MF bands and local comms

This morning with my 20mW ERP on 500kHz I worked G3XIZ around 45km away on CW. Chris gave me 569 (on his meter) when using his loop antenna on RX. He was a very good signal here. Earlier I copied the other stations in his net M0JXM and G3DXZ. Yesterday G3KEV was a good CW signal and PA0A was copied later today.

500kHz QRP transverter with ferrite rod ATU on bench

The new 472-479kHz will be an ideal band for local area CW nets: as my far less than ideal set-up here proves, one can work up to around 45-50km without any problem even with very low ERPs. Running 6dB more power from the PA (I currently have just 5W out) will help further.

This afternoon my 500kHz OPERA has reached yet another new station: G8ALS in Coventry 126km away. My maximum daytime range on OPERA OP4 mode seems to be around 220km, although a few more stations reporting may increase this.

500kHz ERP

Using the coax feed to my 10m/6m halo as a vertical I've worked out the ERP currently on 500kHz OPERA. The RF power from the transverter is around 5W from an IRF510.

The 10m and 6m halo lengths correspond to a horizontal capacitance of around 35pF. Some of the feed from the shack to the bottom of the vertical section is horizontal through the loft and this has not been included (I think it may add loss though). The vertical section outside is 6m long, equivalent to a vertical capacitance of 36pF. Using standard formula this means my effective height is around 4.48m.

Radiation resistance then works out as 0.088 ohms.

Measured antenna current is 0.48A (using a current transformer and detector)

ERP = 0.48 x0.48 x 0.088 = 20mW (or lower if the losses are higher).


 

First 500kHz OPERA reports

Having managed to match my 6m long coax feed line (as a Marconi vertical) up to the 10/6m halo antenna on 500kHz by adding some inductance wound on a ferrite rod in the shack, I've just received my first OPERA beacon reports on the band from ON6EO at a distance of 220km and G0KTN at 210km. Reports were -30dB and -29dB S/N which is marginal.

OPERA mode on 500kHz

500kHz OPERA RX this afternoon (on left are my spots)

Having now uploaded the latest version of OPERA weak signal mode software I have been looking on 500kHz using my, as yet, untuned short vertical antenna. CPU load without waterfall is running at around 40-50% on my Dell Inspiron 630m and the PC is running in a stable way. So far copied PA0A, PA3ABK and M0FMT. If I can get the antenna resonated crudely I may try OPERA TX on 500kHz later this weekend.

10m ROS16 QSO

ROS16 10m QSO this morning: my first for some time

The last time I tried ROS and OPERA on my PC it reacted badly and crashed so I'd been reluctant to try the mode again in a hurry. However, today I loaded v7.0.9 which runs OK when the waterfall is deselected on my 6 year old Dell Inspiron 630m with 1GB RAM and a 1.73GHz Intel M processor.  As an initial test I ran 5W on 28.185MHz and managed to answer a CQ call from DK6SQ who reported me at -13dB S/N.

Denmark active on 472-479kHz band

In the last few days OZ amateurs have been granted access to the new band. Along with Monaco and Germany there are now 3 countries (to my knowledge) allowed to use this new LF band. It has been confirmed that The Netherlands will get access on Jan 1st 2013.

VLF amateur activity

There is a new VLF grabber at Darmstadt Germany that may be useful for 8.97kHz tests. It is at http://skmail.ikp.physik.tu-darmstadt.de/gvw/grabber.html. The grabber is primarliy there for VLF research into earthquake precursors.

Stefan DK7FC reports that the permit he has to use a 300m kite antenna expires soon, so he may try a further soon before that date.  Chris G3XIZ is still hoping to resume VLF tests once a new loading coil is wound. He is looking for a suitable (very long!) source of PVC covered wire.

DYC-8x7 speech processor kit

Funk Amateur, the German magazine's online shop is selling (after a gap I believe) a neat in-line speech processor kit for the FT817 and similar Yaesu rigs called the DYC-8x7. On http://www.eham.net/reviews/detail/2546 it gets good reviews.

I'd like to order one but cannot understand how to go about it not being a German speaker. Google translate doesn't translate all the words, so I am stuck. If anyone can help I'd appreciate it, or tell me if it is available in the UK.

See http://www.box73.de/product_info.php?products_id=945 .

LATER UPDATE
With a step by step translation using Google Translate I managed to register on the Funk Amateur site and place an order.

On-line CW training at LCWO

Typical LWCO log-on page

If you are like me then your CW skills are not the world's best. Even though I am a G3 and licensed since 1967 my CW really is pretty pathetic. On an HF QSO when exchanging callsigns, reports, and serial numbers I'm usually OK, but when ragchewing with seriously good CW operators I'm embarrassed by the amount I miss. Some operators are very good and slow down, but not everyone.

However, for we CW duffers, help is at hand: http://lcwo.net/ is a rather superb on-line CW training facility that I believe could really help improve CW skills with a few minutes' effort each night. I have been to the site before and managed to improve my speed a bit but need to return there and try some more. All sorts of CW training is available at all sorts of speeds. If you want to use CW, which is an excellent mode especially for QRP, then this is worth a visit.

Ultimate QRSS/WSPR kit from Hans Summers

Hans Summers G0UPL has just announced a wonderful new kit. Amongst other modes it also supports stand-alone WSPR beaconing when used with a GPS timing reference, without a PC. This was his announcement on the GQRP Yahoo group earlier today:

All,

This is to announce a new standalone QRSS/WSPR kit by Steve G0XAR and Hans G0UPL. The kit supports WSPR, QRSS, DFCW, FSK/CW, CW, Hell (full speed and half-speed), Slow Hell, and customisable FSK patterns. The WSPR encoding is on-chip. It supports the connection of a GPS module for frequency locking, accurate time, and location (for WSPR). Power output is measured at 185mW on the 30m version. We are selling versions for 30/40/80m and perhaps later 20m and 160m. It does not require a PC, it has an LCD and two buttons to control it.

The price is GBP 15.39 (EUR 19 or US $24 approximately) plus shipping.

You can see all the details here: http://www.hanssummers.com/qrsskitmm and order online at http://www.hanssummers.com/shop . We expect to be shipping by 27-29 June.

The kit supports the following modes:

+ QRSS mode (plain on/off keyed slow CW)
+ FSK/CW mode (frequency shift keyed slow CW)
+ DFCW mode (dual frequency CW, dit's and dah's on different frequencies)
+ WSPR mode (Weak Signal Propagation Reporter)
+ Slow-Hellschreiber (frequency shifted slow Hellschreiber)
+ Hellshreiber (full-speed standard Hellschreiber, and half-speed Hellshreiber)
+ CW (plain CW)
+ Customisable FSK patterns

Other features:

+ 24-character LCD + two-button user interface
+ User-programmable (callsign, message, speed, FSK, mode, etc.), settings stored in EEPROM
+ GPS interface, for locking the frequency in slow-speed modes
+ On-chip generation of WSPR encoded message (no PC required)
+ WSPR maidenhead locator can be generated from GPS-derived latitude/longitude
+ Selectable “frame” size, for stacked QRSS reception
+ Plain CW callsign identifier at selectable interval
+ Produces 150mW RF output, or AF output for driving an SSB transceiver
+ Higher output power by additional PA transistor and/or higher PA supply voltage

73 Hans G0UPL and Steve G0XAR