FT-450D Hum (again)

From what I see and hear, Yaesu is still selling this otherwise excellent HF/6m transceiver with a fundamental design flaw: hum created by poor grounding of the display module when dimmed from maximum brightness. This problem was there on the FT450 but whatever improvement, if any, was implemented in the upgrade to the D version,  it has not worked consistently.  This really annoys me: surely this sort of issue should have been picked up in beta testing? The fix being implemented by many owners seems simple, so why the heck doesn't Yaesu get on a fix it?

OPERA (weak signal mode) - a word of warning

Since installing Opera V1.0.4 a few days ago my Inspiron 630m Win XP PC has started to behave very oddly. For years it has worked in a very stable fashion with very few issues in 6 years of use.  Now it is slow (very slow) even when not using OPERA, CPU load is high and running Ccleaner, which usually takes a minute, took nearly AN HOUR to get rid of 156M of files to be cleaned up.  Now, I cannot PROVE the link, but the coincidence is remarkable.

To make matters worse, the software once installed does not appear to be listed in the list to uninstall. Not being a PC expert I am loath to just remove all the obvious files in case this damn program has left something behind that "leaves its mark".

The lesson is DO NOT INSTALL DODGY, UNSTABLE AND POORLY WRITTEN SOFTWARE unless you know what you are doing and you know how to get rid of it safely and completely.

OPERA, as a weak signal mode is interesting, but I am VERY unhappy that it has messed up my good old faithful PC.

SAQ VLF 17.2kHz test 10.1.12

The historic Grimeton VLF transmission over Christmas on 17.2kHz had to be abandoned because of an equipment failure but Lars (SM6NM) says they are planning another test tomorrow (Tuesday Jan 10th) at 1330UTC.  The sequence will be "VVV VVV VVV DE SAQ SAQ SAQ" running for about 30 minutes and no message. No QSL cards will be issued this time. More details see www.alexander.n.se.  One possible receiver to use is SM6LKM's simple VLF SDR that can be downloaded from http://sites.google.com/site/sm6lkm/saqrx .

This was what they said about the Christmas failure:
 
"The reason for the trouble with SAQ on Christmas Eve was most probably a damaged fuse in the excitation circuit for the 500 V DC generator. The fuse was not completely blown but measured a very high resistance (150 ohm). When we lost the excitation current to the DC generator, we also lost the control current to the choke coils in the conductors to the main motor, and thereby the speed control of the alternator was lost.  It was confusing that the problem occurred exactly when we connected the running alternator to the antenna. We were actually on air a few seconds with decreasing frequency until the antenna was disconnected by the protection circuit in the speed control."

Optical setback (of sorts)

RX set-up at Nine Mile Hill on 481THz tonight

Flushed with my local successes (0.4km) last night, I decided to have a go at looking for the GB3CAM optical beacon 32km away from a local high spot where I know others have copied it sending its 1/15kHz FSK sub-carrier data at 481THz (red light). I set up in the daylight so I knew where to aim approximately and had the PC ready with SAQ receiver (0-22kHz SDR) and Spectran all ready. After dark I started to seriously hunt for the elusive signal    .....but with no success.

Failure can be put down to several possible causes:

1. Difficulty in aiming. Although I knew where to aim, I am uncertain that my spotting scope is correctly aligned on the 100mm optical head and that there is no parallax error. Looking for a very weak signal is therefore hard to start with.
2. Inadequate sensitivity in the optical head. Although I could hear the 50Hz buzz from every street light and house light locally, maybe there is another 6-12dB to be had in basic sensitivity in the optical head.
3. Inadequate volume on the recovered baseband audio. I was monitoring the "live" feed with just a crystal earpiece attached to the head and, although this is fine at home and down a quiet street, it was too low a level to hear weak signals over the traffic noise from the main road which adjoined the field gateway at the RX location.
4. Path loss. According to G4HJW, the beacon keeper, the signal varies from 5-30dB over noise at this location, assuming one is aligned correctly. Although the weather was cloudy and good visibility there was drizzle that came in as I was testing.
5. QRM from car headlights. As cars came along the main road near the test site, I got quite bad buzz from their headlights.

