MFJ / Timewave Noise Canceller Shootout

 

A previous blog described a series of tests that Mark, VA7MM, performed demonstrating the effectiveness of his newly acquired MFJ- 1026 Noise Canceller. 

He, along with Guy, VA7GI, recently had the opportunity to compare the performance of the MFJ against Guy's Timewave ANC-4.

I'll let Mark describe the results:

NoiseCancellerShootout 2017 Report:

Guy Immega, VA7GI, and Mark Mattila, VA7MM, undertook side by side comparative tests of Timewave ANC-4 and MFJ-1026 noise cancellation gear (photos attached) by listening to interference at VA7MM in the HF spectrum between 7 MHz and 14 MHz. The program Spectran was used with the receiver on AM to adjust each unit for best performance and observe the relative performance of each. A system of coaxial relays was used to switch instantaneously between the units (photos attached).

Findings:

For practical purposes Timewave’s ANC-4 and MFJ’s 1026 are equal performers for eliminating interference in the HF spectrum.

Our findings corroborate the earlier findings of VE7CA that are posted on his website.

Switching the units in and out of noise was previously assessed on 40m CW, broadcast and raw noise. Examples of these tests are in a previous blogspot.

Commentary:

- main antenna in the tests was a multiband dipole at 30m above the ground.

- noise sense antenna was a Cushcraft R7 vertical antenna located 20m away from the main antenna.

 - receiver was an Icom IC-746Pro.

 - both units tested have the same nulling capability.

- the preamp on the MFJ was found to be useful in certain instances for boosting the noise signal.

- in one test instance the Timewave unit produced intermod with AM broadcast leaking into the receiver when the noise gain was set near maximum.

- in instances where noise was coming from more than one direction, the filters could eliminate one noise source, or the other, but not both.

General Observations:

- the Timewave and MFJ filters have a learning curve to figure out how to quickly and precisely null out noise. A couple of evenings of tinkering was required to figure out how to use the unit with different noise sense antennas and different types of noise.

- the noise sense antenna is critical and must pick up a strong noise signal for the units to work effectively. In most instances for local interference at VA7MM the noise sense antenna is near the ground and vertically polarized and the main antenna is high above the ground and horizontally polarized.

- both noise amplitude and phase need to be alternately adjusted to attain a good null on the units.

- using Spectran or SDR with the receiver on AM helps in adjusting the units.

Next Steps:

- discussions are on combining the noise canceller with a small vertical plane receive loop on 160 or 80m. The idea is that the combination of the two could enable noise in two directions to be nulled. The receive loop would be pre-amplified. 

- having two noise cancellers in series was also discussed as a means of nulling noise from two directions. An issue with this approach is that more processing electronics are put ahead of the front end of the receiver and this introduces its own noise and may create intermodulation. 

- I like that the MFJ unit has gain controls for both the noise antenna and the main antenna. Other differences include MFJ providing both relay and RF sense T/R switching whereas the Timewave only has RF sense capability. The noise antenna connector on the MFJ is an SO-239which I find more practical than the RCA phono socket on the Timewave. As far as mechanical construction is concerned, the Timewave is more robustly built.


We’re open to any questions on these findings.

73,

Mark Mattila, VA7MM

Guy Immega, VA7GI

MFJ-1026 Noise Canceller Tests At VA7MM

courtesy: www.mfjenterprises.com/

Mark, VA7MM, has been testing out his newly-acquired MFJ-1026 Noise Canceller and has provided several videos of the noise canceller in action.


Like so many other hams, Mark's suburban location has seen a gradually rising noise floor and the noise heard in this video is from an off-site location within his local neighbourhood, located about 400m away.

The noise canceller requires a separate 'noise antenna' in order to cancel any noise on the main receiving antenna and for all of the tests shown below, Mark's noise antenna was a Cushcraft R-7 vertical while using an Icom IC-7600 transceiver for listening.

Test 1 shows the noise canceller being used while listening to a broadcast station on 6.0 MHz:


Test 2 shows the canceller's effect on raw noise while viewing in Spectran:


Test 3 shows the canceller's effect on a 40m CW signal:


Test 4 shows the effect of just the IC-7600's noise blanker on the offending noise:


Mark's comments:

Living in the noise cloud one must resort to special measures to use affected portions of spectrum. I recently purchased an MFJ-1026 noise canceller and have been testing the unit and have attached videos demonstrating the unit’s performance. You will see examples of raw noise, SW broadcast and 40 m CW signals with the unit being switched in and out. Also for comparison is the noise blanker in the IC-7600 failing to eliminate the same noise. 

