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An easy-build 2 meter antenna Xmas project

December 19, 2020 By: Chris G3YHF Category: Club, Contest, Fun, News, Training

Wythall Radio Club’s Christmas Contest is approaching fast!!  If you only have a basic 2 meter antenna or just a handheld, or you want to get out portable, here’s an easy-to-build 2 meter antenna to boost your signal – from Neil G1TZC. 

There is a link to a pdf version at the end.

Many years ago I read an article somewhere about the Slim Jim portable antenna.  It might have been in Practical Wireless, but was a very long time ago.

Thanks to the late Fred Judd (G2BCX) we have this great little antenna available to us.

I decided that now there is an antenna analyser in the workshop (see previuous post on the nanoVNA), it was time to revisit this old friend.  After a bit of digging around the internet, various measurements were found and duly scribbled on a sheet of A4 paper.

From my memories of the one that I built many years ago was made from choc-blok (electrical connector – 15A) and coat hangers.

Initial sketch

We had also better think about some sort of base as well, as this version will be a table top version.

Ingredients

4 wire coat hangers (10 for £1 from Poundland last time I looked)

3 choc blok electrical connectors (15A)

1 length 50ohm coax with suitable connector for your radio

1 bamboo kebab skewer (yes really)

Material to make a base and fixing screws.

Tools

Wire cutters

Pliers

Craft knife

Terminal screwdriver (small flathead)

Tape measure

Soldering iron (optional)

How we make it

Let’s start with the good bit.  Let me begin by apologising for the quality of photographs – they were done on the fly without a tripod or lighting and on a phone.

Take the choc blok.  Cut this so that there are three terminals per strip.  The ones used here were 6 way 15A, but you may be using something different.

Complete and cut connector block

Cut the hook section off the four wire coat hangers and straighten.  Remember if there is any coating this either needs removing or scraping to bare metal for joining areas.

You should now have four lengths of wire.  To absolutely maximise the available metal cut off two of the hooks from the twisted section and straighten.  These will make the two ends of the antenna.  Exact measurements for these can’t be given because your choc blok will vary in size.

       

Fold short lengths of wire with a pair of pliers

Loosen the screws and insert the wire as shown above.  Cutting these slightly long allows you to change the length of the antenna during testing.  Always handy to have a little bit of give, just in case.

Now take two of the long lengths of wire and cut them to 930mmin length.  In a perfect world these will slot through the choc block a bit like a trombone.  Take another two three way connectors and remove the metal terminal from both.  Do not throw these connectors or screws away as we will use them later.

Slide one of the three way connectors about half way along the two lengths of wire and tighten the screws.  This is simply used as a spacer.  Now use the other connector at the open end of the two wires and tighten slightly.  Again, we are going to leave the option to trombone the metal a little if needed.

Take one of the remaining lengths of straight wire and cut it to 580mm.

Now cut the last length of wire to a length of 497mm (500mm will be close enough).

Find the other end section that was made earlier and insert the two wires to make an unbalanced U shape.

More hunting.  Find the two metal inserts that you set aside earlier.  Here we have one of two choices.  If you don’t have a soldering iron to hand then simply slide one of the metal inserts on to each of the legs of the unbalanced U.

If you have a soldering iron, strip the end of the coax cable ready for soldering.

Solder the inserts as shown.  Note one screw hole on each is uncovered.

Once the ends are soldered and cooled slip them on to the unbalanced U section.  The inner is connected to the longer leg and the braid to the shorter side.  Pinch tighten these close to the base of the U.  This will allow you to adjust the feed point.  In the workshop this was set at about 50mm to start.

Now slide a 3 way as a spacer on the unbalanced U section and tighten.  Using the final 3 way slide it in to place so that the short section is just fed through the connector.  Tighten this connector on both sides.

Connect the long side to the original U section and tighten.  In the workshop version the kebab skewer was used in the middle of two of the connectors so that it strengthens the gap section.

Effectively, the antenna is now complete and ready for use.  You could now tie a piece of string to the top and hang it somewhere (or tie spare bit of bent metal to the end and hang it over something).