So, not to be beaten, I will do things to address all these problems and try again quite soon. I think I need a better local test beacon that I can use to (a) check aim, check RX sensitivity and adequacy of the recovered audio.

Quantitative tests with 481THz kit

Today, in daylight again, I did a repeat of my recent tests with the baseband pre-focused red LED TX (20mA), looking for the signal 0.2km along the road. This time I also took my PC and looked for the signal with Spectran and the SAQ SDR receiver. The audio tone was around 40-50dB over noise on both systems.  At this range I would have expected far better S/N. The noise floor looks high. When I blocked off the lens the noise floor went UP about 15dB. Why I wonder?  The picture shows the test set-up. If you click on the image you can see the pre-focused red LED pointing out of the house window and the receiving kit in the bottom foreground. Based on these results speech communication, even with just the same LED and no external lens on TX, should be possible to at least 5km. With 100mm lenses at the TX end, considerably further should be possible.  Below are the test results.

UPDATE: After dark I repeated the range test, just using the crystal earpiece to listen to the signal detected by the PIN diode head. At 0.4km, the greatest distance I could go line-of-sight from my home QTH, the audible signal was STRONG, which is very encouraging.

See my website https://sites.google.com/site/g3xbmqrp/Home/opticalcomms for more details and links.

OPERA - new weak signal beaconing mode

There is a new very weak signal beaconing mode being trialled currently on 136 and 500kHz called OPERA. The current version is available as a zip download at http://www.mediafire.com/?w74a061m48nv806 but this is a beta version and updates are happening quite fast at the moment, so best check the RSGB's LF reflector for the most recent version from Graham G4WGT.

Initial indications are this is even better than WSPR, which as we all know is an excellent QRP beaconing mode. I managed to decode SM6BHZ (just under 1000km) and PA0A tonight when using just my 20m separated earth electrodes (no antenna in the air here at all) on 136kHz.

Over the weekend I may give this a go with a few mW ERP on 500kHz and, when I get my vertical loop re-erected, on 136kHz too.

Early days yet, but a most interesting mode that does NOT need critical PC timing (unlike WSPR) and that can use the PTT line or VOX control to key the TX i.e. it is simple to interface rig to PC.

Optical receiver head completed

481THz optical receiver with 100mm lens

I now have a 100mm lens set-up in some grey drainpipe with 4x sighting scope attached on a tripod together with a "simplified version 3" KA7OEI head (of sorts) with a BPW34 detector. In my version the cascode stage is just followed by a single common emitter stage driving a crystal earpiece, although I intend to add an emitter follower so I can connect to my PC (to use with Spectran/SDR) or a transverter.

A 5mm 20 degree red LEDusing just its own built-in lens was shone out of the stairway window aiming down the street in daylight with 1kHz modulation. It was taking around 20mA. I then walked with the kit to the far end of the street and the signal was solid (S9) in the RX earpiece at a distance of about 0.25km. I now need to find a more distant test range and see how far this can achieve. Depending on results I hope to go looking for GB3CAM next week.

Lightbeam receiver progress

Today I did the part of projects I hate most - drilling holes in aluminum boxes. I can never find the right size drill bits, they are blunt and so on. Despite all this, I managed to get a small metal box complete with BNC socket, phone jack and switch mounted on the end of my optics pipe and carried out some first tentative tests. I am using part of a simplified version 3 KA7OEI optical head based around a BPW34 PIN photo diode. In my case there are no op-amps with discrete transistors used for the amplifiers and buffers following the FET cascode stage.

In the next day or so I want to add the sighting scope and find a way of attaching the whole optical unit onto a stable tripod. At this point and can try some more serious tests for example looking for my own 1kHz beacon at greater distance and, hopefully, GB3CAM at 22km if the system works OK.

The output of the head can feed either a crystal earpiece (to listen to the baseband tones or speech received) or into a PC so that it can be used with an SDR to copy various modes up to around 22kHz.

