29 Oct 2008

OK0EMW beacon on 505kHz

The OK0EMW beacon on 505kHz was audible last night just slightly LF of the DI2AM beacon and visible as a QRSS trace on a waterfall display. This is the first time I have positively identified this signal which is a new country for me on 500kHz listening.

Work on my 500kHz QRP TX has now started, so I hope to have a few mW ERP on the band within a few weeks.

27 Oct 2008

M0KHW was 579 on 502kHz

Ken, M0KHW in Luton was a solid 579 on CW this evening at 1735 when calling CQ on 502.4kHz with 90mW ERP. I did not hear him get any replies though.

26 Oct 2008

G3XIZ on 502kHz RTTY

Using my old pocket PC next to the IC703's LS with Pocket Digi software running I am getting very good copy of G3XIZ over in Biggleswade on 502kHz RTTY. He is only running 250mW to an inverted L antenna. Currently he's sending a list of NoV holders.

25 Oct 2008

CQWW SSB contest - 10m poor so far

Listening on 10m this morning in the CQWW DX contest it sounds a bit marginal with just weakish stations from across Europe audible plus a few Russians and 4X4s. Worked with my QRP EC7AKV, 9A5D, G2F, G0AEV (in Wiltshire by groundwave). Conditions on 10m were even worse after lunch so I called it a day and went out instead. SUNDAY UPDATE - sounds pretty dead on 10m so far apart from G stations plus tropo to ON, PA and MS pings from further Europeans.

These have been the poorest CQWW SSB contest conditions for many years. Next October just has to be better, HI.

23 Oct 2008

Main G3XBM webpages updated

http://www.g3xbm.co.uk has been updated tonight to include the FETer 14 parts 80m QRP rig and to add information about my start on 500kHz transmitting.

SAQ 17.2kHz VLF - testing Oct 24th

There is to be a transmission with the VLF Alexanderson alternator transmitter in Sweden on United Nations Day (Oct 24th 2008) at 09:30 UTC. Start up and tuning from about 09:00 UTC.

This is a good opportunity to try out VLF converters.

22 Oct 2008

500kHz band - my plans

As I've a very small garden and don't like antenna "monsters" which upset neighbours, I'd like to see what results can be achieved on 500kHz with my 15m long wire and a few watts of RF applied to it. So, my next project is a VFO controlled 500kHz TX running a few watts and a simple 500kHz ATU. If I can work 30 miles or so I'd be thrilled to bits.

21 Oct 2008

500kHz band QRP QSO tonight

This evening I made my very first QSO transmitting on 502kHz with my NoV. My TX was unusual: an old Farnell LFM4 audio/LF generator tuned to 502kHz putting out just 20mW with a morse key in the RF output lead then crudely matched with a ferrite rod matching network to my 15m long end-fed wire and central heating ground.

Only a few microwatts would have been radiated but 2 miles away the signal was copied weakly, but solidly, by M0BXT. My signal was slightly chirpy. Listening to the signal on our 50.55MHz talkback link it sounded a decent, solid, signal.

CONCLUSION
A small 501kHz 1W output transmitter simply matched (i.e. no huge low loss coils wound on dustbins!) to even a short length of wire inconspicuously strung down the garden is likely to give quite solid contacts on normal speed CW out to several miles. Using modes like QRSS there is no doubt that such a (low tech) station and antenna would be able to span much greater distances.

Incidentally, the SK6RUD beacon on 500.3kHz was a good signal this evening.

Best DX yet with the FETer 14 parts transceiver

This morning managed a QSO with Dom M1KTA at 18kms on 80m with the FETer ultra-simple transceiver (1 FET - 18mW and regen RX). Dom was perfect copy on the regen RX when running 500mW to his FT817. Another 10dB lower would have been OK. Dom is no CW expert and I am grateful for his perseverance. See Dom's blog at http://www.m1kta-qrp.blogspot.com/

A sked last night with Richard G3CWI "up north" failed though: Richard was a good signal on the regen RX but could not hear my 18mW.

So far, there are 4 two-way QSOs with 3 different stations in the log now with the ultra-simple FETer transceiver (see http://g3xbm-qrp.blogspot.com/2008/10/2nd-qso-with-feter-80m-micro-rig.html)

20 Oct 2008

2-way QSO - "1 active device transceiver" at each end!

M0BXT's 1 valve transceiver (see left)

Last night M0BXT and I had a nice two-way QSO with a difference.