Alternatively, the antenna can be bent through 90 degrees to make a table top version.  Let’s come back to that later.

Testing

Connect the antenna to your analyser – BUT DON’T  DON’T WORRY IF YOU DON’T HAVE ONE!

Testing can also be done by connnecting your 2 meter transceiver, low power setting, with your VSWR meter inline.

(OR if you only have a handheld, and no VSWR meter, then try listening on the 2 meter band.  If you can hear signals (especially if they are stronger than on a rubber duck antenna), chances are it will work fine.)   

Adjust the feed point as required to give the lowest reading you can.  Once you have reached the lowest point you can also adjust the overall length of the antenna from the various connectors.  This may increase or decrease the VSWR readings.  This is a bit experimental but that’s what the hobby is about.  The analyser plot below gives 1.5 or better right across the band.

The antenna should also work on 70cms – two for the price of one!

Analyser plot for the coat hanger slim jim

Optional Base

If the option of base is required here is an option that was put together in the workshop.  A length of 30mm wide pine was left over from lining the workshop roof so this was used for my base.

 

   

Foldable wooden base                                       Close up of skewer

Cut the base slightly longer than the bent section of antenna.  Glue two 30mm square blocks on the underside, one at each end.  Measure another length to be fitted in the gap in the underside.  Make this section 20mm shorter than the gap to allow for rotation to make a foot.  Place this strip in the middle of the gap and screw so that strip can be rotated.  You might want to drill a pilot hole to allow free turning.  If you use a long enough skewer you can use it to stabilise the upright.  Drill a hole small enough for a tight fit and push the skewer in to place.

I hope these instructions worked for you and you enjoyed it as a little project.

You can print off these instructions as a pdf by clicking here.

Neil – G1TZC

Antenna building with a VNA

December 16, 2020 By: Chris G3YHF Category: Club, Fun, News, Training

Neil, G1TZC, a Wythall Radio Club member, writes about his experience with a little Vector Network Analyser….

My local club runs monthly activities and this month there are activities on 80m to 30m and 20m to 10m.

As good as the 1/2 sized G5RV is it just doesn’t cover enough bands for this.

Recently I purchased a four inch screen version of the NanoVNA. I decided to pay a little more for a premium version.

I hadn’t realised when I made the purchase that part of the extra money went on the fact it has a much better antenna connector – the N type connector – mounted to the metal case.

My main advice is read the menu flow chart and take the time to download the online manual. The windows software is the right side of basic.

This has given a great chance to make a couple of antennas for the 12m and 30m. Using the analyser makes the whole process so easy.  You can see some of the screen shots below.

I shall be purchasing some more pvc covered wire to add extra bands. I think this will become my portable “go to” antenna for holiday operating.

It has also allowed me to check my 3 element 2/70 beam and the two colinears. I’ve even found that one of the 2/70 colinears works ok on 23cm.

If you have a little bit of spare cash and you want a handy test tool this is great. It allows you to check that antenna from the end of the coax.

Check out Neil’s qrz.com (G1TZC) page for more of his blogs.

Islands to the fore in November DX challenge

December 01, 2020 By: Chris G3YHF Category: Club, Fun, News

Cayman, Puerto Rico, Madeira, Cyprus, and Malta were among the many islands contacted by Wythall Radio Club members in our November DX Challenge.

KP2M in the US Virgin Islands was a big signal into Wythall on 40 meters.  This station is the home of the Radio Reef DXers group

We also contacted several stations on the Aland Islands located between Sweden and Norway including OHoR and OHoZ.

And back in the Caribbean, contact was made with radio amateur Daniel, ZF2MJ, on Cayman Island.

Congratulations to Chris G0EYO and Neil G1TZC for topping the total DXCC and unique DXCC tables. Neil also just pipped Chris in the 40 meter tables.

On 80 and 160 meters, there was a close contest between the Chris’s G0EYO and G3YHF, with each taking honours on one band.

You can find a list of countries contacted here

We are continuing the 160 meter tables through December, January and February to see what DX members can work during the 4 winter months. 

