Narrow Band TV (NBTV)

Partly because bandwidths are very low, there has been a revival of interest in NBTV systems similar to the early TV transmissions by Baird in the 1920s and 1930s.

There is even a Televisor kit available for about £40 delivered (in the UK) with a CD with some still and moving images and its own test card generator. I am quite tempted!

The televisor kit is available for £35.94 + shipping from http://www.mindsetsonline.co.uk/Site/Home (search for televisor). This is compatible with the 32 line standard of the NBTV Association.  The NBTV Association home page is at http://www.nbtv.wyenet.co.uk/index.htm .

Bandwidths are audio only, so a tape recorder or CD are fine. Over the air transmissions only require audio bandwidths too. Of course, with just 32 lines don't expect brilliant images! The narrow bandwidth should make it possible to transit moving images over a standard FM or AM link.

I think the very first transatlantic DX tests were done using the Baird system in the late 1920s  or early 1930s.

VHF AM and the RSGB

Recently, I wrote to the "Last Words" column in Radcom. I very much doubt my letter will be published. The main thrust of the letter is the (very negative) attitude of the RSGB to the AM mode.

My letter (as sent) is reproduced here. I'd be interested to hear your views.

At the present time G6ALB is experimenting with very low cost 70cms AM modules as the heart of a possible short range (3km) voice transceiver. We have had some success already.

"Thank you for publishing the latest Band Plans in the February 2015 RadCom. Although because of my poor voice (stroke) I tend to use digital techniques, I still enjoy the occasional outing using AM. Like many, I have worked transatlantic AMers on 29-29.1MHz with real QRP and simple antennas.

Yet again, one could be forgiven for thinking AM, especially 28MHz and up, is a dirty word at the RSGB.  AM gets no mention on 28MHz and 50MHz and gets a (begrudging?) comment as a footnote only in the 144MHz Band Plan when other modes get "centres of activity" mentions. For the avoidance of any doubt, AM is alive and well in the 29-29.1MHz sub-band. AM on the 144MHz (2m) band can be found on and around 144.550MHz. There has been AM on 29-29.1MHz for years and years and years! Yes, this is the all-mode section, but why not say this is the 28MHz (10m) AM sub-band? Also, why are 144MHz AM users asked to "consider adjacent channel activity"? AM should easily fit in 6kHz!!

Sorry, yet again, AM is being treated as a dirty and outdated mode. May I remind readers that ex-PMR AM rigs ripe for use on VHF can be picked up for virtually nothing and that there is room for AM on all bands from 28MHz upwards. AM has its enthusiasts on other bands too, but yet again the RSGB seems hell bent on killing off this mode. Why?

73s
Roger Lapthorn G3XBM"

Motorola for sale?

Is the end in sight for Motorola?

See http://www.bloomberg.com/news/articles/2015-02-06/motorola-solutions-said-to-explore-sale-of-87-year-old-company .

When I was at work (I retired 7 years ago) Motorola was our greatest rival. Since coming into existence in the early years of this century, my own company Sepura has been in profit every year. The demise of Motorola is a salutary lesson never to be complacent. How the mighty have fallen.

Cambridge on a winter day

Cambridge Punts

Every Tuesday I travel into Cambridge for my weekly U3AC course called "Maps in the Computer Age".  I am enjoying the course very much.

Usually I drive to the "Park and Ride" car park at Newmarket Road and get the bus into town. The U3AC course is at the U3AC headquarters in Bridge Street, which is about 30m from where the punts are on the River Cam.  At this time of the year the punts are quiet. Come the summer and this spot is very busy. Cambridge has lots of foreign visitors when the usual students go home. If you see a foreigner with a map wobbling along on a pink bicycle it is a good idea to be well clear!

Round Church - very old building

From the punt place you can punt right up via St John's, Trinity, Clare and Kings College.  Kings College Chapel is lovely from the river.   The secret is not to leave your punt pole behind. It is easily done. Luckily the Cam is not too deep. If you prefer, you can pay someone else to do the punting so you can just sit back and enjoy a timeless Cambridge moment.

Bridge St,  Cambridge

Some of the views have not changed much in centuries. The Backs in Cambridge are very beautiful and it is little wonder people travel from all corners of the Earth to visit this beautiful centre of learning.  It is all too easy just to take it all for granted. Certainly, when I worked in the city, I did.  Now being retired, I properly enjoy it. It is still a very beautiful city with fine very old buildings and the River Cam winding its way up behind the colleges. If you have never been, you are unlikely to be disappointed.

Many years ago I was with a friend who parked at the multi-storey car-park just off Bridge Street. We worked a VK6 (S.W. Australia) from the car on 10m SSB.

10m USA WSPR spots today

KE2N (5934km) was the first USA station to spot my 500mW beacon today at 1318z. Compared with yesterday, 10m conditions appear way down. We'll see how the afternoon progresses.

UPDATE 2002z:   K9AN (6505km) was the last USA station to spot my 500mW beacon on 10m WSPR today at 1752z.

Sunspots and 10m

Sunspot number is 82 today and 10m propagation expected to be just "fair".  Yesterday 10m was (for me) exceptionally good.  I very much doubt they can be as good today.

Radio Shack files for bankruptcy protection

So Radio Shack has filed for bankruptcy protection.

See http://www.chicagotribune.com/business/breaking/chi-radioshack-sprint-shops-bankruptcy-20150206-story.html .

This had been on the cards for some time, but the USA's famous radio store has been in trouble for some while. It was formed firstly in 1921. Radio Shack filed for bankruptcy protection last Thursday.

10m USA WSPR spots today (and South America)

The first USA station to spot my 500mW 10m WSPR beacon was KC1AWS (5308km) at 1214z today. With all the DX spots from Australia this morning, it make the USA seem like just the back door and hardly DX at all!

UPDATE 1420z:  10m is wide open today.  YV5ESN (7294km) spotted my 500mW beacon at 1412z.

UPDATE 1900z:   USA stations are still spotting me, The last was W9ZOC (6259km) at 1854z. This may not be the last.

UPDATE 2115z:   W9ZOC at 1854z was the last USA station to spot me from the USA today.

Handheld of the future?

See http://www.southgatearc.org/news/2015/february/ht_of_the_future_at_orlando.htm#.VNi6BC4WKPc .

Southgate News reports that Bruce Perens K6BP will be demonstrating a handheld platform that can cope with many modes at VHF/UHF at the Orlando Hamcation in Florida. This looks like a demonstrator at 100mW RF. With SDRs, quite a flexible, and low cost, architecture is possible.

I wonder which of the "big names" will be first to market with a real SDR design? This could enable them to sell very low cost units, but maybe they would rather shaft us and make big profits?

10m WSPR - multiple spots from Australia

It is now 1140z. Already this morning VK6XT (14719km) in Western Australia has spotted my 500mW 10m WSPR 13 times so far on 10m! This is far from over too! This is now. In a few years this will be stuff of dreams. In the last few minutes he has spotted me yet again.

UPDATE 1246z:  VK6XT (14729km) has spotted me 21 times so far today. This for 500mW seems amazing, but WSPR is amazing. That the WSPR beacon is totally contained in a tiny box (no PC needed) I find quite staggering. As you can see, most of the reports were good ones, certainly not "on the edge" at all.