AmateurRadio.com

A few days ago, the power of the slow speed QRSS mode was nicely demonstrated by Mark, VA7MM (Coquitlam, BC) and Jack, VA7JX (Campbell River, BC, on Vancouver Island).

Mark was transmitting on 630m at a power of just 144mW output, while Jack was receiving on his normal 630m inverted 'L'. Mark tried various QRSS speeds ranging from QRSS3 (3 second 'dits') to QRSS60 (60 second 'dits'). One can clearly see the difference between the three speeds.

Going from the relatively slow CW rate of 6 WPM to just QRSS3 alone, produces a healthy 12db increase in signal level. Going from there to QRSS10 produces another 5db, while going all the way to QRSS60 produces a whopping 24.8db over 6 WPM CW! The trade off, of course, being the amount of time it takes to send the needed information.

In practical terms, contacts can be made relatively quickly at both QRSS3 and QRSS10. After that it becomes a bit of a chore as conditions need to be very stable for long periods of time ... as well, you'll need several hours to complete a two-way exchange.

courtesy: https://www.google.com/earth/

VA7MM - QRSS3

VA7MM - QRSS10

VA7MM - QRSS60

This is over a 120 mile (192km) path but what is remarkable is the rugged nature of the path as shown here:

courtesy: http://www.heywhatsthat.com/profiler.html

Although mostly over water for the second portion, the initial launch of Mark's signal is into a hellish 60 mile path of rugged coastal mountain peaks, with most of them in the 3,000 - 4,000 foot range! If this is an all groundwave path, and I suspect that it may be, it surely demonstrates the amazing groundwave capability of 630m. If there were any skywave involved, I would expect to see some fading on the signal path ... but the QRSS60 signal looks rock-solid and fade-free.

I should add that Mark's transmitting antenna is very minimal at the moment, consisting of an 80m dipole fed as a vertical 'T', tuned but not impedance-matched and ... no ground radials. Pretty remarkable actually.
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

We will be shooting Ham College episode 3 this Friday night, March 27th at 7:00 CDT, 0000 UTC. Join us at www.live.amateurlogic.tv if you want to watch the raw, uncut, live version.
George Thomas, W5JDX, is co-host of AmateurLogic.TV, an original amateur radio video program hosted by George Thomas (W5JDX), Tommy Martin (N5ZNO), Peter Berrett (VK3PB), and Emile Diodene (KE5QKR). Contact him at [email protected].

We are just finishing up the details and it looks like a live episode of AmateurLogic.TV will be broadcast from the Icom booth at Dayton Hamvention, 2 – 4 PM EDT, May 16th.

A special set is being built for the event. It’s going to be a lot of fun!

If you attend Hamvention this year please come by and show your support for ALTV.

George Thomas, W5JDX, is co-host of AmateurLogic.TV, an original amateur radio video program hosted by George Thomas (W5JDX), Tommy Martin (N5ZNO), Peter Berrett (VK3PB), and Emile Diodene (KE5QKR). Contact him at [email protected].

I have recently been made aware of the Socété Québécoise des Collectionneurs de Radios Ancien's / (SQCRA or Quebec Antique Radio Collectors Society) 'Radio Restoration Contest' and have been enjoying some of the published documents describing various refurburations.

Although the group has been sponsoring the refurb contest for over 10 years, this is only the third year that it has been open to international competition. The rules are interesting and are quoted from the SQCRA website:


Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

Up to now, the Japanese “big boys” such as Icom, Kenwood and Yaesu have pretty well dominated the amateur radio market, but the Chinese are on the march. Only last month I bought a 30W pep all mode rig for 10m: this was made in China. See also yesterday’s post about 40m Pixie kits at ridiculously low prices.

Be in no doubt: within a few years we will see the amateur radio market flooded with quality products made in China with low prices. At this point, the traditional Japanese brands will die out or be made in China. By the next solar minimum in around 4-5 years time the dynamics of the commercial amateur radio market will be very different. The writing is already on the wall.

Up to now most Chinese amateur products have lacked the finesse of Japanese products but this is rapidly changing. We are fast approaching the time when Chinese made amateur products will be every bit as good as Japanese products, but at very much lower prices.

