Wednesday, September 23, 2015

For Future Consideration: Transmission Line

This is the second in what may become a series of articles about my preparation for a larger antenna farm, perhaps as soon as 2016. The first article was about my acquisition of a 2-element 40 meter yagi (XM240). This one is about transmission lines. That is, low loss coaxial cable.

The problem

In most HF stations the quality of the coax from shack to antennas is often more about robustness, power handling and weatherproofing. Loss on the HF bands for runs under 100' (30 meters) is usually low for RG-213 (or equivalent) coax, and it will handle a kilowatt if the SWRis modest. For example, a 50' (15 meters) tall tower and tri-bander with 75' of RG-213 has a matched loss of less than -0.9 db at 28 MHz. With an SWR of 2 the total loss can be as low as -1 db. Loss progressively declines on lower bands.

In a large station transmission line loss is often a concern. Consider a 100' (30 meters) tower that (for peace of mind) is a similar distance from the house. With additional cable at the top of the tower and into the shack we are looking at 250' (75 meters) of coax. At 28 MHz the matched loss of RG-213 is now -2.9 db and at least -3.3 db with an SWR of 2. Upgrade to a 150' (45 meters) tower under the same scenario and losses increase to -4.0 and -4.4 db, for an SWR of 1 and 2, respectively.

Of course the situation is less dire at lower frequencies. RG-213 can prove adequate at 7 MHz and lower even for these long runs. But for the hams that build these large stations every decibel counts, since it can make a difference in contest results. This is due to impacts on transmit (getting heard) and receive (copying the weak stations attracted by the big signal). There are other matters to be considered, such as whether the coax can be buried, moisture wicking by a braided outer conductor, UV resistance and more. This is why many hams eschew RG-213 and similar coax, since quality is often questionable. They instead use brand name cables in the same size such as Times Microwave LMR-400.

Better coax can be had, if one is willing to buy new or one is able to scrounge. The former takes money and the latter takes time and effort. I favour the latter, if at all possible. Time is on my side since I will not need more transmission line until at least 2016.

Andrew Heliax

When I built my modest station in 1985 I was fortunate to purchase new hardline at a bargain price. This was 400' of Andrew Heliax LDF4-50A, ½" 50 Ω coax. Even at the low per-foot price I paid it was still a goodly sum of money. I was fortunate to acquire new connectors at wholesale price through a friend in the business since connectors can be very expensive. Divided into 3 lengths of 130' this was still a substantial expense for a set of transmission lines from the shack to the top of the tower.
400' of LDF4-50A hibernating in the garage.

The runs were 130' (40 meters) because the tower was 19 meters high and a similar distance from the tower to the shack. Cables were buried for part of the distance. The antennas atop that tower were yagis for 20-15-10 (Hy-Gain TH6DXX), 6 (Cushcraft A50-6) and 2 (Cushcraft 32-19). RG-213 was used for 40 and 80, which I purchased new in bulk, on the spool. It is these same 130' lengths of RG-213 I am currently using in my station today, after having been in storage for over 20 years. There is still 100' or more on that original spool. The rest went to friends who participating in the bulk purchase.

The LDF4-50A has also been in storage. Heliax is very robust, suitable for direct burial, reasonably immune to moisture wicking, and will support its own weight when hanging from the tower top and (if the tales I've heard are true) survive being run over by motor vehicles. Loss is substantially better than RG-213 despite not being much thicker. At 28 MHz the matched loss is -0.35 db per 100' (30 meters). For the 150' tower mentioned above, the loss over 350' is -1.25 db. That isn't bad but, as we'll see, we can do better.

Buying hardline

When buying Heliax one decision is whether to buy new or used. As with anything purchased used it is a good idea to test first, if at all possible. In the case of coax you want to do a frequency sweep of unloaded cable to ensure it is close to spec for loss and impedance. I've heard of hams who carry a VNA to flea markets for this very purpose. Some old or new but rejected cable may show impedance anomalies above 1 GHz, but be perfectly good at HF, VHF and even UHF.

Used cable often has the advantage of having one or even both connectors attached. With the high price of connectors this can be an advantage. With care the connectors can be removed and reused, and the cable cut (if necessary) to the needed length. Shorter lengths can be connected to make a longer run, provided that splices are not buried. Splices must be waterproofed and use the correct connectors.

