Showing posts with label UHF. Show all posts
Showing posts with label UHF. Show all posts

Sunday, 18 October 2020

R820T2 SDR Radio Receiver

 R820T2 SDR Radio Receiver

My current direction of travel, with amateur radio and other
things in my life, is to downsize so I can continue with my radio hobby in
smaller accommodation when the time comes. I am therefore a convert to Software Defined Radios
(SDR).
These are tiny radio receivers, typically the size of a memory-stick
dongle, and controlled by software on a computer. This means the equipment size
is minimal and the cost/performance ratio of an SDR radio can be very high.



I recently bought a R820T2 SDR from Nooelec on Amazon. I had
previously owned a R820 SDR (see earlier post) but the performance was very disappointing
and I recycled it. I needed another receiver because I wanted to monitor marine
AIS signals without tying up one of my other SDRs or my main transceiver. I had
heard that the performance of the R820T2 was much better than previous R820
radios and at less than £25 I decided to give it a go





The package arrived and contained, as advertised, the
R820T2, a small (300mm) telescopic whip antenna. Before using the R820T2 as a
radio receiver, rather than as a Digital TV, it is necessary to change the
Windows driver using a little utility called ZADIG. This is very
straightforward and there are plenty of instructions on line how to do this so
I won’t repeat them here. Do not
load any TV software that might come with the SDR and of course set a ‘Restore’
point
before changing drivers so you can back out in the unlikely event of
something going wrong.



That done, plug the SDR into a USB port on your computer and
plug your antenna into the MCX female connector on the SDR. If you do not want
to use the supplied whip antenna adapters from MCX to SMA, BNC etc. are
available from electronics suppliers and these make it easy to connect other antennas.





Next, start your SDR software. I use SDR Console and SDR#
(SDR Sharp) which are free downloads. Select RTL Dongle or RTL USB from the ‘radio’
menu, set the frequency you want and the mode and then ‘Start’ and you should
be in business.



So what does the R820T2 + software do?



  • ·        
    It tunes from about 25 MHz to around 1.8GHz so
    it covers the VHF and UHF amateur radio and commercial bands
  • ·        
    It also does the 10m amateur band with limited
    performance.
  • ·        
    It does not care what mode you want to receive –
    SSB, AM, CW, FM, Digital etc. as this is taken care of in software on your computer.
  • ·        
    In addition to amateur radio, you can receive
    broadcast station, marine voice and AIS signals, aircraft voice and ADSB
    broadcasts and much more provided this is legal where you live.
  • ·        
    You can receive signals from amateur radio,
    weather and some scientific satellites, including ISS.











I will say more about AIS, satellites and ADSB other posts.   



I found the 820T2 performs very well and not much worse than
the more expensive SDRs that I own. Filtering is much better than with earlier versions of the R820 SDRs. Certainly works well enough for a beginner to
enjoy or as a secondary receiver for a licenced amateur radio operator.  I use it as a second receiver when operating
VHF and UHF contests as I can see station pop up on the software waterfall
display. Although the whip antenna is small, I found it actually works
surprisingly well if it is located in a good position (high up by a window for example), but obviously ‘real’
antennas will give better performance.  



In summary the R820T2 and one of the software programmes make a very credible VHF/UHF all-mode
receiver and a fraction the cost of ‘real’ radios. It takes up almost no space
so is ideal if you live in restricted accommodation. Its performance is vastly
better than previous R820 receivers and would make a great Christmas or birthday present
for anyone interested in radio or thinking of starting out in the hobby.

Please share your experiences with R820 SDR Radios by commenting here. 


Sunday, 10 May 2020

RSGB VHF/UHF Contests


RSGB VHF/UHF Contests


Each month the Radio Society of Great Britain runs ‘Activity Contests’ on the VHF and UHF bands. Full details are on https://www.rsgbcc.org/cgi-bin/readcal.pl. These are a great way to cut your teeth in contesting, as they are nowhere near as cut throat as HF contests. 

For those new to the radio hobby these contests are a great opportunity to do some listening and to check out VHF and UHF receiving equipment and antennas as there is usually a lot of activity. 

The last part of the contest exchange is of most interest if you are not entering. It is the Locator Square (Maidenhead Locator) which is described in:

When you hear a Locator, enter it in the Grid Square box at
and it will display a map showing the area where the station is located.

European contries run similar contests at the same times so you may hear stations from there as well as UK stations. 


To enter, you must have an amateur radio licence and be a member of RSGB or a member of an affiliated club. Do check the rules before entering as they are quite detailed.
  

If you are not entering the contest then the stations you hear, particularly those far away, will appreciate an email with the date and time you heard them and your location. You can find amateur station email addresses at www.qsl.net. 


Contest Timetable

Every 1st Tuesday
1900-1955
(Local)

2m FM Contest 144.5125 to 144.7875 MHz  and  145.200 to 145.400 MHz

Every 1st Tuesday
2000-2230
(Local)

2m Multimode Contest (see below). Mostly 144.150 to 144.400 MHz

Every 2nd Thursday
2000-2230
(Local)

6m Multimode Contest (see below). Mostly 50.130 to 50.300 MHz

Every 2nd Tuesday
1900-1955
(Local)

70cm FM Contest 432.525 to 432.975 MHz and 433.400 to 433.475 MHz

Every 2nd Tuesday
2000-2230
(Local)

70cm Multimode Contest (see below). Mostly 432.1 and 432.3 MHz

Every 3rd Thursday
2000-2230
(Local)

4m Multimode Contest (see below). I have never entered this contest, but band plan suggests 70.1 to 70.250 MHz

NOTES


For the FM contests, only FM mode can be used, for the other contests SSB, CW, FM, AM, JT6M, ISCAT and FSK441 can be used. Most contestants use SSB and a few call on CW (Morse) as well.

Contest times are UK Local time, NOT UTC.





Good listening, and please leave a comment on here telling us how you get on.