Shack Upgrade

For years, my “ham shack” has been equipment crowded on top of a crate surrounded by other crates and boxes. It was neither attractive or effective.

Can you find the radios? The VHF/UHF rig on the floor would be stacked on the dresser for the weekly Monday night ARES/RACES net.

Ham shack before

There isn’t a lot of space in the corner, so I spent quite a while looking for the right table or desk. I settled on a 24 x 36 inch hardwood table that looks like it belongs in a classroom. A deeper table would work better for radio gear, but this one fit the space, was reasonably attractive, and affordable ($172).

On Saturday, my new table arrived and the cleanup and reorganization commenced. The old crate is now a bookshelf next to the desk.

Ham shack after

With California’s “shelter in place” coronavirus order, the shack is doing double duty as a home office. The big monitor and keyboard are from work.

Ham shack desk

The power supply (adjusted to 15 V) and 100 W RF amp are under the monitor stand. Stereo speakers for the receiver (not the computer) are on top of the stand. I wrote about the speakers and audio amp in an earlier blog post. The dummy load (see this post) is behind the monitor. Farther to the right are the Elecraft KX3 and PX3 on an over/under stand from the North Georgia QRP Club. At the far right is a Yaesu FT-8900R VHF/UHF rig mounted in a Tac-Comm case. That can be quickly disconnected from power (PowerPoles) and the antenna (BNC) to be taken mobile or portable.

The monitor stand is a “Thank You” gift from when I worked at HP. I’d helped out some folks in another division, so they sent me one of the monitor stands they made in their sheet metal shop. It is a beauty, thick aluminum, with stiffening ridges along the front and back edges, and nicely painted in official HP instrument dove grey.

Time to quit rearranging stuff and get on the air!

USMC Antenna Handbook

If you’ve been looking for a practical, free introduction to antennas, the US Marine Core Antenna Handbook (MCRP 8-10B.11, 2016) is a good place to start. The book is especially good for simple HF antennas that can be put up at home or in the field.

USMC Antenna Handbook

The PDF is 193 pages. The main section of text is 160 pages, with a very good 20 page glossary at the back.

If you enjoy learning about antennas from this handbook, your next step should be the ARRL Antenna Book. If you’re not ready to shell out $65 for the 1024 page 24th edition of that book, check your local library. Older editions are less comprehensive, but they still have lots of great info. My 12th edition from 1970 is still useful. Antenna physics has not changed over time, just our understanding of it.

Let’s go over some of the sections of the USMC Antenna Handbook to see the strong and weak points.

Radio Waves, Propagation, and Noise

These sections are very good, especially about HF propagation. It could cover VHF/UHF multipath a bit better. Repeaters are not mentioned. Those are common in amateur radio, but apparently not in the Marine Corps. Serious VHF/UHF amateurs dig into other kinds of propagation not covered here, like tropospheric ducting, meteor scatter, moonbounce, aircraft scatter, and so on. Those are advanced topics, so it is reasonable to not cover them here.

Transmission Lines

This is not my favorite section, but the mistakes here are very common in popular explanations of transmission lines. Unbalanced vs balanced is not a helpful way to think of transmission lines. All kinds of transmission lines carry a mix of differential (balanced) currents and common-mode (unbalanced) currents. Also, it talks about baluns as balanced-to-unbalanced transformers, but they are most useful as common-mode chokes. Still, this is a fairly standard introduction to the subject.

HF Antenna Selection

Very good section, with lots of ideas for how to actually get wire into the air for horizontal dipole or vertical ground plane antennas. You won’t find coverage of ham favorites like the G5RV, off-center fed dipole, Carolina windom, or even the end-fed half-wave. The antennas covered here are all simple and proven.

This chapter does discuss NVIS (near vertical incidence skywave) propagation, something that is fairly recent in amateur practice. The first QST article on NVIS was in 1995 and it has only become popular in the last 10-15 years.

There is one interesting antenna that is new to me, the vertical half-rhombic. This requires a fair amount of space, up to 1000 feet, but is unidirectional and only needs one support.

VHF and UHF Antenna Selection

This section is a bit less useful because it relies on specific military antennas instead of describing types of antennas. For example, the OE-254 is a bow-tie vertical dipole, a low-Q, high-bandwidth antenna, but they just call it an OE-254.

