KiwiSDRs reactivated

After a holiday, and little amateur radio activity, I have reactivated the 2 KiwiSDRs from the home location.

The performance is not as good as at the previous remote and RF quiet location, but is adequate enough for general listening and will provide further opportunities to pursue noise reduction strategies.

KiwiSDR1 is currently devoted to WSPR, KiwiSDR2 is available for public access from the top menu.

I have suspended 70 MHz reception for the moment to free up an antenna port for a KiwiSDR – activity levels have been very low on this band so far this season.

9K2GS received on 50 MHz FT8

The consensus among the VHF community that this week would see the real start of elevated conditions (particularly for those of thus in more northerly latitudes) has been confirmed by regular openings to the Mediterranean countries. This morning, Friday 4th May 2018, the first medium distance DX, 9K2GS, was received on FT8 mode.

Amateurs in Ireland receive new spectrum allocation between 30-49 MHz

Dermot, EI7IX, noted on the ON4KST chat room that the Irish regulator, COMREG, has released new licence guidelines – the highlight of which is a new secondary allocation between 30-49 MHz.

COMREG document

Slovenia and South Africa already have small allocations around 40 MHz.

The multi-frequency beacon, GB3RAL, is active on 40.0050 MHz. This raises the question of some kind of allocation (probably secondary) in the UK.

One can examine the Ofcom Frequency Allocation Table (2017) to see who the existing users of this spectrum are in the UK to determine the possibilities.

Preparing for the Sporadic-E season

Having proved an interesting experiment, the 2m/70 cm SDRPlay antenna was removed to prepare for the arrival of the Sporadic-E season on VHF.

 

The flowchart below indicates the new signal processing arrangement:

Except for brief periods of transmission, the intention is to continuously monitor a range of frequencies and modes on the 50, 70 and 144 MHz bands simultaneously in the hope of capturing short-duration propagation enhancements. This to run concurrently with the existing monitoring from the Wellbrook Loop which covers from 2200-10m.

Modes

 

MSK144 24/7 coverage of 6m, 4m and 2m.

 

WSPR 24/7 coverage of 2200, 630,160,80,60,40,30,20,17,15,12,10,6,4,2m
FT8 24/7 coverage of 6m,4m,2m and 8 lower bands (MF/HF) dependent on day/night.
CW coverage shadows the 8 FT8 MF/HF bands.
Other modes on an ad-hoc basis, such as Opera, contingent on spare CPU capacity.

 

144.360 MHz MSK144, EB1HRW QRB 1349 km

 

144.174 MHz FT8, DC2TH QRB 1104 km
144.4285 MHz JT65b, GB3VHF reception QRB 357 km
144.174 MHz FT8, Sunday afternoon
The 50 and 70 MHz monitor PC, showing MSK144 activity
SDR Console V3 on Core I5 PC (Mode names added to picture)

 

I tried to hear G3ZJO on 2m Opera. I did not succeed, but he decoded me:
Eddie, G3ZJO, receiving my Opera signal on 2m QRB 221 km

SDRPlay feedpoint receiver project for 2m/70cm

After removing all equipment from the remote site and re-assembling what could be accommodated at home, it became evident that I had some spare items which could form the basis of a new project.

Recent discussions with Bri, G0MJI, regarding UHF operating generated interest in developing an antenna project using a receiver as close to the feed point as possible to minimise feed losses, something that could be useful at 70cm and above.

The USB extension cable from an SDR could take the place of a coax run, which would also be cost beneficial as low loss coax has become increasingly expensive. If successful, the concept could be applied in future to the 23 cm band where it could yield greater benefits.

The equipment comprised of the following, most of which I already had available:

 

Assembling parts
Testing SDR fit inside the enclosure
Completed, ready for installation
Installed in temporary position
The USB cable was connected to a remote computer, and SDR Server (V3) was used to send data over the network to be viewed by SDR Console V3.
Tests were conducted with satellite downlink signals and terrestrial FT8 on the 70cm band:
CW Ident of VZLUSAT1 (QB50 CZ02)
 NBFM voice on SAUDISAT-1c (SO50)

 

G0MJI (IO83NI) transmitting FT8 (Distance: 47 km)
The project concluded successfully, with qualifications. The SDRPlay RSP1 does not have a TCXO, so there will be challenges in the UHF range. This could be mitigated by replacing the RSP1 with the RSP1A which has a 0.5 ppm TCXO.  The satellite signals were weak but usable – both passes were of low elevation – a good preamp would probably improve things markedly.
Overall, the ability to independently tune around the 2m/70cm bands with an SDR is a very useful additional capability installed at next to no cost.