 

Conclusions:

 

- the unit is able to eliminate noise in most instances when adjusted properly

 

- the noise sense antenna is critical and several different switchable noise sense antennas may be required for good performance

 

- setting up on AM mode with Spectran helps with fine adjustment

- it outperforms the radio’s noise blanker in all cases tested

With proper tuning and set up, it looks like the MFJ-1026 can make a worthwhile improvement in unwanted noise reduction.  Mark will also be testing and comparing a Timewave ANC-4 Noise Canceller with the MFJ and any videos received will be published here.

The Green Glow

Recent emails from two friends brought new insight into a blog that I had been intending to do for some time.

As has been mentioned on more than one occasion, I discovered radio in the late 50s at the age of 10, after reading an article about shortwave-listening in a drugstore magazine. My father was able to rescue an old GE cathedral from grandpa's downtown barbershop, where it sat gathering dust for several years in the back room storage space. Fortunately, it immediately came to life when plugged in, and soon after, dad spent an afternoon stringing a longwire antenna while scurrying about on the roof of our 3-story house in central Vancouver. My radio-adventures had begun! Life would never be the same. 

As I recall, the first couple of weeks were spent listening to radiotelephone traffic between various tugboats and their dispatchers, in the 2 megacycle marine band. Initially it took me awhile to figure out what I was listening to but found it fascinating to hear the tugboats up and down the coast getting their daily marching orders.

It wasn't too much later that I discovered the international shortwave bands and I was soon keeping detailed logs of my catches and mailing for a coveted QSL. Friday nights were always special as it meant I could DX well into the night and not worry about having to get out of bed for school early the next morning. My 3rd floor bedroom shack was the true definition of 'warm and cozy' and a memory I will always cherish.

Up to this point I had yet to discover ham radio. I must have tuned across a few conversations on phone but evidently hadn't been too awestruck at what I had heard ... perhaps I didn't know what I was hearing or was unable to comprehend some of the expressions they were using or what they were talking about when describing their gear. For whatever reason, the ham radio 'trigger-event' had not yet transpired ... but it soon would.

By this time, I had moved upward, from the Boy Cubs to the Boy Scouts. I must explain that these activities were forced upon me by my parents and not something I particularly enjoyed, especially the midwinter camping trips that were always pouring rain or freezing. Again, from grandfather, I had been provided with an old, virtually uninsulated, WW1 sleeping bag, that wouldn't have kept anyone alive at the western front for longer than a week. These all too regular winter excursions to the rain forest were pure misery and if I wasn't freezing to death then my sleeping bag was usually getting soaked from the river of rain running through the tent ... most of these weekend outings were sleepless and left me feeling like a zombie for the next few days. But ... not every scouting experience was bad and in fact, it was a scouting event that would soon provide the ham-radio 'trigger'!

The opportunity arrived for those that wished, to visit a local 'ham station' to partake in some sort of 'on-the-air experience'. This would have been in 1958 and having been already familiar with shortwave radio, I immediately signed-on.

A few weeks later, about six of us found ourselves in the basement shack of Ernie Savage, VE7FB. Although a stranger to me, Ernie was a well known 75m phone traffic man and an ardent 75m mobile operator. Although he was only about five-foot two, Ernie was a powerhouse of a personality and most of us cowered quietly as Ernie tweaked the dials and with a tight grip on his large microphone, barked louder than his small stature might suggest ... all of us quietly prayed that Ernie wouldn't pass the microphone to any of us.

And then I saw it! Although I didn't know it at the time, it was a pivotal moment in my development and would shape all aspects of my life from that point forward.

The DX-100 !!

As Ernie reached up to change the frequency of his mammoth Heathkit DX-100 my eyes gazed upon and then became fixed on the big Heathkit's green dial ... the magical green dial that could take him anywhere he wanted to go, with just a twist of the wrist. There was something about its semi-transparent, alluring green shade that just grabbed hold of me. It was one of the coolest things I had seen in my first experience with amateur radio and I knew, from that moment on, that I wanted to get involved in this amazing hobby. Instead of just listening to signals, I could be making my own!

