Tuesday, April 30, 2013

First Swallow of the Summer, etc

THIRTY-odd years ago, early in my professional career I moved up to Central Scotland from Yorkshire, where I remained for about six years.   In the late Spring of the first year I was there I noted the date on which I spotted the first swallow of the summer, it happened to be May 1st, and thereafter May 1st has been the "yardstick" with me for spotting these harbingers of the coming Summer.  For some reason I'd never taken any notice of this phenomenon before.

Having subsequently back to South of the Border, some hundred miles to the south, I usually reckon to see swallows two or three days before that particular date, but unusually this year, it is now April 30th, and no swallows have yet come to my attention (I am not saying they aren't hereabouts!). However, unusually this morning the first house martins I've seen were swooping around the front of my QTH.  Usually swallows are to be seen before the martins in my experience.

TS-180S Repair - Part 2

It is now time to report on the progress with my ailing TS-180S.   Until yesterday evening there wasn't much to report save that I had come to a couple of conclusions.

Firstly, the radio definitely has a problem with the PLL circuitry.   That's enough to make one feel that this could be a long haul!   PLL circuits can be difficult to diagnose and fix, as they only work when the loop is closed, and a fault anywhere in that loop could potentially stop the PLL from working.  This radio has a quite early implementation of the "PLL derived PreMix System" which became popular in era immediately prior to the adoption of full synthesis and continuous coverage.  Trio improved the circuitry for their very popular TS-120 model, but I am left to struggle with their earlier attempt.  The PLL circuitry doesn't lock very well, and when it does lock, for a 100kHz change in VFO frequency, the actual het. frequency derived in the PLL Premix system only changes by 60kHz.

The TS-180S PLL Board
 The second conclusion I came to after probing around the circuitry with a spectrum analyser was that the high gain Wide Band Amplifier between the VCO stages and the prescaler/divider was producing a lot of garbage.

I'd previously checked out the condition of the two electrolytic capacitors in this part of the board on my ESR tester, and they suprisingly appeared to be absolutely fine.

With this knowledge I began to ponder how I might break into the loop and possibly inject test signals from a stable source, (ie replace the WBA with a signal generator and see how things behave), but before doing that I decided I would check the DC conditions around the five transistor WBA.   These checks showed that the first transistor in the chain (Q14) appeared to be short circuit in all directions.  Hah!  That is clearly not going to help!


The 8-40MHz Wide Band Amplifier - things are just a bit tight in there!

Anyhow, the faulty transistor was extracted with no little difficulty, tested, and yes, it is completely dud.

Unfortunately I don't appear to have anything close to it in my spares, so it will have to be an EBay search for something suitable.   The original transistor type is 2SC1907 which has a very high fT (>1GHz), so any old gash BC182 just won't cut it on this occasion!  According to the data sheet the 2SC1907 was designed for UHF TV local oscillator applications.

To be continued ...
read more "First Swallow of the Summer, etc"

Monday, April 29, 2013

40 metres



The YL was busy watching the royal wedding this morning so I had some extra "Shack time". I thought I would see if I could find any of the special MR or GR prefix callsigns. I opted for 40 metres, using the TS830 on SSB for a change. I was going to use the TS450 but I couldn't find the mike! Anyway conditions seemed rather noisy but I did get hold of MR0TMW in Co. Antrim and GR0AXY in Edinburgh. Along with GB2SWF (speyside whisky festival). Later I worked F4ELJ in Brest As the band was pretty poor I fired up the SRW linear on 40. You can imagine my embarrassment when running about 350watts I worked PA/DG8KAJ who was running 10 watts!! Well I don't often use the linear so at least I have warmed it up a little. All in all a pleasant morning and quite unusual for me as I havent worked much on SSB lately.
Generally HF conditions seem poor here today with even 20 metres with more noise than activity.
read more "40 metres"

Sunday, April 28, 2013

Icom 706 and 6 metres

I use an Icom 706 Mk1 in my car. Coupled to an LDG IT100 auto atu it works well. Press the "Tune" button on the rig and the ATU does its stuff. Although I use mono band whips for the HF mobile the ATU is very useful in broadening the useable bandwidth.  reading the reviews on Eham I recently saw a reference to this mobile antenna  and am thinking about getting one. It seems it is basically a whip with a balun of some sort in the base. Although it would not be likely to be as efficient as a mono band antenna it would, along with the LDG ATU, allow me access to all bands including or so I thought, 50 mhz, 6 metres-a band which I have not used mobile before. 6 metres is output on the same antenna port as HF on the 706
The 706 covers 6 metres as does the LDG atu. BUT as I found out today the 706 will not generate a tuning tone on 6 when you press the tune button. Neither will the atu work on 6 when I generate a carrier from the rig. Why this should be I have no idea. The Specs of the LDG atu state it covers 50 mhz. Now I believe it is a known shortcoming of the MK1 706 that the "tune" button does not work on 6 metres but why the LDG does not react to a  50mhz carrier I am not sure. As it stands though it seems that if I did get the multiband whip I would not be able to use it on 6 metres.
read more "Icom 706 and 6 metres"

