AmateurRadio.com

630m to HF Crossband

Since getting the new 630m band (472-479KHz) here in Canada, one of my favorite ways of promoting interest in the new band has been 'crossband' activity ... that is, transmitting on 630m while the other stations transmit on a predetermined HF (QSX) frequency, usually on 80 or 160m. There are many amateurs in the U.S. who are interested in getting the band as well as many Canadians that are interested in getting on the band and the crossband activity usually generates a lot of interest. Both myself and John, VE7BDQ, have enjoyed making several crossband contacts this past winter and will once again be soliciting crossbanders this coming Saturday evening.

Our plan is to operate from 0200Z through 0700Z, (1800-2300 PST Saturday). Beginning at the top of the hour, we will both be calling CQ on CW and listening for any callers on HF. CQ's will continue until there are no more callers and will begin again at the next top of hour time slot. This should allow for a wide variation in propagation and the possibility of eastern contacts as the evening progresses.

The frequencies will be:

•  VE7SL TX 473.00KHz QSX (listening) 1808KHz (160m) and 3535KHz (80m)

• VE7BDQ TX 474.00KHz QSX (listening) 1813KHz (160m)

It is hoped that as many stations as possible will give a listen for us and be able to call on one of the HF QSX frequencies. Both John and myself will be running at the maximum allowable eirp for the duration of the activity.

If you have not had a look for any 630m stations, hopefully you will take the opportunity this coming Saturday night ... you really do not need any special antennas for receiving on 630m. Many of the stations that I have worked on crossband have been using HF dipoles for low-noise reception.

I'll be promoting this event on several of the reflectors and groups that I regularly enjoy and I also invite you to pass the word on to others. Please watch the blog for further updates.

See you Saturday I hope!

Regular readers will likely recall  my early January blog describing the sudden and very unwelcome appearance of a severe noise problem badly affecting my LF reception. I had spent an afternoon D/F'ing the noise source (which was being radiated via the local power lines), only to discover that the residence in question was not occupied ... and has been vacant for the past seven weeks as the noise continued.

The culprit

Yesterday I noticed that the home was once again occupied and this morning, with radio in hand, I paid visit. It seems that the part-time residents had been spending the past several weeks in Hawaii and had just returned to the house to check up on things. I explained to the owner what I believed to be the problem and, as suspected, it was a CFL light ... a particularly noisy one. Turning the light on and off quickly verified the culprit light and swapping the bulb out for a different one produced no observable noise, as was the case for one that had been left switched-on in the living room.

Whether the offending bulb was just a poorly designed one, a very early manufactured model or one that was about to fail, I do not know ... but I am amazed at the strength of the QRN (and QRM) that the bulb was able to produce at such a distance, about ten properties away!

CFL Crud on LF

The owner was very concerned that he had unknowingly caused a problem and was very apologetic, as I have found with similar situations in the past.

One of the worst was also a CFL bulb that had actually burned-out and was located in a nearby (three properties away) crawl space. When finally traced, the bulb was heavily charred and had partially melted at the base, yet was still producing an ear-shattering level of crud right into the HF spectrum.

In cases like these, it is often difficult to get an accurate D/F on the signal through normal means since the signal is being propagated via the overhead powerlines. Attempts to D/F the signal almost always point to the closest powerline and not to the signal source. Usually such a noise generator will be confined to your local power grid ... that is, the homes that are powered between the two large power distribution transformers in your local neighborhood. In my case, this limits the search to about 15 homes.

I have found that the best way to tackle this is to make a 'noise map' and to try and measure the noise intensity at a similar point for each property - ie. directly beneath the powerline as it enters the property. This will usually put you at the same vertical distance from the line and will give you a better noise sample that is directly (or not) associated with that property. After mapping this out, if the culprit property is not obvious, then you will at least have narrowed it down to a very few choices. Other types of noise, that can be detected into the VHF range, are probably best detected using normal D/F methods.

After bringing the offending bulb home, I Google-searched the product name and number and came up with a 'product recall' for this particular model.

"According to a Health Canada and Electrical Safety report, the lamp may overheat and melt the enclosure exposing live parts, posing a risk of fire and/or electric shock."

