Low cost rotator

In my search for a low cost rotator for small and lightweight VHF/UHF yagis I see that Conrad Electronics UK sells an "external TV rotator" for £52.99, plus postage from Germany with a free 2 year warranty.

3 core cable, 70 secs 360 deg rotation, 45kg load, 300Nm bending moment, 21.6Nm torque.  See eBay item 180832166179.

Does anyone have any experience of this rotator?

Rotators or big wheels

There was a time when a small rotator capable of turning a modest 2m yagi could be bought for around £40 but there appears to be little available now below £300. The low cost Yaesu rotator (G250?) appears to be unavailable now.  I was thinking about erecting small beams for 6m, 2m and 70cm and was wondering about suitable rotators, but am rather put off by the costs.

A better alternative may be a big wheel antenna with around 3dBd gain omnidirectional, or more if two are stacked. 5dBd is at least as much gain as an HB9CV without the worry of a rotator.

Elecraft KX3 leadtimes

As a potential buyer (still thinking about it), I asked the sales desk at Elecraft what sort of leadtime I could expect if I placed an order for a fully loaded , ready assembled KX3 in the next couple of weeks. This was the reply:

Roger,

Thank you for your inquiry and interest in the KX3 Transceiver.  Orders placed now will ship in 90-120 days. We are working hard to make it less than that, but right now that is my best estimate.

Thank you,
Lisa

So, 3-4 months wait currently.

Homebase-6 (50MHz halo)

Homebase-6 50MHz halo prototype indoors ready for tests

This afternoon I had a go at scaling my Homebase-10 (28MHz wire halo) down to work on 50MHz. I simply scaled the dimensions by 28.3/50.1 (the ratio of the centre frequencies) and performance was almost spot on with a low VSWR in the DX part of 6m. So far I have only tried it in the shack holding the antenna in the air by hand and keying the TX to measure SWR. Next stage of tests will be to erect it in the loft space before erecting a more permanent version within the 10m halo on the top of the mast at the back of the house at a decent height. Still, a promising start. In the end I may opt for a small 6m beam like a Moxon or HB9CV though.

UPDATE 1600z : I have now erected this horizontally in my loftspace although it is more triangular than square. Match is good so I'll see how it performs locally next.

UPDATE 2100z: I am surprised that I'm unable to copy the more distant UK 6m beacons such as GB3BUX and GB3RAL which use horizontally polarised antennas. I need to monitor for longer to see if they appear by MS or tropo.

Winter projects review

Back on Jan 4th this year I put a list of projects that were on my "to do" list on the blog. As winter is now over it is time to review progress (or rather lack of it):

Lightbeam RX. The aim is to detect the GB3CAM 481THz optical beacon at a distance of 32km from my nearest highspot.

Well, the RX has been improved considerably and is now very sensitive and is capable of NLOS reception, but I have still to make a successful reception of this beacon.

Light beam transceiver. Following on from (1), this will either be a transceive head with a transverter or an FM transceiver that I can duplicate so I can talk to others who can borrow the second unit.

This has not progressed at all. It is still my intention to do this.

Rebuilt VLF earth mode beacon transmitter. In a few weeks time I will be able to put out a stable signal on 8.97kHz  (the usual VLF test frequency) rather than 8.76kHz. My intention is to rebuild the whole beacon TX so I can run 10wpm CW, QRSS3, 30 and 60 modes as well as WSPR.

 I have recrystalled and tested the existing beacon for 8.970kHz but the full rebuild has not happened.

Improved LF loop and E-field probe antennas. I want to erect a more permanent external antenna for VLF and LF grabber work and mount these away from the house.
Improved E-field probes have been tested but I have not erected these externally.

Case up the 137kHz transverter. This has been a rat's nest on a piece of copper laminate for too long!

Still to be done.Not started.

28MHz WSPR transceiver based on a 14.060MHz crystal doubled in a DSB direct conversion transceiver circuit.
Not started and now unlikely to be done.

In my defence, I  have done a few other projects including some 160m transmitter and 160m loft antenna work and quite a bit of experimentation on the 481THz kit although few products at the end of this. I want to do one more thing very shortly and that is to erect a 50MHz (Homebase-10 style) wire halo either in the loft space or on the mast outside in time for the Es season.

