AmateurRadio.com

F1AVY's Cloudbounce System

 "Returning to Steve's questions and our general discourse:

..is it (the RX) fairly small and portable...and lensless?

I do have a lens in the RX I now prefer to use - although it happens to be a convex lens from a tabletop magnifier - about 7x12cm giving me a narrow reception beam and a fair bit of gain compared with naked photodiode. There seems to be a general agreement that increasing the size of receiving aperture will capture more light and is the best way to greater gain.

Here I need to qualify gain requirements for my particular applications. I am currently exploring relatively short-distance NLOS paths in urban environments with abundant QRM from city and suburban lights, and this already limits my gain requirements. I developed my own qualitative test of satisfactory sensitivity - by pointing my receiver at individual stars in the sky. If I can hear them twinkle (yes they do twinkle!!!) then I am generally satisfied with the project.

On cloudy nights, pointing the RX into the clouds brings an interesting combination of mains harmonics and general hash from neon lights, clicking pulses from aeroplane lights, sweeping sounds from airport and marine lighthouses. In an environment like this, going to extreme lengths as one would do for very long-range cloudbounce or LOS comms in dark and secluded areas is simply not required and uneconomical. I initially did invest time and money in large receiving boxes with the best components there are, only to find that, unless I moved out into the bush, I could not take a real advantage of the improved performance, and did equally well with smaller and more wieldy portable designs.

"Is the idea, when talking about NLOS, to light up as much sky as possible...and that is why no focusing lenses are employed? Would a focused emitter, as produced by the typical Fresnel lens light box, produce too narrow a beam than desired? It would seem likely that with precise aiming combined with the gain to be had by utilizing fresnels (for example), would produce longer paths??"

There are several separate issues there. One is the implied requirement for a large Fresnel lens in order to obtain a narrow beam. First, how narrow is narrow enough? If we can be satisfied with say +- 5 degrees then there are more wieldy solutions available - most of the high power LEDs now have clip-on small spot lenses awailable separately - usually from third-party manufacturers. These were unheard of until recently. Standard-sized LEDs are available with very narrow radiation pattern, e.g. the SFH4550 at barely +-3 degrees. And one would expect an array of 200+ of them to behave quite like our stacked Yagis, many times over! Hence narrow beam is quite possible even without an external lens.



Osram SFH4550 IR LED

Of course the extremely narrow beams that one would prefer for LOS DX comms would be next to impossible to align in NLOS situation. (Invisible infrared is not a problem in LOS as it can be easily supplemented with e.g. a plain strobe light for alignment purposes.) I find my +-3 degrees array (with similar +-3 deg aperture at receiving end) hard enough to align over the horizon, and it is probably the limit of how narrow one can go to remain practicable in NLOS.

"to light up as much sky as possible..."

It is possible that cloudbounce and obstruction-bounce will develop into separate NLOS techniques, along with atmospheric scatter.  Of course one can think of all of these in some topographies.

I had some success in inter-suburban cloudbounce with high beam elevations at both ends - 30 to 60 degrees. Also with 45 degrees or less elevation with TX and RX about 1km apart side by side and pointing at the same cloud in the distance. Power used around 10-20W, beamwidth +-5 to 10 degrees, red and infrared with similar results (including 950nm). The received signal was just strong enough for telegraphy or qrss, but never near enough for any type of voice modulation. Results were affected by the height of cloud cover necessitating frequent elevation adjustment, and an additional liaison channel on VHF. Signals disappeared entirely as soon as the clouds started producing rain.

I never got any usable results with clear night sky and the TX and (imaginary) RX beams crossing each other at similar elevations. Only at very close distances - the best signals being received with blue and infrared. Presumably Rayleigh scatter with blue. (This raises the possibility of usable atmospheric scatter with UV?)

Only recently I commenced preliminary tests with close-to-ground, low-elevation NLOS and immediately the infrared proved itself to be a clear winner with quite reliable and repetitive results. (Needless to say the signal strengths are marginal compared with direct LOS over similar distance.) Intuitively, one would suspect general scatter and bouncing of nearby objects being the main sources of some of the energy reaching over the horizon, with some contribution perhaps of atmospheric/dust/aerosol scatter.

