AmateurRadio.com

You might remember that before Christmas, I missed the opportunity to try receiving some SSTV pictures from the ISS. Although I missed it, I took the chance to get the SSTV program working with the FT-8900.

At the end of last week, I learned that there would be some more SSTV activity from the space station, so was keen to try it out.

It worked really well. Some images were better than others and others were better than I expected them to be. A real surprise was a surprisingly good decode from a pass when the ISS was a modest 1 degree over the horizon.

The best images were from high elevation passes though. As ever the gear was simple, V2000 vertical, FT-8900 and MMSSTV on the PC.

Tim Kirby, G4VXE, is a regular contributor to AmateurRadio.com and writes from Oxfordshire, England. Contact him at [email protected].

You might remember that before Christmas, I missed the opportunity to try receiving some SSTV pictures from the ISS. Although I missed it, I took the chance to get the SSTV program working with the FT-8900.

At the end of last week, I learned that there would be some more SSTV activity from the space station, so was keen to try it out.

It worked really well. Some images were better than others and others were better than I expected them to be. A real surprise was a surprisingly good decode from a pass when the ISS was a modest 1 degree over the horizon.

The best images were from high elevation passes though. As ever the gear was simple, V2000 vertical, FT-8900 and MMSSTV on the PC.

Tim Kirby, G4VXE, is a regular contributor to AmateurRadio.com and writes from Oxfordshire, England. Contact him at [email protected].

Yesterday I had the chance to have a closer look at the two lenses recently purchased for a new portable lightwave receiver. The initial testing procedure of the page-size fresnel (actual size is 200mm x 270mm) proved incorrect and required more space than the bench top could provide. Eventually the focal length was measured as ~ 368mm +/- for an f/d, or F number, of 1.36 ... a convenient value and much better than the 'other' common fresnel page reader focal length of ~ 600mm. This jibed nicely with the recommendations given in Clint's (KA7OEI) website optical information:

"For practical reasons, it is recommended that an optical system using Fresnel lenses be designed using lenses that have an F-number in the range of 0.5 to 1.5 - that is, around 1. Remember: The "F-number" is the focal length divided by the diameter of the lens, so for an F-number of unity or one, the diameter of the lens would be the same as its focal length."

The lens was able to bring a small LED flashlight (consisting of an array of 21 white LEDs) into surprisingly sharp focus although the shot below does not reflect that due to my camera's poor focus in the darkened room.



The glass 4.5" magnifying lens proved to have a focal point of 203mm for an F number of 1.8. This lense produced an even sharper image of the same light source and may be the best candidate for the portable receiver although the larger aperture of the fresnel might not be worth counting out at this point.

The fresnel may work well for a transmitter and will likely require a small (inexpensive) secondary focusing lens between the LED and the fresnel, in order to have the LED efficiently illuminate the fresnel. The secondary should effectively gather and focus as much of the emitted LED light to just within the boundaries of the fresnel without any wasted light energy being lost to spill-over at the edges.

It would be great to have a permanent lightwave 'beacon' that one could test various receiver lenses and combinations but at present there is very little activity here in VE7 land ... although that is changing, with the interest of another local, VE7IGH (Greg) near Vancouver and right across Georgia Strait from my location. Grant has already built a receiver and will soon start on transmitter construction ... way to go Greg! 
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].

This came in from Steve, G1KQH, today. It is often cheaper to buy the completed, built modules from China than to buy the parts in the UK! What is the world coming to?

I bought 5 LM317s on PCB with heatsinks for a fiver:

 

 http://www.ebay.co.uk/itm/5-x-LM317-Adjustable-Voltage-Regulator-Step-down-Power-Supply-Buck-Module-Board-/221577652687?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item33970ea9cf

 

Why bother building it any longer, that used to be half the fun! The heatsinks would of cost a Quid each over here, never mind the LM317 and the PCB with connectors..

 

Happy days 

 

73 Steve G1KQH

http://www.g1kqh.talktalk.net/

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

Ham College episode 1 is now available for download.

Ham College, the new show for those new to the hobby and those wishing to get into Amateur Radio.