Andrew used his 1 valve 300mW transceiver (see http://tetrode.co.uk/ ) and I was using the FETer 1 FET transceiver. Reports both ways were good over the two mile path.

With the help of Andrew's RF test gear I was able to accurately measure the sensitivity of the FETer rig and its power output. Sensitivity is better than -100dBm (around 2uV) for a reasonably comfortable level in the crystal earpiece. Signals could be detected (just) at around -105dBm sensitivity. The TX has a bit more power than I was able to measure crudely - around 18mW output with a 12V supply. These figures are really quite remarkable for the few parts used.

Next aim is to work some further distances with the FETer. I am sure this will be possible.

19 Oct 2008

Our grandson



Here are a couple pictures of our little grandson, taken in Paris late last week. He is a real character who has given us so much joy and happiness. This is the first time he's seen and enjoyed the autumn leaves.

18 Oct 2008

Heard of the FLEA yet? (Ultra simple rig)

http://ea3fxf.googlepages.com/flea has details of the superbly elegant rig from EA3FXF. Basically this is a simple QRP TX converted into a neat transceiver. The link has lots of information on this rig including a PCB layout and a SPICE (electronic simulation) file. There is also a Google Group on this little beauty although the correspondance is in Spanish. A full article on the FLEA is available at http://ea3fxf.googlepages.com/SPRAT-FLEA.doc . I think Eduardo and Joan must have prepared a SPRAT (G-QRP club mag) article.

Excellent stuff Eduardo, EA3GHS, and Joan, EA3FXF - a wonderful addition to the "ultra simple transceiver" line!

14 Oct 2008

2nd QSO with FETer 80m micro transceiver

This morning I had a second QSO with the FETer 80m CW "micro rig" which uses just 14 parts in total plus earpiece and morse key. The QSO was with M0DRK in the village and the report again S9 suggesting contacts at further distances are certainly possible. I would welcome skeds with stations between 10-30 miles from my QTH (JO02DG in East Cambs) to check daytime range.

This is SUCH fun and proves that solid, reliable contacts can be made with next to nothing. In all, the parts cost about £5.

13 Oct 2008

1 FET transceiver .....QSO No 1

Managed a solid RST598 (yes 8 - a little chirp) QSO on 3.579MHz with M0BXT tonight when I was running just my 14 component MPF102 FET transceiver tonight.

The regen RX in this works extremely well and is pulling in loads of 80m CW and SSB stations at good volume in the crystal earpiece. The TX uses only 4 parts including the crystal!

Now THIS is real ham radio - solid contacts with a tiny, simple, rig that can be built, with brand new parts for about £5.

12 Oct 2008

Cycle 24 ....starting at last??

http://www.dxlc.com/solar/

If you look at the solar flux and sunspot count I do believe, at long last, there are real signs of a climb out of the long sunspot minimum. There have been several false dawns already, but I think this is really it.

LATER: more spots have appeared!

Early "through ground" communications experimenter


http://earlyradiohistory.us/1902stu.htm has some details of Nathan Stubblefield's early (late 19th/early 20th century) experiments with conduction (earth mode) telephony communications through the ground.

Sometime soon I want to try some more experiments with this mode using QRSS or PSK31 at frequencies below 10kHz.

1 FET transceiver built


Today I built a single FET transceiver for 80m using just a handful of components (see pictures)

Currently it puts out 10mW on 3.579MHz (will be changed to 3.560MHz when I get another xtal) and uses the same single MPF102 FET in a tunable regen RX covering 3.50-3.62MHz. On RX it is picking up plenty of CW stations on the FISTS net so must be reasonably sensitive. The first QSO should be tomorrow on a sked with a local station a few miles away. If you want to try to work me using this rig please let me know via email at rogerlapthorn(at)gmail.com.

7 Oct 2008

VLF/LF converter

The VLF up-converter on my website (used to receive SAQ last year) has a new box and had a tidy-up! It works well and is sensitive from around 2kHz up to 200kHz. It should be useful on 137kHz receive. The actual circuit is built ugly style on a small piece of copper clad PCB material and this is about half the size of the 9V battery used to power the converter. The circuit uses a "back to front" SBL1 mixer with a 2N3904 oscillator and post mixer buffer.

The original lash-up received SAQ at RS58 and a QSL card was received for this historic 17.2kHz CW transmission from Grimeton in Sweden.

The various time signals (on 50, 60, 75 and 77.5kHz) are audible as are the Russian Alpha beacons below 15kHz. There are various unidentified data transmissions from 17kHz to around 80kHz audible but not identified.

