M0MCX Amateur Radio Operator

Telescopic Antenna MastHeavy Duty 10m £37.20

40m verticalDX Commander: The best heavy-duty fibreglass telescopic antenna mast supports with many happy customers.

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I’m an expert in antenna design using MMANA software. Check out my tutorial films.

MOST READ POSTS . . .

Compact half-square for 40m band

I've just had an interesting discussion on 40m this evening with Peter, OH6GHI, also an antenna enthusiast. I happened to mention that I was listening to him on both VFOs. VFO A on my dipole and VFO B on my vertical and I found the stereo image very interesting as the polarisation of ...

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Bidirectional switchable 40m wire yagi

I switched on the other evening and heard a very quiet DX caller on 7.142. It was YC0LOU from Indonesia and I could only pick up parts of his call. He called and called and had no takers. In fairness, he was extremely quiet but as the sun was gradually ...

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How to use dual coax feeders as ladder line

Having recently taken delivery of a Palstar AT4K manual tuner, I was keen to get her into production to replace my CG5000 in the attic. Problem: the route to the attic from the shack is complex but I have a number of spare coax runs going that way including a couple of ...

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Working 15m band on a 40m vertical antenna

Note: This article discusses the merits of a 3/4 (three quarter wave) vertical -vs- a 1/4 (quarter wave) antenna. You can build a 40m vertical quarter wave antenna and ground mount it with 16 x 4m radials and operate it at the third harmonic; 21MHz. Actually, all my experimentation has shown that ...

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15m and 10m fan dipole arrangement test

How to join antenna wire together

They used to call this the "AT&T Wiremans Join" but frankly, it's the best way of joining wire together anyway. If you are joining insulated wire, first strip away about an inch of insulation of both ends. If you have stranded wire, twist the strands on each wire together and solder them into ...

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Obligatory evening shot of a three element 40m array

3 Element 40m Vertical Parasitic Array (VPA) Vertical Yagi

Essentially, this is a single 1/4 wave vertical antenna with ground radials, complimented by a pair of parasitic verticals; a reflector and a director. It will deliver around 6db of additional gain over a standard vertical with a beamwidth of around 70 degrees. I have built mine pointing 300 degrees ...

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Converting a 40m vertical to run on 80m / 75m band

Recently, I created a slightly loaded 40m vertical with 25 ground radials. It seems to work very well although the receive noise is pretty lousy compared to my loops and dipoles, however on transmit, it does seem to work as planned; a typical 1/4 wave pattern that outperforms regular dipoles at low angles of ...

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ACOM 2000 Flightcase

ACOM 2000 Flightcase

I had a case made for my ACOM 2000 made a few years ago. I'm pleased to report that it's a great addition to the Ham Radio stock of toys and extremely handy for Field-Day operation.

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How to build a tilt-over 60 foot antenna mast from scaffolding poles

This job is not for the feint-hearted. You will need a natural tendency for engineering, be accurate and be comfortable with knots. However, there's no reason that most small teams of keen amateur radio operators can't build this as a project for field day use. Let me explain how I built the ...

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Raising Steel Antenna Mast on T&K brackets with pulley

I'm gradually swapping out any aluminium antenna poles for steel. Clearly these are very heavy, particularly with an antenna on top. The trick is to use V bolts (like U clamps but in a V shape) and not to use saddle clamps because the pole will not slide easily past the ...

Read More

Solarcon Imax 2000 Review 5/8ths Vertical Antenna 10m

I always fancied a low-angle vertical for 10m band and after doing my research, came across the Solarcon Imax 2000. It was a toss up between this, a Sigma 4 copy or the Sirio 827. The Sigma 4 is now called the Sirio Vector 4000 and I discounted this one because ...

Read More

Aircell 7 coax review – vs- RG213

Aircell 7 coax review - vs- RG213

I have used Aircell 7 now for a number of years and have finally replaced all my patch leads in the shack with precise lengths of Aircell 7 coax from SSB Electronics. For longer runs, I'm still using Westflex and Ecoflex 15 but for portable operation, Aircell 7 is nice and bendy, ...

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How to make a stealth amateur radio wire antenna

How to make a stealth amateur radio wire antenna

Until recently, I had a) a 40m triangular loop in the back garden which I called a "micro-mega-loop" and b) a 60m loaded loop that allowed me to get on 80m. The two loops looked a bit horrendous not only because of the wire in the air, but because I ...

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Kenwood TS-990s User Review

Kenwood TS-990s User Review

I finally took delivery of my TS990s in early January 2014 and it came with the latest firmware from the factory. First impressions, distilled into single words: massive, engineered, beautiful, functional, imposing, radio bling. But not a microphone in sight which I thought was pretty odd but they must have ...

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Huawei E220 External Antenna Modification

Huawei E220 External Antenna Modification

Modern USB Data Sticks don't seem to come with external antenna jacks these days. This is a real shame for geeks like me who want better signals and are prepared to procure external antennas to ensure high quality signals. This project is to ensure that we can have 24 x 7 ...