For December and January, there will be two tables – one for the low bands (80,40 and 30 meters) and one for the high bands (20, 17, 15, 12 and 10 meters).  Each country will count once in each table regardless of the band or mode used.

 

 

Around the World in October DX Challenge

November 01, 2020 By: Chris G3YHF Category: Club, Fun, News

Afghanistan (T6AA – see right), Madagascar (5R8AL ) and Trinidad were amongst the countries contacted by Wythall Radio Club members in their October DX Challenge.

The aim was to have two-way contacts with other radio amateurs in as many different countries as possible on the 20 and 40 meter short wave bands.

With 85 countries worked on 20 meters and 76 on 40 meters, Club members had lots of fun talking to people in other parts of the world.  They used digital, voice and Morse Code transmisions at all times of the day and night.

Here’s a list of countries we contacted.

And below you can see the way the contacts built up…  John 2E0XET (photo left) contacted the most countries, although he was using low power (50 watts or less from his KX3 and small power amplifier) to a simple wire antenna (a doublet) and Morse Code only.  Nice one, John!

Finally, the overall result….

Callsign 20m 40m Grand total
2E0XET 41 17 58
2E0YZW 20 24 44
G0EYO 2 7 9
G0MTN 8 17 25
G3YHF 6 0 6
M0LQY 8 11 19
Grand Total 85 76 161

November’s Challenge is on 160, 80 and 40 meters.

Scouts on the Air contact Wythall

October 26, 2020 By: Chris G3YHF Category: Club, Fun, News

Wythall Radio Club members have been active contacting Scout groups around the world during JOTA/JOTI (Jamboree on the Air/Internet) 2020.

Les 2E0LRV spoke to Scouts from 2 JOTA stations last week end. 

“On Saturday I spoke to several groups of Scouts in Lillehammer, Norway. Their call was LA2L and was being run by Anders Forgen LA6UIA.

On Sunday I spoke to the Scouts from Crystal Lake Illinois, USA, who were using the call K9AT belonging to David J Holmgren, who sent this link about the event

Both Anders and David have passed on thanks from the Scouts.”

Les made both contacts through Hub Net using a Yeasu FT 8800 feeding a small colinear and back in to an All Star node connected to the wonderweb.

Both scout groups were trying various modes to make contacts and the feedback was that the contacts made using Allstar/Hubnet were by far the most popular and rewarding for the Scouts.

Meantime Tim M6OTN worked EA2KV in Spain on 40meters, leaving another happy group of Scouts!

This continues Wythall Radio Club’s support for Brownies, Beavers, Guides and Scouts – see our earlier posts, for example here.

Shields Awarded to Wythall RC members

October 04, 2020 By: Chris G3YHF Category: Club, Contest, Fun, News

Shields have now been awarded to Wythall Radio Club members for their achievements in the Easter Contest and Morse May, delayed due to the pandemic.

Over 40 members participated in the Club’s annual Easter Contest, and highpoints were QSOs with some of our more distant members in Scotland, Torquay and Derby. 

In the 2m/70cm FM section, the winner was Kev 2E0NCO (photo left), who was awarded the Colin Baker G6ZDQ Easter Contest VHF/UHF Shield, in memory of our former Club member.  Over the 5 days of the contest he achieved 124 QSOs with 37 different Club members  giving a total score of 3071 points!

There was very close competition for the top places in the all bands/all modes section.  David G7IBO came first (photo right) with 124 QSOs with 43 Club members over the five days, and a total score of 3655 points. 

He was awarded the David Dawkes G0ICJ Easter Contest all bands/all modes Shield, in memory of our former Club member.

Stuart M0SRZ (photo left) is the 2020 recipient of the Lew Williams Shield.  This annual award recognises a member’s progress with CW (Morse Code), and is in memory of Wythall Radio Club’s former CW tutor and President. 

The shields are shown in the order given above.

100 Countries Worked in September DX Challenge

October 01, 2020 By: Chris G3YHF Category: Club, Fun, News

Yes, Wythall Radio Club members contacted exactly 100 different countries in their September DX Challenge!