3 Oct 2008

New UHF/SHF super-DX mode?


The ARRL Propagation report (link on my website) today reports some interesting findings about very high altitude noctilucent clouds reflecting radar signals, raising the possibility that extreme, INTERCONTINENTAL, UHF/SHF DX might be possible using reflections from such clouds. See
http://www.sciencedaily.com/releases/2008/09/080925144806.htm

"...the clouds contain ice coated with sodium and iron from micro-meteors and sit at about 53 miles (85 km) altitude, mostly between 50-70 degrees latitude, and sometimes as far south (or north, in the southern hemisphere) as 40 degrees latitude or less.

The clouds are highly reflective of radar signals, and instead of diffraction as we see in ionospheric propagation, ripples in the clouds seem to reflect in unison, reinforcing each other.

Noctilucent clouds are sometimes visible at night, because their altitude is so high that they reflect sunlight into areas of darkness. They are also known as polar mesospheric clouds, and appear most often at twilight during the summer."

Imagine working many thousands of miles on 10GHz QRP by a mesospheric
reflection mode. Now that would be something REALLY different!

GI4DPE on 501kHz

501kHz was in a reasonable state a couple of evenings back with Finbar GI4DPE being a steady signal down here on CW in East Anglia. I must get some QRSS software as there have been a few stations on which I have not been able to decode. QRSS "by ear" is not easy!

30 Sept 2008

HF AM excursion - all 9 bands!

M0BXT and I usually have a natter on 144.55MHz vertical AM on Mondays at 8pm. We were on last night but got distracted doing some tests on all 9 HF bands using QRP AM.....

Starting on 10m and working down to 160m we very briefly exchanged reports at 4W and then with some 10-20dB less to see how signals compared across each band on our end-fed antennas tuned via an auto-ATU at each end.

I have to confess to a brief AM QSO on 30m (shame, disgrace!!) but only for 20 seconds at most so no harm was done to the planet.

We managed solid QSOs at over S9 over our 2 mile path on all bands apart from 24MHz where signals were weaker, maybe because our wires had deep holes in radiation on this band. The best band was 80m where signals were 59 + 50dB or so. 160m was also pretty good.

M0BXT and I hope to have our first two-way single valve or single transistor transceiver QSO in the next few weeks on 80m but this will be CW.

19 Sept 2008

Decent DX around despite the sunspots

This last week has seen some decent DX around despite the zero sunspot number. V51YJ is booming in on 20m CW this evening. VK3PA was audible on 80m SSB a few nights back at sunset and YB6INU a decent copy on 40m SSB.

On 501kHz (600m) the SM6BHZ and DI2AM beacons have been reasonable signals in the evening this week.

14 Sept 2008

40m in good shape

Listening on 40m tonight in the contest there was plenty of decent DX around on SSB including PJ4NX, ZW5B, K5ZD (who "QRZ? ed" me with 10w and short endfed), W1UE and others at decent strength.

5 Sept 2008

Icom IC7000S

Anyone know if this version of the IC7000 series (10W low power I think) is available in the UK? This would make a nice QRP radio for many.

Interesting solar fact

August 2008 was the first calendar month with no sunspots since 1913 according to the ARRL propagation report this evening. They also note that cycle 19 (the biggest on record) was preceded by long periods without spots. You never know, cycle 24 might turn out to be a whopper and we'll all work the world on 70MHz with milliwatts.

25 Aug 2008

Simple 432MHz operation webpage

Just added a new 70cms web page to my site at http://www.g3xbm.co.uk .

19 Aug 2008

501kHz tonight

Heard G3KEV calling CQ on 501kHz CW tonight and listening for crossband QSOs on 3533kHz. Although I called him a few times on 80m he did not hear me. Also heard (for the first time) was G3DXZ also on CW. Both stations were RST549 on the FT817 and random 15m endfed wire.

17 Aug 2008

6m and 10m lively today

Both 6m and 10m were lively in Europe today with quite a few QRP QSOs made on both bands via sporadic-E. Nothing heard much beyond Europe though apart from 6V7L being called by many on 10m.

16 Aug 2008

Home Base 10 - webpage link fixed

The link to the Home Base 10 (10m halo antenna) on my webpage http://www.g3xbm.co.uk went AWOL last week. This has now been fixed. The antenna is fully described in September 2008 edition of Practical Wireless p38-40.