Apparently they were indeed manufactured incorrectly and it's just as well that it was found and removed before causing serious damage!

Once again  LF sounds as it should. Hopefully it can remain this way for a long time but with the proliferation on noise-making appliances and 'improvements', I have my doubts.

YJ-200KHz - Victoria Int'l

Listeners towards the central and southern portions of North America reported phenomenally good conditions this weekend, most unusual for a CLE event! Out west and here in BC, conditions were not noticeably enhanced and could best be described as kind of 'mushy' ... most signals were a struggle. The further south you went, the better the propagation became.

CFL Crud

Unfortunately, I am still struggling with noise pollution (cheap or failing CFLs) in a house about ten properties away, creating a constant 60 Hz hum and drifting birdies throughout the band ... as it was during the last CLE. Hopefully the owners of the home will return before the next CLE arrives!

25 04:00  198      DIW       Dixon, NC, USA
24 06:00  200     YJ          Victoria - Sidney Island, BC, CAN
24 04:00  200     YDL       Dease Lake, BC, CAN
25 07:00  200     UAB       Anahim Lake, BC, CAN
24 04:00  201     ZWN      Winnipeg, MB, CAN
24 12:00  201      IP           Lufthansa, AZ, USA
24 07:00  201      GV         Greenville, TX, USA
26 05:40  201      YVZ      Deer Lake, ON, CA
24 06:00  203     ZKI        Kitimat, BC, CAN
24 06:00  203     YBL       Campbell River, BC, CAN
24 06:00  203     TCY       Tracy Municipal Apt, CA, USA
24 04:00  204     ZQR       Regina, SK, CAN
24 11:00   205      XZ          Wawa, ON, CAN
24 04:00  205     COR      Corcoran, CA, USA
24 04:00  206     SOW      Show Low Regional Apt, AZ, USA
24 04:00  206     EF          Castlegar, BC, CAN
24 04:00  207     YNE        Norway House, MB, CAN
24 04:00  207     PY          Fort Chipewyan, AB, CAN
24 07:00  209     ITR         Burlington, CO, USA
24 04:00  209     IB            Atikokan, ON, CAN
25 14:00   209     HGT       Tusi AHP, CA, USA
24 04:00  209     CYT        Yakataga Apt, ALS
24 04:00  211     HDG       Gooding, ID, USA
24 04:00  212     YGX        Gillam, MB, CAN
25 04:00  212     MPZ        Mount Pleasant, IA, USA
24 04:00  212     CGL        Juneau, ALS
24 07:00  212     CFV        Coffeyville, KS, USA
24 04:00  214     LU           Abbotsford, BC, CAN
24 04:00  215     ZAB         Edmonton (Intl Apt), AB, CAN
24 11:00   215     TQH        Tahlequah, OK, USA
24 04:00  216     GRF        Fort Lewis, WA, USA
24 04:00  216     CLB        Wilmington, NC, USA
24 04:00  217     EC           Enoch, UT, USA
24 11:00   218      RL           Red Lake, ON, CAN
24 04:00  218     PR           Prince Rupert, BC, CAN
24 04:00  219     ZRS         Regina, SK, CAN
24 07:00  220     HLE         Hailey, ID, USA
24 04:00  221     QU          Grande Prairie, AB, CAN
24 04:00  222     WY          Wrigley, NT, CAN
24 04:00  223     YKA        Kamloops, BC, CAN
24 04:00  223     AFE         Kake Apt, ALS
25 11:00   224      MO          Moosonee, ON, CAN
24 04:00  224     DN          Dauphin, MB, CAN
25 04:00  225     X5           Vegreville, AB, CAN
24 04:00  225     LWG       Lewisburg - Corvallis, OR, USA
25 04:00  227     YAC        Cat Lake, ON, CAN
25 12:00   227     MHM       Minchumina, ALS
24 04:00  227     CG           Castlegar, BC, CAN
24 04:00  229     AKW       Klawock, ALS
24 06:00  230     YD           Smithers, BC, CAN
24 07:00  230     VG          Vermilion, AB, CAN
24 11:00   230     NRN       Norton, KS, USA
24 07:00  230     BI            Bismarck, ND, USA
24 07:00  233     QN          Nakina, ON, CAN
24 07:00  233     OKS       Oshkosh, NE, USA
25 14:00   233     LG          Seal Beach, CA, USA
24 04:00  233     BWP       Breckenridge, ND, USA
24 04:00  233     BR          Brandon, MB, CAN
25 12:00   233     AZN        Amazon, MO, USA
24 04:00  233     ALJ         Hinchinbrook Island, ALS
25 04:00  235     CN         Cochrane, ON, CAN
25 04:00  236     ZRJ        Round Lake, ON, CAN
24 04:00  236     YZA       Ashcroft, BC, CAN
24 04:00  236     FOR       Forsyth, MT, USA
24 04:00  238     MPA      Nampa, ID, USA
24 04:00  239     OJ          High Level, AB, CAN
25 04:00  381.5   SJX       St James, MI, USA