This adds an additional dimension to your question.. to light up as many objects around the TX(or around RX, or around the obstruction) as possible, or send the focused beam as far as possible? I guess it will very much depend on topography. I can imagine a situation where I would prefer to use a broad floodlight rather than a focused beam - e.g. to illuminate as many as possible of the surrounding tall buildings if transmitting from a ground floor apartment. Or from the foot of a mountain. An opposite rule would apply if it is the receiver that is just behind an obstruction - here a focused TX beam and a broad RX aperture might prove advantageous. And where the main obstruction is midway between TX and TX than the usual narrow-beam configuration would apply at both ends. I think it might be worth trying an infrared TX with interchangeable lenses, and same for the RX...
The portable TRX image shows the general view. Most of the electronics is contained in a plastic box and includes an SLA battery, the RX audio bandpass filter, power amp and speaker, and most of the PWM AM TX circuitry except the final LED driver. The DIN socket provides connection to external RX front end TX output drivers and LEDs, usually held together on a tripod. The header socket is for the external microphone connection, and there are switches for power and speaker and a headphone jack. The crudely made corflute box beside it is the RX front end with lens, photodiode and preamp.





The RX detail 01 shows the business end of the photodiode, and the separate lens box (slides in and out for focus adjustment). Detail 02 shows the preamp with interchangeable photodiode modules - SFH213 for visible to 850nm, and the SFH213-FA for 850nm and below.

Multi-wavelength TX 01 (front and back image) includes several groups of fat LEDs (red, blue and 850nm) with matching lenses providing approx. +-5 degrees apertures. Also the PWM driver on 2x CAT4101 in parallel, external high current power connection, intensity control, and a PICAXE-controlled strobe or audio callsign/frequency sweep beacon.The whole assembly connects to the TRX control box (above) and can provide power to it, draw power from it, or have both DC sources in parallel.Enclosure includes a photo tripod mount on the bottom plate, and velcro strips on top to hold the RX front end.

Pocket-sized 10W IR TX is a small holiday project and still work in progress. The 7x LEDs are 2W each SFH4783 with an intrinsically narrow beam of +-10 degrees - quite appreciable for a naked LED of this size and possibly obviating the need for external optics in some applications. My usual CAT4101 drivers are included and capable of providing 2A at 50% duty cycle. Another Picaxe beacon is on the other side of the heatsink, and the voice modulator is still in progress.



The low-power multi-wavelength TX is another one day project, built to compare relative performances of 850 and 950nm IR. Three almost identical beams of red, 850 and 950 are transmitted in sequence with approx 100mA PWM running each diode. Unique CW ID has been coded for each wavelength.




6x SFH213 photodiode with individual preamps - quite a respectable low noise, high sensitivity front-end that works very well without external optics (SFH213 have a +-10 deg intrinsic apertures). A matching array of small fresnel lenses has been built and tested for narrow-beam reception, but a permanent box is yet to be added.. Some of the other gadgets seen in the foreground."

As mentioned earlier, Jan's experiments with NLOS signals utilizing IR is of particular interest to myself as I would like to continue experiments with VE7CA, on the other side of Georgia Strait...hopefully with Markus not having to move to a LOS position, but simply aiming across the Strait in a direct path, from his yard. Using Argo and QRSS3 mode, it will be interesting to see if any signals can be recovered from the cloud bottoms on some overnight runs.

More information on NLOS work may be found on the Australian Optical DX Group in Yahoo Groups as well as in the UK Nanowave Group....why is it that these two countries have so much homebrew fun??,,,and don't forget Clint's (KA7OEI) superb Optical Communications / Moduulated Light pages!

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

Christmas came and went very quickly this year yet again. I must be getting old these days to feel that I don't enjoy it any longer? No sooner we had done the shopping and all the running around for ourselves and the family, stuffed the turkey, had a few visitors and done a bit of entertaining, we were left with nothing more than a few bones and an empty fridge.

The last of the turkey went in the pot a few days ago and we boiled it up for a nice stew, this was really appreciated as the weather had turned colder here since Boxing day the 26th, we even had some snow! After the stew followed a nice piece of homemade Xmas Cake and a large Scotch keeping one in the spirit of things.




Presents were few this year, I cheekily had asked for the money on purpose because I would like a new wristwatch, when the one I have been looking at for quite sometime comes around in a sale in the New Year at the right price.

However, apart from the analogue meter which I have already purchased from the gift cash pot: (see: http://g1kqh.blogspot.co.uk/2014/12/spare-pocket-money.html ). I did receive a couple of other nice little presents too. A book from the RSGB by Eamon Skelton & Elaine Richards. Building a Transceiver http://www.rsgbshop.org/acatalog/Online_Catalogue_Technical_6.html  (I currently do not have permission from the RSGB to reproduce or copy, so I cannot provide a photo of the front cover, hence the link. I am working on this one!).