Heathkit VF-1 VFO Dial

 

Like so many memories from my youth, this moment is still fresh in my mind ... I can still visualize everything in that room as if I had just left Ernie's shack. Although the warm orange glow emitted by the dials of the equally mammoth Hallicrafters SX-28 'Skyrider' were stunning, it was the inviting glow of the little green Heathkit dial that I found myself focused upon ... how odd this all seems to me now, thinking about it over sixty years later.

Perhaps the Heathkit engineers had learned of the 'power of green' from those earlier genius Hallicrafter's draftsmen ... can anyone deny the alluring appeal of a Hallicrafter's front panel or dial?

Hallicrafters SX-42 Dial

 

Whatever the reason, Heathkit engineers were no slouches either when it came to luring young radio-crazed boys as well as full-grown men with their eye-appealing ads and clever designs.

As a young teen, I could never afford to buy a DX-100 but I was able to buy a VF-1 and added one to my Heathkit DX-20 workhorse. With the lights turned off in the high attic bedroom shack, the orange dials of the Super Pro and its backlit S-meter combined with the seductive green glow of the VF-1. It just couldn't get any better!

Until recently, I had no real idea of why I had found the green dials so enchanting but an email from Mark, VA7MM, finally made it all perfectly clear. Mark offered the most plausible explanation ... the diabolical Heathkit and Hallicrafters engineers had been putting Kryptonite in their dials ... the stuff that even Superman found overpowering and unable to resist!

Powerless

 

It was now so obvious why countless thousands of young boys and grown men had found these products so difficult to resist ... seems we never had a chance.

630m VK's Light-Up North America

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.

courtesy: http://wsprnet.org/drupal/wsprnet/map

The amount of North American activity grows each day, especially now that the DX season has arrived. At one point last night, KB5NJD reports over 100 stations either transmitting or reporting via the WSPRnet activity page! With thunderstorm activity gradually shrinking, reception should only get better over the next few months.

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!

courtesy: http://wsprnet.org/drupal/wsprnet/map

This spotlight propagation to the select regions of the east coast is further mystified by the level of geomagnetic activity overnight, with the K index reaching level 5 and higher!

courtesy: http://www.swpc.noaa.gov/

Interestingly, all of this was right over my head, with not a single peep heard here from Roger. Stations across Georgia Strait, VE7BDQ, VE7CNF and VA7MM all reported hearing Roger as well as being heard by him. For the latter two, yesterday and today represent their initial decodes to down under.

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?

September Prop Awakens

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:

courtesy: http://wsprnet.org/drupal/

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.

courtesy: http://wsprnet.org/drupal/

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!

630m - The Path To VK

Roger, VK4YB

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:

                    VK4YB VE7SL
                    VE7SL VK4YB -20
                    R -18
                    RR 73
               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

The most consistent west coast signal to reach down under is from Larry, W7IUV, in Washington state, operating experimentally as WH2XGP. Larry's path is a little more forgiving although his inland location certainly doesn't help. His first obstacle is about 10 miles away and about 2,000' higher. I would guess that his signal is well above that before reaching those mountains and the remaining higher Cascade peaks would not interfere.

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's (Toby) path profile is similar to mine in that he is confronted very early with a hill to clear. Once over that his signal should be well above the mountains.

VE7CNF To VK4YB courtesy: Hey What's That Path Profiler

VA7MM's (Mark) path profile looks a little better than Toby's as there is a little more distance for his signal to gain altitude before passing over Vancouver Island. Mark was also able to detect VK4YB's WSPR signal earlier this spring and is looking forward to the fall tests with Roger.

VA7MM To VK4YB courtesy: Hey What's That Path Profiler

VE7CA's (Markus) path profile is probably the best of all of us on the west coast as he is located high up on the hills to the north of Vancouver along with an open shot to the ocean.

VE7CA To VK4YB courtesy: Hey What's That Path Profiler

I think my only advantage here is my quiet receiving location as it's going to take some brute-force to get over those nearby peaks. Like many of those operating from the suburbs, higher noise levels really take their toll on weak-signal reception and that will be the biggest obstacle for those operators in the city. Twenty years ago, this would not have been nearly such a problem!

VK4YB Path To Pacific courtesy: Hey What's That Path Profiler

Shown above is Roger's path to the Pacific and illustrates one of the reasons why he has the best signal into North America on MF! Although 30 miles from the ocean, there are no obstructions, yet ... coming soon is a 120' cell tower, directly in line with North America and less than 1000' from his antenna. Hopefully it won't cause any problems other than being a dreadful eyesore.

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!