In summary, I think one can say I am what my mother-in-law called a "fireside fusilier": I'm always gunner (going to) do this and gunner do that!

My old 2m AM rig

This morning, whilst clearing out some paperwork I came across this old B&W photo showing my 2m AM transceiver from the mid 1970s. It had a tunable RX covering 144-146MHz using a free-running VHF VFO (perfectly fine for AM use) and a crystal controlled transmitter; if I recall correctly, it had a few crystals that could be switched. The TX put out around 500mW of AM and was based on the PF2AM transmitter by Pye Telecom, a project I was involved with at the time. It was built in an aluminium box covered in wood effect Fablon.

The rig was also used for CW, goodness knows how, by having an external BFO held near the rig to demodulate a CW signal. Drift was a major issue on CW as you can imagine! Using this Heath Robinson arrangement I had a weekly sked with G5UM some 80km away every Monday night for several months and regularly received 559 using an HB9CV antenna in the loft.

The rig worked some useful AM DX across the UK with the best DX from home being a station in northern France one evening but it was really used as a local natter box in the Cambridge area.

When the ubiquitous Liner-2 2m SSB rig appeared I managed to buy a second hand one and this homemade AM rig was abandoned. I cannot remember what happened to it. It is nowhere to be found, so was probably taken apart for bits, which was a pity. Today I still use 2m AM from time to time and it remains a perfectly acceptable mode for local contacts with very simple kit.

KX3 reviews on eHam.net

There are now 4 reviews on www.eham.net for the new Elecraft KX3 QRP transceiver and the rating is 5 for every one so far. See http://www.eham.net/reviews/detail/10271. Although it is a lot of money it certainly looks one fantastic little radio. I am tempted!

There is a video walkthrough too by K2UM which is worth a look.

The Titanic Radio Page

Lots of interesting information and photos about the Titanic radio room at http://www.hf.ro/.

The photo shown is from the above site (I could not link it) and shows the only known photo of Titanic's radio room. It was taken by a passenger who disembarked in Ireland.

Lynton and Barnstaple Railway

On our holiday in north Devon last week we enjoyed a ride on the steam hauled Lynton and Barnstaple Railway. This is a delightful narrow gauge line that runs through a small piece of Exmoor countryside. When the line was originally build and opened in 1898 this 1ft 11.5inch gauge line ran all the way from the market town of Barnstaple to Lynton on the north coast winding its way around the hills. It included some long 1 in 50 inclines. The narrow gauge was chosen to minimise the costs and to allow tight curves on the line. It closed in 1935. Today the line is run as a trust and only over a very short length although, funds permitting, it is eventually hoped that the whole length can be reinstated as few obstructions prevent this. If you are in this part of the west country I can recommend a visit to this fascinating little line.

This is a video on YouTube showing the line as it was in 1935.

QRP FM pedestrian portable

Today I got back from a week in north Devon where my wife and I had a holiday cottage. The weather was pretty good for the time of the year allowing us to get up onto the hugher parts of Exmoor on several occasions. With my trusty VX2 handportable I managed to work plenty of stations through various repeaters in South Wales but my best DX was a simplex QSO on 145.525MHz with G4TRA in Gloucestershire at 101km. Despite just using the VX2 and a quarter wave whip he gave me a report of 59+20dB when I held the rig horizontal. To quote Steve, "you sound like you are in the next garden". Following this contact I worked MW0ZAP simplex. Time (and batteries) prevented me trying for more QSOs but I'd forgotten how well FM simplex works when you are on top of a moorland hill with a 360 degree takeoff.

FT817 in short supply?

I am hearing repeated stories of the FT817ND being in short supply from various dealers in the UK. One rumour is this is due to component supply shortages so units are not arriving from Japan in the numbers needed.

Of course there could be another explanation: the rig is about to be replaced at long last.  It is not unusual for dealers to be told to run down stocks of the older models which will be harder to shift once a newer model becomes available, except with significant discounting (think of the iPad3).  Once a new model arrives sales will go sky high.

