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Some UK readers may already know of the case of Carl Johnson, M3VWP, who was prosecuted for driving without due care and attention, found guilty, fined and received three points on his driving license for operating his 2m mobile rig whilst driving.

In the UK it is, quite rightly, illegal to use a mobile phone whilst driving – though you can see this law being flouted every day of the week. There is, however, an exemption for the use of two-way radio, which applies to ham radio mobile operation. You could argue – and personally I would argue – that if it’s dangerous to use a mobile phone then it is no less dangerous to use a ham radio. But that’s beside the point. It is not illegal to use a ham radio whilst driving and unless he was actually driving dangerously as a result, M3VWP should never have been prosecuted for it.

Nevertheless, he was, and when summoned to court he decided to represent himself. Despite the existence of many holes in the prosecution’s case – according to his letter in Practical Wireless, Carl was stationary at traffic lights when spotted by the officer, who after an hour at the roadside apparently admitted he didn’t know the relevant law himself – M3VWP was found guilty. He decided not to appeal.

Of course, it’s just my opinion, and I know only what I have read, but I feel sure that if M3VWP had been professionally represented in court, or had appealed, he would probably have got off. A good solicitor might have got the point across that the law against using mobile phones did not apply in this case and that Carl could hardly have “not been in proper control of his vehicle” as he was stationary when spotted by the police.

Unfortunately in the UK only the very poor or the very rich have access to justice. If you’re poor, you receive legal aid, but if you have any means at all you have to pay the exorbitant legal fees yourself, and only the very wealthy can afford to take such a hit to their bank balance. One can only feel sorry for M3VWP for being convicted when he did nothing wrong. It seems that it doesn’t matter what the law says, if the police think you’ve broken it then that’s it.

Radio amateurs in the UK take note. Operating your radio whilst mobile could cost you a hefty fine and even, if you already have some points, lose you your driving license.

It’s a couple of days since the end of the 2010 Dayton Hamvention. Cheryl and I would like to send out a special thank you to everyone who stopped by our booth while we were there. We met a lot of interesting folks and had a great many thought provoking conversations. It was our first time so we didn’t know we’d be out in the sticks, so to speak, but we still had a lot of traffic and a lot of fun.

Now that I’m home and most of the work that piled up on me while I was away has been tackled, I got the podcast we recorded before the event finished and here it is.  There’s no Dayton content this time around. That will come next time. The drawing for the Alinco radio and the other Linux in the Ham Shack swag will happen on Friday and we’ll announce all the winners in the next show and on the Web site so stay tuned for that. In the meantime, enjoy some interesting feedback from listeners and some insight into Richard’s latest mobile rig install. Keep the feedback coming, visit our Printfection and Cafe Press stores and pick up an item or two, and get ready for next year in Dayton. Linux in the Ham Shack will be back.

73 de The LHS Guys

Well, I was wrong. Or was I?

When I got home after my NA-034 operation, I wanted to try to understand what happened. I was sure that I’d operated solely off a car battery in the past and as long as I was connected directly to the battery I hadn’t had any problems. Based on some testing that I did, I discovered that I may have been mistaken. The short version is that I discovered that by using the battery in my car without the engine running, I was able to reproduce the “strange noise in headset” that I recently wrote about, and that by running the car engine, that problem went away. There’s a bit more to it though. Read on if you’re interested.

I needed to have some way to measure the voltage from the battery and the amount of current that it was drawing while the radio was transmitting. While I could do this with a couple of meters when I was home, based on some recommendations that I got from W3FF, K8EAB, and NE1RD, I picked up a Super Whattmeter from Astroflight for around $50 plus shipping. These devices are used by folks who fly electric model airplanes because you really don’t want your battery to die when it’s up in the air. As it turns out, they are well-suited for monitoring your power when operating portable. Of course, they work fine too in the home shack, though my power supply has meters so it’s not needed. The picture here shows it hooked up that way for testing, and you can see that the Astron supply is supplying 13.8v.

As a side note, I started using quick-disconnect connectors made by Workman Electronic quite a number of years ago, before Anderson Powerpoles became popular. I was looking for some kind of quick disconnect power connector and found patch cables similar to the ones in the picture at a hamfest. I typically cut them in half and crimp them onto whatever I need to, be it battery clamps, the power cord for a radio, and so on. The good part is that I’ve been able to find them surplus at hamfests (though I’ve seen from a number of places online that they are now discontinued) but the bad news is that they don’t match what most other folks use. I keep meaning to make myself a set of adapters to connect to Powerpoles.