Lightwave Madness

The 288 km path  courtesy: REAST

One of the local lightwave builders, Mark (VA7MM), brought my attention to some outstanding lightwave work conducted several years ago, by a group of very dedicated amateurs in Tasmania.

A pair of articles describes their successful attempts to send signals, via cloudbounce, over the astounding distance of 288km (180mi), crossing Bass Strait between the north Tasmanian coast and southern Australia.


What did it take to transmit lightwave signals over such a distance? Basically a system similar to the ones recently employed in our own local lightwave experiments but on a grander scale ... much grander!

The receiver is based on one of the KA7OEI designs, with modifications to increase its sensitivity. The receiver, and several other designs, can be found on Clint's website here, probably the best source of information on amateur lightwave available anywhere.

The lightwave receiver  courtesy: REAST

Although the basic receiver used a typical-sized fresnel lens, what really set it apart from most was the use of a large (10mm x 10mm) Avalanche Photo Diode (APD) for the detector, to maximize the field of view produced by the fresnel and gather every bit of light possible ... at a cost of $1200!

The 10mm x 10mm rx APD courtesy: Hamamatsu

The transmitter was also big, consisting of an array of 60 red Luxeon III LED's, similar to the Red Rebel Luxeons used in our own local tests. Each LED had its own 12cm square fresnel lens, heatsink and method of focusing. Certainly this was a mammoth project, by amateur lightwave standards.

The 60 LED TX array courtesy: REAST

One of the biggest problems when using such a high-gain system, is the difficulty in pointing. They found that aiming in altitude was simply a matter of pointing a few degrees above the horizon but azimuth pointing was much more critical, requiring accuracy to within a half-degree.

Earlier long-haul tests out to 209 km used the digital JT65 mode for signal decodes but the 288 km test used a fairly esoteric weak signal mode called WSC built on the Spectrum Lab software. This mode is capable of digging almost 20 db deeper into the noise than JT65, down to almost -50db.

An in depth description of the two long-haul events, including equipment schematics, can be found in "288 km Cloudbounce from Tasmania to the Australian Mainland" and in "209 km with Narrow Beamwidth Transmitter".

The 288 km crossing project evolved over several years and is all very well documented, from the first early steps, at the Radio and Electronics Association of Southern Tasmania's (REAST) website here.

This adventuresome project was largely the work of VK7MO, VK7JG, VK3HZ and VK7TW. Their work is most inspiring and much can be learned from seeing what they discovered when transmitting into the cloudy nighttime skies.

Such an endeavour as this makes the local, much shorter Georgia Strait crossing, seem like a cake-walk, but I can't imagine using anything that big and bright here without causing trouble ... it would probably appear much too 'laser-like' to talk one's way out of a jam. Pointing anything resembling a laser light into the air these days is simply begging for trouble.

I can however, envision a scaled-down version, perhaps consisting of an array of four Luxeons ... at least on my end of the path, but even pointing one of those from the city could be problematic. Perhaps any NLOS lightwave attempts across Georgia Strait will need to be well away from Vancouver and its two-million sets of eyes.

A Second West Coast Lightwave Adventure

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

One thing that I noticed on Monday night was the very loud QRM coming from the sodium vapor lighting used on the ski hills just above Toby's location. The resolution of my Fresnel lens was just not sharp enough to be able to isolate Toby clearly without also being saturated with the lighting noise ... from my end, the ski-hill lighting appeared just above his deep-red LED.

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!

Local Lightwave Activity / A New 630m Resource Site

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)

As well, Mark, VA7MM, is also putting together a similar system to join the fun ... it's great to see new local activity!

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)

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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!

More VE7 Lightwave Activity

Two more VE7's are well on their way to getting in on the lightwave fun in the Vancouver lower mainland region. Toby, VE7CNF, and Mark, VA7MM, are constructing stations similar to the ones built by myself and Markus, VE7CA.

Toby and Mark live close enough that a clear-air scatter QSO between them might also be a possibility. Having another near-by amateur, or even in the same city, is a great source of motivation ... not to mention having someone else to actually talk to, once the system has been built.

Except for the LED focusing sled, Toby's fine-looking transmitter box and LED driver / modulator, are now complete. The receiver is next on the list. I believe this will use one of the inexpensive ($5) fresnels lenses, purchased locally at Princess Auto, that seems to work very well for the price.

photos courtesy VE7CNF

At this pace, perhaps a four-way VE7 lightwave QSO will soon be in the making!