Listening for NDBs is a practical way to check out your LF receive capability, should you be interested in developing a good 630m station or in following the nuances of night-to-night MF propagation.

There's been a lot of discussion lately on the Yahoo Groups ndblist regarding the "low-noise vertical" (LNV) and it's seemingly excellent performance. Originally described by Dallas Lankford as a good performer from LF to SW, ndblist member, Phil (KO6BB), recently refurbished his earlier built 'LNV', but this time with better feedline and appropriate ferrite cores for the antenna's matching transformers. Some of his description appears below.


To recap. I put the LNV up last spring to overcome the bad IMD products
from local BCB stations I was seeing in the LF region when using the
Roelof Active Whip located about 36 feet AGL. The low noise vertical is
... about 30 feet of antenna, set at roof-line level in this mobile home. As I wasn't sure how well the antenna would perform, I first made it a "Zero Dollar" project, using items I had on hand. Those items included two toroid cores salvaged from a defunct computer PS. I figured that since the supplies operate in the kHz range (as witness what a dirty supply will do to your LF reception), they would be suitable for at least a trial run of the antenna. The balanced feedline was some CAT6 cable I had on hand.

The antenna was a great success, because while it had much lower signal
output than the active whip, it also had ZERO IMD from the BCB stations,
and also less local 'junk' (read noise). The tunable pre-amp I use more
than made up for the lower output of the antenna, after all Signal/Noise
ratio is EVERYTHING in this hobby, NOT how high you can make the "S"
meter read.

The central valley summer heat (often in the 100's) took it's toll on
the CAT6 feedline outer jacket insulation, and while it still seemed to
work OK, I figured that it wouldn't be long before water started to get
into the line and probably degrade it in rainy/foggy weather.

Anyway, I went ahead and ordered the proper toroid coils I needed along
with 25 feet of nice 300 Ohm foam twinlead, and got a couple plastic
boxes to put it all in and made the toroid units. While I was at it ordered
two Amidon FT193-J toroid cores to complete the LNV the way I REALLY wanted to.

Today I installed it all, putting a heavy twist in the feedline to try
to reduce any stray noise pickup on the balanced feedline. I'd say
probably not likely but why take a chance.

OK, here are the results. I took signal level readings of eight 24/7
stations, both before and after changing out the wiring/baluns. The
bottom line is, the new antenna IS an improvement in the NDB range,
tapering off slightly at the high end of the broadcast band. Yeah, it's
'only' a couple "S" units at it's best, but when you're digging for that
weak NDB even 1 "S" unit is a LOT! I'm going to 'assume' 6dB per "S"
unit as I have calibrated the "S" meter of the R-71A receiver.

NOTE: This is 'fuzzy' math, don't take them as 'exact' on the dB readings.

FREQUENCY BEFORE AFTER DIFFERENCE
203 TCY S2 S4 2 S units (12dB)
205 COT S3 S5 2 S units (12dB?)
344 FCH S9+7 S9+15 (8dB)
374 LV S6 S7 1 S unit (6dB)
580 BCB Sta S9+35 S9+38 (3dB)
770 BCB Sta S9+32 S9+32 No Change
880 BCB Sta S9 S9 No Change
1450 BCB S9+10 S9+5 (-5dB)

SO, it looks like the antenna is definitely an improvement where I'm
REALLY interested in it (the NDB band). I could have probably tailored
the toroids for maximum performance, but just used the 81:9 turns ratio
on the outdoors (antenna) and 9:9 on the indoor unit as I'm FAR too lazy
to run up and down the ladder to remove the toroid box, change turns and
retry it again!!!

