On 6m again this morning

Conditions (tropo) are up on 2m today with the Kent 2m beacon measuring strongly on the FT817ND's S-meter. Usually, the S-meter does not even move. I don't know if tropo has as great an impact on 6m (I think not) but so far today just the usual good reports from G4IKZ (18km). Later, I hope to catch some sporadic-E (Es) propagation or even some GDX by 6m tropo, or more distant "semi-locals".

G4IKZ's first report was at 0648z when I first turned the rig and PC on today.  Reports vary by about 6dB but this could be G4IKZ rotating his beam rather than propagation. I'd be surprised if propagation varied by 6dB over such a short path. The other explanation is my local noise floor is increasing as the day goes on and more local appliances are activated? Another explanation is aircraft reflections from small planes over Cambridge? Maybe there is more activity today. That could explain the Doppler on my signals too.

Otherwise all very quiet  here so far at 1000z. It is a bit early in the day for Es which usually peaks around lunch and teatime unless the band is really humming.

Currently, I am not monitoring 10m, but the sunspot count is 130 and 20-30MHz propagation forecast to be "good", so HF should be good.

2m GB3MCB - 410km: no luck at all

The mid-Cornwall 2m beacon GB3MCB is 410km away on an all-land path and, as yet, I have still to receive it, even for very brief periods. I keep looking, but without any success so far.  By now I would have expected the odd MS ping or aircraft reflection but, so far, an absolute blank.

Can anyone confirm it is on-air?

UPDATE 1900z: A very weak signal,somewhat low (144.46802MHz CW) may have been a weak ping from this beacon? Too weak to tell and no callsign copied.

First 70cm beacon copied - 70cm PI7CIS

This morning, I managed to copy the 70cm beacon at PI7CIS (by ear) using my 5 ele yagi. On  my FT817ND dial it was at 432.41536MHz, somewhat lower than the supposed frequency (432.416MHz) , as a result of RX drift at my end and thermal drift of the TX. I would guess it is at least 10dB down on the co-sited 2m beacon. Neither signals move the FT817ND's S-meter. As my first 70cm SSB/CW reception I was very pleased. Conditions may be marginally up in that direction, but not by very much.

It looks like this 70cm beacon is just below the noise floor here normally, so a slight lift is needed to detect it.

GB3ANG (Angus 2m beacon)

Have now turned the beam about 20 degrees further north and looking for GB3ANG. Unlike GB3NGI this one seems a little low in frequency, as if the stability is not as good. I have had 2 brief periods of copy and these may have been off an aircraft or by MS. This beacon is considerably weaker than the one in Northern Ireland and below the noise floor here.  Being just below the noise floor means it will be a useful indicator of conditions to Scotland: if the beacon is audible it will suggest a lift in that direction.

Ultimate 3 Beacon

So far today I have not yet been on the radios at all. No 10m WSPR, no 2m/70cm beacon hunting.

Later, if I feel well enough, I may make a start on my Ultimate 3 Beacon Kit.  It would be good to get this running but I have been waiting until I felt a bit better (less giddy). Now is maybe the time? Perhaps I'll start on an easy board today.

2m - GB3NGI Ballymena beacon

This beacon is about 530km from me yet it appears to be on the edge of copy at all times - wait a few minutes and out of the noise pops the callsign and QTH locator. This appears to be a high powered beacon at an excellent site. Its 4 el beam aims towards England so is just about optimum. This is another useful propagation indicator and at a good distance too.

I am still in the process of finding out which 2m beacons are always there, which are usually below the noise floor and which ones can be expected to be copied in reasonable lifts. At the moment it looks like this:

   GB3VHF (Kent) always there
   ON0VHF (Belgium) always there
   PI7CIS (Holland) always there

   GB3NGI (N.Ireland) just below noise (peaks copied)
   GB3ANG (Angus, Scotland) just below noise (peaks copied)

   GB3MCB (Cornwall) below noise - not yet copied

   Others - still TBA.