I crimped a set of the quick disconnects onto the Whattmeter and did a test with the power supply and radio in the shack to ensure that the meter was working and found that it worked perfectly. The shack power supply was putting out just over 13.8 volts with the Icom 756 Pro II drawing around 3 amps while receiving. (Interestingly, this is about 0.6A below what the ARRL reported in their testing, but I’ve had some repair work done on the radio and it’s possible that some of the newer components draw less than the originals.) The next step was to reproduce what I’d set up while in Florida.

As luck would have it, the weather was beautiful this weekend, and as we had no plans on Sunday, I took the 706, the Buddistick, the Whattmeter, the antenna analyzer, and a length of coax outside. I set up the Buddistick on the front lawn (I just had it on the mini-tripod sitting on the lawn, though I did put the radial over a couple of plastic lawn chairs to keep it off the ground) which while not optimal for DX, took me all of 5 minutes to set up with a good match to the radio, as verified by the antenna analyzer. I connected the radio to the antenna then connected the power cables to the car battery, with the Whattmeter in-line. My thoughts were to do a few tests with the engine off, fully expecting that I wouldn’t have any issues, then turn the engine on to see what kind of difference it made. I found an empty frequency on 20m and started testing. As soon as I transmitted, without looking at the meter, I knew that, to my surprise, I’d reproduced the problem: That nasty noise in the headphones was back.

What I figured I’d do was to collect data using various levels of transmit power to see the effect on the voltage and current draw. The meter itself also shows power in watts, though of course that’s trivial to calculate if you already have current and voltage. (From Ohm’s law, P=I×E). I quickly discovered that the car battery wasn’t able to supply sufficient voltage unless I was transmitting with about 10 watts or less. The specification for the 706 MkIIG is that it requires 13.8vdc ± 15% meaning the minimum allowable voltage is 11.73vdc. With the car engine turned off, I measured 11.68v with the radio drawing 5.79A when transmitting using 10w. At 40w (the next step I measured; when I was in Florida I was able to “get away” with 40w when testing with KH6ITY), I measured 11.52v while drawing 8.23A.  At 60w transmit power and up, the voltage dropped to about 11.4v but the radio was simply unable to draw the current needed.

With the car running, it was a completely different situation. Even at full transmit power (100w), the voltage supplied to the radio was 13.24volts at 14.77A. (I’m not sure why my current draw measurement at that power was different from the specifications for the radio, which were also pretty close to what the ARRL measured). I took the results and plotted it out in transmit power vs. watts consumed for both the case with the engine on and the engine off, and it’s pretty clear that with the engine off, the battery simply isn’t able to supply the required power. (You may need to click on that chart to have it display in a readable size. If you’re reading this via email and that doesn’t work for you, go to the web version of this post at k2dbk.blogspot.com and it should work from there.)

You can see from the chart that not only couldn’t the battery supply sufficient power for the transmit needs, it was only able to supply less as the radio tried to use more, presumably because the battery simply couldn’t “keep up”. So all my empirical testing seemed to prove that with the setup that I was using, I simply couldn’t operation at full power using just a car battery with the engine running. 


However, similar to bees who simply don’t know that they can’t fly, so they do, apparently my radio didn’t know that it didn’t have enough power to operate, at least during my 2004 and 2006 operations from NA-034, so it worked just fine. During those operations I know that I did not have the car running, yet I had no issues with power. The key for me know will be to find out what has changed. I am using the same power cables and the same radio (the antenna was different, but that shouldn’t matter), yet something has changed. The next thing I am going to do is to see if perhaps there is a problem with the power cables that may have occurred over the years. 

Although I attempted to measure the resistance in the power cables and came up with a measured 0.1 Ohms, my meter is probably fairly inaccurate at such low resistance, so I did a calculation instead assuming that I’ve got all 12 AWG wire in place. (Part of it is actually 10AWG, but I’m using 12 to account for any losses due to connectors and splices.) Using a 12v supply with a load of 15A (matching what I saw when the engine was running) and a length of 20 feet, the voltage drop calculator that I used shows an estimated voltage drop of around 8%. Allowing a bit of wiggle room for the length, it appears that the voltage drop would be somewhere between around 6% and 10% which corresponds to a voltage at the load (radio) of between 11.3v and 10.8v. Even the highest end of that range is too low for the radio to operate properly. Dropping the transmit power to 40w results in the voltage to the radio of about 11.5v which is a bit below spec but probably would allow operation, with some minor distortion. That seems to match what I had experienced.


The other factor that I haven’t played around with much is temperature, and I’ll leave that as an exercise for the reader. At this point, I think the best thing to do is to shorten the power cable as much as I reasonably can, replacing the section that is currently 12AWG wire with 10AWG wire. I suspect that will help ensure sufficient current flow while minimizing voltage drop.