Some additional notes.

NOTE 1. I have three ground rods dedicated to just this antenna, two 8
footers and a 4 footer. While I was playing with the antenna taking
readings AFTER the work, I disconnected one of the 8 foot rods to see
what effect that had. Signal levels dropped approximately an "S" unit
across the board. So GOOD grounding on this antenna does make a difference!

NOTE 2. I'm NOT exactly sure why it happened, but after the antenna
work here, there was even LESS "local grunge" in the background than
before, even with the stronger signals, making for even better copy on
weak ones than I otherwise expected. . . It DOESN'T make sense to me,
but then, antennas ARE the magic art.


It appears that the grounding plays some importance in the performance of this "non-resonant" aperiodic antenna and the fact that it is non-resonant on the frequencies of interest likely also plays an important part in its good S/N performance.

Several years ago I noticed something similar. My own 10' tuned air-core loop made an excellent receive antenna on 160m, even though the loop was tuned to around 300KHz! Although signal strength was several S-units below my transmitting antenna, the loop was extremely quiet and weak signals were much easier to copy ... In fact I often heard signals on the mis-tuned loop that I could not hear on my resonant half-sloper radiator.

Another ndblist proponent of the low noise vertical is John, in Colorado, who employs three ... one of them a great-looking tilt-over version. The tilt-over is nicely demonstrated in his short you tube video below.


The antennas are also used in combination via his Quantum Phaser, when DXing the broadcast band. The excellent phasing results can also be seen in his short video, while using a wonderful, like new,  Hammarlund SP-600 JX.


Dallas Lankford's original article may be found here, while an earlier more encompassing discussion will be found here. A third Lankford article, discussing 'Signal To Man Made Noise Ratios' and comparisons of various receiving antennas, also makes for interesting reading.

Perhaps the 'LNV' might be the antenna you're looking for to boost your LF/MW reception.

Another VE7 has been bitten by the 630m bug ... well, intrigued enough to start building a station. On the weekend VA7MM (Mark), in Port Coquitlam, asked if I could take a listen for his low power signal. I'll let Mark describe his setup:

"My transmitter is a HP8640B signal generator. It is stable and has 1 Hz
frequency readout with maximum RF output of 20dBm. CW keying was done by latching the antenna on and off of the HP8640B. The latching relay was driven by the send relay in an IC-746Pro running with full break-in CW
turned on. A 1N914 switching diode was installed across the relay coil as
the back EMF from the relay was measured using my oscilloscope to be a +50V spike. This effectively attenuates the voltage spike. A good safety
precaution before installation.

A second HF radio, an IC-7600, was on a separate wire antenna for receive
only and with Spectran running for signal analysis.

In the final setup three series coils totalling 330 uH and a series of
parallel variable capacitors adjusted to about 1000 pf were installed in a
series resonance circuit outdoors at the base of a sloping dipole with the
apex at about 40 m. The antenna outside shielded and center conductor were connected effectively making the antenna a vertical. There was no impedance matching. One ground radial about 300' long was laid out laying on the surface of the ground. The resonance circuit was tuned using a combination of a Blackberry Z10 smart phone real time video chat link of Spectran from the ham shack in combination with a portable VHF audio feed to both visually and audibly tune the resonance circuit for maximum output. I tried a parallel resonance circuit but it did not work.

The straight line distances between QTHs from Google are:

VA7MM to VE7SL: 60 km
VA7MM to VE7CNF: 10 km

Amazing that a piece of lab equipment can be enabled with a few hours of
tinkering to transmit a signal on the 630 m band a distance of 60 km.

Thanks for the first 630 m band contacts. It was fun. Now I'm going to start planning a permanent capability on 630 m."

Mark's setup reminds me of a Rube Goldberg machine but it all worked well enough for him to put out a solid 559 signal at 60km distance and provide his first official 630m contact.

