Do people complain you’re quiet on the repeater?

One of the biggest complaints on our local repeaters is that people are quiet with very low audio.  Often they’re using the cheap Chinese handheld wirelesses such as the Baofeng UV-5R or similar which have a reputation for being quiet.  There are well documented ‘fixes’ available such as drilling out the microphone hole.

However it’s not just those radios.  Listening this evening, one station asked another how far away he was speaking into the microphone and the answer was “about four inches”.  This is a big part of the problem.

By holding a microphone this distance away from your mouth you’re introducing two problems. Firstly, most fist mics are designed to be held close to the mouth.   By moving the mic further away, you’re reducing the audio hitting the insert massively.  Secondly, if you’re holding the mic away from your mouth, even the slightest movement of your head from side to side will mean you’re even further away and the volume will get even lower.

There are videos of people on YouTube where they’re holding a fist microphone a foot away from their mouth. How anyone ever hears them, I really don’t know.

I’m naturally fairly quietly spoken but I’ve never had any complaints of quiet audio.  I’ve found the best way to hold a fist microphone at 90 degrees to my mouth so I’m speaking across the insert. This reduces any breath noises, pops and sibilance and by holding the mic directly against the side of my face, it’s always nice and close to my mouth and it’s always consistently in exactly the same place.

How not to hold a fist microphone

How not to hold a fist microphone

The best way to hold a fist microphone for good loud consistant audio

The best way to hold a fist microphone for good loud consistant audio

This is a good habit to get into, it means the microphone is always in the same place, it’s getting maximum audio and because you’re speaking over the mic instead of directly into it, you won’t be popping and adding breath noise all over the place.

If you’re regularly told you’re quiet or that your audio ‘comes and goes’ then perhaps consider the way you hold your microphone rather than diving into the radio and looking for the mic gain.

I’ve been told that somehow these blog posts are being cross posted to a couple of amateur radio newsgroups automatically.  I’m not responsible for this and I have no control over it.  I wouldn’t choose to have my entries replicated there but I can’t do anything about it.  If you’re reading this on a newsgroup then please be aware that I won’t see any replies or comments.

Posted in Amateur radio, Operating tips | Comments Off on Do people complain you’re quiet on the repeater?

Installing a good quality TCXO into my Kenwood TS-590SG

Over the years as I’ve operated QRSS and WSPR, I’ve noticed that my original TS-590S and then the replacement TS-590SG have always been slightly off frequency and suffering from a little drift.  This frequency inaccuracy was barely 30Hz which seems minuscule but when monitoring a section of the band which is only 200Hz wide, the 30Hz error was very noticeable.  I worked around this though, calibrating my grabber software so that it was as accurate as I could get it.

The drift was another matter and once I started monitoring on 10m, it was very obviously there.  As the radio warmed up, it would take a good hour after being switched on for it to settle down and then over the course of a day, as the shack temperature changed slightly, the shift on received signals would be quite clear.

I must stress that for normal day-to-day use, this drift probably wouldn’t even be noticed.

Over a year ago I started looking at various options.  Kenwood sell a replacement “Hi-stability crystal controlled oscillator” but at a cost of over £110, I decided that was out of the question.  My next step was eBay where there are a large number of third party equivalents selling for about a tenner.  These seemed too good to be true and after quite a lot of investigation, including reading discussions on various TS-590 reflectors, I decided not to buy one.

I was pointed towards Mark’s TCXO site where Mark, W7MLG has been doing a lot of work on these modules.  His figures confirmed what I’d suspected about the cheap copies in that they’re not very good at all.  Mark has done a lot of measurements of different modules which can be read here.  It’s all summed up in his conclusion:

It is apparent that there is a significant problem with all three samples of cheap TCXOs that were tested. They increase transmit phase noise by about 12 dB in the 15 kHz range offset from the carrier. This is likely to be detected by someone operating in close proximity. Receiver performance when using up-conversion was also degraded.

Mark has produced his own TCXO and I signed up for one of at the end of March last year.  I’ve been following the progress of the manufacture of these boards with great interest and was very pleased to see that I’d been allocated one of the last units of the first batch.

It arrived today and and it’s a really professional looking board, here’s the front along with an (old) £1 coin for size comparison.

