Posts Tagged ‘10m’
Tenner 10m CW transceiver
February 15th, 2015 | 
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The Tenner is a very simple CW rig for 10m. It produces about 500mW output and has worked across the Atlantic on many occasions. Offset RX-TX seems to work out at about right, although no special circuitry is employed. This simple circuit just works. Although I used an “at hand” SBL1, any double balanced mixer is likely to be OK. Although I did not try it, a homebrew DBM would be fine.
29MHz AM
The 29-29.1MHz sub-band continues to be the best place to find HF AM. This is the HF band with most space, although there are AM enthusiasts on 160m and other bands. When these bands are not busy AM has its place.
When 10m goes “off the boil” 29MHz AM will be ideal for local nets with very simple gear. Ranges are fine for local nets. Also there is a ready supply of ex-CB kit around, although making a wholly homebrew QRP rig for 29MHz AM is a nice group project. There are some ideas for starters on my main website.
As an example of how effective 10m AM can be see http://www.macnaughtonart.com/10metlog-ss24.htm .
Falling sunspot numbers?
Sunspot number for Dec 27th 2014 has fallen to 92 and 10m propagation is forecast to be “fair”. Although we’ll still get good days, we must now expect sunspot numbers to gradually decline as the years go by towards the next sunspot minimum. Usually the decline downwards tends to be faster than the climb after the minimum, although many are predicting that the next maximum (cycle 25) will be miserably low.
See http://www.solen.info/solar/ .
See also http://sc25.com/ .
Simple 10m DSB transmitter
From Steven, G7VFY comes news of a very simple 10m DSB transmitter from the blog of KA7OEI. This is an experimental very low power transmitter. It is unlikely to be of use in serious applications, but the range might surprise some. On 10m, the antenna is efficient and on a clear frequency it has the potential to get a long way. Over 1000km would not surprise me on a totally clear frequency. After all, 1mW (or so) is about 53 if a 100W signal was 59+12dB. On 10m such signals with 100W are very possible.
See http://ka7oei.blogspot.co.uk/2014/10/the-pointless-10-meter-dsb-qrp.html .
ARRL 10m contest this weekend
A reminder that the annual ARRL 10m contest is this coming weekend. Conditions are likely to be good on 10m, so this is a good chance to work some worldwide DX. Next year with the decline in sunspot numbers, this is not likely to be as good. Unfortunately my operating time will be very limited because of visitors.
Nevada bargain on 10m Multi-mode radios
See http://www.nevadaradio.co.uk/amateur-radio/transceivers/mobile-transceivers/alinco-dr-135dx-uk .
Nevada is selling Alinco multi-mode 28-29.7MHz radios on special deal at £99.95. For “export only” they can be expanded to also cover CB frequencies. Such expansion is not legal in the UK. At less than £100, this is a very good price for a 10m multi-mode rig.
I admit I “lifted” the original image from the Nevada website. As it was Javascript, I was unable to link, as I had wished, to the original images. If using this image on this blog is a problem, it will be immediately removed, although I hope Nevada see this as free publicity.
Simple 10m rigs
As 10m slides to the “quieter years” of the solar cycle it will soon be time to look again at using this band for local communications. It makes an ideal band to natter across town and I still think a 10m Fredbox is worth a go. The receiver, a simple super-regen is extremely simple, very sensitive with a simple RF amplifier, but lacking in selectivity so would NOT be useful when the band is busy. At night time in the quieter years it would be perfectly fine. The alternative is a simple 10m DSB rig, which would be compatible with SSB transceivers.
At the moment, my poor health is stopping me doing both of these projects.
See https://sites.google.com/site/g3xbmqrp3/hf/10m_op?pli=1 .
See https://sites.google.com/site/g3xbmqrp3/hf/tenbox .
See https://sites.google.com/site/g3xbmqrp3/hf/10msimple_sb .
