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How Much Does Emergency Power Cost?

Some folks are criticizing the ARRL for not modifying the Field Day rules in response to the Wuhan virus epidemic. Most of them are looking for a way to operate Field Day from home but still have a club score of some kind. I posted my thoughts here: Don’t Mess With The Field Day Rules.

The Field Day (FD) rules allow for a home station with commercial power to participate in FD as a Class D station. However, Class D stations cannot work other Class D stations for points. If the home station has emergency power (batteries, gasoline generator, etc.), then it is a Class E station that can work all FD stations for point credit.

Emergency Power: Too Difficult?

I’ve heard some hams argue that it is too difficult to set up emergency power for their home station. In many cases, the argument is actually that it is too expensive to do this.  I can see this point if you run out and buy a name brand gasoline generator…a Honda EU1000i costs about $950.

This raises the question of what is the lowest-cost way to equip a home station for emergency power?  Let’s consider the case of a typical 100W HF transceiver such as an IC-7300 or FT-991A. These radios require a 12 V power supply at 22 A maximum on transmit. Receive current is much lower, typically 1 to 2 A. Under FD rules, we don’t need to power our computer or other accessories from emergency power, just the radio. If we assume a 50% duty cycle, this class of radio consumes about (22+2)/2 = 12 A average current. (Yes, you could choose to operate QRP and really stretch the battery but let’s stay with the 100 W scenario.)

Get A Battery

So what is the cheapest way to get this done? Let’s take a look at using a deep-cycle battery. Walmart has an RV/Marine battery for $75, rated at 101 AH. Assuming 12 A of current, this battery would support about 8 hours of radio operating. This is going to be way short of the 24 hour operating period of FD but it might be enough to support a less intense operation.  We could also do some things to stretch out the battery life, such as reducing our transmit power. Dropping to 50 W would roughly double the operating time to 16 hours, which should be enough for a single-operator station.

Of course, another option is to double the battery capacity by using two batteries. These amp-hour ratings on batteries are always a bit idealistic and our transmit duty cycle might be more than 50%. Let’s assume we buy two batteries to give extra margin and allow us to run 100W. We will also need a simple charger, which costs about $25. So there you have it, 2 x $75 plus $25 = $175 for a decent emergency power source.  (If we decide to use only one battery, the cost drops to $100.)

Now $175 is a significant investment and only you can judge how well your ham radio budget can support this. For many people, this is affordable and the real question becomes is this how you want to spend my hard-earned cash.

This is my best shot at a low-cost emergency power source. Do you have a better idea?

73 Bob K0NR

The post How Much Does Emergency Power Cost? appeared first on The KØNR Radio Site.

Activating SOTA W0C/SP-099

The view of the Collegiate Peaks from SP-099.

Way back in 2013, Joyce/K0JJW and I did the first SOTA activation of W0C/SP-099, an unnamed summit in the San Isabel National Forest. As is often the case, we just reviewed the forest service map and drove down a road that got us sort of close to the summit and headed on up. On this initial activation, we came from the south, which is a viable route, but not all that great. Later, Walt/W0CP found a much better starting point to the east of the unnamed summit, so we were interested in trying that out.

The driving directions are to take County Road 187 south to CR 185, then turn off onto 185E. Consult the San Isabel National Forest map for context. The graphic below shows the immediate area near the summit.

The blue line shows the hiking route to SP-099.

The only mildly tricky part of FS 185E is that it passes through a section of private property that is surrounded by national forest. There are a number of private drives along the road (most of them gated and labeled “No Trespassing.”)  However, 185E keeps on going and pops out the other side, where a wire gate marks the reentry into the national forest. Walt indicates a good place to park is at Lat/Lon 38.78067, -105.98301. The road was in good condition and should be passable with a high-clearance 2WD vehicle.

At this point, headed west towards the summit, hiking off trail. There is very little downed timber so the walk is quite enjoyable. The specific route is not critical but stay north of the private property.

Typical terrain and vegetation heading towards the summit.

My GPS app shows the hike at 0.85 miles one way with 460 feet of elevation gain. This is easy peasy, so we have started to call this unnamed summit “EZ 99”.

Joyce/K0JJW hiking near the summit.

We worked a number of stations on 2m FM and then headed on down. (We also activated Bald Mountain W0C/SP-115, about two miles west,  on the same day.)

This summit is now on our highly recommended list, an easy-to-access, pleasant hike in a beautiful area of Colorado.

73 Bob K0NR

The post Activating SOTA W0C/SP-099 appeared first on The KØNR Radio Site.