W7MLG TCXO board for the Kenwood TS-590SG

W7MLG TCXO board for the Kenwood TS-590SG

Rear side of the W7MLG TCXO board for the Kenwood TS-590SG

Rear side of the W7MLG TCXO board for the Kenwood TS-590SG

Fitting the TCXO was very simple – Remove the bottom cover, unplug one cable and remove one screw, take out the old board, fit the new board, plug it back in, refit the screw, remove two jumpers and put it all back together.  The whole procedure took far less time than it’s taken to write this post.

W7MLG TCXO board fitted inside my Kenwood TS-590SG

W7MLG TCXO board fitted inside my Kenwood TS-590SG

Having done all that, the important thing is the performance, how well does it work?

I’m testing a Raspberry Pi based QRSS grabber at the moment and so I fired my TS-590SG up on 40m and configured my own QRSS transmitter to transmit on the same band into a dummy load.  I tuned the radio to the centre of the QRSS segment and configured the software appropriately.  Once I’d got the levels set correctly (RF gain right back, attenuator in, etc) this is the signal I monitored:

My own QRSS signal monitored on 40m

My own QRSS signal monitored on 40m

It’s bang on frequency and there’s zero drift.  I didn’t need to tweak the grabber in any way whatsoever, I just told it what frequency the radio was set to and what frequency range to display.  This couldn’t be any more perfect.

The next thing to check was the higher bands.  My QRSS beacon normally sits on 10m so I tuned the receiver up there and configured the grabber in the same way, I set the base frequency and the range and let it rip.

Monitoring my own 10m QRSS signal

Monitoring my own 10m QRSS signal

Again, this is spot on frequency with zero drift whatsoever.

This TCXO has transformed my QRSS grabber and it will be the same if I use the wireless for WSPR.  It’s really good to know that I’m now bang on frequency and I don’t have do any faffing about and adjusting the grabber to show the correct frequency.

The final cost for this including shipping, VAT and the customs ‘handling fee’ was around £65 which is significantly cheaper than buying the Kenwood SO-3 module.  It’s more expensive than the eBay copies but I consider it a very good investment.  I thoroughly recommend the 15.6 MHz TCXO Board for Kenwood TS-590S by Mark Goldberg, W7MLG.

Usual disclaimer for when I write about products – I have no connection with Mark’s TCXO Board apart from being a very happy and satisfied customer.

I’ve been told that somehow these blog posts are being cross posted to a couple of amateur radio newsgroups automatically.  I’m not responsible for this and I have no control over it.  I wouldn’t choose to have my entries replicated there but I can’t do anything about it.  If you’re reading this on a newsgroup then please be aware that I won’t see any replies or comments.

Posted in Amateur radio, Construction | Leave a comment

Update on my 17m FT8 DXCC challenge

My last update on this challenge was back in October and I did very little towards it until the New Year.  Since the last time I posted about this, I’ve worked an extra 27 DXCC entities on 17m using just FT8 taking me up to my current total of 77 entities worked.

This brings my total number of DXCC entities worked on 17m using all modes up to 147 and it’s interesting to note that my FT8 count overall is now at 83 which exceeds my JT65 count of 76.  This really shows how the amateur radio community has embraced FT8 because I’ve made about three times more QSOs using JT65 than I have FT8.

Here’s a list of the countries I’ve worked so far in this challenge.

As an unrelated footnote, I’ve been told that somehow these blog posts are being cross posted to a couple of amateur radio newsgroups automatically.  I’m not responsible for this and I have no control over it.  I wouldn’t choose to have my entries replicated there but I can’t do anything about it.  If you’re reading this on a newsgroup then please be aware that I won’t see any replies or comments.

Posted in Amateur radio, Data, DXCC-17m-FT8, FT8, HF | Tagged , , | Leave a comment

I’ve got my Special Contest Callsign back

In 2013 I was issued a Special Contest Callsign (SCC) and used it very successfully for a number of contests which you can see on my Contest results page.  Because I wasn’t active in the qualifying contests very much after that, I couldn’t renew it when it expired at the end of 2016.  Part of my inactivity was due to the problems I had with interfacing the radio to the computer which I resolved last year.

After entering a few contests in 2017 I realised that I’d probably got enough points to be able to renew my SCC.  It took some scrabbling around and looking up my old results to confirm that I was just one point away from being able to renew.  Towards the end of December the results from the WAE RTTY contest were posted and my result gave me two points towards my callsign.

I submitted my application at 20:38 on the 21st December and at 14:38 on the 22nd December I received the NoV for M7P.

