Thursday 30 December 2010

Winter Sports Kit

Well, the festivities have gone into remission for a day or two and my mind has switched back to the shack - not to address the boring software task which is the next step on the path to multi-band operation for the multi-mode beacon, but to get stuck into a good honest piece of mechanical work...

I had already completed the electronic side of the touch paddle - but it needed an enclosure to make it suitably robust to use in anger. I found an old Hammond enclosure, which once contained a small switch-mode audio amplifier which recently went belly up (I'm still not sure why). The donor enclosure even had a nice PP3 battery enclosure - but I needed to make a new "front panel".

The front panel has the job of supporting the paddle "blade", which is made of a sandwich of three pieces of PCB material. It occurred to me that soldering would be a good means of mechanical as well as electrical connection - so I decided to use similar fibreglass PCB material to make the new front panel.

Here's the system, without its lid on...


and this shot from the reverse angle shows how the "blades" are mounted...


Here's the finished article (with the rather more expensive "Bencher" paddle lurking ironically in the background)...



The new touch paddle partners nicely with my Funster Plus rig, to make the "Winter Sports" package seen below...


Also visible at the left of the lashed-together rig is a new, experimental CW filter I've been working on - more details to follow.

I enjoyed my first QSO with the new, boxed touch sensitive paddle with John, g4oyc and now have the opportunity to make a few more QRP contacts - with no moving parts!

...-.- de m0xpd

Friday 24 December 2010

One Step Closer to MultiBand

Today, making the best of a day off from the usual pattern of Fridays, I took another small step on the path to multi-band operation for the multi-mode beacon (Blogs passim). I had completed and tested the new bandpass filter (populated for 30 and 40m operation, with one as yet undedicated channel). Now it was time to install the new element in the box...

As the cold spell continues, work in my unheated workshop remains a non-starter. Accordingly, I had to drill all the new holes in the aluminium enclosure using a hand-held drill in the shack. That was going to be easy enough - but the bigger problem was with the marking out that preceded the actual drilling (all the measuring / marking kit is in the workshop and measuring, marking and centre-punching whilst balancing an object on your knee is hardly ideal). Fortunately, I had an idea...

Now - I'm sure this is "old hat" - but it had never occurred to me before. I could make full-size templates for all the boards (the new bandpass and the controller, which needed to be moved to accommodate the new board) in paper, using the Eagle PCB package with which the boards were designed. I printed them out and pasted them into the desired positions...


VoilĂ  - marking out done "automatically" - drilling the holes was a breeze!

Here's the bandpass board in situ, beyond the re-located controller...


Notice that I didn't bother to remove the paper templates - they're not doing any harm (in fact, they add a layer of insulation, potentially useful should anything - like a rogue nut - roll under the board and short to the case).

I also decided to take the opportunity to tidy up the power distribution arrangements - previously I'd just soldered more and more pairs of wires onto the tags of the 2.1mm DC Socket and things were getting awkward. Nothing that a scrap of Veroboard and a few Molex connectors couldn't handle. I even had the foresight to include two spare connectors (which will power the receiver and the switching output LowPass filter when I get time)...


It is working FB on 30m (I've arranged things such that the BandPass board "defaults" to 30m on power up). Now, I've got a pretty big/boring programming job to do to get the system running on 30 and 40m - adding to the menu system, switching the new bandpass filter and controlling the DDS. Just the sort of job to fill up a few quiet hours when I need time away from the fun, food and drink of the Christmas festivities - or from "Winter Sports"!

Talking of which, I am listening to "the message of the angels" from King's as I write. The last verse of the Processional (with Cleobury's descant) sounded a bit shambolic, I must say! Things can only get better...

...-.- de m0xpd


Update:-

Well, the service has ended and it certainly did not get better!