As a reminder, I am using a barefoot FT817ND with a 3 el 2m yagi (5m AGL) fed with 17m of low loss coax. My site is on top of our local"hill" (20m ASL) next to the windmill with a decent take-off in nearly every direction.

On 70cms SSB/CW  I have still yet to hear anything -  no beacons or stations yet, but I am still looking. The antenna is a 5 el with the same low-loss Westflex coax feeder.

I shall be active in the next 2m and 70cm UKAC contest sessions (next 2 Tuesday evenings) trying to find out how well the station works.

New UHF beacon GB3UHF

I am looking forward to this new GPS frequency locked 432.430MHz beacon GB3UHF near Wrotham Kent (IO91) becoming active. It is to be co-sited with GB3VHF. It is at an interesting distance and should be copyable on my 2m halo, even though I shall be slightly off the main beam. Approved by OFCOM, it is now awaiting a site sharing agreement that could take some while. It is NOT yet on-air as far as I know. There is a real shortage of UHF beacons in the UK. GB3BSL (Bristol 432.934MHz)  is off air I believe.

The new beacon's frequency will be 432.430MHz to a pair of 3 el J-Beam yagis beaming roughly towards the Midlands (288 and 348 degrees headings). Being 3 el beams, the aim is quite broad.

See http://www.gb3vhf.co.uk/GB3UHFdetails.html

10m with125mW (Ultimate 3 WSPR beacon)

As you may recall, I am building an Ultimate 3 WSPR beacon for 10m as soon as I feel up to the task. Currently I am too clumsy building because of my stroke. The reports yesterday and today with 500mW on 10m suggest the majority of spots would still be achieved with 6dB less power, QRM permitting.

Just maybe I'll try the beacon initially at its 125mW design level.  I was intending to run about 2W pep finally.

My last 500mW TX burst on 10m (at 1634z)  just now got no less than 11 different spots, with all but one (IT9) being received from the USA.  And conditions today are not as good as yesterday!

UPDATE 2300z: The last spot of my 500mW 10m WSPR signal was at 2136z tonight. My last spot (of others) was at 215oz (KE5XV). Best spot of my 500mW signal was from CX2ABP at 11127km

Ultimate 2 QRSS beacon TX

The Ultimate2 QRSS kit

The latest edition of SPRAT, mine arrived yesterday, reminded me that G0XAR and G0UPL have produced a very nice QRP beacon transmitter for weak signal modes including QRSS and WSPR. This unit can run stand-alone without tying up a PC to generate the WSPR message, although a GPS module is needed to get the WSPR time sync. The beacon will work on all HF bands with a suitable low pass filter and do other modes like QRSS too. There is even a version that can do WSPR and QRSS in alternative time slots.

See http://www.hanssummers.com/ultimate2.html . At just £17.50 this is a great value kit for those interested in weak signal beaconing.

457kHz personal rescue beacons

http://www.pieps.com/en/avalanche-transceivers/231-pieps-vector

When in Switzerland last week and thumbing through magazines I noticed references to 457kHz personal rescue beacons to help locate people buried in avalanches. They are small, lightweight, like GPS units, and have a range of 40-80m and a battery life from a single cell battery of up to several hundred hours.

There is useful information on these at http://en.wikipedia.org/wiki/Avalanche_transceiver and on http://www.pieps.com/en/safety-equipment/232-pieps-backup .  Although of no direct amateur radio application, I thought this an interesting device.

Clear air forward scatter optical kit

The schematics below are of the RX and TX used in the recent "over the horizon" NLOS 481THz optical tests. As you can see, not too much complexity involved considering the useful science that results. All parts are inexpensive and readily available. Nothing critical apart from the PIN photodiode and the 280000mcd red LED which I got from Hong Kong via eBay. 100mm optics used at the TX and RX ends.

