New Controller Board

Having confirmed operation of the divider scheme on the output of the multi-mode beacon's Si570 local oscillator, I set about making a new controller board.

The new board shared most of the features (and PCB layout) of the old version, adding only the divide chain (using the old TTL chip) and control for the BandPass filter. To date, I had set the BandPass board up by manually setting the band select lines and pulling down the "chip enable" to latch the address (corresponding to the desired band) into the (74LS137) de-multiplexer. Now, I could arrange for the PIC16F873 to do all the hard work for me!

Here's the new board...

You can see the Si570 "piggy-back" surface mount board and the new divider network (with a jumper to select divide by 2 or 4). I also up-rated the power supply arrangements by substituting a 7805 for the 78L05 that was on the original controller. The two four-way headers at the bottom of the image provide ground, two select lines and an enable for the BandPass and a switchable output LowPass (when I finally get round to building it).

Here's the new board in situ...

A few more lines of code were written and now there's a satisfying "clunk" from the relays every time I change band.

Operation confirmed by my first spot after the mods - this time from Erich, dk6ug...

Now I shall be able to flip back and forth between bands with laughable ease (as the great H E L Falkus used to say).

...-.- de m0xpd

Multi-Band Reception Reports

The multi-mode, multi-band beacon (Blogs passim) has been running continually since I added the frequency divider on the local oscillator. I started up on 40 metres and got pleasing reports...

Jan, pa9qv, who previously had spotted me "upside down" on 40 metres, now saw my QRSS and S/MT Hell the right way up...


Johan, on5ex, who also was used to seeing me upside down, was consistently showing my righted signals on his fine grabber site...

I was also pleased to be received by Joachim, pa1gsj, who originally suggested the idea of adding a frequency divider to my Si570 DDS...

I was fortunate that Pavel, ok2bma, was just beginning experiments with QRSS reception when he came across my signals - Pavel was kind enough to email from the Czech Republic with a reception report...

All the time these QRSS reports were coming in, the WSPR mode also was being received on 40m, with best DX to arctic Norway...

After all this successful performance on 40m I switched back to 30m - so nice to do that with the push of a button!

Maik, dl4dtl reported my signal on 40m before the switch (here you just see the closing ' d ' of my call in Hellschreiber followed by my call in FSKCW)...

and after the switch on 30m...

I now have made the PCB for an up-dated version of the controller board, with integral frequency divider (now selectable between divide by 2 and divide by 4 just in case I decide to give 80m a try) and with additional outputs to control the bandpass filter board and a switchable low pass filter (if I ever get round to making one). More details on that to follow.

In the meantime, many thanks to all those who have reported reception of my various signals on various bands!

...-.- de m0xpd

Inadequate User Manuals

Well - my purchase of a new telescope has been the kiss of death for clear skies over the North West of England. However, last evening I managed to get outdoors for a few minutes...

I've been very pleased with the optical performance of the new Skyliner-200P FlexTube AUTO, but very disappointed with the tracking function - I couldn't get it to track at all.

I thought about the geometry involved and what must be going on inside the telescope's control system and realized that it was necessary for the telescope to know where it is pointing in azimuth to have any chance of tracking. I searched around on the internet, eventually finding an owner's manual for a scope from the same manufacturer (SkyWatcher) with a tracking AZ mount (which shares the same controller). That manual said you have to power up the 'scope with the tube facing North, thereby creating a known azimuth reference (my manual mentions NOTHING about that).

I tried that last night - and it still didn't work.

At the same time as realizing that the scope needs to know which way it is facing in AZ to be able to track, I recognized that it also needs to know where it is pointing in EL - but I had assumed that it has absolute angular sensing in EL (the elevation axis is limited in range and has an angle scale marked on the mount)...


After the "pointing North doesn't work" failure last evening, I wondered if the angular sensing in EL also needs a start reference (i.e. if the EL angular encoder is relative) and remembered reading (in the manuals for the other scopes) descriptions of powering up facing North AND with the tube at 0 degrees EL - the "home" position.

I tried that and - hey presto - tracking!

This is awful - there is absolutely no mention of this in the manual. OK - so I can figure it out, but what about all the other poor sods who buy one? Of course, we can pretend that anybody who wants a tracking 200mm telescope enough to buy one would be smart enough to figure out how to operate it despite the handicaps that "User Manuals" represent. The cynic (not to mention the realist) in me doubts that is true.

The fact is the manual is a disastrous "cut-and-paste" of segments from manuals for other products which, together, does not add up to a complete statement of how this device ought to work. Caveat emptor.

Having gotten that off my chest, I must say how very pleased I've been with the limited observations we've made so far. Obviously, looking at the moon is child's play - here's the result of my first experiment with the webcam adapter I got from my cousin at Sky's the Limit and a throw-away webcam...


The image was taken before I figured the tracking issue (above) and before I learned how to drive RegiStax, so I hope to do better in future!

Also, views of Jupiter have been stunning (until it sinks under my neighbour's garage) and the Great Nebula in Orion, m42, has been amazing too (once I got my bearings by figuring out I was splitting wide open the trapezium, theta-1 Orionis, even at lowest magnification). Now I'm waiting for Saturn to get its act together and appear higher in the sky at a decent hour (later this month / early next).

Why - I might even be able to track it!

...-.- de m0xpd

Upright Multi-Mode on 40

After the recent inverted fun-and-games, today I have my beacon running on 40 meters - in all three modes...

I followed Joachim, pa1gsj's sensible suggestion simply to divide down my DDS oscillator output (derived from the Si570) in order to place it within the right ball-park for 40m operation. I had a 7474 double D-type flip-flop in the junk box, so I pressed that into service to make a divide-by-two stage. I figured the old TTL device's output would be able to drive the mixer well enough. Here's the additional sub-system, which I knocked up on Veroboard...


After some messing around with tuning, made complicated by the spacing between the WSPR and QRSS sub-bands on 40m (they're almost adjacent on 30m - so close that I can QSY using the VXO - on 40m I have to actually change the DDS frequency between modes), I had the CW and S/MT Hell outputs running "right side up" (unlike last time). Here's a locally captured grab...

At once, the WSPR emissions evidently were on target - here's the first spot, reported by Jorgen, oz7it...

I would be very grateful for further reports / spots.

Tomorrow I'll add a frequency doubling to all my 30m DDS settings to undo the action of the new frequency divider!

...-.- de m0xpd