There is a commonly-heard myth that connectors are lossy and must be avoided for best performance. This isn't true at HF, and not true at VHF and UHF is constant impedance connectors are used (e.g. N). The trade-off is the whether the price of the hardline is low enough to justify buying connectors. They are often hard to find the used market, and are rarely inexpensive.

As we should expect bigger coax has a bigger price. This is where scrounging comes in particularly handy. However, the situation is far from hopeless. Back in 2007 Andrew stopped producing LDF cable, replacing it with the improved AVA line of products. More LDF began finding its way onto the surplus market at attractive prices while the commercial world made the switch to AVA.

If you do scrounge you will find that surplus new LDF4-50A and even LDF5-50A often costs little more than new LMR-400. But, as I said, scrounging takes time. When the opportunity appears you have to act, since you don't know when or if another deal will come your way. Be especially acquisitive of connectors should they be offered at a good price. If you don't need them you can always sell the surplus to your friends. You'll put a smile on their faces, and probably have a ready crew for your next tower project!

Bigger is better

Back in 1985 there were hams who found it funny that I'd run Heliax on HF. For short runs, they had a point. However, the specs of the no-name coax most of them used was not to be trusted. At least I knew what performance I was getting, and that the coax would hold those specs for a very long time even when exposed to the weather or buried.

Hardline specs in TLW do not exactly match Heliax
But that's for short runs. For longer runs at competitive HF stations (or short runs on VHF and UHF) bigger cable than LDF4-50A is desirable. The most common choice is the next step up in size: LDF5-50A. This coax is ⅞" in diameter, with a proportional improvement in loss and power handling. At 28 MHz a 100' length has a matched loss of -0.2 db, or half the loss of ½" Heliax as expressed in decibels. Loss over exceptionally long runs can be better than -1 db up through 10 meters, and even 6 meters.

Specs for LDF and AVA are easily found on the internet. You can also use N6BV's TLW application to approximate loss performance for Heliax. LDF7 and AVA are not in the menu so you'd have to make those a user-defined cable type. TLW is packaged with recent editions of the ARRL Antenna Book.

Going all in

This series of articles titled "For Future Consideration" is about actions I've taken to prepare for my future station. The foregoing discussion is just a lead-in to the latest step I've taken. Sometimes when you least expect it the used market tosses exactly what you need into your path. You have only to pull out your wallet when opportunity knocks. This is what I've done.

Luckily my one-car garage is fairly deep, allowing room for storage. That space has been filled over the years with lots of stuff that I should have sold or thrown out years ago. This I have now done to make space for my newest arrivals.

In the photos at right you can see that I am planning for some long runs of low-loss transmission line to multiple antennas on tall towers. The 400' of LDF4 is dwarfed by the new rolls of Heliax piled up against it. Most of it is LDF5-50A, both new and used. Connectors are either attached to the used lengths or new in the box. These are a mix of N and 7-16 DIN connectors, and at least one UHF connector.

The new LDF5-50A is on the original wooden spool. It weighs a lot. Two of us were needed to roll it up the steep incline of my driveway. Since the photos were taken most of the separate rolls have been placed atop the spool to conserve space and to protect them from wintertime saltwater contamination.

There are also several short runs of cable (<10 meters each) that are suited for stacking harnesses and house entry. Or I can cannibalize them for the connectors.

As additional eye candy there is a roll of LDF7-50A, which is 1-⅝" diameter. The matched loss on this cable is virtually nil on HF (-0.1 db/100' at 28 MHz). Is this size of cable really necessary? Perhaps not on HF, unless the towers are 100 or more meters from the shack, but I do have some interest in returning to VHF DXing. Some contest super-stations use this product on the upper HF bands.

To give an idea of how large this cable is the adjacent selfie photo shows me holding a DIN connector for LDF7-50A next to the coax roll. Putting connectors on large Heliax requires some large tools and care but is not much more challenging than attaching connectors to more ordinary varieties of braided coax. There is no soldering to be done, and the large size eases handling.

Do you really need hardline?

Only you can decide. How much is 1 db worth to you? Or 3 db, the equivalent of stacked yagis? At HF the low loss of hardline is not needed for receive since reception is noise limited. The situation is quite different on VHF and UHF, and even 10 meters, unless you use a remotely switchable low-noise amplifier (LNA).

Transmit is another matter. Country regulations and award programs, including contest categories, almost always specify power at the transmitter. This is as true for QRP as it is for QRO, although the motivations may differ: protect what little QRP power you have, or emit the strongest, legal QRO signal. For everyday use it is often more convenient to use an amplifier to overcome transmission line loss. That is, if you are not already at the legal limit.