Military VHF/UHF antennas need to work over a wide range of frequencies, but amateurs can use antennas optimized for the small number of bands that we are allowed to use. The most common single- and dual-band ham antennas are not described here, designs like collinear phased verticals, Yagi-Uda beams, haloes, Moxon beams, J-poles, and so on.

Field Repair and Expedients

Read this before ARRL Field Day! Here are some suggestions of what to do when an antenna insulator breaks.

Improvised insulators crop

Antenna Farms

Some really good advice on choosing antenna sites, useful even if you are just putting up one antenna. I don’t think I’ve seen this covered in detail in any other book. A lot of hams will end up with at least two antennas, one for HF and one for VHF/UHF, so this is a worthwhile read. We won’t normally be considering security measures like barbed wire and automatic weapons, so you can skip to the Technical Considerations section.

And that’s all! Enjoy learning about antennas.

BaoFeng HTs and Spurious Emissons

The January edition of QST has some disturbing data about dirty transmitters in BaoFeng HTs.

Amateurs are responsible for their transmitters being clean, but most of us don’t have the test equipment to check that. Also, manufacturers must meet the FCC regulations for every transmitter sold.

The ARRL Lab set up at hamfests and tested the HTs that hams had with them. Over four years, only 5% to 9% of BaoFeng HTs passed the test. Alinco, Icom, Kenwood, and Yaesu had 100% pass rates. Wouxon improved from 83% to 100% over the years.

QST 2020 01 HT Testing

From “Technical Correspondence”, QST, January 2020, pages 60-62. This chart is on page 61. QST is available online to ARRL members. This is a link to the article online.

The FCC rules for spurious emissions are in 47 CFR § 97.307 – Emission standards.

What if you already own a BaoFeng, like me?

Run low power. This will reduce the amount of power in the spurious emissions. Reducing the power from 5 W to 0.5 W should reduce the spurious emissions by 10 dB. The spurs still won’t be 40 dB below the carrier, but they will be lower in terms of absolute power. It can’t hurt. It will make your battery last longer, too.

What if you want an inexpensive HT?

Instead of a $50 BaoFeng, save up a bit more for a $75 Yaesu FT-4XR. From my research, this is the only HT under $100 from a major radioo vendor.

The FT-4XR uses the same chipset as the BaoFeng, so it has roughly the same feature set. But it has a clean transmitter and better interference rejection in the receiver. It also has ham-specific firmware, like automatic repeater offsets. That should make it easier to use.

The FT-4XR also uses the same antenna connector as BaoFeng, so aftermarket Nagoya antennas might fit. I would probably try the Nagoya NA-771 for $17, which might fit. I’ve heard recommendations for the Diamond SRJ77CA ($27).

I linked to DX Engineering’s page above, but the FT-4XR is available at similar prices from Ham Radio Outlet, Gigaparts, and other ham stores. Amazon has it at a higher price ($83), oddly.

BaoFeng UV 5R Yaesu FT 4XE

How did this happen?

It appears that the BaoFeng radios were designed for the much more lenient Part 90 emission regulations and do not meet the amateur radio regulations.

An article by AD5GG compares BaoFeng UV-5R emissions to Part 90 (private land mobile) and Part 97 (amateur) regulations. The BaoFeng meets the weaker Part 90 limits, where spurious emissions are not to exceed -20 dBc (dBc is relative to carrier). Part 97 limits spurious emissions to -40 dBc, 100X lower than the Part 90 limit.

Designing for the Part 97 limits requires additional low-pass filtering on the output. The new parts may only be pennies, but it would require a new board design. Maybe new versions of the BaoFeng HTs will be designed to the stricter standards, but I’ll have to see proof of that. The UV-5R is up to the third generation, at least, and still not compliant.

How to get an Amateur Radio License

What are the steps for getting your first amateur radio license?

Start by taking an online test for the Technician license. It is easy and free. You will probably do better than you expect. After the test, note the areas that you need to study. hamexam.org is my favorite online test site. You only need a C (75% correct) to pass.

K6WRU license blur

Now that you know what to study, get a study buddy, get some study materials, or best, both. The No Nonsense Technician-Class License Study Guide by Dan Romanchik (KB6NU) is free as a PDF and is exactly what it says. Study the sections where you are having trouble and keep taking practice tests until you are happy with your scores. Download it from the KB6NU study guide page.

Take a break from your studying to find a license test session. That will give you a deadline. Use the ARRL license exam session search to find a session.

