain lookout location were VA7MM, his YL VA7MAY and Markus, VE7CA who initially scouted out and found this nice site for our original lightwave contacts. Thanks to Markus who snapped a picture of the diehard lightwave crew!
|VA7MM, VA7MAY and VE7CNF|
Although Toby's signal was very strong, the lighting hum was strong enough to cause some receiver front-end desensing and slightly modulate Toby's CW signal with a touch of AC ripple. I did not notice this hum when working VE7CA at the same location a couple of years ago. It's possible that there was no snow on the ski-hill at the time and the lights were not turned on.
Moving the receiver just a few degrees to the west made a huge difference, as the hummy background noise level returned to the quiet hush of a dark sky.
Toby's recording of my signal is much cleaner as there are no bright lights when looking towards Mayne Island. It is really interesting to hear the rapid fading, almost a flutter, on my CW signal, as the light passes through various levels of ever-changing haze above the water.
Midway through our one hour QSO, Toby reported that my signal had dropped measurably as had his signal on my end. Although I could see no obvious clouds in the path, I did notice a red glow out in the Strait that had not been there earlier. When I turned off my transmitter, the glow disappeared, indicating that there was indeed some low level haze that had crept up on us, and enough to cause some signal absorption on the path. Thankfully signal levels returned to normal, and actually were a bit stronger, about fifteen minutes later, when the haze thinned and the skies had grown a little darker.
Towards the end of our QSO, I had the chance to test out my #2 receiver. It was built so that I could do some NLOS cloudbounce testing here on the island, without having to separate my main system's transmitter/receiver pairing. At the time, there were no lenses available from the overseas manufacturer, so my quest for a suitable lens led me to a local 'bargain style' hardware importer (Princess Auto), who had a good supply of $5 lenses. The lens seemed to function well in my local tests but it had never been put side-by-side with the higher quality lens in my main transceiver. As it turned out, the $5 lens worked very well, easily detecting the 51km signal although it didn't sound quite as loud since the receiver I built for it was intended to interface with my laptop and lacked the additional audio amp I had built for the main system.
A final interesting observation was made, when on a whim, I placed a large cardboard shield over the bottom quarter of the transceiver's receiver lens. The signal strength didn't appear to change at all. I gradually blocked more and more of the lens but astonishingly, was still able to copy Toby's CW with all but a 1" strip of the lens completely covered! This would tend to indicate that we would be able to communicate with a very much smaller Fresnel or optical glass lens, such as a 4" or even a 2" inch magnifier. As I commented to Toby on CW, the possibilities for experimentation are endless.
All-in-all it was a very successful evening and the mountain-top gang seemed to enjoy the outing as much as I did, and ... the QSL is in the mail.
Hopefully there are other VE7's in or around Vancouver that might be interested in throwing a signal over this way some night ... I'll leave the light on for ya!
Toby, VE7CNF, has sent me some mail indicating that his new lightwave system is ready for a two-way test!
His system is very similar to the ones built and deployed by myself and Markus, VE7CA, in late 2013. The culmination of that activity is described here, in 'On Making Nanowaves - Part 6'. Our lightwave QSO and homebrew gear were later described in a 'how to' article in the 'The Canadian Amateur' as well as in the newest edition of 'The Radio Amateur's Handbook' (2016).
Toby describes his most recent pre-QSO backyard testing:
The lightwave gear appears to be working well. Focus looks good and the
finder scopes are doing their job. There's a reflective sign high up on a
hydro tower 170 meters away that's handy for testing. It lights up bright
when the transmitter's on it.
Back scatter off the clouds above my house worked too. I heard my CW beacon, audible 339, off a patch on the clouds about 1 degree wide. I don't really know if it was clear air scatter from closer by, or scatter off the clouds, but the spot was small. That's with the tx on the front deck, and rx in the back.
I used Spectran to check the noise from city lights in my area. At QRSS10
speed there are spectral lines at 540, 600, and 660 Hz. They aren't too
strong, but those are some frequencies we should avoid.
|VE7CNF's lightwave system - TX (L) & RX (R)|
Hopefully the weather will co-operate enough to allow us to make a two-way QSO later this week. Plans call for Toby to set up near the same location in West Vancouver used by VE7CA as it offers a clear LOS path to Mayne Island, 54km to the southwest.
|54km Georgia Strait crossing (courtesy: https://www.google.ca/maps)|
Rik, ON7YD, has set up a new website devoted to information specific to 630m. His 472kHz.org site looks as if it will be a valuable resource for those looking to get information and a start on our new band. At present, there is some really great information regarding transmitters, antenna systems and calculating E(I)RP levels. Have a look!