Sunday, 21 May 2017

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.

Monday, 15 May 2017

The G3XBM Experimental Blogs

G3XBM's 5W Earth-Mode Tx (courtesy: G3XBM)






My interest of late has been piqued by the ongoing VLF experimental work by several European amateurs.








Recalling that Roger, G3XBM, did some VLF experimenting a few years ago, I have been reviewing some of the excellent hands-on information gathered and published in his ham radio blog and to some of his other VLF pages.

It's not the first time that I have found project-inspiring reading within Roger's blogs. They really are a treasure-trove of useful information, construction notes and accumulated test data gathered from his methodical approach to so many interesting topics ... experimental amateur radio at its very best.

A few years ago I was immediately hooked by his experimental lightwave work, both line-of-sight and clear-air / cloudbounce scatter ... so much so that I also became involved in some lightwave work with other locals who were also inspired by Roger's information, culminating in our own West Coast Lightwave Adventure.

Roger's VLF experiments are also proving hard to resist, especially those of the earth-mode type and I may find myself falling victim to his detailed Sub 9kHz Amateur Radio pages and the Earth Mode pages in particular.

It seems that most amateur VLF work is being done in the vicinity of 8kHz since this part of the frequency spectrum is unassigned. I gather that one can conduct earth-mode tests in any portion of the VLF spectrum since no signal is being 'radiated' as is typically done via antennas. Further investigation remains to see if I need a 'developmental licence' to conduct some radiated (non-earth-mode) experiments in the 8kHz range as well.

Getting a VLF signal from here on Mayne Island across Georgia Strait via earth-mode or via conventional methods would make an interesting challenge and would certainly result in some new homebrewing opportunities.

courtesy: https://www.google.ca/maps

Here on the island, I often hear audio associated with the container terminal and ship-loading operations near Tsawwassen, directly across the strait from here. I feel that this may be aided somewhat by the solid sandstone of the island being directly connected to the other side, so perhaps an earth-mode system utilizing the ocean as one-leg of a buried loop might be an interesting experiment to tackle ... or groundwave transmissions across the ocean via an antenna, to the other side, providing I could find someone to listen.

I see just two Canadian amateurs experimenting on VLF ... VO1NA (Joe) and VA3VVV (John) near Toronto. Any VE3's in the area who are interested in VLF may wish to contact John and exchange notes. He has a Facebook page showing his VLF setup. Interestingly, Joe's 30W VLF signal on 8.270 kHz has just crossed the Atlantic! Joe is documenting his VLF experiments here.

All of G3XBM's VLF blogs can be downloaded for reading or for printing via this link. Similarly, his lightwave experiments can all be found here ... both links will yield several pages of material if you click on the 'Older Posts' link at the bottom of each page.

The best way to follow these is chronologically which requires going all the way to the end of the final 'OlderPost' link and follow along with Roger as he gradually develops, evaluates and improves the gear that he needs to make progress. This is fascinating reading.

But be suitably warned ... you may readily fall victim to his experimental work as well and suddenly find yourself with another exciting project!

Wednesday, 10 May 2017

May's 'Red Ryder' EME Ops

There still seems to be a number of 'big guns' showing up each month, that I have not heard or worked before as well as several 2-Yagi 'little pistols' that I am able to work under very good lunar path conditions. I suspect that having just 1-Yagi puts me in the $2.95 'Red Ryder' category!



With the QSL's from last month's surprisingly good EME conditions just starting to arrive, May's moonbounce operation continued to produce good results.







Whether this is because of better than normal lunar path conditions or just a result of my neighbour's tree-pruning, remains to be seen.

The few days of operating in early May were, as usual, planned to take advantage of the Moon's closest approach as well as the Moon's most northerly declinations. The latter condition puts moonrises directly out in front of the house and looking across Georgia Strait's many miles of saltwater. The extra theoretical 'sea-gain' appears to be a reality under these conditions and allows my 9el Yagi to garner another 6db on both transmit and receive paths, making it perform more like a '4-Yagi' array.