Winter project list

In this first post of 2012 I thought I'd list the projects that are "on the to-do list" for the coming few months. As always, this is subject to change without notice as my interest and enthusiasm goes through waves:

1. Lightbeam RX. The aim is to detect the GB3CAM 481THz optical beacon at a distance of 22km from my nearest highspot. So far I have breadboarded several good sensitivity optical detector heads and the next stage is to complete the packaging of this into a screened box and attach it to my optics which also need a bit of engineering to complete. Target is this to be completed next week.
2. 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.
3. 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 may also add a 100W PA option later. With this kit I hope to improve my personal earth mode DX record of 6km.
4. 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. Up to now I have used my 80m square vertical loop on RX but this is currently down.
5. Case up the 137kHz transverter. This has been a rat's nest on a piece of copper laminate for too long!
6. 28MHz WSPR transceiver based on a 14.060MHz crystal doubled in a DSB direct conversion transceiver circuit.

Now, how many of these projects get done is a matter of conjecture, but I hope at least 50% of them will get finished.

Happy New Year

A very happy New Year to all readers of this blog.

2012 should bring us even better HF conditions as we approach the peak of Cycle 24. With luck and hard work we may get a new MF band around 480kHz. As ever, there are challenges from VLF to light beams to be enjoyed and I hope you have as much fun with our hobby as I shall.

My priority once the Christmas holiday is over is to complete my 481THz lightbeam transceivers and test these locally. Further projects will be to improve my VLF earth mode DX and to set up a lower noise VLF grabber in anticipation of more activity in the months ahead. In addition I shall continue with QRP WSPR and QRP operation mainly on 10m and 6m.

Netherlands on 500kHz and 70MHz

Some good news: amateurs in The Netherlands now have access to the 500kHz band (again) and 70-70.5MHz (4m).  Countries permitting 4m operation are growing every few months. Let's hope one of the major equipment manufacturers includes the band in multimode HF-6m rigs. Adding 4m cannot be too hard.

Elecraft KX3 can now be ordered

On Dec 27th 2011 Elecraft announced that their new QRP radio can now be ordered with deliveries starting in about 8-9 weeks time. As a QRP radio the KX3 is likely to be "best in class" with some excellent features, but it is not low cost when loaded with options and imported into the UK after VAT and any duty is paid. See the KX3 page for more details.

The basic KX3 includes:

   * 10 watts output typical (13.8V) on 160-6 meters. (Up to 5W using internal batteries)
   * All modes (SSB, CW, Data, FM, AM)
   * Many features from the Elecraft K3, including the same full-size LCD
   * Advanced DSP features, including PSK31 and RTTY text display, noise reduction, auto-notch
   * Built-in 8-AA-cell battery holder
   * USB serial cable for firmware upgrades and for use with logging/contesting software

Available options include:

   * KXPD3 precision attached keyer paddle
   * KXFL3 dual-bandwidth roofing filter module for SSB/CW/Data modes
   * KXAT3 internal wide-range automatic antenna tuner
   * KXBC3 internal NiMH battery charger
   * MH3 hand mic with UP/DN VFO controls
   * RS232 control cable (optional replacement for supplied USB cable)

Although I certainly covet this little radio, I have not decided if I can justify the purchase, or indeed afford it!

Happy Christmas

To everyone that reads this blog from time to time, may I wish you and your friends and families a very happy and peaceful Christmas. It is a time to both give and receive love and kindness - enjoy it.

Shortwave broadcast QSLs

Talking about QSL cards makes me think of my very first QSL cards received back in the 1960s. In those days I used the ISWL QSL bureau which handled broadcast band QSLs (I think it still does) and well remember the thrill when I got my very first cards. The first ever QSL was from Radio Nederland and it was an exciting moment. Somewhere I still have that red card with a windmill on!

In the subsequent years I did a fair bit of QSLing when using just my shortwave crystal set and got a few cards back from these reports. I heard stations all over the globe using that simple crystal set with best DX being Radio Havana Cuba, All India Radio and even Radio Australia, all direct and not via any relays. Not bad for just a tuned circuit, a diode a resistor and a crystal earpiece. I must have another go at a shortwave crystal set just for fun, especially as HF conditions are so good now, but these days shortwave broadcasting is not what it was. Using a decent toroid and a bridge detector it should be possible to arrive at a sensitive design with quite good selectivity.