It would be interesting to know if the BBC OB crew were the usual (and usually excellent) "Choral Evensong" team - poor microphone placement could have explained some of the apparent timing issues. Otherwise, more questions will be asked of Dr Cleobury, who himself asked an awful lot of the trebles to follow him on his uncomfortable harmonic contortions in the "Adeste Fidelis" descant.

Finally, perhaps it would be kindest quietly to draw a veil over the dubitable liturgical design (not to mention the ordinary, secular nonsense) demonstrated by singing "Born this Happy Morning" at a quarter past four in the afternoon!

Wednesday 15 December 2010

WebSDR

Finding myself away on a business trip once again, with time to twiddle my thumbs, I decided to take another look at what can be accessed via the Hotel’s internet connection.

Regular readers of these notes may recall that previously I’ve played with “simulated” radio connections through HamSphere whilst in ZL and QSONet whilst in HB.

Well, today I’m back in HB-land but, rather than playing with web-based simulations of the ether, I’m listening to the action on the CW segment of 40m – the real thing.

All this is thanks to WebSDR, which is a network of public-spirited Hams, who make available a software defined radio, a server and some special code developed by Dr Pieter-Tjerk de Boer of the University of Twente.

There are several people offering WebSDR receivers as I write, as listed on the WebSDR.org homepage and shown in this map…


The receivers cover various bands – I’ve particularly enjoyed listening to Dan, yo3ggx’s system in Bucharest, KN34bk. Here’s a partial screenshot of the waterfall display on Dan’s page, running Pieter-Tjerk’s application …


This is useful, interesting and fun. Not just a great boon to travellers away from their own shacks but worth looking at from home too!

Thanks Pieter-Tjerk & Dan.

…-.- de m0xpd

Monday 6 December 2010

Touch Paddle

The "warm spell" yesterday allowed me to make not only the PCB for my band-pass filter for the multi-mode beacon (Blogs passim) but also a PCB for the experimental capacitive touch paddle.

An unaccustomed bout of insomnia had me up very early this morning and I took the opportunity to get the PCB stuffed and working - here's the new PCB sat next to the original breadboarded prototype (and using the same capacitive paddle "blades")...


I couldn't resist trying the paddle on the air - so hooked it up to my Funster Plus (which has an internal keyer) and called CQ.

I didn't get any replies for a while but heard Andre, f5ukl, calling CQ and I answered him. He gave me a 559 and has offered to send an MP3 of the QSO - so I'll be able to hear the Funster Plus AND the new touch paddle from the "far side".

Many thanks, Andre.

I have to say, I'm very impressed with the touch paddle - I'll put it into an enclosure and use it in anger - it might not have the charm and feel of mechanical paddles, but it sure was cheaper than the Bencher!

...-.- de m0xpd

Sunday 5 December 2010

Band Switching Arrangements

Having enjoyed little success with diode switching for the multi-mode beacon's band-pass filter, I've crossed over to a simple relay-based switching arrangement.

Each of the three bands in the unit under development has its input and output switched by a single-pole change over relay, as shown below...

The relays are switched by the circuit below (only one channel shown)...


I might not have used this design - but for the fact that it inherits much of its circuitry from the failed diode-switching circuit - indeed, I've actually stolen the components from the "diode" board!

The cold weather has been in remission today, such that I felt able to get out to the
PCB etch tank (which lives in what used to be the children's play house - now its just another "shed"). I made the re-designed PCB, drilled the myriad holes, populated and tested.

Here's the partially completed board...


I've populated two bands - for 40 and 30 m (these being the most popular QRSS bands at the moment). I've just got to wind and fit the toroids.

I'm going to leave the third channel unpopulated for the moment until I decide which other band to use.

The weather forecasters are suggesting it is going to get cold again - good job I got the PCB made today!

...-.- de m0xpd

Tuesday 30 November 2010

Touching, Brass Monkeys and a Versatile Singer/Songwriter

One of the things that caught my eye at this year's G-QRP Rishworth Mini-convention was a range of touch-sensitive paddles and associated keyers in the exhibition of homebrew. I'm afraid I don't know the brewer's name (but would be pleased to add my thanks here if anybody can help identify her/him).