Low loss can give you the flexibility to locate your tower and antennas further away, to reduce noise pickup and interactions with buildings and other antennas, and perhaps allow use of a better area (a small hill?) for construction, maintenance and radial field. Although this wouldn't apply in a typical urban or suburban lot, many hams move to rural locations to fulfill their radio ambitions.

I did the arithmetic for what I want to achieve with my future antenna farm. Purchasing an abundance of Heliax was the right decision, for me.

Matched loss versus SWR loss

One final note on the limits of low-loss transmission line. This is as true for open-wire line as it is for coax, even if some books say otherwise. To give an example I'll draw your attention to an article I wrote some time ago, regarding the practical limit of solving antenna mismatches (high SWR) with a tuner in the shack.

In that article I discussed the challenge of attempting to use antennas for higher bands on 80 meters. My choices at the time were an inverted vee for 30 through 10 meters and a 40 meter delta loop. The SWR in both cases is exceptionally high due to the low radiation resistance. The feed point impedance at 3.6 MHz of the inverted vee was 3 - j1000 Ω, and of the delta loop was 0.5 - j80 Ω.

The matched loss of 130' of RG-213 is -0.5 db on 80 meters. For the inverted vee and delta loop on 80 meters the total losses are -25.6 and -13.8 db, respectively. For the same length of LDF5-50A the total losses would be -17.6 and -6.2, respectively. These are better but still far too large.

The lesson is that when using coax with a very low matched loss, correcting a high SWR with a tuner in the shack remains a poor choice. It is almost always better to correct the mismatch in the antenna design or with a matching network at the feed point. Tuners don't solve all ills, and neither does Heliax.

Sunday, September 20, 2015

Sleep, Interrupted

Shortly before dawn this morning the smoke alarm sounded for a couple of seconds. It's almost impossible to sleep through, just as designed. Suddenly awake, I guessed it was a false alarm, probably due to a mains power glitch. But I couldn't be sure. The lack of smoke was no assurance since there are 3 alarms, one on each floor of the house, and they're wired together so that if one triggers they all sound.

Fighting off the temptation to go back to sleep I took the prudent step of walking through the house in  the pre-dawn quiet to confirm nothing was amiss. Once I reached the basement I was fully awake and could not resist the lure of the shack. Although conditions were poor due to a geomagnetic disturbance there is still the possibility of DX toward the Pacific, including the low bands. Northward paths were heavily attenuated, which I discovered while playing in the Scandinavia Activity Contest.

Very disturbed conditions confirmed by the high K-index, as posted at WM7D's site

First I just had to check propagation toward northern Europe. I expected little and I heard nothing. It was daylight in Europe so the low bands would be closed in any case, and solar flux was too low to open the high bands until after sunrise. So I tuned around 40 meters even though the DX cluster network didn't display anything of interest.

I came across a strong signal operating DXpedition style near 7.015 MHz. I could just barely make out some distorted backscatter signals up 1 to 2 kHz, confirming this was a split operation. A couple of QSOs later he signed his call: E6GG, the current multi-station DXpedition on Niue. Two QSOs later I was in the log. I then spotted him, which seemed to grow the pile-up quite quickly.

Continuing to tune around I found FK8CE coming through. I kept tuning since I'd already worked him on 40 meters, only pausing to spot him. Flipping down to 80 meters CW I found a pile-up on E6GG. Since it was still 20 minutes before sunrise, with my poor antenna I heard nothing. However it was nice for a change to hear the band so quiet; all the neighbourhood lights and appliances were switched off at that early hour.

Not willing to wait for the sunrise enhancement of 80 meters propagation I shut down and headed upstairs and back to bed. I was soon asleep, happy that another band country was in the log. It just goes to show that if you get on at the right time there is interesting stuff to work even through dreadful conditions.

Tuesday, September 15, 2015

FT-1000 MP Mark V Field: Mods for IMD and Key Clicks

There is a long tradition in ham radio of making modifications to commercial equipment to add features or improve performance. It is often viewed as worth the risk of (potentially) lowering resale value if those mods mar the equipment or deter buyers that want a "pure" unit, for the increased utility or mere pleasure of it. Since there are few of us who can design or build a modern transceiver from scratch, it also can be an opportunity to place our personal stamp on  the equipment, if only to show we can do it.

