Yaesu FT-450 Grounding Problem - Fixed.

If there's one thing that I will always be glad I did, it's buying an FT-450.  It was a second hand, first production run (pre-'D') model, in mint, unused condition. After tens of thousands of QSOs, it's proven itself to be a rugged unit that can take whatever punishment you throw at it.  You can send digital signals all day with the FT-450, and the crystal won't drift a jot.

However, from time to time - and I mean very infrequently - some ops (usually when there is a solid, strong signal both ways) will report a high-pitched tone on the audio.  Some have asked me if I'm in an aircraft!  I've always put it down to a noisy fridge compressor that sits behind me in the kitchen.

This week, I've been connecting-up a boom microphone, so today was the time to test it out.  To ensure the new mic wouldn't sound horrendous before I started operating in earnest, I got to grips with the transmission audio monitoring function on the FT-450, transmitting on a rather dead 15m band.

This proved very enlightening!  I could immediately hear the distinct high-pitched noise that does indeed render the audio as though it comes from the cockpit of an Airbus!  On selecting high mic gain, the noise was unacceptably distracting.

Before you worry, remember that maybe less than 1% of my contacts have reported actually hearing the sound.  It's much more common to get good audio reports, in fact.

I did some online searching, and found a useful discussion, identifying the source as poor ground bonding between the front control panel and the main body of the rig.  You can find the discussion here.

Now, I'm not very good with electronics, but this basic stuff did seem within my skill set, so I opened up the case to see if fixing this would remove the noise.

And there they were!  Three springy strips of copper that, as you might expect after a few years, were lightly tarnished.  On testing the quality of the connection between circuit and the spring metal, even a simple multimeter was enough to tell me, through its intermittent buzzer sputtering, that the ground connection was poor.

Removing the front panel.

Now, I have to agree with some of the comments online that this inadequate design for the grounding of the front panel is really unacceptable for a major maker like Yaesu.  I have no idea at all why a proper, soldered connection was not provided, but simplicity of assembly might be the answer.

Two of the three copper grounding spring strips.  They make for a poor connection.

The solution to this problem is very easy.  You just need to solder a thinnish wire to the solder base that fixes one of the metal springs, and then run this through the 'bulkhead' - there are only a couple of possible passages - to connect to one of the circuit board mounting screws, which have a good connection to the chassis.

Remember to solder to the front panel first, because doing it the other way around - like I did - means you have to try and solder a short wire to the front panel very close to the rig body (d'oh!)

Step 1.  Pass a thin wire through the ribbon wire slot. Ignore the red tag connection already made for now - I did things the wrong way round in my attempt...

Step 2. Now wiggle the wire to emerge through the lower right corner hole (from front)

Step 3.  Solder the wire to the solder base of one of the copper strips (use the nearest one to the hole in the chassis), and replace the front panel onto the rig.

Step 4.  Cut the wire to the right length, and secure it with a soldered ring connector fixed on the nearest available circuit mounting screw, which attaches to the chassis as a good grounding point.

Job done!

And the result?  Switched on - radio still working (phew!) - and no noise at all.  Just like the comment on the forum said, this fix resolves the noise issue completely.

But what a stupid design error!

Solar Power and Ham Radio

Over the past year or so, I've had a small solar PV system running as a test of both how much power - and how much RFI - I can expect to generate.

Cheap, cheerful and ubiquitous.  These Chinese inverters are safe and work well, but also produce copious RFI.

The test unit is hooked up to the house mains with a Chinese inverter.  This does produce a large amount of RFI on all bands.  On 160m, the RFI is entirely intolerable, even though I don't operate there.  On other bands, given the low price of the unit, the RFI is just about tolerable.

Serious RFI from a poorly-considered solar PV installation (NOT Outback Power's system)

A lot of discussion on EMC issues is now taking place in the ham media.  What strikes me, though, is that, whilst a lot of people complain and measure the spikes on their waterfalls, few bother to tell us what does work well.