Notice of Variation for M7P

Notice of Variation for M7P

There are some good reasons to have a Special Contest Callsign – Being only three characters, they’re quicker to use in all modes and are far more distinctive.  A very nice bonus is that if you pick one of the more unusual prefixes then they’re quite rare.  Some contests use prefixes as multipliers and people will generally be looking to work as many multipliers as they can.  It’s nice to have a relatively rare prefix.

I’ve given it a quick airing this year and just made around a hundred or so QSOs in various contests, giving away a few points.  It’s nice to have it back again.

You can find out more about Special Contest Callsigns and how to apply for one (if you qualify) here.

As an unrelated footnote, I’ve been told that somehow these blog posts are being cross posted to a couple of amateur radio newsgroups automatically.  I’m not responsible for this and I have no control over it.  I wouldn’t choose to have my entries replicated there but I can’t do anything about it.  If you’re reading this on a newsgroup then please be aware that I won’t see any replies or comments.

Posted in Amateur radio, Contesting | Leave a comment

QSO statistics for 2017

I’d just like to record my annual stats as extracted from ClubLog for 2017

As is normal for me, most of my QSOs were data.  The majority of those were RTTY although a fair few were using the new FT8 mode.

I’m not unhappy with those figures, especially when you consider how poor the HF bands have been for the year.  Remember, we’re still the best part of two years away from solar minimum (cycle 24 started in December 2008) so in all reality, I think that we’re probably four years away from when we’ll notice any improvement in HF conditions.

As an unrelated footnote, I’ve been told that somehow these blog posts are being cross posted to a couple of amateur radio newsgroups automatically.  I’m not responsible for this and I have no control over it.  I wouldn’t choose to have my entries replicated there but I can’t do anything about it.  If you’re reading this on a newsgroup then please be aware that I won’t see any replies or comments.

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OK DX RTTY contest 2017

What a difference five years and nearly half of a solar cycle makes.  Last weekend I entered the OK DX RTTY contest and upon checking my log, I realised it’s been five years since I last operated in this contest.

In December 2012 we were approaching solar maximum and conditions were excellent.  Five years later, we’re approaching solar minimum (although we’re still a couple of years away) and conditions were, to be blunt, bloody awful last weekend.

I had things to do in the shack so luckily I wasn’t tied to the wireless all day Saturday and was able to do other stuff.  It’s just as well.  In 2012 I managed nearly 350 QSOs on 15m but last weekend, all I could rake out was 32 contacts.  I tuned around a few times and I simply didn’t hear any other stations calling CQ on 15m at all at any point.

Conditions would have been the same everywhere so it would have been rubbish for everyone else making a single band 15m entry.  The results for this contest are normally out very quickly so it won’t be long before I find out how well (or how badly) I did.

** update – 25/12/2017**
The results are out, just two weeks after the contest.  I was 4th out of 9 entries in the section.  How different this is to 2012 when there were 58 entries in the 15m category.

You can see the SH5 log analysis via my contest results page.

Map of stations worked by G6NHU on 15m in the OK DX RTTY contest 2017

Map of stations worked by G6NHU on 15m in the OK DX RTTY contest 2017

Posted in Amateur radio, Contesting, HF, RTTY | Tagged | Leave a comment

Building a Hendricks 41dB Step RF Attenuator

Two or three years ago I had a browser tab sitting open on the Hendricks 41dB Step RF Attenuator from Pacific Antenna/QRP Kits in California.  For some reason I never ordered one and when I finally remembered that I was going to get one, they were out of stock.

I dropped them an email back in March this year and James told me that they were hoping to either redesign or restock and then in September he emailed me to tell me that they were restocking.  As soon as the kit appeared back in the shop, I ordered one straight away and it arrived just a few days later.

There’s not really much in the attenuator but here’s everything that came in the kit followed by a picture of the circuit board and all the components ready to go.

Hendricks 41dB Step RF Attenuator kit

Hendricks 41dB Step RF Attenuator kit

Hendricks 41dB Step RF Attenuator kit - All the components

Hendricks 41dB Step RF Attenuator kit – All the components

I was struck by the quality of the circuit board.  Very solid, good through hole plating and very decent sized pads on each side.

It didn’t take me long to fire up the soldering iron and get to work.

The first two resistors soldered into the Pacific Antennas QRP Kits attenuator

The first two resistors soldered into the Pacific Antennas QRP Kits attenuator

Back of the first two resistors fitted to the attenuator

Back of the first two resistors fitted to the attenuator

Because the solder pads are so large on each side, rather than rely on solder to flow from one side to the other, I made a point of soldering on both sides.