Thursday, April 25, 2013

Ready to Go


Ok, It does't look much but today I made up a doublet for the HF bands. 40 metre top section, 10 metres of 300ohm feeder and a 4:1 Balun.
Its going to be fun fitting this into the garden, in fact half of it will be in the field behind the house. In any case I am hopping it will be a little better than the shortened dipole is on 80 metres and will hopefully work a bit better on the other bands.
I haven't put it up yet,thats a job for another day.
read more "Ready to Go"

Wednesday, April 24, 2013

Band I TV and Radio Meteors - the End is Nigh!

I have blogged a couple of times already about the disappearance of VHF analogue TV in Band I, today I came across a little more information about the demise of the few remaining sources available to we "Meteor Reflection Enthusiasts".

It seems the Ostrava (Czech Republic) transmitter on channel R1 (49.76MHz) will close on 30th November 2011, and the Lousa (Portugal) transmitter on channel E3 (55.25MHz) will close on 26th April 2012, in almost exactly a year's time.

Spectrum Lab Capture of Metor Burst

Quite what, if any signals will be found for displaying meteor reflections once these disappear, I know not, but in the meantime I have resolved to make some audio recordings so that the use of the audio software I use (R_Meteor, SpectrumLaboratory, etc) can be demonstrated should anyone show any interest!

R_Meteor Capture of above SpecLab event

Amateur signals such as beacons are too low in power to fill the gap.   Maybe some QRO beacons are required?   Not very "green", though!
read more "Band I TV and Radio Meteors - the End is Nigh!"

Monday, April 22, 2013

Wrestling with PHP, MySQL and Simple Machines Forum ...

Like a lot of busy folk, I've been looking forward for some time to the few days off work around the Easter / May Day holiday period (enhanced (in length at any rate) by Royal Shenanigans of course) to allow my poor old brain to cool down and to start functioning again.

So it was I returned to tackle a little problem I had set myself a few months ago, to install a Simple Machines Forum on my own web server, with the principle objective of using said forum as a tool to help our local Repeater Group operate.

I'm not an IT professional, but as I understand it, a Simple Machines Forum is some nifty code written largely in PHP, XHTML with some neat CSS, and which is in turn a "front end" to an SQL database.  I hope I've got that right, but that's how I've got it figured in my head at any rate.

Conventionally, people wanting to install SMF applications (which are free!) usually upload the said files to a web server provided elsewhere, and apart from tweaking the forum to look feel and operate like you want, that's more or less it.   Not that I am belittling such things, as they do take quite a bit of tweaking, it seems.

Of course this just isn't good enough here in the G4FUI shack, as I am running the repeater group web site in question on my own PC so the operation is a wee bit trickier.

You have to install PHP (free), MySQL (also free!),  configure Apache (the web server I use) to talk to PHP, and you have to configure PHP in turn to connect to the SQL service so that SMF can build a database and shuffle data in and out of it on demand.

It all sounds a bit geeky, doesn't it?   Well that is precisely how I found it.

Luckily there is a lot of helpful information out there on the web, and after a bit of "Googling" I found some advice which seemed to be pretty well aimed at my own requirements.    As a side note, whilst I was browsing through the various troubleshooting suggestions I couldn't help but notice the lack of hostility and aloofness which I have found on some of the equivalent Linux pages.   Maybe I'm imagining it?

The first serious attempt to get all this working was a month or so ago, and that ended in failure, so the project was "parked" until the Easter break.

The second attempt was much more successful.   Careful reading of the online advice revealed a little trick with a command line box.  This didn't produce a working system but it did produce an error message which was a bit of a giveaway "unable to find ..." followed by a file name which looked sort of  familiar.

The file in question had featured in one of the configuration files (php.ini) I had carefully edited a while ago, and if I'd only spelled the name of the file correctly my system would have been up and running a month or so ago!

D'oh!  Just one little letter makes such a big difference!
read more "Wrestling with PHP, MySQL and Simple Machines Forum ..."

Tuesday, April 16, 2013

More work on the TS830

Here is the 830 minus its covers



One of the replacement 6146Bs


The two valves in Situ





Pa compartment cover screwed back on!