Eight stations were worked this time around, with six of them being new 'initials', bringing my EME total from 95 to 101. Several of these stations were speaker-audible, at CW levels.

          NTØV #96
          IK7EZN #97
          EA2AGZ #98
          G4SWX
          F6HVK #99
          G4CDN #100
          DK5LA #101
          DK3BU

IK7EZN's cross polarized 4 x 13 array    

EA2AGZ's 4 x 16 array

DK5LA's cross polarized 8 x 16 array ...very loud!

For now, any earlier thoughts of building a 4CX250 300 watt amplifier have been put on hold, while I continue to slowly work my way through what seems a never-ending list of workable stations.

Friday, 5 May 2017

LF / MF News From Monitor Sensors





A note from Roger, VK4YB of Monitor Sensors, reports some interesting news.








You might recall that his company manufactures a very versatile and well-engineered 630m transverter which was used at both ends of our two 630m JT9 contacts last year during the fall equinox propagation peak between North America and down-under.

Roger now reports that Monitor Sensors will be producing a new 2200m transverter, with all of the bells and whistles found on the 630m unit which has proven to be a real workhorse.


Monitor Sensors 2200m Transverter

The Monitor Sensors TVTR2 2200m Transverter enables any Amateur Radio Station, equipped with a conventional HF transceiver, immediate, all mode, access to the new 135.7-137.8 kHz, 2200m band.
The receiver design incorporates a 7pole Chebyshev filter, 3kHz wide roofing filter and a 5 pole Chebyshev filter in cascade before the double balanced, commutating mixer, fed by an ultra stable, temperature compensated, extremely low phase noise, MEMS local oscillator. The mixer is followed by a Chebychev band pass filter into an ultra linear, low noise, current feedback, IF amplifier. The receiver noise floor, in a 500Hz bandwidth, is -125 dBm and yet the onset of compression is not reached until +11dBm. A front end 20dB attenuator can be switched in for even higher signal handling. Overall receiver gain is set to +6dB, or -14dBm with attenuator in.


The transmitter input circuit incorporates a 0-14 dB switched step attenuator to prevent over driving. The same mixer and local oscillator are used on the transmit side. The PA uses 6 rugged lateral FETs in class AB push-pull to easily achieve the 50 watts rated output. Lateral FETs are inherently linear and thermally stable. The transmitter can be run at full power, indefinitely, into a dead short or open circuit without any danger of damaging the FETs. Transmit-receive switching is automatic with user selectable VOX delay. Alternatively the PTT line may be used.


The transverter employs extensive and accurate metering. Power input and output, SWR, Frequency, Attenuation in use, Temperature, Supply Voltage, Current and Resistance are displayed.
Transmission is inhibited if carrier frequencies outside the 135.7-137.8 kHz band are detected. A tuning screen may be selected which displays SWR in digital and graphical form for easy antenna adjustment. The menu system is self explanatory and users report no manual is needed, although one is supplied. A USB socket is provided for future code upgrades (free of charge) from the Monitor Sensors web site.


The transverter has been designed for the best possible protection against accidental mishaps. It will survive reverse polarity supply and the injection of 100 watts of HF into any of its ports whether in transmit or receive mode. If supply current exceeds 25 Amps, the supply is cut in 3 microseconds. This electronic breaker can be reset by simply switching off and on again. The transmitter will shut down in the unlikely event that the internal heat sink reaches 90°C. The cooling fan is under the proportional control of the microcomputer and begins operation above 35°C. Any unusual operation will cause the screen to turn red and an appropriate warning will be displayed.