Now, I have no information at all, so don't write to ask me, but I would dearly love to know the truth.

2m/70cm DXing

See http://www.f9ft.com/ antennas

On a few occasions in the last year I've operated /P in the RSGB's UK Activity Contests (UKAC) on Tuesday evenings and thoroughly enjoyed them. Even with just a small halo on 2m and a 4 el yagi on 70cms I was surprised how much could be worked and the high levels of activity.

It is some years since I've used 2m and 70cms from home with a horizontal yagi and I am tempted to erect something to give it a go. I know that outside of contests activity these days is low, but it still seems like worth doing. Whether I erect a rotatable yagi or a stacked turnstyle remains to be seen. It is a long time since 2m was filled with G8 stations using FT290s, 30W linears and Tonna 9el yagis!

Right now I have other antennas erected on the 2 small masts attached to the house and it may be some months before I make changes, but maybe I will get something in the air and see what happens. As well as SSB/CW DX there is so much more to explore these days with digital modes.

Gmail Tap

OK it is April 1st but this is actually not such a daft idea http://mail.google.com/mail/help/promos/tap/index.html

Trying to see the light (very dimly)

As other nanowave enthusiasts have told me, it is very useful when experimenting with light beams at 481THz to have some sort of lab test range that allows repeatable sensitivity measurements. So, today I rigged one up.

Up on the ceiling of my "lab" I've semi-permanently fixed a standard brightness LED fed via a 1K resistor with a 1kHz tone from my 0-1MHz audio/LF generator. I can now adjust the output until the LED is only just visible to the naked eye, with difficulty,  when the room is totally dark. I then place my optical heads (without lenses) on the same spot on the workbench aiming upwards to the very very dim light. The spacing is about 1.5m. I had to check that the signal being picked up was optical and not inductive coupling from the wiring. With this setup, my most sensitive detector can detect the beam at around S2 in a pair of headphones.

I've been experimenting with the drain current of the detector FET and with optimisation of the post cascode stages of my KA7EOI head and may have made 1-2dB S/N improvement. With this test setup I can make very repeatable sensitivity measurements. However, as the tests require TOTAL darkness I have to judge the S/N by ear. My laptop could be set up outside the room with a long screened audio lead allowing Spectran to be used to measure quantitatively the S/N but I'd have to ensure the darkness of the room is preserved.  For an example of this see http://reast.asn.au/optical/Light_Preamp_Performance_Comparisons_20071119.pdf .

At least now I can do lots of initial tests at home and only venture into the field when I have good confidence in the system performance.

Elecraft KX3 - first products delivered

This email appeared on the KX3 Yahoo group today:

"I will do as I told the crew at Elecraft and help the pressure.

At 9:10 AM this morning (Sat) a nice brown truck pulled up in my drive and after I signed for it, gave me a 12"x8"x6" box that said "ELECRAFT KX3 Ultra-Portable HF/VHF Transceiver s/n 0024

Yes ... I got a call yesterday

I am hoping within a hour to be on 20 meters chasing WG0AT on his SOTA trip and putting it thru its paces on digital.

Thank you all at Elecraft ..

The game begins
You will be happy .......

Paul KB9AVO"

8.971kHz VLF earthmode test

30t loop on the ground feeding E-field probe

An 8.971kHz earth mode (VLF through the ground) test was conducted today at 1.6km and 3.5km from home. The TX was 5W QRSS3 into 20m spaced baseline earth electrodes: one a 1m copper rod at the
far end of the garden and the other end grounded to my copper hot water tank in the house.

At the RX end I was using either (a) a 30t tuned loop feeding either the PA0RDT or G3XBM tuned E-field probe, and (b) the same E-field probes but fed with a 19 inch whip instead of the loop.

Good signals were received at both locations with the loop into both probes but there was no detectable signal when receiving on the 19 inch whip into the EFPs.

It was a struggle to see the difference between the PA0RDT and G3XBM E-field probe/preamps, but I think results with my tuned drain design may have been marginally better on this test.