Highlights included contacts with Western Sahara, the Falkland Islands and tiny Sant Marten island in the Caribbean.

The ‘ton up’ was reached using digital mode FT8 on the 40, 20 and 10 meter bands.  Not bad for this stage in the sunspot cycle and in late summer.

Lee G0MTN contacted 76 unique counties (each country counting only once across the three bands) while Ian M0LQY contacted 136 overall (the total of countries worked on each of the three bands).   

Lee and Ian shared the top 3 spots with Chris G0EYO.

As expected most contacts were on 40 and 20, although several countries were reached on 10 meters.

For a full list of countries worked, click here.

There was quite a race to the finish……

 

Workbench Review – QRP Labs QCX+ Kit

September 08, 2020 By: Chris G3YHF Category: Club, Fun, News

Earlier this year Ian M0IDR reviewed the original QCX kit from QRP Labs.  Now it’s been redesigned as the QCX+, which Chris G3YHF reviews here. 

QRP Labs have recently started shipping the new QCX+, a single band CW/WSPR transceiver kit.  Mine arrived carefully packed along with the additional metal enclosure.  

Although the QCX+ as delivered is CW only, the original QCX has been modified by experimenters to enable SSB and digital modes.  The QCX+ is likewise a rig designed for modification – with lots of spare pin headers and a separate development board.  

I built the 30m version, pictured above. 

There is an impressive downloadable manual running to almost 200 pages, covering the build, alignment, operating features, fault finding, facilities for experimenting and more! 

The build instructions are very detailed and easy to follow, with a large diagram illustrating each step.  The proof is that my rig worked first time!!  That was a relief!

I initially checked and sorted all the components, putting them in labelled envelopes to make them easier to find. 

The trickiest part – winding the four section RX transformer (centre top of picture) – is the first task and gets this job out of the way.  Then each type of component is installed in turn.

The silk-screen printed PCB is a delight to work on.  My trusty 25 watt Antex iron was just right for soldering the components to the 2 PCBs.  Although there is more room on these PCBs than on the original QCX, a small tip is required to keep the solder points neat and avoid problems. 

Thanks to Ian M0IDR for advice on this, as the QCX+ was the most complex build I have attempted.

The manual emphasises that the enamelling on the wire used for toroid windings needs to be burnt off during soldering, and that failure to achieve this is the most common reason for a QCX build to be unsuccessful first time. This requires the soldering iron to be applied longer than normal.  Continuity testing for zero ohms across the winding is recommended.  I had a couple of instances where I needed to resolder to completely burn off the enamelling.

In fact, I continuity tested each component before triming any loose wires.  I find my analogue multimeter is better to use for this than a digital one, as the needle flicking right across the scale clearly indicates a good connection.

Alignment is simple process using the rig’s inbuilt test equipment, which includes a signal generator. 

I had two small self-inflicted problems in the build. 

I discovered that I had soldered the ends of one of the RX transformer windings the wrong way round, having already trimmed off the wire.  Luckily, I also found that I had wound one too many turns.  I managed to unwind the extra turn without having to desolder the other 6 connections on this toroid, and then had enough spare wire to solder this winding back on to the PCB.  Phew!

This error arose because I wanted to finish installing the transformer even though it was late in the evening.  The moral is: stop before you get tired!

The second problem was that when I switched the rig on, the LCD lit up but didn’t show the initial ‘choose band’ screen.  A quick check and I discovered I’d omitted to install the microcontroller into its socket. 

The rig in test mode is shown above, before fitting in to the enclosure.  This is a sturdy 4mm/2mm thick with laser etched lettering.  The 2 PCBs – one holding the LCD – join at right angles and slide easily into the enclosure. 

It’s easy to remove the top of the enclosure or slide the PCBs out to make mods to the rig.

The rig is easy and intuitive to use.  As a 99% CW op, I was impressed at how clear the CW signals were in such a small rig.  The 200hz filter must help in this regard, and although it’s a sharp filter there is no ringing. 