I've got something of an affection for keys in general and have dabbled with making both straight keys and paddles (the latter just for fun) - but I've never tried electronic touch-sensitive paddles before. Having been touched by them (and vice versa) for the first time at Rishworth, I decided to make one...

I found a truly elegant design by Matthias Volkert, df4sq, in Sprat 48...


and - whilst I'm not interested in the keyer part of Matthias' beautiful, simple, efficient design (having the m0xpd PIC keyer and its Funky derivative), I decided to try the paddle section.

My version follows Matthias' words and music pretty closely, but with the addition of open collector outputs to connect to a keyer or a rig...


I knocked up a quick version on a solderless breadboard...


(eagle-eyed readers will see the power supply plug-in of a few weeks ago pressed into service)

The paddle was rough-hewn from PCB offcuts...


The whole thing worked very well indeed. I was keen to try it on air, but the bands were out of action last weekend due to a cacophany of QRM caused by something called CQ WW DX ("- . ... - / - . ... - / - . ... -" ad nauseam). [There is, of course, the possibility of shelter in the quiet haven of 30m during a storm of contesting - but that is occupied by my beacon!]

What's worse, I couldn't even go outside into the workshop to make a nicer paddle or a PCB for Matthias' circuit due to a spell of very cold weather! It would be nice to have been able to say "unseasonably cold weather" at that point - but extreme winters are becoming a habit.

Despite the frustrations of contesters, cold spells and failed attempts to build a switching bandpass filter, last weekend did have one high spot - and very high it was too...

A daughter had kindly given me tickets to see Sheffield's Versatile Singer/Songwriter in his "A Man with No More Rolls" tour at the DanceHouse...


Brilliant.

Anybody not familiar with Graham (a.k.a. John)'s work should take a look at his very acutely observed, skilfully delivered and immensely entertaining take on northern life.

...-.- de m0xpd

Multi-Band Beacon: WiP

I spent some time at the weekend looking at "upgrading" the Multi-Mode Beacon (Blogs passim) to MultiBand operation. The internal DDS makes all the frequency control easy - but I need additional BandPass filters to suppress unwanted sidebands...

I designed a set of filters, similar to the 30m version already in the beacon, based upon the series resonator design in EMRFD (page 6.76). Here's my Spice Model of the (three) filters, configured for 40, 30 and 20m operation...


The predicted frequency responses of the filters are shown in the graph below...


OK - so we've got a set of bandpass filters - how should we select between them?

Obviously mechanical switches are out of the question (the rest of the Beacon being electronically controlled) so I looked for a more subtle approach. I thought I'd found it in Doug DeMaw, w1fb's article in QST, January 1991, page 24...


... in which Doug describes switching between parallel filters using diodes.

I designed a circuit, in which the chosen band is loaded into a (74137) latching demultiplexer, which switches the biasing voltage to the appropriate diode switch - here's the important part of my design...


I even got as far as a PCB...


The system works, but only up to signal levels of ~ 100mV. Above this, the diodes introduce significant non-linearity (which negates the whole purpose of the bandpass filters!!). Unfortunately, there's around 0.3V of output from my present 30m bandpass filter in the beacon, so this circuit isn't suitable - back to the drawing board!

OK - I guess Doug only intended the design as a Rx front end band-changing scheme but I was expecting the switches to work up to a larger fraction of the diode forward voltage drop.

Today, in a recourse to good old brute force "steam hammer to crack a nut" engineering, I've ordered up a bunch of PCB relays. I'll replace those dumb, non-linear diode switches with something a little more clunky!

...-.- de m0xpd

Friday 19 November 2010

Best East-ward dx

The last 24 hours have seen some pleasing dx spots of the WSPR emissions from my 30m multi-mode beacon (Blogs passim)...