WSPR QSL cards?

Just been having an interesting debate on Facebook about someone requesting an eQSL for an exchange of WSPR reports. Some would argue that, simply exchanging reports via the WSPR database does not constitute a "real" QSO, so a QSL is not appropriate. Indeed, some would say the WSPR database report is itself a confirmation of the report (which it is) so what is the point of a QSL card? On HF contests it is VERY common for only one callsign to be heard in reports such as, "G3XBM 599233 TU" yet such exchanges are used for DXCC credits if a QSL card is sent following such a "contact".

Personally I would eQSL a full 2-way exchange of WSPR data if done within, say 10 minutes, on any given band and consider this valid. I will only do this in response to one received. Others may violently disagree!

Quartz crystal suppliers in the UK

Recently I wanted to buy a couple of non-standard crystals for a VLF project with the crystal divided down using a 4060 divider. After asking other people for advice it looks like Quartslab can provide the service.  Individual crystals range from around £12-14 depending on frequency and type.

This is not cheap, but at least they can offer the low quantity service. There is a minimum order charge of £22.29,  so I will probably order a couple of crystals for 4.59264MHz to give me a stable signal on 8.970kHz when divided by 512.  The company contact is Dave Hayes G4AKY 020 7100 6357.

Ultra-simple WSPR

G3XIZ has been having a lot of success on 40m WSPR recently using a 100mW DSB transmitter to generate a WSPR signal. All that is needed is an audio source (for the baseband WSPR signal), a balanced mixer and a PA. Of course, with this arrangement 3dB of power is lost in the "other" sideband which will appear outside of the WSPR sub-band. At some point - when I've got my lightbeam kit finished in January - I hope to try this arrangement on 28MHz WSPR. A very inexpensive 14.060MHz QRP frequency crystal will double to 28.120-28.130MHz so will be ideal to generate a 28MHz DSB WSPR signal at 28.1246MHz. Of course one could convert the TX into a phasing exciter and null out the other unwanted sideband. This should not be too difficult either as the phasing has only got to be good over just a 200Hz wide audio band, unlike speech which needs good phase balance over the full 300-2.4kHz band.

15kW HF PA - definitely not for a QRP man!

A friend sent me this link http://www.dc9dz.de/en/index.html which shows the design and construction of a 15kW HF PA circuit for the amateur bands based around the Eimac 4CX10000D valve. Although I have no real interest in very high power and I do not expect to hear this on the air (please no!), it is a rather elegant piece of radio engineering.

EU bureacracy threat to ham radio kit building?

The excellent Southgate Amateur Radio News site has some information which should concern amateurs who build kits. They recommend writing to your local MEP to make you views known.

"Thilo DL9KCE, reports a threat to amateur radio kits and modified equipment arising from changes to the EMC directive.  Currently amateur radio kits and modified equipment are specifically excluded from the directive but under the proposed changes they would be fully subjected to the EMC directive. The resulting high compliance costs could make it uneconomic to develop and sell kits so killing off the kit market. If radio amateurs wished to modify equipment it appears they would also incur additional costs and bureaucratic hassle."

The aim of the EU as a common market for trade is sensible but, like many here in the UK, I abhor it when the bureaucrats in Brussels start to interfere and try to fix things that are not broken. I don't want to get into a debate here about the merits of the Euro, but do feel that 2012 will be a year in which the citizens of Europe, and that includes the UK, will face some very tough decisions.

Waters and Stanton - wake up guys!

Today, having still received no feedback from Waters and Stanton about my emailed question on the FT-450D TX hum (has Yaesu fixed it yet?), I decided to ring them up, check prices and ask the question directly. To my amazement the sales person said, "I have never heard of the TX hum problem". Well, he can't be too well in touch with the market and customers then.

I also asked what was the best price for the rig ("same as in the magazines, no deals") and then asked if they still had the 3 year warranty running. "What 3 year warranty? I've never heard of that." I pointed him in the direction of several recent RadCom and Practical Wireless adverts.

In summary, I was NOT impressed with the responses, or rather lack of them, from this well known UK supplier. At a time when business near Christmas is tight surely it is important that sales staff  know about the product and can answer questions as simple as "what is the length of the warranty?".