6 Aug 2008

Good 6m opening tonight

What an evening! Only worked one EA station on 6m QRP but heard some amazing DX. Firstly D4C Cape Verde Is (working piles of Europeans on CW) who was audible on the vertical colinear on the side of the house at 539 at best. Also heard was Lefty K1TOL in Maine, USA who was peaking 569 on the same vertical antenna. Really thought I had a chance of working him again with 6m QRP but was not so lucky this season.

Home-base 10 antenna - QSO with USA

10m opened up to the USA this evening and I managed to get RS53 from N2MM in New Jersey with QRP SSB to the Home-base 10 10m halo. This antenna is really working very well indeed. There is an article showing how to build this antenna in Sept 2008 edition of Practical Wireless.

5 Aug 2008

G3XBM website updated

My website at http://www.g3xbm.co.uk was updated today with a page on the Moxon 70cms antenna including a diagram and a few pictures.

3 Aug 2008

70cms Moxon results


Well, the 2el Moxon made from my wife's coat hanger was tested in the 432MHz low power contest today and it worked very well considering how tiny it is and how it was made! Best DX was F8BRK at 326kms who gave me a 519 report. In all 10 QSOs were made in a few hours of operation with 5W from the FT817. A total of 8 QTH locator squares were worked in very dismal conditions and rain.

2 Aug 2008

70cms Moxon 2el yagi

There is a 432MHz low power contest this Sunday, so I have made a small 2el Moxon yagi to use /P with the FT817 in the contest. I have no idea if I will work anyone with it. It was built using one of my wife's coat hangers. If you hear G3XBM/P be sure to give me a call. I shall be operating from JO02CC or JO02DD square in East Cambridgeshire. Both have clear take-offs to the north round to the west, but not so good to the east.

26 Jul 2008

DSB10 - more progress

I have now breadboarded the 10m DC receiver for this rig using a single balanced mixer with 2 diodes followed by two stages of audio. It works well and was pulling in plenty of stations in the IOTA contest this weekend on both SSB and CW without any sign of AM breakthrough. I think the secret is plenty of LO injection to switch the well balanced diodes hard.

21 Jul 2008

10m DSB Rig - started at last


For some time I have been toying with the idea of building a simple but effective 1-2W DSB transceiver for 28MHz. Well, this weekend I made a start by breadboarding the transmitter up to, but not yet including the final PA stage. The 2N3904 has been used throughout plus a couple of 1N4148 diodes (which seemed well matched) for the TX balanced mixer. Output from the balanced mixer was sub milliwatt so a couple of linear stages lift the output to around 50-100mW pep. With a single 2N3866 PA stage this should take me up to the 1-2W pep level.

Next stage to breadboard is a mixer-VFO. I am thinking of a 20MHz xtal oscillator (because I have a crystal) and an 8MHz VFO. Ideally I'd like a higher xtal oscillator so the VFO is lower in frequency and more stable.

The RX was breadboarded last week and uses a single balanced diode mixer followed by 2 stages of audio. This works really well with no sign of AM breakthrough at all.

15 Jul 2008

Pipit20 rig on air


This last week I have been building again. Not much, just another DC transceiver built ugly style. The rig covers 14048-14070 VXO controlled and puts out about 500mW using the OXO design. It uses an SBL1 mixer on RX followed by 3 stages of AF gain. Only station worked so far is M0BXT but hoping for some Europeans maybe at the weekend. It suffers a bit from AM breakthrough and the 2N3904 transistors used in the AF sections are too noisy really. This is really not a perfect radio, more a work in progress.

Why the name? The Pipit was a similar (better!) radio design I put in SPRAT many years back for 15m.
.

2 Jul 2008

Micro80 4-transistor transceiver QSO


After some time without use, I resurrected the little Micro80 4 transistor transceiver for 80m last weekend. To increase the power a bit I've now got provision to run it from an external gell cell battery at 12v, so giving me about 2dB more RF out compared with the 9V internal pack. Using it with the bench PSU was impossible because of 50Hz hum pick-up. I also managed to improve the AM breakthrough by around 10dB at least by putting a 4n7 cap across the base-emitter junction of the first stage of the darlington in the RX AF. This makes it a usable radio on 80m at night now as it is not obliterated by the BC stations around 4MHz. Success soon followed with a solid QSO with G3XIZ in Biggleswade around 30 miles away late Sunday afternoon.

24 Jun 2008

Wet square on 6m

Just beat the pile-up to work UT1FG/MM on 6m SSB in IN38 square out in the Atlantic. Obviously I have not worked this square ever before!