VLF E-field probe update

Today I compared the PA0RDT E-field probe against my own VLF design (on the sub-9kHz website) that uses an 8-9kHz tuned circuit in the FET preamp drain. To do the test I had my wife hold each E-field probe at arms length above her head in the bottom of the garden whilst I made screenshots on the PC. The S/N on Alpha beacons and 18-22kHz MSK signals is similar with the PA0RDT and mine but the PA0RDT design has a lower noise floor. So, in future I will use Roelof's design. Some measurements made by G3ZJO today compared the PA0RDT design against the narrower band VLF E-field probe by DK7FC and Eddie's results suggest comparable performance within the limits of experimental error.

E-field probe tests

This afternoon I built a version of the PA0RDT E-field probe. In the shack the interference was horrendous, but in the garden with the laptop PC just below it the reception of the VLF Alpha beacons and MSK signals around 18-22kHz was excellent. I need to do more noisefloor measurements and elevate the probe higher, but I think this is going to work well when mounted at the top of my neighbours tree that overhangs into my garden. This is a sycamore which I trimmed back a few months ago. The E-field probe can be mounted "in the clear" some 20m from the nearest house at a height of around 5m off the ground. I now need to rebuild it into a watertight box and think how I am going to get the output and power feed to the shack that is at the wrong side of the house some 30m away. Some have used CAT5 twisted wires for this purpose and I guess this would be a good, simple solution, although less suitable if I want to use the probe at 137 and 500kHz where a coax feed would be better.

ZL9 Campbell Island (near New Zealand)

There is to be a DXpedition to Campbell Island (OC-037) in November this year. See http://dx-world.net/2012/zl9hr-campbell-island-dxpedition/ .  This reminds me of the excellent conditions on 20m AM back in the 1960s when I remember hearing a station on Campbell Island working the UK with S9 signals early one morning. In those days I'm sure the prefix was ZL4 though.

Is it just me, or is it much more difficult to hear and work DX stations these days compared with back then? Some believe that the ionosphere has actually deteriorated in the last 40 odd years so that, despite rising sunspot numbers, conditions are not as good as they were years ago.

SPRAT 150 is out

The latest edition of the GQRP club's SPRAT quarterly magazine arrived on my doorstep today. As always, this is filled with a variety of interesting articles and this edition even includes one I wrote about 481THz optical comms "over the horizon", but don't let that put you off, HI.

GQRP club membership, with SPRAT 4 times a year, remains the best bargain in amateur radio in my opinion. More details on the GQRP club at www.gqrp.com .

I note that GQRP club sales is now selling fundamental crystals for 28.060MHz (suitable for my Chirpy rig) at just £2 each. This is a useful source of QRP related parts for club members.

Join!

Amateur radio postage stamps

The excellent Southgate Amateur Radio News page today mentioned that Luxemburg is bringing out a postage stamp to commemorate the 75th anniversary of the Luxemburg radio society. See http://www.southgatearc.org/news/march2012/amateur_radio_stamp_for_luxembourg.htm .  This got me wondering how many other countries have issued stamps with an amateur radio theme? I recall the USA doing a ham radio stamp in the mid-1960s.

Wondering if there were others I did a search on Google images for amateur radio postage stamps. Interesting.

VLF E-field probes compared?

Both the PA0RDT and DK7FC E-field probes antennas are suitable for detecting weak VLF amateur signals around 8-9kHz when used with the right PC software. See https://sites.google.com/site/sub9khz/antennas for the schematics of these and others.

What I'm wondering is has anyone done a "like-for-like" test to compare their performance? With a near identical test set-up (same height above ground, same ground and PSU noise conditions) it should be possible to compare noise floor, sensitivity (S/N of Alpha beacons, VLF MSK signals), and by looking for the intensity of the intermod line at 9kHz from broadcast signals in Europe get an indication of dynamic range. Has anyone done this test at VLF? If not, it looks like I shall have to do it and "suck it and see".

Incidentally, the PA0RDT voltage probe antenna makes an ideal antenna for shortwave, medium wave and long wave DX SWLs. It is essentially a high dynamic range wideband receive antenna which is tiny, yet capable of excellent results if mounted in the clear in a low noise environment ideally away from house electrical interference.