Unless this supplier wakes up a bit I think I will defer my decision about purchasing the FT-450D.

Incidentally, they did say that Yaesu would be at Hockley this weekend for the W&S open day. I expect people going will ask about the TX hum question directly. And I wonder if there will be any news about the FT817's replacement?

Simple speech processing

Recently Peter Thornton G6NGR sent me a number of example circuits for speech processors, some dating back to the 1960s. Anyone who operates QRP SSB on HF or VHF will appreciate how important "punchy audio" is when running low power. One circuit I remember working extremely well was one based on an idea by John Hay G3TDZ. Back in the 1970s I was using 100mW AM on 2m and wanted to be heard across Cambridgeshire. My audio stage consisted of a couple of pre-emphasis stages followed by a hard audio clipper and a low pass active filter. The result was an amazingly punchy signal with barely any change in audio level when talking. The 12dB/octave pre-emphasis helped to ensure that clipping of LF signals did not result in many artifacts within the audio passband. The LPF was essential because the heavy clipping  results in many audio harmonics which would otherwise result in a broadened signal. With just 100mW and a dipole the QRP AM signal was excellent copy across the county. I keep meaning to try the same circuit (if I can remember it) with the FT817. It would produce a mighty punchy QRP signal!

KX3 release date

The Elecraft KX3 10W QRP transceiver is edging slowly towards formal release for orders. There is an enormous pent up demand for this 0.1- 10W QRP full featured HF/6m radio. Elecraft are still expecting to be able to announce that orders can be placed by the end of December with first products reaching customers in Feb 2012. I am still unsure if this is a possible candidate for my replacement to the IC703.

FT-450D hum?

Although usually/mostly a QRP operator, I've been considering an update to my main station transceiver since selling my 10W IC703 to a local friend. One possible candidate rig is the 5-100W Yaesu FT-450D. It is getting very good reviews with excellent comments on its  receiver features. For a "full feature" HF/6m radio it is good value for money.

But, I am bothered about one thing: many reviews and comments on the FT-450D Yahoo group confirm a design issue with TX hum, believed to eminate from the poor grounding of the display unit. Nothing I've seen or heard has convinced me this widely reported issue has yet been properly fixed by Yaesu. This is not a problem with the display set to its brightest setting, but should one pay around £800 for a radio with a fundamental design issue not solved in a recent upgrade? No.  A question to Waters and Stanton asking if Yaesu has fixed it has not received a reply yet after 2 days: I suspect they don't want to say "no". I have said that if it hums it would be returned.  So, until I hear the problem has been resolved my "buy" decision is on hold. I am in no great hurry.

More optical comms tests

A few days ago I received some 10000mcd 5mm "high brightness" Toshiba TLSH180P LEDs from Maplins.  Today I did some tests without optics using these. Still using just my NE555 1kHz oscillator output directly driving the LED the signal is considerably brighter. It should be some 10dB better than the high brightness LED used before. Using the Toshiba LED both as TX and (unbiased) RX detector the signal could be detected over a range of around 20m in daylight. The beamwidth of the LEDs is narrower (8 degrees) so aiming is quite critical. Further may well be possible with very careful beam alignment.

So, with 100mm lenses at each end (24dB minimum gain each) 5km should be possible and maybe up to 20km.  Progress on the full FM/SSB systems has slowed as Christmas approaches with other activities taking priorities in the family, but the 481THz work is my main priority ham radio-wise.

You Kits SSB transceivers

For some reason I have missed the news that YouKits are producing (or about to) 2 band and 4 band HF SSB/CW transceiver kits at very reasonable prices. See http://www.youkits.com/ . One is a backpack and one a handheld. Quite interesting. See TJ2A and TJ4A code numbers on their website.

Micropower generation/power harvesting

Linear Technology lists the LTC3108, an Ultralow Voltage Step-Up Converter and Power Manager than runs with an input of just 20mV producing a 5V output to power things such as low power wireless devices and processors. Surely there must be an application for such a device in ultra-QRP portable equipment? Imagine, where can you find 20-500mV of noise from? 50Hz crud in the ground, a thermo electric sensor, solar cells etc. I wonder who will be the first person to make a QRPp uW beacon powered using the 50/60Hz buzz available between a couple of earth electrodes in the ground?