In the end competition is healthy but this is likely to result in the death nell for all manufacturers not in China. We could well see the death of Ten Tec and Elecraft unless they design in the USA and make in China. The volumes of loyal customers who would be willing to pay USA manufacturing prices would be far too low, sadly.

Of course, we have already seen this with most consumer products and white goods. In the end, China will become too expensive and we will look for slave labour rates elsewhere. Sadly we live in a very odd world. This cannot go on for ever, but we are all complicit. At the moment we are exporting most of our manufacture to China.

Roger Lapthorn, G3XBM, is a regular contributor to AmateurRadio.com and writes from Cambridge, England.

The recent posting by BCB / NDB DXer, Steve Ratzlaff (AA7U in OR), describing the poor performance of his initial LNV, prompted another round of valuable discourse on the Yahoo NDBlist Group. Steve indicated that his new 40' LNV was virtually deaf compared to his loop and active whip. ... until he rewound the transformers.

"I've fixed the very low sensitivity of my 40 foot LNV. The transformer
needed more turns for my particular setup--that made all the difference
in the world. I'm also using coax cable, not twin lead--that apparently
makes a big difference in the proper transformer turns ratio too. But
the LNV with preamp is now about the same sensitivity as the active whip.

My transformer primary uses 110 turns, to give good reactance at
the low end of the NDB band. I started with 21 turns on the secondary,
tuned to my local beacon LGD on 296 and looked at the signal level,
removing two turns each time until I got to 8 turns. A broad peak was
with 16 turns which is what I used for the final secondary turns. That's
a turns ratio of 110/16 = 6.875.

Total coax run from the mast to the middle of the home is about
135 feet where it enters the home.

I did some ground rod checks for signal level too. I have 3 ground rods
installed at the LNV--6 foot, 4 foot and a short 2 foot. I started out
with all three connected and took a reference signal reading, then just
the 6 foot; then just the 4 foot and then just the 2 foot. Signal level
dropped several tenths of a decibel for the 2 foot rod and was the same
for the 4 and 6 foot rods by themselves and for all 3 rods connected. So
my particular setup likes something a little longer than 2 feet for the
ground rod. I'll leave all three rods connected for now since they're
already in place.

The LNV being in a different location is now quieter on some lower end
signals where the active whip is noisy due to the whip being closer to
AC power--a nice thing. The low end 195-205 kHz especially are often
unusable due to noise; the LNV is much quieter for those, apparently due
to it being 100 feet farther from the AC power at the home.
So, the bottom line is my LNV is now working like it should, I believe.
I'll continue to use it and do more comparison checks since I can switch
my antennas instantly."


From Roelof, PAØRDT:

" ... I believe the  term low noise vertical is a bit misleading. These verticals are only suffering less from local noise compared to loop antennas when
located close to the house.
The reason is that the vertical is receiving the electric field and
the electric field of local noise sources located in the house fall
off very quickly outside the house, especially at LF and MW.
A loop antenna does receive the magnetic field of local noise
sources and this field does not fall off close to the house.
I can demonstrate this effect here any time with my modified ALA1530
and mini-whip antenna.
"Matching" this type of vertical to the 50 ohm input of a receiver
is interesting. Connecting it directly to the receiver input, will
load the antenna too much and the voltage across the antenna
terminals will collapse.
This problem can be solved by using a high input buffer amplifier as
used in active whips or by a voltage step down transformer.
Due to imperfections in the step down transformer, e.g.
inter-winding capacitance and insufficient inductance of the
receiver tap / secondary winding, signal output will be way down
compared to an active whip of the same length, using a high input
impedance buffer amplifier.
You can use a tuned vertical to overcome this, however doing so the
broad band nature of the antenna is lost.
Living close to strong broadcast stations, which prevent the use of
active antennas, this particular type of E-probe is an excellent
alternative."

And from Anthony Casorso in CO:

"Motivated by your posts, I build a new transformer using an FT140J with 100 turns on the antenna side and a 10 tap secondary with a rotary switch to select the tap. The taps were from 8 turns to 26 turns in 2 turn increments.

courtesy: www.dxengineering.com/

Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

 

Fred Lesnick, VE3FAL, is a regular contributor to AmateurRadio.com and writes from Thunder Bay Ontario, Canada. Contact him at [email protected].