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Kenwood TS-2000 Remote Mobile Controller RC-2000 Review

Kenwood TS-2000 Remote Mobile Controller RC-2000 Review

If you’ve been keeping up to date then you’ll know that I have chosen the TS-2000 as the primary radio on board our new narrowboat, “Wherethehell-Rwe”. At the helm (which is a dead give-away for my yachting heritage) I have specified the RC-2000 which should be rather fun to muck ...

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Special Event Operating Procedures

This note will be particularly beneficial to those who may be required to run a special event station either on the lower bands or maybe on VHF. These tips & tricks will also help you anywhere on the band, regardless of your circumstances. Preface: There are a number of aspects that ...

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Coax Loss Comparison

I can never find the comparison charts between RG213 and Henry Westlake's Westflex W-103. At last, I'll have this logged forever now. Per 100 meters: RG213/URM67(Mil spec) Westflex 103  100 MHz                      7 dB 3.2 dB  144 MHz                    8.5 dB 4.5 dB  200 MHz                     10 dB 5.4 dB  300 MHz                     13 dB 6.2 dB  432 MHz                     15 dB 7.5 dB  1000 MHz                   27 dB 13.0 ...

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I’ve just had an interesting discussion on 40m this evening with Peter, OH6GHI, also an antenna enthusiast. I happened to mention that I was listening to him on both VFOs. VFO A on my dipole and VFO B on my vertical and I found the stereo image very interesting as the polarisation of his signal to me changed.

half-square-basic-designWe got talking about half-squares and I confirmed that we were talking about the same thing, basically 2 x 10m verticals separated by a 20m top section. The half square is fed in one corner and according to my MMANA model, this should present 50 ohms and a great SWR curve across the whole of 40m.

(read more…)

I switched on the other evening and heard a very quiet DX caller on 7.142. It was YC0LOU from Indonesia and I could only pick up parts of his call. He called and called and had no takers. In fairness, he was extremely quiet but as the sun was gradually moving around the sky, he finally became audible and it was worth giving him a shout. 400w off my inverted V at 7m height got his attention but I needed a few blasts for him to get my call right. I put him on the cluster and he had a pile up.

Now, the point is, had I had more gain, I’d have not only heard him better, but he’d have heard me quicker too.

So I could add more height to my Inverted V but the difference between 7m and 10m isn’t actually that much at 5 degrees off the horizon – not even a db. Hardly worth writing home about.

40m-wire-yagi-drawingAnyway, this was the QSO that made me sit up and take stock of what I could do. I was seriously considering phased verticals for DX when I thought up the idea of having a switchable wire yagi. Either firing East or firing West.

Like me, you may already have an inverted V dipole up for 40m, all you need to is build another one about a quarterwave in front – or behind your existing dipole but out of a single wire. You don’t need to feed this with coax, it’s a parasitic element, like a 2 element yagi.

(read more…)

palstar-at4kHaving recently taken delivery of a Palstar AT4K manual tuner, I was keen to get her into production to replace my CG5000 in the attic.

Problem: the route to the attic from the shack is complex but I have a number of spare coax runs going that way including a couple of RG58 cables that I installed about 10 years ago as backups. Actually I originally installed three RG58 lines but I’ve been using one of them to send 12V up the line to the ATU.

parallel-cox-to-ladder-lineAfter MUCH research, I finally used about 20 feet of parallel coax feeders, connecting ladder line to both ends. To clarify, I run about 12 feet of ladder line from the ATU to the parallel RG58 cables. I soldered the ladder line to the inner core of the RG58 coax and shorted the braid-to-braid. My 20 feet of RG58 runs to the attic, through walls, up ceilings etc and in reverse, I connected the ladder line to the RG58. Again, I shorted the braids of each line to each other with a solder blob. My ladder line then has another run to the feedpoint of a large 60m loop that runs through the attic and around the garden.

The results have been quite amazing. Comparing my 40m reference dipole to the the CG5000 (SG230 type) ATU feeding the 60m loop has always shown that the loop was about an S point lower than my reference dipole for most stations.

(read more…)

Note: This article discusses the merits of a 3/4 (three quarter wave) vertical -vs- a 1/4 (quarter wave) antenna.

You can build a 40m vertical quarter wave antenna and ground mount it with 16 x 4m radials and operate it at the third harmonic; 21MHz.

Actually, all my experimentation has shown that if you multiply the quarter wave resonance by 3.03, you’ll have the next available usable band. In this case, if you tune a 40m vertical to 7.00Mhz, you’ll have the whole of the 15m band to play with with a centre-point of 21.300Mhz. Oh, and you’ll still have the whole of 40m band under 1.3:1.

Now here’s the controversy:

Most people who read antenna publications or the ARRL handbook believe that if you actually make this antenna, you’re creating a cloud-burner on 15m.

Technically correct – but practically – and completely – wrong!