After reading a letter in the latest QST from someone who found they had almost no RFI with their solar inverter (a system which was not fitted with individual panel conditioners), I contacted the author to find out what he had that was so successful.

So, as today's handy tip, if you live in the US or Canada, is that these boys and girls apparently make good quality, low RFI inverters and answer questions pretty smartly.

For the rest of the day, I shall be hanging my head in sadness at the stupidity of the UK population, and it's decision to leave the EU...

Hawai'i Buses Arrive All At Once

Happy midsummer's day!

With bright sunny mornings waking us up at some strange hour these days, it's not very often I've been turning to 20m for some DX.  With sporadic E underway, it's usually 6m.

Two islands bagged in a few minutes - and confirmed!

But this morning, idly spinning the dial to 14.076, I discovered several Hawaiian stations coming in at very good strength.  The terminator was very far away, so the precise propagation mechanism for these signals is a little bit of a mystery.

What was the propagation mechanism? 

Hawaiians seem quite relaxed about confirming QSOs, no doubt because the whole damned world is on their back to do so!  Whilst I've had SSB confirmed to gain my WAS award some time ago, I've been waiting much longer for one of the very many QSOs I've had digitally to be confirmed.

Within minutes this morning, I had not one but two QSOs with those distant shores, and both were good enough to confirm almost immediately on LoTW.  Usefully, these can be uploaded to the QRZ.com logbook as well, which is always good for showing off!

Studio Mic for Ham Radio - Saving $$$...

I've never been really interested in audio-twiddling and processing.  But, recently, the hand mic that sits on my kitchen table has become something of an irritant.

So, in true arse-about-face fashion, I started out the process of clearing the table top through buying a studio mic boom.

An entire boom mic system for just £65 - about the same price as a Heil boom.

And how much does someone like Heil and their various outlets expect you, poor ham, is going to fork out for a piece of thin metal and some springs?  Well, about £65, seems to be the answer.

Enter Dawson's Music, who provided me with a great-quality boom, plus a good length of cable, for just £15.

Now for the microphone.  If you are a mere consumer and hunt through the ham outlets, pretty much all you are going to find is a Heil mic.  Now, whilst these have, in most cases, a good reputation, something marketed as a high-fidelity broadcast mic is something you might expect to see in a commercial FM station, not an SSB ham station.

Add to this overkill the fact that they cost something like £230, and it's clearly time to look for an alternative.

On receiving some kind advice on QRZ.com, I decided to buy a Behringer XM8500.  This is a cheap-and-cheerful recording studio mic, costing...wait for it...£15!  Whilst it may be cheap, it gets a very high score from hams on E-Ham's review site.  Indeed, it gets a much higher score than many Heil mics.  That was good enough for me!

Remove the fitted Behringer mic stand coupler (shown partly out) to reveal just what we need - a thread for the boom attachment!

I got myself in a real internet search engine tizz when I tried to figure out how to wire the mic to my Yaesu FT-450.  Seems like I was making things too complex, because people like Technofix make simple adapters for this very purpose.  Turns out the Heil 3-pin units (for which the adapters are marketed) are simply the normal XLR standard connections that you find at the back-end of any studio mic.  So the Heil 3-pin adapter for the FT-450 is equally suited to any XLR, 3-pin mic.  It also features a socket for a PTT switch of your choice.  Technofix provide both hand and foot-operated varieties.

As for a shock mount - certainly not a necessity, by any means - E-bay and Amazon outlets supply these for a £45 saving over the price Heil expects you'll pay for theirs.

So, all-in, the whole change from hand to boom mic cost me about £65.  Or, alternatively, a minimum of £150 less than had I chosen even the cheapest Heil mic (not that there is much choice for an FT-450 from that maker.)  I could have saved about £20 off that if I made the adapter myself.  I decided to leave the shock mount, because hams expect to hear the odd bump and creak!