My other tech present was a nice little DMM in the shape of a probe from Mastech Model MS8211:








First thoughts about this, it comes in a sturdy box with instructions and a certificate, complete with a nice case, a couple of leads for the Com, one with a probe and the other with a croc clip attached. The whole unit has got a nice rugged feel about it.

I am looking forward to reviewing the DMM along with the book further down the Blog.


A Happy New Year to you all!




Steve, G1KQH, is a regular contributor to AmateurRadio.com and writes from England. Contact him at [email protected].

2014 was a stellar year for amateur radio. The year-long celebration of the ARRL Centennial was nothing short of fantastic. The QSO Party and the summer convention were major successes. Our hobby has never received so much attention by popular media. For one entire year, ham radio became the ‘Kardashian’s’ of the hobby world. The ARRL deserves most of the credit for their hard work and vision in promoting our hobby while working tirelessly to foster future growth and protect the valuable resources we enjoy.

Amateur Radio and electronics are woven tightly together and 2014 was without doubt the Year of the Raspberry Pi and everyone jumped on the bandwagon, including radio enthusiasts. It wasn’t difficult to find numerous ways to put these credit-card sized, $35 computers to work in the shack — replacing desktop computers employed for dedicated functions. The trajectory of this trend is nearly vertical and we can expect to see even more interesting uses from it in the coming New Year.

The HF bands cooperated with the major DX operations in 2014. In fact, what appears to be a double-peak in this current solar cycle created some real excitement — about the same time the experts declared us to be on the backside of decent and headed toward minimum. I’m amazed by the courage of operations like FT5ZM that moved forward with their plans despite predictions of less than great band conditions, and brought joy (and QSL’s!) to DXers everywhere.

Logbook of the World adoption picked up steam in 2014. The online service has now crossed 100 million confirmations and the number of users could cross 100,000 in the New Year.

Operators on the International Space Station delighted the world with SSTV transmissions in late 2014 reminding the entire planet that amateur radio still has a shack in space!

Amateur Radio really took to social media in 2014. Facebook and Twitter being the primary beneficiaries of Maxim’s progeny. The ARRL Facebook page has nearly 50K “likes” while its main Twitter account has over 20K followers. Yes, we’ve been tweeting up a storm and the @CallSign label appears on almost everything #HamRadio these days. This won’t last forever, Internet time moves fast and things change in a heartbeat online. Still, these forms of social media are continuing to expand and amateur radio seems firmly affixed for the ride.

Every year it seems we lose more of the old guard, passings that leave us feeling a little off-balance in our mission. 2014 was no different in that regard. Though many of our giants have left us, their work and inspiration continues — in us. That’s the point. The tasks that we undertake and share today, are passed along to tomorrow.

It’s been that way with our passion since the basement experimenters first began to decode the secrets of radio, and passed them along to the next generation of basement experimenters in order to perfect the art and science of radio.

And that work continues into another new year — a new century — a new millennium for amateur radio.

Nostalgia is a wonderful place of retreat to warm and nourish your soul but those are chapters in a book already read. RIGHT NOW is infinitely more exciting because we don’t know what will come next, but we get to write the next chapter!

Filed under: Ham Radio, Syndicate Tagged: history

Jeff Davis, KE9V, is a regular contributor to AmateurRadio.com and writes from Indiana, USA.

Stories you’ll find in our January, 2015 edition:

K3LR: Contesting With the Big Guns
By Mark Haverstock K8MSH

Looking at the cover photo on this month’s TSM prompts the question, “Does this guy have enough antennas?” That’s a question that’s been asked hundreds of times by drivers on Interstate 80 who pass by the amateur radio antenna farm just east of the Ohio border. Tim Duffy K3LR says, “No. You can never have too many antennas!” Since 1987, Duffy has spent countless hours building his dream station, as well as collecting numerous contest awards along with the operators that make up the K3LR Contest Team. This is their story.

Monitoring Utility and Amateur Radio Transmissions with a DVB-T Dongle
By Mario Filippi N2HUN

With a small investment, any radio hobbyist can expand the reception capabilities of a DVB-T dongle to include long wave, medium wave and short wave frequencies. Creative individuals in the software industry have realized the potential of these diminutive, economically priced devices and have crafted programs that allow the dongle to function as multi-mode Software Defined Radios, when attached to a USB port of a computer.

Volunteer Interceptors: Listening for Terrorists
By Bob Patterson K5DZE

Any amateur, SWL or scanner monitor, who listens to a range of frequencies on a regular basis, soon learns what normally is heard over that range. These frequencies become the operator’s “radio
neighborhood.” Should a Volunteer Interceptor (VI) service be organized within the radio enthusiast community to monitor radio frequencies for possible national and international threats?