There might be a fee for the exam, up to $15. You can take tests for all of the license levels at one session, so go ahead and take the test for General. You might pass!

After that, find a mentor to help you get on the air. In amateur radio, we call these people an “Elmer”. Use the ARRL club search page to find one near you. On the Web, try the Amateur Radio Elmers Facebook group.

Choosing a radio? That is a different post.

Simple Base for Morse Code Key

I wanted to mount my Morse code key on a base so Scouts could use it at Jamboree on the Air (JOTA) this coming October. A $15 walnut “display base” from Amazon was just the right thing for that. Now we can set up a “Send your name in Morse code!” station.

Flameproof key 3

The key is a CTE-26003A “Navy Flameproof” that I bought when I was first licensed, back in the early 1970’s. I’ve never used it and it was never mounted on a base. It looks brand new. The “CTE” manufacturer code is for “Telephonics”, which matches the name on the key.

flameproof key manufacturer

A few hams offer nice bases for sale, but they were either too big or I was too cheap. This black crackle finish metal base is designed specifically for the Navy flameproof key and is reasonably priced at $30, but it is huge and weighs three pounds. Not quite was I was looking for. I also found some very nice exotic hardwood bases. Those were lovely, but I was looking for something more utilitarian.

I spotted the Plymor Solid Walnut Rectangular Wood Display Base with Ogee Edge on Amazon and chose the 6 x 4 inch size as the best match for the key. I picked up some #6 screws and fiber washers, plus some vinyl feet to keep it from scooting around on the desk.

flameproof key parts

The official Navy name for the key is “KEY SIGNALLING SEARCHLIGHT TOTALLY ENCLOSED TYPE 26003A” (spelling is original). Maybe some of the signaling searchlights were acetylene, so they needed a flameproof key. It is a very nice straight key considering that it was designed for very slow Morse code.

After I collected all the parts, I found a very similar wood straight key base project. That one uses lead shot to weight the wooden base, then felt on the bottom.

Plastic Pipe Roof Antenna Support

I noticed a clever antenna mount on another ham’s roof, so I built one myself. Putting my VHF/UHF antenna at the highest point of the roof has really improved my ability to copy some of the far-flung participants in our weekly ARES/RACES net.

plastic pipe antenna mount close-up

A cradle built from two-inch ABS DWV (drain, waste, and vent) pipe sits across the ridge of the roof. Legs two feet long go down on each side and a two-foot section is a vertical antenna mast.

My antenna is a Diamond X50NA, same as the X50A, but with a weatherproof Type N connector. I did additional weatherproofing with 3M Temflex 2155 rubber splicing tape and Scotch Super 33+ electrical tape.

I had spotted an antenna mounted like this and contacted the ham at that address. Rolf Klibo, N6NFI, replied with an article he’d written for the SPARK newsletter describing the mount. With that, I was off to the hardware store.

I used two-inch ABS DWV (drain, waste, and vent) pipe in two-foot sections. I cut up two of them to make the four pipe sections that go along the ridge of the roof.

The X50NA mounting hardware fits masts up to 2 3/8 inch, which is why I used two inch pipe. For coax strain relief, I used a conduit hanger that fit. Zip ties attach a loop of coax to the hanger so the full weight of the feed line isn’t pulling on the connector. That can rip the coax right out of the connector, or harder to diagnose, pull just one of the shield or center connector loose.

Antenna mount 3 Antenna mount 4

For a commercial version, I’d look at the Rohn NPPK, a steel frame that fits over the roof peak. It is designed to have a rubber mat underneath and four 18 pound concrete blocks holding it down. I’m sure it is far more secure than my DIY plastic pipe mount.

Rig on a Board Update 1

The “rig on a board” is working well. I’m a little worried about it scratching the central console, so the next version should have a cloth surface there. I’ll probably use a thinner board with some carpet or corduroy covering it.

Rig on a board 1

A wider board, maybe 10-12 inches, would leave plenty of room for the mic.

The wood for the prototype is 11/16 x 7 (measured), about 20 inches long, cut close to the middle. I used a regular door hinge. It has a little bit of play, but not too bad. A piano (continuous) hinge might be a better choice, especially if I use a wider board.

While I’m mounting things, an external speaker would help. I’ve plugged in one that I use with my Lowe HF-150 shortwave receiver and that improved the audio.

Hmm, 1/2 (or 5/8) x 12 (or 10) x 20 seems like a job for some scrap plywood. Just need to find some scrap carpet.