On the surface, the 10m long 40m vertical that’s used on 21.225MHz does indeed look like a cloud burner. Here it is. 15m band in green -vs- a pure quarter-wave in red).

quarter-vs-three-quarter-wavelength-vertical-antenna-plot

(click to expand quarter-wave in red, three-quarter wavelength in green)

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The A3S is 14Kg (That’s 30 pounds in US money :) )

I was worried that the combined weight of a Create Rotator an aluminium pole *and* DSC_0106an A3S Cushcraft might be too much for my little lighting rig.

To test it out, I fitted the Create Rotator to the mast and added a 20Kg dumb-bell weight and started the motor.

It lifted without an issue so I’ll go ahead and plan to use the A3S for next field day.

How mad is that? !

DSC_0041Had a ball with CQWW this weekend putting just over 1,000 QSOs in the log. 10m was very busy. The band scope on the TS-990s radio was extremely full with hardly a gap from 28.300 to 29.000 (and some!).

A couple of times, I used Audacity (software) to record out the back of my Kenwood TS-990s and caught some interesting sound-tracks.

Mostly, I forgot to hit the record button, particularly when I hit a very fast pile-up to the US but I found time to catch the tail end of this one after it had slowed down a bit.

 

Here’s a “perfect” example of a CQWW “rubber stamp” contact.   (read more…)

I had a case made for my ACOM 2000 made a few years ago. I’m pleased to report that it’s a great addition to the Ham Radio stock of toys and extremely handy for Field-Day operation.

60-foot-mast-featured-image

This job is not for the feint-hearted. You will need a natural tendency for engineering, be accurate and be comfortable with knots. However, there’s no reason that most small teams of keen amateur radio operators can’t build this as a project for field day use.

Let me explain how I built the one shown in the pictures, then I’ll cover the learnings with you later along with my own do’s and don’ts.   (read more…)

This is actually three separate dipoles connected to one feepoint

I love engineering challenges and I needed an elegant solution to mount a vertical antenna right on the corner of my house.
In the end, I used 3 x 24 inch T brackets from Barenco Antenna Hardware store. Poor Brian (Barenco owner) was a little confused by my request but he dispatched my order all the same and I’m pleased with the results.

By the way, a little tip. Don’t use those RawPlug type anchor bolts, they expand and they are tightened and could break off the side of the brick, particularly right on a corner. Instead, use Multi-Monti bolts. These cut a thread inside a pre-drilled hole. The beauty of Multi-Monti bolts is that you can remove them and re-install them at will. If you want to fill in the hole afterwards, use Frame Mastic from ScrewFix (or similar). You will never know your aerials were once there.

(read more…)

15m and 10m fan dipole arrangement test

They used to call this the “AT&T Wiremans Join” but frankly, it’s the best way of joining wire together anyway. If you are joining insulated wire, first strip away about an inch of insulation of both ends.

If you have stranded wire, twist the strands on each wire together and solder them into a single fat strand.

DSC_0217

(read more…)

Dsc_0033

I’m gradually swapping out any aluminium antenna poles for steel. Clearly these are very heavy, particularly with an antenna on top.

The trick is to use V bolts (like U clamps but in a V shape) and not to use saddle clamps because the pole will not slide easily past the U bolt saddle clamp.

(read more…)

DSC_0039

Most radio amateur operators look at a pole* and immediately wonder how they might use it in their hobby. It becomes a weird past time and can become somewhat of a burden when passing for instance, a section of tubing in a handy-man store. I have to stop and work out if they nest together – or will they go inside some other tube I might have.

However, I have solved one riddle which is what diameter pole can I slip inside a standard steel scaffold tube?

(read more…)

Dsc_0001

Dsc_0002I always fancied a low-angle vertical for 10m band and after doing my research, came across the Solarcon Imax 2000. It was a toss up between this, a Sigma 4 copy or the Sirio 827. The Sigma 4 is now called the Sirio Vector 4000 and I discounted this one because of the size of the radials which seemed excessive for my plot , Same with the Sirio Vector 4000 which is just too tall. Even so, the Sirio Imax 2000 is still 24 feet in length. But read on, it’s actually fairly stealthy for such a tall antenna.

(read more…)

Dsc_0113I have used Aircell 7 now for a number of years and have finally replaced all my patch leads in the shack with precise lengths of Aircell 7 coax from SSB Electronics.

For longer runs, I’m still using Westflex and Ecoflex 15 but for portable operation, Aircell 7 is nice and bendy, easy to col up – and has pretty low loss, particularly for HF and short runs (up to 20m for VHF).

(read more…)

dsc_0291-960

I use a lot of fibreglass poles with wires strewn up the sides, normally in a lazy helical fashion so that they don’t flap about too much.

I have great success with these poles as regular readers know however I have noticed that certainly wet weather can detune them ever so slightly. Effectively, they become slightly longer and I fathom that as the fibreglass supports become wet, I am achieving some slight inductance with the water that drips from the surface and gets between the wires and the poles. As soon as they are dry again, the tuning comes back to normal.  (read more…)