Troubleshooting a Radio Interference Problem

I recently encountered a problem when using my Yaesu FT-950. Sometime during the CQ WW WPX Contest, I noticed an annoying tone (“a birdie”) in my receiver. I’ve had this radio for many years, used it quite a bit and this was the first time I encountered this problem. It struck me as very odd because it did not go away when I disconnected the antenna and it did not change frequency when I tuned around.

I immediately had visions of needing to tear the radio apart or send it back to Yaesu for repair. Instead, this happened…

When it comes to troubleshooting problems, it usually pays to fiddle around with it and see what happens.

The post Troubleshooting a Radio Interference Problem appeared first on The KØNR Radio Site.

Aiwa Six-Band Radio Flashback

Normally, I avoid posting items of a nostalgic nature, preferring to keep moving forward and not getting stuck in the past.  I am going to make an exception today because I stumbled across some photos of my first radio receiver that went beyond the standard AM/FM broadcast bands.

Aiwa AR-158 radio
This Aiwa AR-158 six-band receiver covered AM, FM, Marine Band (1.6 to 4 MHz), Shortwave (4 to 12 MHz), VHF1 (110 to 136 MHz), VHF2 (148 to 174 MHz).

Aiwa AR-158 Radio

As a kid, I remember saving up my money and buying this radio from the local “dime store” about 3 miles away from my house. It was a 6-band radio made by Aiwa, not a very common brand. I am not sure of the exact model number but it was probably the AR-158.

Of course, the radio had the standard AM and FM broadcast bands, but the real fun came from the other bands. The  “Marine Band”,  1.6 to 4 MHz, picked up some shortwave broadcast stations. The “Shortwave Band” covered 4 to 12 MHz, allowing me to listen to broadcast stations from around the world. The VHF1 band covered the aircraft band from 110 to 136 MHz. I probably did not realize it at the time but the radio must have selected AM for that band. The VHF2 band provided FM reception from 148 to 174 MHz.

Top view of the Aiwa six-band radio.

This receiver gave me my first experience with the wonderful world of radio. My best buddy, Denny/KB9DPF, bought a similar radio about the same time, so we were always comparing notes on what we heard: Radio Netherlands, Deutsches Welle, BBC London, Voice of America, Radio Moscow, Radio Havana, Radio Johannesburg and more. Sometimes I would hear SSB ham stations but they just sounded like Donald Duck on the AM receiver.  I remember stumbling upon the signal from WWV and wondering what this ticking clock signal was all about. Whatever it was, it was really cool.  (Yes, I listened to it for hours. Just because.)

The VHF Bands

The VHF aircraft band was fun to listen to, although the transmissions were short. I don’t remember if I could hear the control tower from the local airport (probably not) but I could receive aircraft transmissions. The VHF2 band was very interesting and probably planted the seeds for my interest in VHF. I could listen to the local police and fire radio calls.  Tuning was a bit tedious because the receiver had an old-school analog VFO. No digital synthesis on this radio.

The radio picked up the 2-meter ham band, so the actual tuning must have been a bit lower than 148 MHz.  Hearing hams chat on the local 2m repeaters got me thinking about getting an amateur license. This receiver did not have a squelch, so listening to two-way FM signals was filled with lots of receiver noise!

Have Fun

Even back then (in the 1960s), this was not a great radio receiver… imprecise tuning, no squelch, limited shortwave coverage. By today’s standards, it’s even worse. But I had a boatload of fun playing around with it and exploring the radio spectrum. So maybe that’s the thing to be learned from this story:

Whatever radio equipment you have, use it.
You can probably have a lot of fun.

73 Bob K0NR

The post Aiwa Six-Band Radio Flashback appeared first on The KØNR Radio Site.

Don’t Mess With The Field Day Rules

Given the Chinese/Wuhan/COVID virus situation, many hams are anticipating a change to their ARRL Field Day operation. I’ve also seen a number of proposals to modify the FD rules to allow for a different kind of operation. I appreciate that kind of thinking outside the box but I think it is misguided. One of the strengths of FD is it already has a set of flexible rules and operating classes, so you can adapt it to what you or your club wants it to be. See my post: ARRL Field Day – Season to Taste

Some Ideas

What are some of the proposals? The first one I noticed is a proposal to allow all Class D stations (home station with commercial power) to work other Class D stations for points. The FD rules do not currently allow this. Class E stations (home station with emergency power) are allowed to any class station. Obviously, this rule is to encourage people to develop emergency power capability (and use it) for their home station. This is perfectly aligned with the emcomm focus of Field Day.

Another proposal is to allow a “backyard operating” class, where you set up a portable station in your backyard. Of course, this is already allowed under the rules as a Class B station.