More optical tests looking for elusive GB3CAM

This evening, thinking it would be a good opportunity to look for the GB3CAM optical beacon (yet again) I took the trip to nearby Nine Mile Hill (32km from the beacon) with the kit recently used to detect G4HJW's Phatlight beacon over the horizon at 8.6km. My RX is now pretty sensitive. However, I failed yet again to detect anything of GB3CAM. Actually it was a little hazier than my first tests (when I had sensitivity issues) but I was disappointed not to detect a thing. All I managed was a chat with the farmer in whose field gate I'd set up my optical kit and PC: he seemed happy with my explanation.

I've asked the beacon keeper if the beacon was actually on-air - it could have been off I guess. 

My other question of Bernie G4HJW, the beacon keeper, is what the ERP of the GB3CAM beacon is compared with his phlatlight beacon at home that I'm consistently able to copy at 20-30dB S/N in 0.17 - 0.67Hz bandwidths non line-of-sight, whereas I've so far been unsuccessful receiving the Wyton optical beacon line-of-sight. At 32km haze will matter more and it may just be that on the occasions I've tried I've either had insensitive kit or poor optical conditions. I did try very carefully scanning the horizon this evening after sundown for a good 15 minutes without detecting a thing and I had a very good idea where to aim.

160m WSPR this evening

If JT65 is hard going on 160m this definitely cannot be said about WSPR: having switched on just a few minutes ago I am seeing and have been seen by plenty of stations in northern Europe with my 5W to the tiny loft vertical.

MSF 60kHz off air until April 6th

If you use the 60kHz LF signal from MSF Anthorn to lock your frequency reference or digital watch you may have a problem for a couple of weeks: it is off the air!  It is scheduled to be off air until 20:00 UTC on April 6th. See http://www.npl.co.uk/science-technology/time-frequency/time/products-and-services/msf-outages.

PA1B's QRPp website

Bert PA1B has an excellent website describing his experiments with very low power on HF. Using his FT817 with various simple attenuators he has been able to work some remarkable DX with powers ranging from 1mW to 500mW. His website explains how he has achieved this. It is an inspiring page showing just what is possible.

QRP JT65 to HB9 on 160m with indoor antenna

Just seen that HB9FX has copied my 160m QRP JT65 signal at -24dB S/N. Still finding it hard to make 2-way QSOs with this mode on 160m, but it proves the tiny indoor loft vertical antenna is radiating OK. Best DX report on JT65 is still the SP station about 10 days ago at over 1000km.

10m DX

This evening there were some interesting west African stations coming through on 10m.  6V7Z in Senegal on SSB and J52HF in Guinea Bissau on CW. I did not try to break pile-ups with my QRP and instead worked CT9/DL3KWR on QRP CW. Following this I moved down to 12m and worked N1WPU on CW also with QRP.

First ever 2-way international ham QSO on VLF

From Marcus DF6NM via the RSGB LF reflector earlier today:

"Today between 7:30 and 14:00, Lubos OK2BVG and I successfully completed a two-way contact on 8.97 kHz. We believe that this is the first international QSO ever on VLF.

The distance between Breclav (JN88KS) and Nuernberg (JN59NJ 69es) is approximately 424 km. The weekend before, Lubos and I had found that we could see each other's VLF transmissions from our small home antennas in a slow spectrogram, using about 0.45 millihertz FFT resolution ("DFCW-6000"). This long integration requires about 2000 seconds of continuous non-interrupted carrier to reach full sensitivity.

We decided to use absolute frequency encoding of characters ("MFSK-37" mode), which has a simple structure but is significantly more efficient than two-frequency DFCW. The software signal generators in SpecLab were used to create 30 minute dashes by editing the frequency in 1 mHz steps every half hour. This can be automated by opening a textfile which is read by the "periodic actions" function. Between transmissions, additional half-hour gaps were inserted to let the FFT ring down, and allow for TX-RX reconnections.

Characters are identified by reading the frequencies above 8970.000 Hz, with 8970.000 to .009 assigned to the numbers, .010 idle or space, and .011 to .036 the letters A-Z. Lubos used a Rubidium standard to lock his transmit samplerate, while both receivers and my TX were synchronized by military MSK signals from GQD (22.1 kHz) and DHO (23.4 kHz).