Unfortunately it is also true in too many cases that equipment is sold with fundamental design flaws. There is no incentive for the manufacturer to act when the market doesn't react. That is, if sales proceed according to plan and customers are not complaining, why take on the expense of recalls and factory mods? The truth is that few hams will notice or care.

In the case of the FT-1000 MP Mark V Field I purchased last winter there are two particularly nasty problems: key clicks and excess IMD (inter-modulation distortion). Yaesu did eventually fix the key clicks issue in late models (about 8 years after the rig was brought to market) and never did deal with the IMD problem. It isn't as if Yaesu didn't know about the problems. They appear to have chosen to ignore them.

Lucky for us that there are so bright lights within the ham community who care about these issues, and have the technical ability to find and solve these problems. Those of us eager to transmit clean signals and have receivers up to the demands of the toughest QRM during contests and DXpeditions are thankful these people exist. In this case we can thank Tom Rauch, W8JI. His intensive effort to solve the problems of this otherwise excellent rig are appreciated by many.

Many however neither know nor care. If you don't believe me just listen on the bands. When someone in a CW QSO reports they are using an FT-1000 MP all you need do is tune to either side of their signal. Every time I've done this there were key clicks. For the stronger signals these extended several kHz from their centre frequency. This is not good.

Dime versus 220 Ω SMD resistor from the IF board
Danger lies ahead

Assuming you are like me, and you want to benefit from the solutions W8JI and others provide us, it is not always clear sailing. Sometimes the difficulty of successfully executing the mods is understated. Modern electronics is full of tiny SMD (surface mount devices), masses of cable harnesses and connectors and tightly fit boards and enclosures that make access and interconnection quite challenging.

Some of the challenges with which I am most familiar include:
  • Eyesight: My vision is no longer perfect as it was in my youth. This is true for many of us. Component miniaturization makes it difficult to see well enough to avoid disastrous results. My case isn't helped by the out-of-date eyeglass prescription I am currently using. A hand held magnifying glass helps or, better, a magnifying plate with its own stand to keep both hands free.
  • Soldering: Temperature control and tip selection on our irons is important to proper removal and attachment of circuit board components. The risks are solder bridges, lifted traces and even damaged solid state devices. With an ordinary iron you'll need to be especially careful to avoid damage.
  • Wiring harnesses: Tightly bundled wiring harness and the connectors they plug into must often be moved or disconnected for the required access. Labelling or a pre-disassembly photograph are helpful during reassembly.
  • Fitting: Modified boards must withstand re-installation without component leads touching chassis metal or other exposed components, and not pinching or disturbing fragile wiring harnesses and connectors.
  • Lost hardware: We all drop screws and retention clips, and even SMD components. They're small and our hands are big. Use magnetic tool tips and angle the equipment so that dropped hardware doesn't slide to where it cannot be readily retrieved and can cause damage when power is turned on.
The following is my story of making the W8JI key clicks and IMD mods for the FT-1000 MP. Things did go wrong. I will at least tell you now that in the end I was successful. Perhaps you can learn something from my experience. You should refer to the W8JI article for the reasons and details about the mods.

Interestingly I started this mod in late July. I put it aside until late August when conditions were rotten and I had a few spare hours, finally completing it a few days before publishing this article. For 6 weeks the rig sat uncovered in the shack with wires poking out the side. When the mood would strike me I'd move it to the workbench and continue. This approach may seem odd, but then I don't operate much during the summer so there was no need to rush.

RF board connection for the key clicks mod

This is the most difficult step of the mod because of the difficulty accessing the underside of the RF board. The board is under the fan and power amplifier, and it is encumbered with almost solid, thick wire harnesses with connectors galore. Many of these must be removed before the board can be flipped over.


What I soon determined was that I had two distinct strategies to flip the RF board. But before I describe them, I want to draw your attention to the above photograph of the area (taken after the mod was complete). Compare it to the picture on W8JI's mod page. There is an important difference.

My variant of the FT-1000 MP is the Mark V Field. It does away with the external high-voltage DC power supply, replacing it with an internal AC supply (or operation from an external 13.8 VDC supply) and a power reduction to 100 watts. The metal enclosure to the right of the RF board is the power supply. Other versions of the rig don't have this internal power supply.