TVTR2 Specifications


RF frequency range 135.7 to 137.8 kHz
IF frequency range 1805.7 to 1807.8 kHz (others available in the 160m band)
Transmission modes CW, SSB, WSPR, and all other data modes
Output Power 50 Watts Continuous, 100% duty cycle @13.8V supply
Input and Output Impedance 50 Ohms
Supply voltage 13.8 VDC @ 15 Amps nominal, 10-16 VDC operational
Rx noise floor -125 dBm (500 Hz bandwidth)
Rx 3dB compression point +15 dBm (Rx attenuator out)
Rx IF rejection better than 75dB
Rx conversion gain +6dB nominal
Roofing filter in-band ripple +/- 0.5dB
Tx 3rd order IMD -33 dB below PEP, typical at 50W output
Tx 5th order IMD -45dB below PEP, typical at 50W output
Tx harmonics and spurii All better than -50dB
Tx conversion gain +10dB nominal
Power input connector 2 * Anderson Power Poles (one Power cable supplied)
RF connectors 3 * SO239 (one PL259 to PL259 cable supplied)
PTT connectors 2 * RCA (one RCA to RCA cable supplied)
USB connector Micro B USB, (matching cable supplied)
Dimensions 12½ * 4¼ * 3 inches, 320 * 120 * 76 mm
Weight 3.4 lbs, 1.6 kg


In addition to the transverters, Monitor Sensors will also be manufacturing solid state amplifiers for both the 2200m and 630m bands with power levels at around the 450W output level. Like the transverters, these will be 'linear' devices as well. It is possible that a duo-band amplifier will also eventually be produced.

It will be interesting to see if any other new gear becomes commercially available from other manufacturers once the LF / MF ham bands are introduced in the U.S.A. , something that is expected to happen fairly soon.

Sunday, 30 April 2017

The May 'Bug Roundup'

Vibroplex "Blue Racer"



Ever since earning my ticket as a teenager back in '63, almost all of my on-air activity has been focused on CW ... I've always loved it.




For my first year on-the-air, I used a nice brass hand key purchased locally for just a few dollars but once I had mastered that and I was just unable to send any faster with it, I purchased a Vibroplex 'Original', for, if memory serves me correct, around $40. I used it exclusively until building a homebrew memory keyer in the mid-70's and the Vibroplex saw little service for several years.

The Vibroplex 'Original'
Back when I first got on the air there were very few amateurs using keyers. Most used bugs and the remainder used the brass hand pumps. It was very easy to tune across the band and identify any of the locals just by the sound of their fist ... like snowflakes, no two were the same. The same went for most stations that were very active. DX or otherwise, one could usually tell who it was long before the callsigns were heard.
So much has changed now with the almost exclusive use of electronic keyers and everyone pretty much sounds the same, which is rather a pity I think.

Once my interest in building vintage-style vacuum-tube transmitters evolved, my interest in bugs was reactivated and over the years I have purchased a few more.

I'll do anything I can to promote and encourage the use of CW and especially hand-generated CW. That's why I was excited to read a recent e-mail from W6SFM, posted to several lists that I read, announcing the Bug Roundup!
 
The Samuel F. Morse Amateur Radio Club, a Sacramento, California based CW enthusiast club wanted a special time to bring bug operators together on the air. In the same spirit as ARRL's Straight Key Night, participants are encouraged to make simple, conversational, “chewing-the-fat”, "Rag Chew" QSOs using their bug type key. This is an opportunity to exercise, share and exhibit your personalized fist. This is NOT a contest. Simply Call "CQ BR" so folks know you are a Bug Roundup Participant. Grab that bug, clean those contacts, and let’er fly! Let’s hear that “Banana Boat / Lake Erie Swing" or that commercial KPH/WCC quality fist.

Reserve the day! Saturday May 20th - Sunday May 21st, 2017
7:00 AM to 7:00 AM Pacific Time (LOCAL)
1400 UTC through 1400 UTC

For more information, to register your station and key for participation, and to help assist in spotting, potentially increasing QSOs, an On-line chat window link can be found near the bottom of Bug Roundup home page located at http://www.w6sfm.com/Bug_Roundup.html We hope to hear you all on the air!

It looks like a fun event and might make another good reason to fire-up your old boatanchors on CW once again. It looks like you can keep track of activity and possibly set up skeds via their chat-window page during the BR.

In any event, my biggest decision will be to choose which bug to use as I have five at last count. I think I'll be brave and try the Blue Racer but will probably have to dampen it down a bit as they are really quite fast.