I would be very interested in any feedback from anyone who can shed a bit more light on these issues, as I know that there are other factors that may come into play, such as the battery chemistry and perhaps other parts of the car’s electrical system.

It was a fine day, too fine to stay indoors, so I decided to go out for a couple of hours and do some more mobile operating with the K2 and MP-1 antenna. I didn’t want to drive all the way to the coast as it takes a bit too long so I wanted to find a good site nearer home. I studied the map and found a likely spot not much more than three miles away near Tallentire Hill. There is a narrow lane that runs high up along the side of the hill with a good takeoff from north through west to south. At the high point there is a wide verge where you can park clear of the road. The only people who disturb you up there are a few dog walkers from Tallentire village, so it is ideal.

Today 15m didn’t seem quite as good as on Tuesday – or perhaps being beside the sea made a difference? Anyway after a while of tuning around on 15 I moved down to 17m and had a 5 minute chat with Sonny W8FHF in Ohio. Shortly after that I heard W1AW the ARRL headquarters station in Newington, Connecticut calling. It was being operated by Ron, K1RKD from nearby West Hartford. As an ARRL member I was particularly pleased to work HQ and Ron promised to log me on the computer so I would receive a QSL card via the bureau.

I heard several other US stations and also Javier, XE2CQ very loud. I was sure he would hear me given the chance but he was having a long chat with someone and I didn’t get an opportunity to call him. I made one more Stateside contact, with Roger N4ZC near Charlotte, North Carolina, though he struggled a bit to hear my 12W signal so it wasn’t a long one.

I went back to 15m after that, but the only other station I worked was Yussuf, CN8YZ, 59 both ways (he was running 25W.) Not great DX but still a nice contact.

I am getting a bit hooked on this mobile lark as I seem to be hearing much better DX than I do from home and it is just so pleasant to hear atmospheric band noise and copy weak signals instead of the awful racket demonstrated on my recent video. In fact I must find out where I can obtain another power cable for my K3 as I would like to try my best radio in the car. It would be nice to have a bit more power, although I’m getting a real kick out of making SSB contacts with 12W to a mobile whip, but the main thing is the K3 receiver is much better.

With rain being forecast for the rest of the week I thought I would take the opportunity to make a few more mobile contacts. Before I did I decided to make a modification to the antenna that I hoped might improve the SWR of the MP-1 on the magnetic mount.

The Moonraker 7in. Turbo mag mount is not, in fact, a 7in. diameter magnet. It is more like a 5in. diameter magnet inside a steel case shaped like an upside down dinner plate with a 7in overall diameter. The magnet is not a tight fit inside the recess of the plate, so by drilling close to the flange I was able to make a hole without drilling into the magnet, to which I attached a terminal for one of those push-on electrical connectors. This could be used to attach a wire to ground the antenna to the car body. But as I hadn’t found a suitable grounding point I decided instead to make up a set of quarter wave counterpoises for 10m, 15m and 20m which I attached to a mating connector.

This time I thought I would drive to the coast to see whether being close to the sea would help me work across to North America. I parked beside the road half way between Maryport and Allonby, looking across the Solway estuary to the Scottish mountains in the distance. It was a sunny afternoon, the sky was blue and the sun glittered off the sea. A nice mobile QTH for a spot of operating.

I set up the MP-1 on the magnetic mount and checked the SWR on 20m using the antenna analyzer: it was about 2:1 as it was before. I then connected the counterpoise, expecting the SWR to come down to a 1:1 and was amazed to find it made absolutely no difference. It was as if there was no connection to the counterpoise at all – though I checked, and there was. Possibly the SWR curve changed slightly but the null stayed exactly the same, which was very disappointing.

I switched to 15m, tuned the MP-1 for best SWR and had a listen around. The first contact was with Nick, UY3LA from Lozovaya 150km south of Kharkov in Ukraine. My report from him was 55 to 59. He spoke good English and we had a chat for five minutes. I told Nick that my wife was in Kharkov at this very moment, and he invited us to visit him the next time we are both in Ukraine.

I heard some nice DX including FM5WD, A71CV, XE1HH, VU2JQ and CU2AA. I also heard several Stateside stations but could not get through to any of them. I switched to 17m for a while and made a couple of European contacts with good reports, which surprised me as there was a small hill about 80ft high immediately behind me in the direction of Europe. I’ll never understand HF propagation.

I also had an eyeball QSO with a local from Allonby who drove by and saw my antenna. He was a fellow radio enthusiast and wanted to say hello. It turned out the radio he was enthusiastic about was the 11m kind, but he was interested in getting a ham license so I told him to contact the Workington club for more information. He has a better antenna than me – a Sirio vertical up at 20 feet above all the TV antennas. I can just imagine what my neighbours would do if I tried that. That’s the trouble with living in a “posh” area.