The good news is the 6146bs I had work. The neutralisation process I am not sure about however. As the handbook suggests I tuned the rig up on 28.500, turned the SG switch on the rear off and using my R1000 receiver adjusted  TC1 for a minimum "s" meter reading on the R1000. The only problem was that I didn't get a sharp reduction in the S meter reading, in fact it didn't vary much irrespective of where TC1 was. So I left TC1 more or less where it was with the old PA valves.
At present the rig now has healthy RF output with a pa current well within the specifications. Everything seems stable with no fuses blown so far. I may get a local amateur friend to look at the PA neutralisation issue again before I use the rig in anger though!
read more "More work on the TS830"

Saturday, April 13, 2013

Time for a change?

Well it is for these 6146b valves that I pulled from my TS830s tonight. They don't look in good shape

 If you don't know how they SHOULD look (I didn't!) I will post a picture of one of the unused 6146s I have shortly. Hopefully you can see that the metal filament in the valve is warped. Both 6146s are basically the same
I think the state of the PA valves may be at least part of my TS830 problems. Next job then is to try replacing the 6146s and going through the neutralisation process.
read more "Time for a change?"

Friday, April 12, 2013

Matching my speed




Having finished work a little early today I was sat in the shack, I only had a few minutes as the YL wanted me to take a short walk with her. I decided to call CQ on CW  on 15 metres. Now at the moment I am still using a straight key and I would estimate my sending speed at around 12 to a maximum of 14 words per minute. I was only running 25 watts to my 80/40 metre dipole so I wasn't really expecting any instant replies but immediately UR8IB came back to me. Great.............but hold on, I think he was sending at about 20 words per minute. Well I am pleased to say that I got the basics of the QSO, name and report etc but it was a struggle. His CW was good but a bit too fast for me! Still I am making progress it seems.
On my trip home from work today I was also lucky enough to work on 20 metres SSB R50YG in honour of the Russian cosmonaut Yuri Gagarin.


The mystery of the TS830S goes on. Opening the PA compartment I could see nothing that had obviously blown. I removed and reseated the 6146 PA valves and checked and adjusted the bias adjustment as the manual states. I was then  able to get a reasonable RF output on 80 and 40 metres into a dummy load. Attempt sat trying to tune on 30 metres and 15 metres resulted in another blown fuse and a dead rig.I am lucky in that we have locally here an amateur who is experienced in working with electronics and particularly valved gear. He has suggested the trying a replacement pair of 6146's first (I have a few spares) if this doesn't make any difference he has offered to take a look at the rig.
read more "Matching my speed"

Saturday, April 6, 2013

Progress................of a kind!

Well my TS830s isn't quite as badly damaged as I thought.It is now working OK on receive at least. Why is it now receiving? Well I am almost too embarrassed to admit this-but lets just say its important to make sure the fuse holder in the rig is screwed fully home!!
In any case switching on the heater switch shows that I have some plate current to the PA valves but the current rapidly increases within seconds and if the heaters were left on the fuse would simply blow again. The fault here seems to be similar to the one I had with my small SRW linear- that too showed a rapid increase in plate current. That fault turned out to be a combination of a blown capacitor in the finals stage along with a dying resistor. I hope to get some time over the weekend to open up the PA stage of the rig to have a close look.

I spent some time this evening trying to get the data lead I bought to work with my FT1000MP but to no avail. The DIN plug on the lead was indeed incorrectly wired according to the pinout data in the Yaesu manual. Two of the wires (earth and PTT) were going to the wrong pins. I resoldered these to the correct pins but I still cannot get the software to key the rigs PTT. I think I will stick to the TS450 for data-it works well in this mode and is simple to use. I feel a bit annoyed that I am left with a lead that doesn't do what it was bought for-but I guess it could be easily adapted to suit another rig. I have come to the conclusion that the 1000MP is not really suited to the data modes.
read more "Progress................of a kind!"

Wednesday, April 3, 2013

Not good news

With the higher bands opening up nicely over the weekend I thought I would try my hand at some CW on 15 metres. I started to tune up my trusty TS830s when it blew the fuse. Not the mains fuse, the fuse in the rig. Since this has happened before I was not too concerned and i had some spare fuses to hand. I replaced the fuse and a few minutes later as i keyed the rig, everything went dead again. This time replacing the fuse had no effect. A totally dead rig, no transmit and no receive. I checked the mains plug but no, that fuse was fine. In truth I knew something was more seriously wrong as when the rig died this time there was a small wisp of smoke coming from the top cover! I took off the covers, hoping to see something obvious, perhaps a blown capacitor but there was no visual sign of the fault. Opening up the PA compartment again revealed nothing obvious. i guess it is time to download the service manual and try to check some voltages so it looks like I am going to have to devote some time to the 830s and maybe seek the help of one of the more technical locals eventually. Since this rig is around 30 years old now and has never let me down before I should not complain.

In the meantime I have rewired my CW Key so it works on the FT1000MP. I had a QSO on 80 metres CW with it last night. It works OK but it just doesn't sound as nice on receive as the old TS830.
read more "Not good news"