As well as the familiar transatlantic hops, there is a nice spot from Steve, a45swl in Oman - 6049 km from my qth.



This is the furthest east my 6 Joule WSPR "flashes" have been spotted to date - and from the badly "out of tune" antenna system too.

Despite (what I imagine to be) the low density of receiving stations, it is nice to know that my signals are getting out to the Arabian Peninsula - thanks Steve.

...-.- de m0xpd

Thursday 18 November 2010

Breadboard PlugIn Modules

I am - as regular visitors will have noticed - a fan of "Solderless Breadboards", which I find very useful for prototyping. Their usefulness is much extended by the addition of simple "PlugIn Modules" - hardly a novel idea, but immensely practical.

Today I made a power supply module, to save me adding the same set of components almost every time I knock up a new circuit...

It implements a simple 5V supply, taking power either from a 2.1mm DC jack (e.g. from a WallWart) or from a 2-pin "Molex" header (e.g. from a Battery) and regulating with a 78L05...



In truth, I power stuff under development from bench PSUs (current limiting is such a good idea for the accident-prone) but I still find it simpler to have local voltage regulation on the board - saves messing around with knobs and voltage adjustments!

Notice the little LED to remind me when power is present.

Here's the finished board...



The power supply joins an increasing collection of such "PlugIn" modules I've made over the years - usually to interface a connector or switch to the breadboard without the use of flying leads (which always live up to their name and fly off in my experience).

Here's some of the family...



There's an FCC68 break-out (used to connect the Microchip ICD2 to a PIC project under development on the Breadboard - although I tend to use the PICKit 2 nowadays - not least because of simplicity in connection!) and two flavours of switch - one "upright" and one in a more laid back posture.

I'm going to add some more modules - perhaps my favourite QRP linear amp (as previously seen in the Radio Times amplifier) and some other RF building blocks.

...-.- de m0xpd

Wednesday 17 November 2010

OT: National Treasure to Perform at The Wedding?

I would just like to add my own two pennies' worth to the groundswell of popular opinion expressing the hope that "England's Rose" will be invited to perform at The Wedding.

In light of the Chanteuse' last intrusion into Royal Soap Opera, this might present a (mercifully rare) opportunity to give another airing to that classic anthem "The Circle of Life".

...-.- de m0xpd

Saturday 13 November 2010

The Keys are Breeding

Spent an hour at Rochdale and District ARS' "Traditional Radio Rally" this morning. I'm not quite sure what is "traditional" about it - save the rather loose affiliation between some of the visitors and modern standards of personal hygiene.


Couldn't resist another "Key WT 8 Amp" to accompany the one I'd restored from Rishworth a few weeks back. This one is a No 3 Mk I, dated 1940 and carrying the further identifying mark "ZA4605" (on further inspection, I notice this is also stamped on the base of the Rishworth model)...


This MkI is differentiated from the key I got at the G-QRP Convention by the use of a compression spring under the arm (the Rishworth Key has a tension spring above) and by the solid, machined "saddles", rather than the diecast excuses which had failed on my earlier purchase. The flat faces and sharp corners of the machined components are visible on the new key...


If anything, the new key feels better than the one I restored the other week (in which there is a little play in the un-restored central pivot).

Also, I got an old instrument case (which will live again in a new application). I didn't buy it for the case but rather for the goodies I harvested from it...


It is worth the money I paid for EITHER the BNC sockets OR the switches - for both and the case itself, a bargain!

...-.- de m0xpd

Tuesday 9 November 2010

To Tune or Not To Tune?

Now here's a pretty problem...

Last night inadvertently I left my multi-mode beacon (blogs passim) running into the g5rv - but with my MFJ 969 tuner in BYPASS Mode. The results were surprising - in fact, I think I have achieved significantly better dx than with the antenna "tuned".

Here's a map of spots over the past 24 hours...