I later had a browse of some adverts in RadCom.  I was rather surprised to see a headset there sell for £207.  This is a lot of money for two small loudspeakers and a microphone attached to some springy steel! The £207 headset looks very similiar indeed to my pilot's headset - which costs just £105.  Given that reliability is considerably more important for flying than ham radio, and that pilots are hardly poor folk, it seems hams really are being taken for the biggest ride.

The Band is Dead, And Other Rubbish...

It's no secret that the Sun is now approaching the quiet years of its endless cycle.  As a result, the higher HF bands of 12 and 10 metres have been much less active than even a year ago.

That said, it's often not clear whether the band is dead because of everybody acting like sheep and assuming, say, 12m is dead, or that there really is no propagation.

Heading for a lull.  The Sun is approaching solar minimum.

There also seems to be some lack of understanding amongst some operators in that 12m is frequently subject to sporadic E propagation.  Indeed, 12m can even be used successfully for auroral propagation, whether directly, by reflection off the auroral curtain, or indirectly, from auroral Es.  Because most hams are not in the auroral oval region, few know about this.

Sure, we can turn to models like VOACAP and the like, and they tend to be quite useful.  However, WSPR stations on 12m are very far and few between, and it's often the case that only station is active on 12m WSPR.  You only have to look at 6m WSPR during good propagation to realise that insufficinet stations give a very misleading result: often, you can see no links across WSPR stations, whilst someone is 59 on SSB!

Two nights ago, I called CQ on JT65A, 12m.  Straight away, I had a strong return from a PY station.  It was clear there ought to be far more stations on there, so I sent a question as to "why no ops?" to the cluster.

That did it!  Within seconds, the 12m band came alive with JT, RTTY and SSB.  The propagation mode, though most wouldn't realise it, was entirely multihop Es.

So it does seem that acting like sheep and assuming that, because nobody else seems to be there, there's no point transmitting, is a bit silly.

Next time you hear a 'dead' band, try being the one who sends the first signal, see what happens...

Sporadic E Visualised (2016 Updated Edition)

The 6m sporadic E season is firmly upon us, with good hints of short-lived Es clouds over the past few days.

Whilst I watch the WSPR screen carefully, it's often seen that signals sometimes follow strange deviations by Doppler shift.  Most times, this is down to reflections from passing aircraft.  But not always.

If you've ever made an SSB QSO on 6m, or followed WSPR traces during the peak of the season, you will know that Es propagation can come and go in seconds, but also last for a few hours.  Oftentimes, the signal comes and goes in gentle wave-like patterns.  Overall, the Es paths are quite complex, even if the underlying mechanism is relatively simple.

Polar mesospheric summer echoes at 46.5MHz - loose links with NLC and Es.

Now, the ionisation that leads to Es is at a height of 90-120km.  This isn't visible, other than by radio reflections.  Noctilucent clouds, on the other hand - which also occur in the summer months (but do not appear at all in winter, unlike Es) - are readily visible from mid-high latitudes (~40-65 N and S.)  Like Es, NLC also drift east to west, or NE to SW in the summer.  NLC occur somewhat lower in the atmosphere, at about 80-90km, but are subject to pretty much the same dynamics - mostly driven by gravity waves (not gravitational waves!)

We also see reflections at 46.5MHz from polar mesospheric summer echoes - PMSE - at the same height as NLC.  PMSE is caused by ionisaton, and NLC form around charged, metallic meteor debris.  Clearly, all these phenomena are linked to a greater or lesser degree.

Noctilucent cloud over the Irish Sea, 2009.

Whilst NLC are not always linked to Es occurrence, there is a loose correspondence.  The point of this post is to highlight the likely similarity in the form of Es clouds with the visible NLC.  From there, we can start to appreciate how these strange changes in propagation conditions occur, and what kinds of structures cause them.  No doubt Es clouds are modulated pretty much in the same way as NLC - dominated by the breaking of gravity waves propagating up from the lower atmosphere.