With about 80 watts from an audio amplifier, I could get up to 0.38 A antenna current into my top-loaded vertical 9 m above the roof, radiating on the order of 10 to 15 microwatts. I believe that Lubos is using similar equipment, perhaps a couple of dB stronger. For receive, my soundcard was connected straight to the loading coil and antenna, whereas Lubos has an active probe at a quiet site remote from his TX location.

We wanted to go for a "full QSO" format with reports and confirmations, beyond the rudimentary three-dash "micro-QSO" format which was used in June 2009 between DJ2LF and myself. With single-letter suffixes, we ended up proceeding as follows:

07:30-08:30 "NB" ;Lubos' call: df6Nm de ok2Bvg
09:00-10:30 "BNM" ;my reply and report: Bvg Nm M
11:00-12:00 "RO" ;his confirmation and report
12:30-14:00 "RTU" ;my confirmation and thank you

Although today the noise was not as low as it had been before, we managed to exchange the essential information in 5.5 hours until 13 UT, after which QRN from lightning in southeast Europe became strong enough to obliterate further copy.

Attached image contains captures from Lubos' grabber at Apollons temple (top) and my receiver (bottom), with screenshots from the DK7FC and OE3GHB grabbers pasted inbetween. The original captures are at http://df6nm.bplaced.net/VLF/ok2bvg_df6nm_120325/. All spectrograms were stretched to the same timescale (5 min/pixel). On the left hand side, you can see a MFSK pre-test from Lubos, sending his call to hs own grabber at very low power. There was also a long dash from OE3GHB on 8970.030, and a carrier from DJ8WX on 8970.022 is visible at DK7FC.

The rightmost part of the captures shows the essential eight dashes from our QSO. You can see that I had almost lost Lubos' "B" when my noise blanker triggered heavily on local QRM, inducing me to give an "M" rather than "O" report. But hovering the cursor to 8:15 UT does show the peak at 8970.012 Hz in the spectrum graph. My final "R" is just barely visible at .028, whereas the following "TU" at .030 and .031 ended up drowning in the increasing noise.

During the lowest noise period (9 - 12 UT), the dashes were visible (though not decodable) in 4.5 mHz "600" spectrograms. At that time, our symbols also appeared on Paul Nicholson's spectrogram http://abelian.org/vlf/fbins.shtml#p=1332712800&b=110&s=sp

Thanks again to Lubos for the effort and patience! Although exchanging half-hour symbols is tedious and may sound boring to some, both of us enjoyed it and actually found it quite exciting.

Best 73,
Markus (DF6NM)"

DX reports with JT65 on 10m QRP

This evening I called CQ on JT65 on 10m as the band was closing (I thought) and was surprised to see a couple of reports appear from LW9DC (Argentina) at 11272km. No QSO resulted, but a report of -16dB was quite good with the 5W and halo antenna. A little later I got reports from LU2XPK (13419km) and LU2XPL (13426km). Again no QSOs, just reports from these stations on http://jt65.w6cqz.org/freceptions.html.

VLF activity this last week

Whilst I was away on holiday there was considerable activity around 8.970kHz from Europe with Henny PA3CPM now putting a consistant signal from his small home station antenna on the G3ZJO grabber. Activity is continuing this weekend.

One of my priorities in the next 2 weeks is to get my VLF receive set-up back in full working order as this has been off-air for a couple of months. I will try a new E-field probe this time around and see how results compare with my 80m square wire loop. The PA0RDT or DK7FC E-field probes are well proven designs that work well if mounted high and in a low noise environment. See https://sites.google.com/site/sub9khz/antennas for details. Antenna size is less important than S/N and dynamic range on VLF RX. This is why tiny voltage probe antennas can work so well.

160m WSPR

Just back from a week away on holiday and sorting out things like washing, post etc. So, whilst this is going on I have set the WSPR beacon running with my 5W into the short loft vertical to see what is about.  In the next couple of weeks I have some work to do on antennas in the garden.