The 481THz receiver

The 481THz beacon transmitter

New 481THz QRSS3 beacon ready for action

Completed 481THz beacon electronics

This afternoon I finished off the electronics build of the new dual frequency optical beacon TX for 481THz (red light) over-the-horizon (NLOS) tests. In the end I opted for QRSS3 on a choice of 2 sub-carrier frequencies selected by toggle switch together with the option of a continuous sub-carrier transmission on either frequency to help beam alignment. I have not incorporated an FSK facility at present. All that remains is to align my sighting scope with the optics so that I can use this to help with aiming. Currently the beam appears off-centre in the spotting scope cross-hairs.

As I now have the option of a lower sub-carrier frequency, I need to revisit the improved RX to see if I can better optimise sensitivity at the lower frequency. Theoretically the detector should be several dB more sensitive at a lower sub-carrier frequency which should help with NLOS tests where signals are weak.

The beacon is powered by a 19.5V 4.5A ex-Dell laptop SMPSU, although I only need around 300-400mA with the current LED, which is exceedingly bright.  In the picture above you can see the BACK of the LED and that is pretty bright. At least with the PSU the whole beacon is self-contained.

New frequency for LF QRSS3 beacon : 137.766kHz

Using the strong German commercial station DCF39 on 138.830kHz (it is S9+ with me) as an accurate frequency reference, I have checked the frequency of my QRSS3 QRP beacon and it is running higher up the band than I thought due to the way the crystal is loaded. 

Frequency to look is 137.766kHz   +/- . It should be within 1Hz of this frequency. 

Reports and screenshots (looking now in the right place) would be very much appreciated. I shall leave the beacon running all today at QRSS3 speed.

Weak signalling comparisons

Over the last few days I've been trying out my Lesser Chirpy 10m 80mW CW rig putting out CQ calls on 28.060 periodically and listening for replies and RBN reports. In three days I've only managed 2 RBN reports at around 3000km with it. So, this morning I fired up the hombrew WISPY WSPR beacon on 10m to see what happened. This runs about 6dB more power at around 200-250mW pep effective on the WSPR band. On the first transmission I got 3 reports immediately at 2200-3500km. With WSPR it is SO much easier.

Conclusions? Well if you just want to know what propagation is like then a small homebrew WSPR beacon is all you need. If you want the fun of the chase and the chance of a few QRP CW contacts with a human then the Lesser Chirpy rig is up for the challenge.

Life is too short to sit there endlessly calling CQ with the key though. So, I think Lesser Chirpy will be brought out when  conditions and activity are good. Otherwise WISPY will whisper away quietly in the shack whilst I get on with designing interesting new little projects, HI.

UPDATE: After a few hours of 10m WSPR at 200mW I had a page of reports out to around 6500km. Back on 10m CW I tried a brief call with the FT817 at 5W and got a couple of USA spots on the RBN. A further 30 minutes of calling CQ with the 80mW transceiver and no reports or QSOs. Think I'll have to come back to 10m QRPp another day!

New VLF Beacon TX

Today I completed the build of my new VLF beacon transmitter. The beacon puts out 5W into a 50 ohm load, which is very close to the resistance of my 20m spaced earth electrodes. The beacon operates at either 8.970kHz or 4.485kHz with (a) continuous carrier, (b) 10wpm CW or (c) QRSS3.

VLF Earth-mode Beacon Transmitter

The main changes were to separate the keyer and the PA, mount the whole unit in a larger metal box and to use a 3C90 matching transformer with a fixed turns ratio having measured the ground resistance, which does not change greatly. On a continuous carrier soak test the case temperature only rises about 10 deg C, so frequency drift in the oscillator divider frequency source should be only around 0.1Hz at final frequency.

Having got the beacon finished, the next stage is to start work on some improved receiving kit and to see what sort of range can be achieved through the ground. My best DX so far with the original beacon was 6km, but this is certainly not the limit.