The AC supply boxes in the RF board. The board must be slid toward the supply so that the connectors protruding out the rear of the chassis don't impede lifting of the board. With these constraints there is little room to manoeuver the board, requiring more wire harnesses to be moved out of the way. So now we come to my options:
  1. Disconnect a large number of the connectors so that the wire harnesses can be pushed out of the way.
  2. Disconnect a smaller number of connectors but sever several of the plastic cable ties that bundle up multiple wires.
The first option requires taking copious notes and photos, and great care to avoid damaging wires and connectors. The second option is quicker and less complex but requires care in the re-bundling of the wires to avoid stressing wire terminations and to properly route and seat the bundles. The latter item is necessary or the fan unit will not seat properly or risks catching a wire with the fan blades, all due to the tight packing imposed by the power supply. (Of note, the fan in the Mark V Field has a higher duty cycle, even when only receiving, due to the heat produced by the power supply.)

I chose the second option, though I can't say whether that was truly the best. Be thankful if you do not have the Field version when you undertake this mod. The soldering, routing and testing of the one wire for the mod was comparatively trivial.

Soldering the wire to the underside of the RF board was the simplest step in this part of the mod. The adjacent blurry photo shows the care required to avoid solder bridges. The photo is actually of the IF board wire, but the idea is the same.

IMD mod on the IF board

This is perhaps the easier of the two mods. All one has to do is: turn over the IF board, remove an SMD resistor and solder in a new resistor. While the board is exposed a wire for the key clicks mod must be attached, which will be used later.

The IF board is easy to get to. It's on the bottom of the chassis and only requires the removal of 6 screws and unplugging a few multi-pin ribbon cables. Everything else can be easily moved out of the way as the board is lifted and turned to expose the bottom side. I used needle nose pliers to safely lift the screws, with the Phillips screwdriver still holding down the screw to keep it from slipping away. Some care is needed to unplug the ribbon cables so that they are not kinked or subsequently tangled when the board is lifted.

So much for the easy part. The 220 Ω resistor (R2046) should be removed with solder wick or similar device since there is no easy way to lift the SMD component from the board when the solder on one side is heated. I couldn't find my roll of solder wick (it's hiding somewhere!) so I moved the iron quickly between sides of the resistor until it slid off the board. As we'll see, this may have been a poor choice of technique.


My first attempt to solder in the new 220 Ω resistor did not go well. I got too much solder on the lead to the old SMD tab which was then difficult to remove. Holding the lead down onto the tab while I soldered overheated the tab and it lifted from the board. You can see the ugly result above. The other end solders onto the junction between R2049 and Q2016. The resistor end of the foil trace is the safest place to make the connection since it is easier to access and there is no risk of overheating the transistor. Again, I made a mess.

When I was done I slid a short length of tape under the resistor to prevent the leads from accidentally touching any other exposed conductors. I then remounted the board, applied power and confirmed that the radio still worked. However all was not well. When moved back into the shack I discovered that while it received fine the noise blanker didn't work.

The next day I took it all apart again and checked my work. The resistor lead to the old resistor pad had separated. After checking with an ohmmeter that there were no other obvious problems I resoldered the resistor to the pad and made sure it was secure and had continuity. This time when I tested the rig the noise blanker worked.

Key clicks mod on the IF board

With the IF board back in place it was relatively straight-forward to add the circuitry for the key clicks mod. The only important decision is how to mount the circuit, so that is stable and at no risk of contacting the chassis or other components. Happily there is enough room to entertain options.

I chose to use a spade lug as the principle support. The lug also serves as the ground connection, by being secured to one of the screws holding the IF board to the chassis. Bits of black electrical tape prevent unwanted contact between components, wires, circuit board and chassis. W8JI suggests using a small terminal strip, which I could not quickly locate in my junk box. On his web page he shows another way, with the whole assembly freely floating and encased in heat shrink tubing.

The schematic on W8JI's web page does not label the components, and shows variable resistors which allow tuning the circuit for best key clicks suppression (adjustment of waveform ramps). For my own use I hand drew a labelled schematic.


As simple as this mod is, I still managed to make a wiring error. I discovered the error while testing the mod. Using a second receiver I confirmed that key clicks were reduced, but there was some key-down hash and key-up residual carrier energy. Checking my work I discovered I'd connected the IF board wire (top of schematic) to R2 instead of R1.

After correcting the error I was pleased to see that the mod worked as expected. I then replaced the lower half of the chassis. The top was left uncovered until I decided whether to retie the cable harnesses passing between the fan and the RF board.