The beacon is regularly spotted in North America, but this performance exceeds anything seen before - and the spot by Jay, w5olf in Colorado (not so far from my old home in WY) is the best dx (4537.4 miles) the beacon has achieved to date. This transatlantic spot and others into Florida and Maine were achieved this morning, continuing the recent trend for improved day-time dx. All this with the antenna de-tuned...

Here's the indicated SWR (as measured by sending a CW tone from the FT817 into the system - the beacon barely moves the needles of the meter) with the tuner active...



Here's the SWR with the tuner in BYPASS...


What's going on?

It appears that either i) there are losses in the tuner in "TUNED" mode that exceed the benefits of tuning or ii) the source impedance of the beacon is very different from 50 Ohms (the final stage is a low-pass filter, designed from standard methods assuming 50 Ohm operating impedance).

Perhaps you can suggest another explanation?

In the meantime, I guess I'll keep running the beacon into the UNTUNED g5rv !

...-.- de m0xpd

Sunday 31 October 2010

Frequency Hopping WSPR

Since all WSPR transmissions are within tightly defined time windows and within a narrow frequency band, it is possible for two stations accidentally to interfere with each other by an unfortunate choice of transmit frequency. I decided that my multi-mode beacon presented an opportunity to experiment with "Frequency Hopping"; deliberately changing the transmit frequency in order that my "signal sees a different channel and a different set of interfering signals during each hop. This avoids the problem of failing communication at a particular frequency, because of a fade or a particular interferer."

I had fitted my control keypad into the beacon box...


... and successfully adapted my menu software to allow me to select manually from one of eleven different frequencies within the band, roughly 10 Hz apart, by adjusting the internal DDS. Then all I needed to do was implement "Slow Frequency Hopping" by allowing the controller automatically to increment the frequency through these steps after each 6 Joule burst of WSPR transmission.

For the early experiments I also shifted the DFCW and S/MT Hell emissions, as you will see...

Here's the (locally monitored) signals towards the end of the QSY cycle...


You can see the rising WSPR frequencies (at 11:48 and 11:58) and the "reset" back to the lowest frequency at 12:08.

In between, you can see my DFCW and Hell signal encroaching into the WSPR band (also there are local images which appear at spacings of [multiples of] 50Hz - so I guess they're mains "hum" related).

This was faithfully received by a number of stations, including Helmut, df5ff...


In the course of developing the code I made some accidental QSYs, including this in the DFCW signal received by Joachim, pa1gsj...


The refined controller software now allows me to "frequency hop" the WSPR signal, whilst maintaining a constant QRG for the QRSS emissions. I can switch the frequency hopping on and off and nudge the frequencies of the WSPR and QRSS signals up and down their respective bands independently.

I'll let you know if all this delivers any measurable benefit - benefit or not, it has certainly been fun!

...-.- de m0xpd

Friday 29 October 2010

Daylight DX

The multi-mode beacon has been across the pond several times (in all modes) - but previous dx has been achieved discretely, under cover of darkness.

However, today I've gone transatlantic to new WSPR participant Frank, vo1hp, in St John's, Newfoundland...


Frank has reported three spots of my 50mW signal during my "afternoon"; 12:00 - 18:00 local. At once, my signals are also getting down into Portugal and the "toe" of Italy. Clearly conditions are significantly better today than of late.

Perhaps that's good news for all those who will participate in this weekend's CQWW event on 'SSB' (whatever that is).

...-.- de m0xpd

Sunday 24 October 2010

Refurbishing a "Key WT 8 Amp No II"

Had a great day yesterday at the G-QRP club's Rishworth Convention.

I was lucky to be able to chat with Roy, w7el, and thank him for his excellent "Otpimized Transceiver" design, which has inspired - more or less directly - several of my homebrew efforts, including the VFO and Rx for the Funster Plus and the beacon receiver. Introducing Roy (who turns out to be a first-rate presenter), George g3rjv mentioned the Optimized Transceiver, rightly describing it as a "Classic".