Over-the-horizon on 480THz

My order for 3 off 12W red LEDs known as PT54 Phlatlights has arrived. These are VERY VERY bright LEDs mounted onto substantial heatsinks which emit a strong signal on 480THz. They were originally intended for portable projection systems. One of mine is going into my QRO optical beacon running continuous carrier, CW, DFCW, QRSS3 or QRSS30 to use in further over the horizon (non line-of-sight) beaconing tests using the scatter from particles in clear air and the reflection off the base of clouds. Last winter my own simple beacon running at around 300mW was detected several km over the horizon using QRSS3. G4HJW's optical beacon using a Phlatlight LED was detectable in my village some 8-9km over the horizon. In neither case could the red glow from the TX be detected by eye.  This week I also received some SFH213 10 degree half angle PIN photodiodes which should be considerably more sensitive than my BPW34 detectors currently in use. Estimates suggest at least 6dB more sensitivity.

Together, the QRO optical beacon running from home, focussed with a 100mm lens (gain about 24-30dB), and a portable high sensitivity 100mm lens based detector should allow plenty of scope for innovative NLOS tests on dark winter evenings.

Just realised: 5W out (for example) into a 30dB gain lens "antenna" is equivalent to 5kW of light power in the beam. That is SOME bright light. Clearly great care is needed in siting and aiming such a system to ensure safety.

TX only WSPR beacon

UPDATE 11.9.12: see later post for improved version

WISPY is a full 2-way WSPR transceiver but there may be occasions when just a simple WSPR TX is needed. This is the (current) schematic of the WSPR TX beacon for 10m, but the very same schematic with a different crystal and values should work on any HF band. On lower bands the doubler could be removed and a simple on-frequency crystal substituted.  The doubler approach was the cheapest way for 10m WSPR.

The schematic needs rationalising and some further simplification, so treat this (as always) as a design starting point.

144MHz across the Atlantic?

A new beacon, GB3WGI in Ulster, has been approved by OFCOM. When turned on it will radiate at least 100W ERP (possibly much more) in the direction of the USA. It will be monitored in the USA and Canada for possible 144MHz openings across the Atlantic.

For many years people have speculated about the possibility of working across the Atlantic on 144MHz. On very rare occasions, this might be achieved by various propagation modes including multi-hop Es, auroral E, tropo or MS, or more probably a combination of these. There have been tantalising hints that this path has been open before now, but no objectively verifiable proof. With new weak signal modes it surely will happen sometime soon.

Successful 481THz NLOS test (8.63km)

8.63km non line-of-sight reception of 481THz optical beacon

Bernie G4HJW set his high power optical beacon running a 1.082kHz tone this evening pointing in the Burwell direction on a non line-of-sight path from his home QTH at Little Wilberham. He then came over to Burwell to compare his RX and my own from a test site on the edge of the village clear of the village lights. Distance was 8.63km.

Both on Bernie's RX kit and my own we got solid copy by ear of the beacon at a distance of around 8.63km NLOS using 100mm optics. Once found, the signal was solid.  I then set up the optics on the tripod and fed the signal into Spectran where the signal was 30dB over noise in a 0.17Hz bandwidth. Listen here for a recording (best played back using Spectran with 0.17Hz bandwidth settings)

G4HJW's beacon TX

There was hardly a cloud in the sky, so this was largely by scatter from the mist/dust in the air. Bernie says signals have been stronger on other nights. Best reception was with the RX aimed just above the horizon, maybe 5-10 degrees at most above.

This was very gratifying as it is the furtherest NLOS signal I have copied and it verified my RX kit is now working at good sensitivity.

When I got back home I did try to copy the beacon by ear out of the bedroom window but the tree cover and lights made copy not possible. However I will try again later in the week with Spectran running and narrow bandwidth.

Simpler 481THz beacon TX

This afternoon I built a simpler CW/QRSS3 beacon for lightbeam experiments. Rather than use a crystal divided down in a 4060 IC I simply used my K1EL keyer IC's sidetone output to drive an IRF640 which drives the 1W LED. 10wpm CW or QRSS3 beacon message is therefore produced on an 800Hz subcarrier. The stability of the sidetone from the PIC keyer is quite sufficient for QRSS3 although not good enough for QRSS30 or 60.