One of the more innovative ideas I’ve heard is to allow multiple stations (not colocated) to operate under one club callsign, coordinating their operation via the internet. This approach emulates a “normal” Class A FD operation, while everyone is locked down at home. This is not allowed as a Class A station:  “All equipment (including antennas) must lie within a circle whose diameter does not exceed 300 meters (1000 feet).”  This is roughly equivalent to a group of Class D or E stations working together towards a common score. Why not just operate as independent Class D and E stations, which is more like a real emergency situation?

Adapt and Innovate

Our local radio club is considering different ways to adapt, seeing this as a training and learning opportunity. We will probably encourage our members to get on the air individually, with emergency power. We will likely encourage members to work other members, providing some kind of incentive or award. So our FD may look more like a local operating event, in addition to working distant stations. VHF/UHF will probably play an important role so that we include Technician licensees. Not sure just yet.

We are all experiencing some serious challenges this year and Field Day is not going to be the same. I am a bit surprised that the first thought about Field Day is to change the rules to make it easier or somehow better. I think we just need to adapt and innovate within the existing format. Existing Field Day Rules have plenty of flexibility.

That’s what I say. What do you think?

73 Bob K0NR

The post Don’t Mess With The Field Day Rules appeared first on The KØNR Radio Site.

Your First (and Second) Ham Transceiver

We recently completed a Technician License class that produced a herd of new ham radio licensees. This always leads to a discussion of what radio should I get? Often, this is centered on the idea of getting a handheld VHF/UHF radio to get started. That is a good first move. However, for many new hams it is worth looking ahead a bit to potential future purchases.

Handheld Transceiver (HT)

Let’s start with an HT. Even if your ham radio future is going to be on the high-frequency bands, an HT is a useful tool to have. After all, FM VHF is the Utility Mode for ham radio. Many new hams opt for an inexpensive Chinese radio such as the Baofeng UV-5R. Recently, I’ve been steering them toward the slightly more expensive Yaesu FT-4XR (around $70).

A basic handheld radio.

It is a significantly better radio than the UV-5R but still affordable. Some new hams decide to spend more on an HT, which is also a good option. There are many radios to choose from in the $150 to $350 range.

For hams just interested in local (perhaps emergency) communications, this might be the only radio they get. If it meets your needs, that’s just fine.

FM VHF/UHF Base Station

Another option to consider is to set up a more capable station at your home, focused on FM VHF/UHF operating. This is probably going to be a dual-band radio that covers 2 meters and 70 centimeters, FM only. One way to do this is to use a mobile transceiver powered by a DC power supply and connected to an external antenna on the roof.

A mobile transceiver deployed as a base station.

With higher power (50W typical) and a good antenna mounted in a high location, this type of station has better range than an HT. See A VHF FM Station at Home and Considering a VHF/UHF Antenna For Your Home.   This could be your first radio but why not have an HT in your toolkit?

The All-Band Base Station

Many new hams have their eyes on working distant stations via the high-frequency bands. For many people, this is what ham radio is all about. (Honestly, you’re going to need your General license to really participate on these bands.)

Yaesu FT-991A all band transceiver

The equipment manufacturers have developed the Do Everything Transceiver that covers 160m though 70 centimeters in one box. (Well, they do leave out the 1.25m band which is lightly used in North America.) The leader in this category is arguably the Yaesu FT-991A. This type of rig has the advantage of providing all modes on all bands, including SSB on 2 m and 70 cm. While most VHF/UHF activity is FM, SSB (and CW) can be a lot of fun.

Setting up operations on multiple bands will require some additional antennas. This can be a deep topic so take a look at this introductory article to understand it better: Antennas…How Many Do I Need?

Two-Radio Base Station

Another approach that many hams adopt is to build their home station around two radios: a 2m/70cm radio to cover local communications and a high frequency (HF) radio for the lower bands.

The 2m/70cm radio is the same idea as the FM VHF/UHF Base Station mentioned previously.  It is really handy to be able to leave this radio on your favorite 2m frequency while still having another radio available to operate HF. Compare this to the All Band Transceiver approach which can normally only receive one frequency at a time.

A very popular HF radio these days is the ICOM IC-7300. Like many HF rigs, it covers the HF bands of 160m through 10m AND tosses in the 6m band, too. Recall that 6 meters is actually a VHF band but the general trend is to include this band in HF rigs.

ICOM IC-7300 HF plus 6m transceiver

The Mobile Station

Another popular operating style is to have a transceiver in your vehicle. Because our society is so mobile, this approach can be very compelling. This might just be an HT that you take with you when mobile. The rubber duck antenna might be sufficient but an external (magnetic mount?) antenna can really improve your signal.