With masses of audio gain available, and no RF control, I found winding the ‘VOL’ control back helped bring any weak signals out of the noise.  There is full QSK, although this can be switched off.

Tuning rates are 1kHz, 500Hz, 50Hz and 10Hz – selected by depressing the tuning knob.  This scrolls in a loop – so from 10Hz it goes round to 1kHz.  A long hold on the tuning knob is supposed to enable the cursor to move to the left, i.e. from 10Hz to 50Hz.  However I found it difficult to avoid starting my stored CQ message, which is also activated by depressing the same knob.  

Keyer speed and RIT are available with one and two presses of a button.  There are twin VFOs and memory functions, as well as a message facility and CW decoder.  Many other functions are available and adjustable.

There are sockets to enable CAT control and to connect an external GPS RX to the rig’s GPS interface. 

The rig is specified to deliver up to 5 watts depending on supply voltage.  Using a 13.5v PSU, my QRP power meter read 3.5 watts out (normal power meters don’t give accurate readings at QRP levels).  As I don’t have a variable power supply, I tried the rig connected to a SLAB measuring 12.3v and it delivered 2.75 watts out. 

According to the data sheets in the manual, it should deliver 4 watts at 13.5 volts.  The manual – and discussion on the QCX forum – advise taking a turn off each of the low pass filter torroids in case the cut-off frequency is too low.

Overall, I’m delighted with successfully building this kit and with it’s performance on air.  My first 3 qsos received reports of 549 from Italy and 559 from Germany (another QRP op) – both in response to my CQs – and 569 from Norway.  Later in the evening I worked east coast USA, receiving 559.  I heard a VK, although only S3.  The RBN for my CQ calls gave very good SNR reports.  The antenna was a dipole at about 25 feet.

So I’m looking forward to having some fun on 30 meters with this QRP rig! 

The kit is suitable for someone who has undertaken some basic constructional projects, can solder effectively and wants to move on to something more complicated.  It certainly left me feeling much more confident about tackling an advanced project.

 

August DX Challenge results

September 01, 2020 By: Chris G3YHF Category: Club, Fun, News

There are lots of counties to work on 30, 17 and 12 meters – as the results of the August DX Challenge at Wythall Radio Club show.

Mali (TZ4AM – QSL card left), the Falkland Islands and Trinidad and Tobago were amongst the more exotic countries reached by Club members.  For a full list, click here.

Tim M6OTN contacted 95 unique counties (each country counting only once across the three bands) and 152 countries overall (the total of the countries worked on each of the bands).   Chris G0EYO had 71 uniques and Neil M0LUH was close behind at 66. 

These three station were all using FT8, a digital mode of communication, and modest power with simple wire antennas.

This graphic shows how Club members’ unique countries increased over the month… 

FT8 is well suited to poor propogation conditions – which may be why the CW-only stations of Chris G3YHF and John 2E0XET were not as successful. 

However it is rumoured that some FT8 ops monitored the bands while they were doing other things – which is harder for CW ops to do!

The September DX Challenge is a FT8/FT4-only event on 40, 20 and 10 meters.  

Good luck and we hope for some excellent DX results!

Free on-line courses for amateur radio licences

August 25, 2020 By: Chris G3YHF Category: Club, Fun, News, Training

STOP PRESS – THE INTERMEDIATE COURSE IS NOW FULL.  FOUNDATION COURSE STILL AVAILABLE.

Wythall Radio Club will be running ONE online courses in September.

The 8 week Foundation course starts on the 13th September .

The examinations for both these courses will be done under the RSGB’s new remotely invigilated on-line examination scheme in the candidate’s own home.

Practical Assessments for the Foundation course have been suspended until such time as the COVID lockdown makes it safe for them to be re-introduced and the Practical Assessments for the Intermediate have been taken out of the syllabus altogether.

There is no charge for doing these courses and we do provide individual tuition via quizzes etc.  Please note that there are specific IT requirements which have to be met for the online examinations.

If anyone is interested in doing these courses with us please contact Chris G0EYO [email protected]  ASAP.