As of today, the following VE7 stations have now made two-way contacts on the new band:

               VE7BDQ
               VE7CNF
               VE7SL
               VA7JX
               VA7MM

It would be great to see some activity from northern BC, VE6, VE5 and points further to the east. How about it fellas?

Interest in Canada's newest ham band, 630m, continues to slowly grow. Toby (VE7CNF) in Burnaby, BC, has made his first and second CW contacts on the new band!

Both myself and John (VE7BDQ) had the pleasure of working Toby on 473.000 CW on Thursday afternoon. Here is Toby's description of his station at present:


"I have put together a low-power 630m WSPR transmitter here. I have a USB-TG44A signal generator clocking a phasing-type SSB modulator with WSPR audio coming from a laptop. The modulator gives 45db suppression of the carrier and lower sideband. This drives a ZHL-32A 1-watt linear amplifier. I have a matching transformer and loading coil at the base of my 80-meter inverted-L antenna. Wire height is 10m.

Courtesy: VE7CNF

Courtesy: VE7CNF

Toby has indicated that he will soon start construction of a dedicated DDS-based transmitter, with more power to work with. Situated on a normal-sized suburban lot, and base-loading his 80m inverted-L, is proof once again that fancy antennas and a few acres are not needed to have fun on 630m. Toby's initial night WSPR tests were copied by WH2XGP (W7IUV), near Quincy, Washington, at a little over 200 miles (325km) and on the other side of the rugged Cascade Mountains!

It seems that if I'm not chasing down noisy power poles or hunting for drifting wireless headsets, both of which have tried their best to tax my 6m reception this past year, I spend several hours each year chasing down delinquent noise generators!

I spent yesterday afternoon searching the neighbourhood for the source of an annoying and disruptive 120Hz hum. Testing my patience for about a week now, the AC buzz has been ripping-into my usually quiet LF reception, disrupting efforts to participate in the latest CLE (189) listening event. Although conditions have been poor, as usually occurs during these events, the signal-shrouding AC hum has made the event a real struggle.

I had been hoping that, whatever the source of the suddenly-appearing interference was, it would disappear as quickly as it had arrived. I had first noticed it several weeks ago, but it would always go off around bedtime and often was not there at all in the evenings...but the past week it has been there 24/7.

Yesterday I had finally had enough and with Sony 2010 in hand, along with its built-in ferrite bar antenna, I tuned the radio to 630m and started walking around the neighbourhood.

The first thing I noticed was that the signal was being propagated along the overhead powerlines and it was difficult to get a direction of the true source...all nulls pointed to the closest line. Walking to the north, the signal gradually became weaker and reversing direction to the south produced an ever-increasing AC hum...progress! I eventually found a corner where the QRN peaked, and walking in all directions from that point saw the noise diminish...getting warmer!

There were four possible homes here that could be the cause of the problem. I spoke with three of the four homeowners, all of whom seemed genuinely concerned about the source. They all let me into their homes and, with radio in hand, look for the source of the (by now) loud buzz. None of the three homes seemed to furnish the nasty noisemaker.

House number four was unoccupied but was, I was told, up until about a week ago. Venturing on to the property, the S9 buzz started to climb and by the time I had reached the porch, the Sony was on the verge of self-implosion...getting very hot now! A knock on the door confirmed that nobody was home but...behind the curtain, there it was...a floor lamp was turned ON!!

With the source now located I could now breath a little easier but unfortunately could not hear any quieter. Hopefully the owners, who go back and forth to the mainland frequently, will return soon and that LF will once again sound as it should.

What could be screwed into that floor lamp? I'm betting on a poor-quality or about-to-fail CFL bulb.

The one on the left is the actual bulb that I removed from a crawlspace, about four years ago, three houses away. It had been creating the same sort of buzz, only louder, as it was much closer. It was not emitting any light whatsoever yet continued to generate noise as well as present a real fire hazard. The house occupants had left it switched 'on' in order to discourage the local otter population from making a winter home in their crawlspace. Somewhere along the line the bulb had failed and started generating large amounts of AC hum.

This one was tough to find, as even several blocks away, it was very loud. It seems that power lines make wonderful LF antennas. I had to make a map showing signal strengths at many locations to find the source... my neighbours have since given me a key to their house, just in case it happens again!

So...what do you think is in house number four?