Results

I don't yet know if the IMD is improved since that will require a more comprehensive test. I do know from recent contests and DXpeditions that I could elicit audible IMD products within a few kHz of exceptionally strong stations and, one time, in a pile up of American stations calling K1N on Navassa Island.

The receiver testing by Sherwood Engineering shows this rig not measuring up to the best with regard to IMD. However I don't know if this is with W8JI's mod. He claims narrow spacing IMD improvement by at least 10 db, and perhaps as high as 20 db. If true that would put this receiver closer to the best. That isn't bad for a 20 year old rig that can be economically purchased on the used market.

Key clicks are far easier to test. No special equipment is desired unless want a precise measurement. Before the mod it was easy to hear key clicks on a second receiver. Use an attenuator and dummy load to ensure that the receiver is not overloaded. I ran full power from the FT-1000 MP into a dummy load -- transmitting a series of dits -- and had no antenna attached to the KX3, on which I listened. The signal strength was over S9 but well within the receiver's dynamic range.

After the mod the audible key clicks almost entirely vanished. As W8JI says, this is not a perfect cure so there will be some residual clicks that a careful measurement will discover. It is however perfectly adequate. I no longer need to feel uncomfortable about using this rig in a CW contest. Don't hook up an unmodified FT-1000 MP to an amplifier or a big antenna until you do this mod! I guarantee that if you don't you will be noticed. Be considerate of others, and protect your reputation.

The one that got away

While I was busy modifying the rig I had the idea of adding something new, for computer-assisted contesting. Quite a few contest and other rig control software support computer keying via a serial COM port. In particular, the RTS and DTR pins of an RS-232 interface. Since these pins are unused on the FT-1000 MP CAT (computer aided transceiver) serial interface I wanted to add the switching circuits for PTT and CW keying onto the same interface.

This turned out to be more difficult than I expected. The DB9 connector on the rear of the chassis, along with the sockets for PTT and CW key, are mounted on circuit boards. That is, they are not chassis-mounted sockets. Adding the circuitry therefore requires lifting and flipping the associated boards to access the points where wires need to be soldered. This would not be easy considering the host of interconnecting cables that would have to be disconnected to accomplish the task. The added wires should also, ideally, have connectors themselves to allow the boards to be more easily removed in future.

I reluctantly decided not to bother. The mod would in any case be of questionable use when operating multiple radios, such as for SO2R contesting. The better and more forward looking approach would be an external keyer such as the USB WinKeyer which is supported by most software and is emulated by some other commercial keyers.

Saturday, September 12, 2015

Comments, Feedback and Questions

I have an explanation below regarding why the pace of articles has slowed recently. This is temporary, and mostly for good reasons. What I want to focus on is some administrative detail. As blog readership increases and I have to deal with the peculiarities (absurdities?) of the Blogger platform, this is a good time to make some adjustments.

Getting in touch with me

I am always happy to correspond with readers, whether just to say 'hello' or if you have questions about one of my articles. Either of the following email addresses will work: ve3vn@rac.ca or ve3vn.fn25@gmail.com

Of course you can always leave a comment on the article. But use email when you want a personal response.

Requesting antennas models and more

I do not upload the EZNEC models and other files to general access. I suggest you send me an email with your request. Many have already taken advantage of this offer.

Comment policy

As of today all comments are moderated. I did this so that I can review comments before they are posted. While this can delay their publication for up to a day or two (depending on my availability) it means I was able to remove the spambot challenge for anonymous and uncredentialed commenters.

Blogger has its quirks, of which the comment credential technology is a big one. It is cumbersome and works poorly (or not at all) with some browsers. I am trying to make this easier for you and for me. You can write the most critical comment you like and I will publish it. I will only delete comments that are wildly off topic, abusive, spam or other forms of self promotion.

Feel free to bring to my attention any technical errors. I want to know about my mistakes so I can fix them. However, I'd appreciate that you silently overlook typos and grammatical errors.

Where are all the new articles?

I've been busy. My time has been split between radio activities, summer fun and a host of family and other responsibilities. There are at present several articles partly drafted which will be published once those activities are complete. Some are antenna articles, particularly those on my fall plans for 40 meters and 80 meters. Others are on equipment purchases for my future antenna farm, and changes to my shack equipment.

I foresee quite a few articles showing up over the next couple of months. Right now I am in over my head with things that absolutely must get done before winter, including preparation for the serious start of contest season in October. Recent poor HF conditions have helped to keep me focussed on what's important.