Eventually I returned to 15m where I could still hear several US stations. I called K1JDL who said “I can hear a mobile in there but I just can’t pull you out” and then immediately QSY’d. Then I called Tom W0WP in Iowa who came right back with a report of 57 to 58. We had a really good chat for 15 minutes and Tom said that he “didn’t miss a word.” He was running 1200W to a TH6DXX so I said he must have a good receiver as my power was 20dB less than his. I thought he would say he was using a K3 but in fact he was using a TS-2000! However he is out in the country in a plot of several acres and the nearest neighbour is a quarter of a mile away so he doesn’t suffer from man-made QRN. I can only dream!

Mission accomplished: my first Stateside contact from the mobile and a good solid ragchew to boot. I decided to call it a day and go home for tea.

It occurred to me recently that the reason why I can rarely bring myself to work anything other than digital modes is because the noise level on the HF bands at home is so high that listening to the radio is too unpleasant. Tune across the band and you hear dozens of carriers against a background of hash and buzz, with odd patches of warbly noises. Although the noise falls off on the higher bands the carriers if anything get worse. Forget about listening for beacons on VHF! I don’t think the problem is solvable, as I believe I am hearing the combined output of all the houses in the neighbourhood, not the product of a single rogue device that could (theoretically) be tracked down and eliminated. So my instinct is just to work digital modes with the volume turned off.

People have often asked me why I don’t operate portable or mobile from the car to get away from all this QRN. My usual answer is that I often operate for an hour or so here and there and it isn’t practical for such a short time as that. Operating from the car on a cold dark winter night isn’t as attractive a prospect as doing it from a warm shack, and my wife would probably take a dim view my going off for three or four hours at a time just to talk on the radio in any case. But Olga is away at the moment and I’m getting fed up with digital modes, so I thought I would give it a go.

I already had a Superantennas MP-1 which I bought for portable use, but haven’t made much use of it for that due to the British weather rarely being warm enough to tempt me out. (Yes, I know SOTA types operate from hilltops in sub-zero temperatures and howling gales, but I like my comforts and they’re masochists.) A quick trip to Maplin in Carlisle resulted in the purchase of a Moonraker 7 inch Turbo mag mount with the requisite 3/8 fitting. Then I drove out to a quiet spot to try it out. The spot I chose isn’t an ideal radio location as it is surrounded by hills, but I haven’t yet found somewhere with a good take-off that isn’t a “viewpoint” and packed with tourists, or anywhere that I can drive on to the beach.

I took the antenna analyzer along which made tuning the antenna a lot easier. I started off on 15m, where I got an SWR of 1.5:1. For the radio I took along my Elecraft K2, which has been little-used since the K3 came along. I set the power to 12W and searched for someone to work.

My first mobile contact was with John 9H5JW, a British expat living in Malta. He gave me a 58 report to my 59 (he was running 100W). We had a good chat for ten minutes and I felt the MP-1 was doing a really good job.

Next I heard KD4FNI from Ozark, Alabama. He didn’t hear me, unfortunately. My next contact was with Nick RV3EFR near Orel for 59 both ways. Then I tried to call Harry 7Q7HB in Malawi. He was working another mobile in Finland, but unfortunately when he finished there was a bit of a pile-up and he didn’t hear my call. He was strong enough that I’m sure we could have made a contact, as was KP4BD in Puerto Rico whom I also called without success.

My third contact was VU2DSI from near Mumbai in India. He gave me a 56 to his 59. I’m pretty sure I haven’t worked India before, even from home, so I was very happy with this. The /M suffix is really worth about 10dB of gain. “Will the mobile please call again.”

My final contact on 15m was with Mauro I5HOR near Florence. He gave me a 55.

I was pretty happy with those contacts, but I wanted to see how the MP-1 performed on a mag mount on the other bands. On 10m I got a 1.2:1 SWR, though there was nothing to be heard on that band. I went up to 40m and the SWR dip was pretty sharp and would only come down to 3:1. On 20m I got around 2:1, and managed a quick QSO with Franco IZ4NPE for a 58 report on that band, so it was not too bad.

Clearly the poor ground through the mag mount affects the SWR of the MP-1 on the lower bands. The K2 ATU can take care of this quite happily, but possibly performance is compromised as well. A permanent mount on the car isn’t an option, nor would it be worth the trouble for the amount of use it is likely to get. I will have to see if I can drill the mag mount and fit a terminal that would allow me to attach a temporary ground wire to the car body, or even a resonant counterpoise, if that would make a difference.

All in all it was a worthwhile exercise that I’ll probably try again. To make a contact with India from a parked car using 12W to a whip antenna is quite an achievement!