AMIKO A3 FTA Satellite Receiver
By Ken Reitz KS4ZR

If Apple made a Free-to-Air (FTA) satellite receiver it might look and perform like the AMIKO A3. In fact, opening the A3’s box, you might think you were opening a Mac; electronics manufacturers all seem to have taken a tip from Apple’s packaging concept. The Mac reference is a plus and a minus. Like a Mac, the A3 is modern in design, ruggedly built, and takes a little getting used to.

Why Go Digital?
By Cory GB Sickles W3UUV

Digital voice (and data) radios are certainly here to stay. This is one of the fastest growing and evolving aspects of amateur radio today. Although DV’s roots extend back more than 25 years, we’re still introducing new ways to communicate with ones and zeros, through methods that will eventually put analog VHF FM where HF AM is today.

Scanning America
By Dan Veenaman
Monitoring Digital Systems

Federal Wavelengths
By Chris Parris
A Year in Federal Monitoring

Utility Planet
By Hugh Stegman NV6H
More Russian “Numbers” Mysteries

Digital HF: Intercept and Analyze
By Mike Chace-Ortiz AB1TZ/G6DHU
Have PacTOR, Will Travel The High Seas!

HF Utility Logs
By Mike Chace-Ortiz and Hugh Stegman

Amateur Radio Insights
By Kirk Kleinschmidt NT0Z
Current Balun Bonus: Noise Reduction?

Radio 101
By Ken Reitz KS4ZR
The View Ahead, Through the Rearview Mirror

Radio Propagation
By Tomas Hood NW7US
Fundamentals: Radio Wave Propagation

The World of Shortwave Listening
By Jeff White, General Manager, WRMI Shortwave
Shortwave Listeners make their Voices Heard

The Shortwave Listener
By Fred Waterer
Change and Opportunity in the New Year

Maritime Monitoring
By Ron Walsh VE3GO
Marine Radio Traffic and Heritage

The Longwave Zone
By Kevin O’Hern Carey WB2QMY
Firing Up the Neophyte 1
(Formerly: A Cure for PPHD)

Adventures in Radio Restoration
By Rich Post KB8TAD
Back to the Future

The Broadcast Tower
By Doug Smith W9WI
This is a Test. This is only a Test.

Antenna Connections
By Dan Farber AC0LW
On The Road Again: Mobile Antenna Concepts

The Spectrum Monitor is available in PDF format which can be read on any desktop, laptop, iPad®, Kindle® Fire, or other device capable of opening a PDF file. Annual subscription (12 issues, beginning with the January 2015 issue) is $24. Individual monthly issues are available for $3 each.

Ken Reitz, KS4ZR, is publisher and managing editor of The Spectrum Monitor. Contact him at [email protected].

It’s always interesting to see which of my blog posts are getting the most attention. According to my website stats, these posts got the most views in 2014. It turns out that most of these were written before 2014 but they are still getting lots of hits.

The top post was 2012 Jeep Wrangler Radio Install. When it comes to doing mobile radio installations, I’ve often found it helpful to search the web for information. There’s nothing like seeing how someone else did their radio install to get some help and guidance. With this post, I tried to repay the favor and it seems that lots of people have gotten use out of it.

The second most popular post is Can I Use My Ham Radio on Public Safety Frequencies?  I wrote this one back in 2012 but always seems to get a lot of hits. It is getting a bit out of date, so I should probably update it.

Next up is Solving the Baofeng Cable Problem. This article explains how to solve one of the biggest challenges of programming those low cost HTs from China. Also on the subject of low cost HTs is this popular post: Yet Another HT From China (Baofeng UV-B5).

Another popular post is my list of favorite ham radio iPhone apps: The Incomplete List of Ham Radio iPhone Apps.  This post from 2011 is definitely out of date but keeps getting lots of hits. I’ve updated this list a couple of times now and the most recent post is here: The Completely Updated Incomplete List of Ham Radio iPhone Apps. For some reason, the obsolete post still gets viewed the most.

Well, that is the top five posts but I am including a sixth bonus post at no extra charge. The FM/VHF Operating Guide is arguably one of the best time-tested articles I’ve written, originating way back in the twentieth century. It has taken many forms and revisions over the years and is now a static page on k0nr.com.

Thanks for stopping by k0nr.com and have a Happy New Year.

73, Bob K0NR

The post Top Five K0NR Blog Posts from 2014 appeared first on The KØNR Radio Site.

Bob Witte, KØNR, is a regular contributor to AmateurRadio.com and writes from Colorado, USA. Contact him at [email protected].