Many hams install a VHF/UHF FM transceiver in their car. This provides a more capable station (more power, better antenna) when mobile and it’s always there for use. Again, this will probably be a 2m / 70cm radio that operates only FM, the most common mobile ham station.

Some folks set up their mobile station to include HF operating. This is one way to sidestep HF antenna restrictions at home and it fits into our mobile society. There are Do Everything Transceivers that come in a mobile-type form factor. The Yaesu FT-857D is a popular mobile radio that covers HF, 6m, 2m and 70cm in one rig.

Yaesu FT-857D all band mobile transceiver

General Progression

You can see that there are some paths that hams tend to follow in terms of equipment. What you decide to do is going to depend on your interests and budget. Of course, when you are first starting out you may not know what part of ham radio is going to be your favorite and your approach may evolve as you gain experience.

A good first, affordable step is getting an HT. This puts you in touch on the air with the local amateur radio community. It is clearly a VHF/UHF FM play which aligns well with your Technician operating privileges. You can choose to expand on this general direction by adding in an FM VHF/UHF Base Station,  an All-Band Base Station, or a Mobile Station.

If you are interested in using the HF bands, then think about either the All-Band Base Station or the Two-Radio Base Station. Again, obtaining a General class (or Extra class) license is going to be important for HF.

I’ve tried to keep this discussion focused on newly licensed hams. As you gain experience, you’ll find all kinds of other operating activities that are available to you. Sometimes these can be supported by the equipment described above…sometimes you’ll need to purchase additional gear. I’ve mentioned specific radio models that I have experience with but there are many others to choose from. Take a look at the eham.net product reviews to see how well other people like a particular radio.

73 Bob K0NR

The post Your First (and Second) Ham Transceiver appeared first on The KØNR Radio Site.

Mobile DC Power: One Fuse or Two?

[My apologies. I fumble-fingered WordPress and published a draft version of this article that was incomplete. This is the corrected version. ]

Sometime during the 20th Century, I learned that fuses (or circuit breakers) are used in electrical circuits to prevent catastrophic failure. Fuses open in response to an electrical fault that causes excessive current to flow. The job of the fuse is to minimize the damage and keep things from catching on fire. When I started installing amateur transceivers into vehicles, I learned that you should connect wires directly to the car battery (or darn close) and you should fuse both the positive and negative power leads. I was surprised by the need for two fuses, but there are technical arguments for it. Besides, the transceiver manufacturers recommend it in their manuals. (See figure below.)

DC power connection as shown in the manual for an ICOM amateur radio transceiver (IC-2730).

I am focusing this discussion on a typical 2m/70cm FM transceiver installation – that is what I have the most experience with and that is the most common ham mobile installation. Such a radio typically draws ~10 A on transmit, so the DC power is usually fused with something like a 15 A (or 20 A) fuse. Keep in mind that a 15 A fuse is not going to protect delicate circuitry but might stop more serious damage or fire.

Connect To The Battery?

Alan/K0BG has an excellent website that provides guidance on mobile radio installations. He points out that modern vehicles usually have an Electrical Load Detector (ELD) inserted into the negative lead of the battery, so that the vehicle control systems can monitor the state of the battery. It is important to connect your radio on the “other side” of the ELD, near where it connects to the vehicle chassis. Oh, and never use the existing vehicle wiring to power your radio (especially not the 12 V accessory plug).

The negative power lead for a transceiver power should be connected to the chassis side of the ELD. Figure: k0bg.com website.

One Fuse or Two Controversy

Recently, I became aware of controversy with regard to proper fusing. Some people are questioning the practice of fusing both DC power leads, while others are vigorously defending it.

For example, there is a lively eham.net discussion here.  Ed/W1RFI provides some useful insight on the ARRL forum.  Alan/K0BG covers the topic of DC power on his wiring and grounding page.  Tom/W8JI argues for the one fuse approach on his website.

What Do The Manufacturers Say?

Generally, you should follow the advice of the manufacturer on any equipment installation, so I took a look at a few owner’s manuals. Most (or all?) of the manuals for the amateur gear show the two fuse method. See the ICOM example below. (Note that they don’t show the presence of the ELD.)

DC power wiring diagram for a Yaesu amateur radio.

I also took a look at some commercial land mobile radio manuals. Motorola shows the single fuse approach.

DC power wiring diagram from a Motorola land mobile manual (CM200- 300).

Hytera also shows a single fuse in its land mobile manuals.

DC wiring diagram from a Hytera land mobile manual.