In episode 1 we bring you some news, discuss what an ‘Elmer’ is, talk about early radio history, build a spark gap transmitter, present 10 more questions and answers from the Technical class question pool, and more.

Your excuses for not becoming a Ham have just expired.

1:15:46

Download
YouTube

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].

Some radio time

A few things fell into place on Friday I got home from work in good time and I really had no house chores to do when I got home! It was radio time for the first time in about 2 or more weeks, I thought about checking the solar conditions….but that may bring dark clouds to my radio party. I decided to not let the propagation god's decide my afternoon but let the radio instead. I just wanted to jump in and see what was up in RF land. The weather has been very cold here the past few days in around -16C or lower. The MFJ 178 loop stays on the balcony all the time (under a patio table cover for ascetics) I hooked the coax up to it and the SWR was great on 15m, 20m and 30m all came in at 1.4:1 or less. I spent some time calling CQ at the QRP watering holes but no bites. I was getting reports on the Reverse Beacon Network so my signal was getting out. It was then the to use the Elecraft P3 to see how the

P3 external screen

bands looked if there were  other stations either calling CQ or in a QSO already. Most all station heard were State side except on 30m there seemed to be either a DX-pedition or a rare call. The station was weak and was running split and I did try to contact him but with no success. It seemed he (or she) was answering calls from only EA land at the time as that was the common call he was responding too. No contacts were made this Friday afternoon but that does not make the time a ZERO on the radio! I was able to feel the excitement of spinning dials and hearing the crackle of the bands in my headphones. In the past I have sometimes gone for weeks on end without any radio time for one reason or another. This time with the short time I had it seemed each and every radio related program I opened on the PC was wanting me to download updates! That I can do later as by the time the updates are done, as well as any hiccups as there always is with updates my radio time would had been long gone. So this time around it was time to skip the updates and just get right into radio.
Mike Weir, VE9KK, is a regular contributor to AmateurRadio.com and writes from New Brunswick, Canada. Contact him at [email protected].

Courtesy: http://www.arrl.org/

I've now completed a set of tank coils for the new'29 MOPA project. These were wound with 3/16" copper tubing which has become very difficult to source. Luckily, after much searching, I was fortunate enough to find several rolls locally at a very attractive price. Although I do see it quite often on e-bay, sellers either refuse to ship to Canada or their shipping charges are far too high to make it worthwhile. The larger 1/4" rolls are still readily available, but for any given inductance, will take up a lot more room on the breadboard if space is an issue.

These coils cover the amplifier tank, the Hartley oscillator's tank, and the antenna coupling link. Respectively, the coils measure 4.9uH, 4.0uH and 1.9uH.

Winding these is always fun but the method used requires that the needed length be predetermined and cut from the roll beforehand. The first time I did this, when building my TNT transmitter, I learned the hard way to always add at least another foot to cover the additional length eaten-up by turn-spacing and for coil end flattening and mounting.


While visiting Vancouver for a few days I was able to find a couple of pieces needed for my non-line of sight (NLOS) lightwave experiments.

I purchased a nice 4.25" magnifier lens, with suitable focal length, as well as an inexpensive page-size fresnel magnifying lens. What is particularly pleasing is that the fresnel is a rigid lens, about 2 mm thick, unlike most page magnifiers that are thin and floppy. I have yet to test its blur circle or determine its focal length.

I plan to use one or the other of these lenses in a small, portable lightwave receiver module that I can carry to the other side of the island to listen for the main large transmitter, aimed slightly above the horizon, in beacon-mode. If the smaller fresnel does the job, it will be an inexpensive source for anyone else needing a simple lens for either transmitting or receiving.

If the deep-red light tests prove successful, I'll switch the system to IR light but at this stage I'm not sure how focusing and optimizing receivers and transmitters can be done with a light source that is essentially invisible? Perhaps using an IR source that is right on the edge of deep-red will still have enough visible light to allow finding the optimum focus more easily.



More information on NLOS experiments can be found in Yahoo's Optical DX Group as well is in G3XBM' s 481thz blogs.

As well, anyone in the Vancouver lower mainland (as far as the northern Sunshine Coast area) that might be considering lightwave ... I'd love to work you! Pretty well any high spot in this region is direct LOS for me.
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].