All the 'vertical' resistors in position

All the ‘vertical’ resistors in position

I fitted all these resistors and then moved on to the ones below the switches.  I worked from left to right and when I’d fitted R3, I realised that I had no more left.  There was no R16 in my pile of components.

Panic.

I looked around, I checked the bench, I checked the packaging, I checked the floor but there was no sign of the missing resistor.  I checked my component rack but I didn’t have any 270R 2W 5% resistors in there.

I quickly realised I was going to have to find a spare resistor from somewhere.  I can’t remember exactly how it happened but I got into a conversation on a local repeater where I happened to mention that I was a resistor short and a good friend popped up a few minutes later to tell me that they would drop one over to me later that afternoon.  I asked where they’d got it from and they told me it was a local shop.  I was planning to head over to town later anyway so I said “thank you very much, I’ll pick it up myself”.

When I collected the resistor, I looked at it with disappointment.  It was the correct size and value but the style was very different to the resistors already on the board.  Even though the board was going to be mounted in a box, I wasn’t happy with how it was going to look.

The non standard 270R resistor in the attenuator

The non standard 270R resistor in the attenuator

You can see that it’s totally and utterly different.  You can also see that it’s not soldered in, I just couldn’t bring myself to solder it.

eBay called and I found these.

They looked perfect, correct value, correct power rating and correct tolerance.  They came as a pack of five and I ordered them, paying the extra 20p for next day delivery.

About an hour after ordering these, I rolled my chair back and it stalled on something.  I looked on the floor and there was the missing resistor.  If resistors could smile, I’d swear it was smirking at me.

Within thirty seconds it was soldered in place.

All the resistors fitted to the 41dB step RF attenuator

All the resistors fitted to the 41dB step RF attenuator

The next thing to fit was the large slide switches.  These are big and chunky and feel very positive when chunked backwards and forwards.  I fitted them all with no problems at all except somehow (and I genuinely have no idea how) this happened.

The broken switch

The broken switch

I tried to find a replacement switch locally of the same style with no joy so I emailed James to ask about getting a spare.  James was very helpful and just a few days later a care pack arrived from California.

Two spare switches

Two spare switches

Because I’d done such a good job of soldering everything in, getting the broken switch out was a nightmare.  It took me a good half an hour of working with both a solder sucker and some desolder braid.  It goes to show the quality of the board that I was able to spend so much time on it with a hot soldering iron and not damage it at all.  I’ve never used desolder braid before but that and the solder sucker eventually did the job.

The circuit board showing where the switch was removed (click for a full size version)

The circuit board showing where the switch was removed (click for a full size version)

With the broken switch removed, I fitted one of the replacements which left me all ready for the next stage.

Hendricks 41dB Step RF Attenuator PCB all built and ready to go

Hendricks 41dB Step RF Attenuator PCB all built and ready to go

The next stage was testing so I hooked up my DVM and checked the resistances were all correct with the associated switches.  All looked good.

After this, it was time to prepare the box.  The supplied box has a nice brushed finish and  decided I was happy to leave it like that rather than paint it.  There are some nice decals provided for labelling and the instructions recommend spraying the box with “Krylon clear” first.  This is a USA brand of lacquer spray and not available in the UK so I sourced this alternative from Wilko.

Wilko clear lacquer spray

Wilko clear lacquer spray

After a couple of minutes shaking and spraying, the box was left to dry for 24 hours.

The box, freshly sprayed and drying before applying the decals

The box, freshly sprayed and drying before applying the decals

This looks fine but once the lacquer dried, it didn’t really look very attractive.  I mentioned this to a friend who very kindly offered to hydro dip the box and lacquer it for me.

Once it was all done, I assembled everything into the box for testing.

The finished attenuator

The finished attenuator

It’s quite a dark finish but I think it looks good.  I used my analyser to test the actual attenuation and on 40m, it’s within half a dB or so of specifications and so this will be a useful addition to the shack as it’ll allow me to match the output of my two WSPR transmitters for proper aerial comparisons.

Considering the complexity of some things I’ve built over the years, this should have been a simple build.  It just goes to show that the gremlins can creep into anything and everything seemed to go wrong with this one. I’m just glad it’s finally completed and working as intended.

Posted in Amateur radio, Construction | Leave a comment