I was also pleased to meet up again with another Roy, gm4vki, who was displaying his Russian Cold war era R354 "spy" transceiver. I was first to answer Roy's CQ after he'd got the R354 running earlier this month and I was using my replica Paraset - much joking about "spy to spy contacts" and ending the cold war!

Amidst all the other junk I collected to feed my kleptomania, I was pleased to find a 1941 "8 Amp" straight key going for a song (five quid actually). Fellow WARC member Jim, g3nfb, told me how he had "liberated" a similar key as a youngster - directly from a Lancaster!

I noticed that the key had a little damage - but it wasn't until I got it home that I realized the diecast yokes at either end of the key were cracked (I guess they used all the good metal on the Lancasters) ...


The bits had been put back together with superglue (which had made an insulating open circuit in the rear yoke with the result that even though the key felt nice, it didn't work as an electrical switch).

It has been a long time since I did much in the workshop (what with all the recent fun and games with the beacon) so I decided to spend some of today making some replacement parts to bring the key back to working order. I found some 1/2 inch thick alloy plate and hacked out a blank, which I squared up in my horizontal mill (itself a piece of history)...


I marked up for a couple of replacement "yokes" back-to back...


... and soon had them roughed out ...


After drilling and tapping the various holes, I filed the yokes to shape, trying to recreate something of the look of the cast originals. The result is seen below - I deliberately left the orange £5 price tag on for the camera so I can feel good about it!


Here's another view - it is mounted on a brass baseplate (which itself bears the marking "Key and Plug Assembly No 6" - no idea of the provenance of that component but it sounds "military").



I think it looks pretty authentic and - most importantly - it works again. Now perhaps I'll turn my attention to the pa0klt synth kit I got from Jan, g0bbl.

...-.- de m0xpd

Monday 18 October 2010

Back to the G5RV

Last weekend I knew I wasn't going to be using the g5rv, so I decided to try my multi-mode beacon into that antenna once again.

Regular readers will recall that I have installed a dedicated antenna for 30m beacon work (with the intention of leaving the main station antenna free for other uses). The dedicated beacon antenna is known to be something of a "compromise" - it is just a pair of Moonraker 30m whips mounted on one of their "dipole centres", to make what I have named the "runt dipole".

When I first set up the system, I had results slightly poorer to those achieved with the g5rv, but I was ready to accept the poorer performance in return for the ability to run other modes at the same time as the beacon (which runs 24/7).

I switched over to the g5rv on Friday 15th and was immediately rewarded by an email from David, ea1faq, telling me that he'd got a nice grab of my S/MT Hell signal...


As you see, David had captured my DFCW signal as well - in fact David has done great service to me, having also spotted the beacon's WSPR signals many times in the past. That's 3/3 modes - thanks David!

I left the beacon running to allow me to average over a full 72 hours of performance on WSPR and very soon it became clear that the performance with the g5rv was much better than before. Here's a comparison of the original averaged report rates on the g5rv (blue), the averages on the new "runt dipole" (red) and those on the recent return to the g5rv (green)...


For those of you who have not seen these averages before, I am counting the number of reports of each five-and-a-bit Joule "flash" of WSPR signal, which occur every ten minutes and averaging over several days of data. For the original g5rv data, the average runs over 13 (consecutive) days. For the new "runt dipole", the averaging extends over nearly five weeks (hence the smoother curve), whilst for the re-visit to the g5rv, there's just last weekend's three days of data averaged together.

In all cases, the beacon is running 50mW of power.

In spite of the risk of comparing Apples with Pears, I think it is fair to say that the performance with the g5rv is significantly better than it was before - and significantly better than with the "runt dipole".

As if the performance figures with WSPR weren't enough to be happy with, my email inbox this morning contained another pleasant surprise...

Colin, g6avk had posted on the KnightsQRSS list a description of an unusually strong signal...