The atmospheric radar at Aberystwyth, Wales, captures significant ionisation in the mesosphere in June 2016.

It's interesting to think about how the fading heard on 6m, for example, might be linked to the passing of structures along the path between sender and receiver.  Here's a screen grab of how a JT65A signal changed over the course of just 48 seconds.  Remember that the wavy output is a result of signal strength, not modulation.

The variation in QSB periodicity can be explained by the essentially infinite range of gravity wave wavelengths, and also their velocity, which ranges typically from 40-80m/s.

Gravity wave-induced structure in an extensive NLC display from 2015.  These move across the field of view with considerable speed, partly explaining QSB periodicity.

Giving the RSGB Another Chance (Updated 2017 June 19)

Some two years ago, I left the RSGB because I didn't feel it was representing UK radio in the way it ought to be.

Today, I rejoined.

My primary reasons for leaving were:

(1) The Managing Director is paid "over £60,000" pa, and the Society doesn't seem to think it needs to tell the members - who all contribute to this enormous pay packet  - just exactly how much over £60,000 that pay packet is.

(2) Various dissatisfactions with the domination of the Society by those who are only really interested in contesting and their personal standings in the hobby.

(3) The debacle of the 'K for Kernow' regional secondary locator, and the duplicity shown towards those campaigning for it.  Said by some to be linked to (2).

(4) Too much elitism in general, and too much niche-writing in RadCom.

So why rejoin?

Well, despite being dissatisfied with the state of the RSGB, I have been willing to see change where it occurs.  Reading RadCom lately, I can see that there is an increasing focus on issues that really matter - such as EMC and spectrum defence.

It is also true, perhaps rather sadly, that the RSGB is the only recognised voice of UK amateur radio, and not supporting it, however non-ideal it may be, doesn't help the hobby.  This is a double-edged sword, of course, in that the RSGB knows it's the only kid on the block, and in tha past, has led to complacency.

I am not at all naive with respect to the RSGB, which remains a strongly Anglo-centric organisation, run exclusively at the top by white, middle class, middle-aged men.  There are huge problems with attracting ethnic minorities, women and younger members into the hobby.  I really can't see that the Society has achieved anything in respect of any of these issues, nor particularly that it has tried.

Planning issues also remain a big failure for the RSGB, although it continues to claim its involvement in applications makes approval "more likely."  When challenged as to evidence for this, which is practically impossible to gather as things stand, the Society failed to provide any.  Anyone who knows the planning system will tell you that the same application shoved in front of two different officers at the same council will often yield very different outcomes.

So, let's see where the RSGB goes with its new Managing Director - and how long it can keep me from getting fed-up again with its tendency to default to London Wireless Club ways.

UPDATE:

The new membership pack arrived within 48 hours of putting my application in the post.  Nothing much has changed - except for the member services part of the RSGB web site, which I have to say is a vast improvement over what existed just 18 months ago.  

Inevitably, I want to feel proud of the RSGB and what it does.  I just hope that the next few years build on recent improvements, and that there isn't a big let-down at the end again. 

UPDATE (2) - June 2017

I've left a year later!

The continued and persistent refusal of the RSGB to tell its members exactly what the top pay of its staff is remains a soapbox issue for me.  

RadCom, whilst showing improvmeents, has failed to print a couple of letters about the pay issue. 

RadCom has also produced a major blooper recently, printing an article about station earthing that, for those with PME systems, could be very dangerous.  SO far as I know, months later, it haasn't produced a corrective article, although it has sought a suitable author for one.

I haven't seen a single article about planning matters in RadCom, nor is there a general perception that the society is doing any lobbying, a continuation of its recent history.

So, what's the point?  The magazine is of no use to me.  Times are hard for members, yet the RSGB pays around £60,000 to someone (and won't even say who.)