Elecraft KX3 internal photos

Elecraft KX3 rear view inside

Lots of QRP operators are eagerly awaiting the release of the KX3 from Elecraft early in 2012. This is a very compact all mode 10W rig suitable for home or field use. It was first lauched back in May 2011 and Elecraft have been busy completing the design and doing field tests. I came across some internal photos on VA3KV's site that I'd not seen before which give some idea of the design. It can be fitted with internal batteries and an internal wide range auto-ATU making it a very versatile transceiver packed with features. Spec is expected to be excellent and not far off that of the K3.

481THz progress update

TX beacon optics

This morning I bought a length of 110mm waste pipe from the local Plumb Centre shop. It came in a 3m length and only just fitted in the car to get it home! After lunch I created my first attempt at some optics inserting my Poundland 100mm lens into the end of a cut section of the pipe. At the focal length I mounted my 10 pence high brightness, prefocussed, LED beacon with Bluetac. With this (crude) set-up on an old tripod and with a taped on gun-sight to help with aim, I set the TX baseband beacon running and pointed it from the stairway through a double glazed window aiming down the road. With my handheld baseband head using just the high brightness 10p LED as the detector I walked down the road to see how far I could get. In the beam in daylight I could detect the signal at the receiver at 120m. With a magnifying glass in front of the RX LED signals at 200m were strong (could not test at greater range), but it was difficult to keep the RX aligned. The red LED was quite strong visibly at the 200m test point even though running just 15mA or so through it. The double glazed window no doubt added a small amount of attenuation. What I'm not sure about is how good (or bad) this result is. Clearly with a really high brightness Golden Dragon LED the range even with this system would be considerably further.

LF tests with the earth electrode "antenna"

Following the great success on 160m with the 20m spaced earth electrodes yesterday, I fired up the WSPR transverter into the same "antenna" today on 137.5kHz. Although I managed to decode G8IMR at 188km several times, no reports of my signal were received. This ties up with tests last year which suggested the earth electrode system was around 8dB down on my 80sq m vertical wire loop. With results on 137.5kHz hard to get with 500uW ERP it was perhaps not surprising that no-one managed to decode me on the earth electrodes.

I now have a choice on 137kHz: either re-erect the wire loop, but double the wire thickness when I do so, or change to a Marconi vertical with a large loading coil. The thicker loop will increase ERP by up to 6dB but I suspect more is to be had with the vertical. It would be daft of me not to give the Marconi a try both on 137.5kHz and on 500kHz. Even with my limited space I can still manage around 8m of vertical with around 20m of top section.

Amazing evening on 160m ...without an antenna

160m WSPR reports - using 5W to 20m spaced earth electrodes

What an amazing evening: tonight I let my 5W WSPR beacon run with my VLF earth electrodes (20m separation with a low wire feed) as the "antenna" i.e. no conventional antenna in the air at all. Just look at these results! 6 countries and best DX 896km to the Shetland Is. If the earth electrodes are acting as a "loop in the ground" then the Shetlands are in the wrong direction i.e. in the null of the loop.

Sunday I intend to try 137kHz with the earth electrodes as I now have some 6dB more power than the last time this was attempted.

Earth electrode "antenna" on HF

Today I had to prune the tree to which my 80m sq wire loop is attached, so the loop had to come down for a while. Instead I connected up my 20m spaced earth electrode pair "antenna" with the connecting wire about 1.5m off the ground coming back along the garden fence. This is the antenna I use on VLF earth mode tests with the best DX reception of my signal being 6km away when using 5W at 8.76kHz.

I have been amazed how well this works on 160-40m this afternoon. This is the log this evening on 160m with 5W WSPR - best DX report so far from OZ7IT at 853km. On 40m I reached over 2000km with a report from the north of Norway.

10m - still WIDE open

A small wire halo antenna, 5W from an FT817 and WSPR software and these are the loggings of my 28MHz QRP signal in just a few minutes this morning. Best DX report 16964km from VK2ALC.