Courtesy of the QRP-ARCI and Jeff Hetherington VA3JFF

 2015 QRP-ARCI NEW YEAR’S SPRINT

A) Date/Time: 1500Z to 1800Z on 1 January 2015.

B) Mode: HF CW only.

C) Exchange: Members send: RST, State/Province/Country, ARCI member number Non-Members send: RST, State/Province/Country, Power Out

D) QSO Points: Member = 5 points Non-Member, Different Continent = 4 points Non-Member, Same Continent = 2 points

E) Multiplier: SPC (State/Province/Country) total for all bands. The same station may be worked on multiple bands for QSO points and SPC credit.

F) Power Multiplier: >5 Watts = x1 >1 - 5 Watts = x7 >500 mW - 1 Watt = x10 >200 mW - 500 mW = x15 >55 mW - 200 mW = x20 <55 mW = x25

G) Suggested Frequencies:

    160m  1810 kHz
    80m  3560 kHz
    40m  7030 kHz (please listen at 7040 kHz for rock bound participants)
    20m  14060 kHz
    15m  21060 kHz
    10m  28060 kHz

H) Score: Final Score = Points (total for all bands) x SPCs (total for all bands) x Power Multiplier + Bonus Points

Bonus Points: If you are operating PORTABLE using battery power AND a temporary antenna, add 5000 points to your final score. (You can NOT be at your shack operating from battery power using your home station antenna to qualify for this bonus.) This is to help level the playing field for contesters who work from the field against contest stations with 5 element yagis at 70 ft.

I) Categories: Band: Entry may be All-Band (AB), Single Band (e.g., SB-160, 80,40,20,15 or 10), High Bands (HB); 10m, 15m and 20m) or Low Bands (LB); 40m, 80m and 160m Antennas: Entry may be A1 or A2 A1: Single Element Antenna If you are using a single element antenna such as a dipole, inverted V, loop, or a vertical you can enter the A1 category. ( Note that with a vertical you can have as many radials as you want but only one “vertical” element. ) A2: Multiple Element Antenna If you are using a multi element beam, vertical array, or any antenna that has more than one driven element or uses reflective or directive elements you are in the A2 category.

J)How to Participate: Get on any of the HF bands except the WARC bands and hang out near the QRP frequencies. Work as many stations calling CQ QRP or CQ TEST as possible, or call CQ QRP or CQ TEST yourself! You can work a station for credit once on each band.

K) Email Log Submission: Submit Logs in plain text format along with a summary stating your Call Sign, Entry Category, total # of QSOs with members, total # of QSOs with non-members on different continent, total # of QSOs with non-members same continent, total # of SPCs worked, Actual Power and Station Description, along with score calculation to [email protected]

L) Snail mail Log Submission: Submit Logs in plain text format along with a summary stating your Call Sign, Entry Category, total # of QSOs with members, total # of QSOs with non-members on different continent, total # of QSOs with non-members same continent, total # of SPCs worked, Actual Power and Station Description, along with score calculation to:

ARCI NEW YEARS SPRINT
C/O Jeff Hetherington
139 Elizabeth St. W.
Welland, Ontario
Canada L3C 4M3

Deadline: Entries must be postmarked on or before 8 January, 2015.

M) Results: Will be published in QRP Quarterly and shown on the QRP-ARCI website.

N) Certificates: Will be awarded to the top scoring entrant in each category. Certificates may be awarded for 2nd and 3rd place if entries are sufficient in a category.

Thanks, Jeff!

An idea of my own - maybe participate in this sprint with a straight key?  A little SKN and QRP to boot?  Just a thought!

72 de Larry W2LJ
QRP - When you care to send the very least!
Larry Makoski, W2LJ, is a regular contributor to AmateurRadio.com and writes from New Jersey, USA. Contact him at [email protected].

LNR Precision is now flagging a price of $575 (£380 UK) for its new HF QRP radio the LD-5. I guess this price doesn't include shipping?

Currently it is flagged "Out of stock".

http://www.lnrprecision.com/store/#!/LD-5/p/39885476/category=10468544

I gave a short mention about this radio back in October:

http://g1kqh.blogspot.co.uk/2014/10/lnr-ld-5-no-news-is-good-news.html

Plus a link to its manual a few weeks later:

http://g1kqh.blogspot.co.uk/2014/10/lnr-publish-ld-5-manual.html

If I was buying this radio here in the UK, I would like to see it supported by a dealer, so I hope you all are reading?










Steve, G1KQH, is a regular contributor to AmateurRadio.com and writes from England. Contact him at [email protected].