ICOM makes both amateur and commercial land mobile gear, so I wondered what they recommend for their land mobile product line. Ha, funny thing, they show two fuses, with a comment that says, “Depending on version, the fuse holder may not be attached to the black cable.” Well, isn’t that special?

ICOM land mobile transceiver wiring diagram shows two fuses but says the negative one may not be there. (IC-F5021 manual)

So is the two-fuse thing some kind of ancient amateur radio practice and the land mobile industry has gone a different path? Sometimes industries adopt “standard” approaches and then forget why with time.

Some Circuit Analysis

After reading through all of the arguments, I tried to distill them down to their essence. I created a wiring diagram that may help explain the concepts. Or maybe not. An automobile is a complex electrical and electronic system, so any practical diagram risks oversimplifying the situation. But here’s my best shot at it.

Wiring diagram for radio transceiver installation, including some major vehicle components.  (click to enlarge)

The center of the diagram shows the body/chassis of the vehicle which is connected to the negative lead of the battery, through the ELD. The transceiver is directly connected to the + terminal of the battery (via Fuse 1) and the chassis side of the ELD (via Fuse 2).  The engine starter is connected to the battery with heavy cables and is also connected to the body/chassis.  While there are a large number of other electrical devices in a modern vehicle, only one is shown here as an example (with a switch and fuse).

The circuit shows the antenna connected to the radio with a coaxial cable. The shield of that cable is almost always grounded to the vehicle chassis at the antenna. (Magnetic mount antennas are one exception and I am sure there are others.) I can say that every mobile installation I’ve ever done had the coaxial cable connected to the chassis. This is an important point because it provides a chassis connection for the transceiver at point C (whether you wanted it or not). There may be other ways that a transceiver is connected to chassis (point B), including the mounting bracket, external speaker, microphone or other accessories.

Arguments For and Against

The argument for fusing the negative lead is to protect against return current from other devices that find its way back to the battery through the transceiver’s negative power lead.  For example, the starter could have a fault in its negative cable, causing the current to flow through the chassis to the transceiver and back to the battery.  The starter current can be hundreds of amperes which would likely overload the radio wire which is sized for 15 amperes. The fuse will open and protect the negative lead (and maybe the radio, to some extent).

The argument against fusing the negative lead is that if the fuse opens up, it could cause problems. Suppose Fuse 2 opens up due to some transient condition. If the transceiver is completely isolated, Fuse 2 would remove power from the transceiver. However, the return path at the antenna coax (point C) will most likely allow the radio to continue functioning using the coax as the negative return. Typically, this is RG-58 or similar cable, which is not intended to carry significant DC current and may fry under the load. If the current is coming from a fault in the starter wiring (big current), this is going to be a bad day for your mobile.

My Conclusions

I think both arguments have merit but choosing one fuse or two requires estimating which problem is most likely and judging the overall impact of the fault. The negative lead fuse can do only one thing well: protect the negative lead. It might provide some protection to the transceiver but there are a lot of sensitive circuits inside the radio that will get destroyed with 15 A flowing. Again, the connection at point C means that the radio will be connected to chassis and current can flow.

If Fuse 2 is eliminated it allows for the flow of high currents through the negative lead of the transceiver. This is not desirable but is it better or worse than the current flowing through the coax shield? Probably better. If a high current device (the starter) has a wiring failure that dumps large currents into the chassis, it may find a number of return paths. Lots of current is going to flow somewhere and potentially cause damage, with or without a negative lead fuse.

I will note that bonding the transceiver to the vehicle chassis has some benefit (point B in the diagram). You may or may not have this connection depending on how you mounted the radio. This electrical connection can shunt any currents away from the coaxial cable, hopefully doing less damage that way.

What am I going to do? My future mobile installations will have only one fuse in the positive lead.  I’ll also bond the radio body to the vehicle chassis, with a hefty, low-resistance connection.

My existing mobile installations all have two fuses. I won’t be changing them out because the risk of inducing a problem with the negative lead fuse is rather low. I don’t see the negative lead fuse as a big risk. If you choose to follow the amateur radio manufacturer’s two fuse recommendation, I understand.

A Request

The amateur radio equipment manufacturers need to give this issue a fresh look. At a minimum, the presence of ELD’s needs to be addressed and the common recommendation of wiring directly to the battery is obsolete. But the one-fuse-or-two issue should also get a careful look by the manufacturer’s engineering teams.

That’s my analysis. What do you think?
(Runs and ducks for cover.)

Note: This article is my technical opinion but my attorney says to tell you that you are responsible if you destroy your vehicle while wiring up your transceiver.

The post Mobile DC Power: One Fuse or Two? appeared first on The KØNR Radio Site.


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