Well this surprised me this evening, whilst working in shack #2 this huge S3-5 signal appeared on 30m, on checking my grabber in shack #1 it turns out to be Paul M0XPD.



The subject of Colin's post says it all: "Freak condx or QRO :)". I assured him that it is still the same old QRPp 50 mWatts and that the only change is the antenna. However, the great WSPR performance (compared to that achieved six weeks ago) certainly suggests that propagation has improved markedly too.

Thanks to all those who operate receiving stations for WSPR and QRSS - I'll get round to doing some Rx myself some day.

...-.- de m0xpd

Sunday 10 October 2010

Bad Case of the DTs

Fear not, dear reader - I haven't given up the sauce. I am not in withdrawal, suffering severe autonomic instability. I refer not to Delirium Tremens, but to time differences, dt. Specifically to the "DT" data column in the WSPR GUI...


Everything was going FB with the multi-mode beacon and its new internal DDS until Thursday, when I started to notice large (and apparently random) timing errors. You can see the fall-off in performance on Thursday in this plot of the number of spots in each 24 hour period over the past two weeks...



The time errors "DT" were accumulating at an alarming rate, suggesting an impossible variation in my beacon controller's fundamental clock frequency.

Eventually I discovered it was caused by some kind of interaction between the new Controller board and DDS and the main VXO system. The interaction was either conducted through ground, power lines or interface lines or through radiation from clocks, RF sources etc... Whatever the cause, simply un-plugging the controller (and reverting to the SDR Kits USB synth) has cleared up the jitters for the moment.

All of which gives me time to address the issue of providing an interface between me and the Beacon Controller system. Remember - I needed some switches...

I had so much fun with building the DDS board in surface mount technology that I decided to stick in the nano scale and got some tiny tactile momentary action switches from Farnell (seen here against a PIC 16F873 for scale)...



Here's the schematic of my keypad...


...a conventional layout in which columns of switches are sequentially pulled low by pull-down transistors (in this case MMBT3904s - the surface-mount version of my beloved 2n3904) and read in "rows". I arranged two columns of three switches - four "arrow" keys to navigate up/down, left/right and two (as yet) un-designated switches.

The "arrow" keys are seen at the right-hand-side of the finished "Keypad" board...



That was the easy bit - now to code the PIC!

The actual software interface to the keypad is simple enough - the only real issue being the optimisation of the delays and rules for switch de-bouncing. I tested for two consecutive valid "reads" of the same key, separated by a small delay and then imposed another delay before looking for another key push. However, reading the state of a key and getting that state to do something useful are two very different things - especially in assembly language!

I have implemented a menu structure, in which the left/right keys are used to navigate from the "standard" operating configuration ("Menu 0") to a umber of other menu "pages". Each page has a (programmable) number of options, which are selected using the up/down keys (including a Boolean "On/Off" option if required)...


Here's a (bad) photo of the display telling me where I am...




The banner "Menu 1" is just a text string, such that I easily can replace it with something more descriptive...

Whilst I haven't yet finally decided what to do with the controller, the outline plans are for...

Menu Name # Options Function
1 dF ~10 nudge freq up/down to avoid QRM
2 Band 4 Change Band (30m, 40m, ??)
3 Frequency Hop On/Off cycle through a defined band

That's all development effort (i.e. tedious coding) for the future - for now I must return to the job of fixing the timing errors inside the beacon. Some screening and some (more) power supply de-coupling will be the first ports of call.

...-.- de m0xpd



Post Script

Once again Google kindly has arranged for the image upload feature of Blogger not to work early on a Sunday morning when I want to post. He might not be watching me, but Big Brother is certainly deciding when I'm allowed to make my diary entries.


I did "try again in 30 seconds" - several times but to no avail. However, as you see, it worked fine when I came back at 09:15 local, by which time the servers had woken from their slumbers (but I still can't change the colour of the "Post Script" heading - What You See Is NOT What You Get).