Holidays and light

Starehole Bay near Salcombe today

Being on holiday in South Devon at the moment it is a good time to do some walking on the cliff tops in the spring sunshine. Now, most people looking at the beautiful coastal scenes will think, "this is a beautiful view" or "aren't we lucky having such good weather".

So do I, but I find myself looking out to sea and thinking how would a 481THz light signal scatter off waves in the sea? Would my beacon be copyable around the coast by aiming a few miles out to sea and aiming a receiver (located down the coast) at the same spot in the sea? How would my QRSS3 light beam beacon signal scatter off those metamorphic schist cliff formations? 

I need a holiday .....oh, I'm on one!

All for the want of an SMA-BNC adaptor

This week my wife and I are on holiday at my brother's home in South Devon. I don't bring much ham gear with me these days, but I packed my VX2 dual bander and a small mag-mount to erect when static on the car roof.  Packed the rig, charger, several whips, mag mount  ......but I forgot to put in the essential SMA-BNC adapter.

Never mind, there are plenty of things to do instead of amateur radio including seeing the house in Island Street, Salcombe where my dad used to live in back in the 1920s now on sale as a second home for rich bankers at £325k. The house has no views, is tiny, has nowhere to park the Rolls and floods when there is a very high Spring tide.
 

KX3 - more pictures

Some nice shots of the new Elecraft KX3 QRP transceiver at http://www.worldwidedx.com/elecraft-kx3/134267-elecraft-kx3-hands-preview.html.  This rig has still to start shipping nearly 12 months after first announced although the first units should be on their way to happy customers within weeks now. There were some late changes following extensive field testing and some supplier issues.

QRM on VLF?

DK7FC, PA3CPM and DF6NM have all been TXing today around 8.970kHz with reception reports coming in from many of the western European grabbers. DF6NM is running some 20dB less ERP than Stefan yet is appearing on UK grabbers quite well just HF of DK7FC. PA3CPM is a much weaker signal although he has been copied by Paul Nicholson in Todmorden UK. Activity is likely to continue over the weekend. Here is a screen grab from Eddie G3ZJO's VLF grabber today showing 2 of the active stations quite clearly. Notice the timescale on Eddie's grabber: between markers it is 4 hours in his DFCW6000 window, so don't expect snappy QSOs on VLF.

Dropbox Windows Registry issue - NOT fixed!

Having struggled to get Dropbox files sharing working on my main WinXP PC I today did a full uninstall and loaded a new version 1.1.45.exe from http://dl-web.dropbox.com/u/17/Dropbox%201.1.45.exe and I was back in business for the first time in 3 months. Within 10 minutes though, the same "unable to access vital Windows registry data" message reappeared! What the heck is going on???

iPod Touch external audio - success!

Thanks to some input from Robin G7VKQ I have now managed to get an external mic to work with my iPod Touch 4g. He referred me to http://www.blackcatsystems.com/ipad/iPad_iPhone_iPod_Touch_Microphone_Wiring.html which shows that a resistor to ground is needed to make the device recognise the external mic is in place. In the end I found a couple of ways to make the connection work (shown below).

When used with the Spectrum View app from Oxford Wave Research I was able to connect my lightbeam receiver to my iPod Touch 4g and record QRSS3 and CW transmissions. This is 10wpm CW being received at home between rooms by scatter in broad daylight.

iPod Touch 4g repair video

Ever wondered how one would go about repairing an iPod Touch 4g if one went wrong? I chanced upon this video describing how to disassemble it. This Apple device is quite remarkable as it does so much in such a small space and having seen just how it is constructed inside I am even more impressed. However, even having seen this excellent video I think it is beyond my skills to repair it if it went wrong.

iPod Touch, SpectrumView and external mic input

A few days ago I mentioned SpectrumView as being a very useful package for the iPhone and iPod Touch 4g for audio measurements and spectrum analysis. Well, I've now got a 4 pin jack plug and wired it up (according to the best published data I can find) as an external mic input. To my great disappointment nothing happened and the internal mic was still being selected. I am wondering if something has to be asserted to select the external mic input? Anyone know please? What did I do wrong? The ring nearest the jack body is the mic input and the next ring down is supposed to be the ground. I checked the plug was correctly wired. Help!