Tag: k7daa

Cheap & Super-Portable Magnetic Loop antenna for 20-40 meters

On: By: K7DAA

Most of you know how much I enjoy playing with mag loops. I think I have something like 5 of them from different manufacturers, as well as my first one that I built myself. I showed a few photos of my homebrew baby on Ham Fun night a few months ago. My first contacts on 10 watts were to Maryland and then Hawaii a few minutes later on 17 meters from Morgan Hill. The really fun part about mag loops is that they don’t have to be hoisted high in the air. The two contacts I made that first day had the loop base about 2 feet above the grass in my front yard!

Just for fun, here’s a short clip of my Chameleon P-Loop in action. The station you’re hearing was 59 on 20 meters from Utah to Mississippi on my Yaesu FT-818 running 2.5 watts:
https://www.youtube.com/watch?v=mpmnCcrtKAo

Anyway, I know that some of you would like to try building a mag loop, but that it might be a little fiddly or require some tools you might not have. I just happened across this video from K6ARK, a SOTA guy that’s really into super-light, backpack-able radios and antennas, and he shows one that only weighs 8.5 ounces and can be put together easily without bending copper or aluminum tubing into a loop:

https://www.youtube.com/watch?v=Uz5ZKkxGDQ4

I thought this interesting (QRP power only) build might inspire you to try making one of your own. This one is not super-hard to make, doesn’t require any specialized tools, and packs away into a very small space. You might have to come up with some minor accommodations if you don’t have simple metal-working hand tools.

For example, the nice bracket that he made for the BNC connector could be replaced by simply cutting and stripping a piece of RG-174 or RG-58 coax and using a hose clamp to connect the coax braid to the ground point. Then solder or twist a simple 8 to 16 inch length of any kind of wire to the center conductor of the coax to make the “gamma” match. You can use either an alligator clip as shown, or even just another hose clamp to attach it to the main loop body. Just move the connection points around for the best SWR.

The little plastic switch box with the tuning capacitor is maybe a bit more of a challenge, but you can even substitute it with a 18-30 inch length of coax (for 20 meters), if you’re OK starting with just a single frequency/band. The capacitance between the shield and center conductor of the coax replaces the capacitors in the box. Just attach the shield to one side of the loop at the top, and the center conductor to the other side, leaving an insulator between the two ends of the loop. Something like a piece of scrap plastic, pvc, or even just a chunk cut from a soda pop bottle would work.

Leave the far end of the coax open, and measure your resonant frequency with a NanoVNA or some other wideband SWR meter. Snip the length of coax shorter a half-inch at a time until it resonates on the frequency you want. There–done!

I’m embedding a video by VK3YE showing this “coax-as-a-capacitor” method on his mag loop. You don’t necessarily have to make a big copper loop like this, or copy his tunable capacitor made of scrap pc board and a rubber band. You can just simply cut the open end of the coax a bit at a time as I mentioned.

The interesting thing about this antenna is that you can run a full 100 watts through it. Note just how low to the ground it is. That wasn’t just for the camera. I know some hams might think it’s impossible to get out with something this small and stealthy, but it really works!

As I’ve mentioned before, the only real downside is that mag loops are very narrow-banded, giving you only about 20-30 kHz of the band without retuning. Maybe the scrap pc board and rubber band kludge isn’t such a bad idea in that case. But…let’s say you’re really into FT8, or just want to join a daily net. This might just be your ticket! Stick it up in your attic and away you go…

Icom’s Novel Idea For Ham Bands Above 2.3 GHz

On: By: K7DAA

Icom has announced that they are thinking about creating a new transceiver system for the 2.4 and 5.6 GHz ham bands.
What? You didn’t know we have bands in frequencies so high? Well, we do, but they’re obviously not very popular, with no current commercial radios that cover those microwave bands.
So far, they’ve published 4 very short pdf files that show what their concept is, and have just recently shown a mock-up at the 2022 Dayton HamFest in May. They are also planning to attend other major hamfests to try and gauge the level of interest.
According to their latest paper, they were very pleased with the response from hams at Dayton.

Icom has tackled one of the major problems when using these microwave frequencies. You and your transceiver want to be in your nice, warm shack, but you want your antenna to be high and outside. Running coax out to the antenna is a big problem. At these extremely high frequencies, coax loss is a real killer, even using very large and expensive hardline.

The basic concept is to use an IC-705 QRP transceiver as the controller (note the 5780 MHz frequency on the display above) for a remotely-connected, weatherproof up/down converter box that would sit outside on a pole or tower, using a very short connection to its antennas. The IC-705 has an Ethernet connection that runs up to the converter box on the tower. Power for the converter is supplied by PoE (Power over Ethernet) coming from the IC-705.

Now, I don’t know if the present IC-705 can produce that PoE voltage, or if you’ll need to buy a new one. Icom just says the concept is “based on” the IC-705 design. I guess we’ll see how it goes as they release more info. Keep in mind that this is still just an idea that they are shopping around, much like how auto companies show off their concept cars at the auto shows. If the public (us) show enough interest to justify the cost of designing it, maybe we’ll see one in a year or three.

Here is a simple block diagram showing what they’re thinking. The IC-705 is on your desk in your shack. An Ethernet cable plugs into it, and goes outside and up the tower to the transverter unit. This minimizes coax loss, which is super-important at such high frequencies:

Below is the outdoor unit that would mount on the tower. The GPS antenna connects to an internal high-precision frequency reference that will keep the microwave radio locked closely onto the frequency. This addresses another issue where normal transverters would not have tight enough frequency control to allow for an SSB or other signal to stay within the IF bandwidth of the radio in your shack.

Quick Links to Things We Covered on Tonight’s Net

On: By: K7DAA

Here are a few web URL’s to items we discussed on the 3/30/22 net:

Online tone generator–send DTMF over a radio or other device that doesn’t have a TouchTone pad:

https://onlinetonegenerator.com/dtmf.html


Source for SDR receivers and adapters for all sorts of uses:
https://www.sdr-kits.net/

Fully assembled little adapter boards for under $25 that you can add to your radio if it doesn’t have a built-in panadapter (waterfall) display). You would then connect this amplified IF output to an SDR dongle, add some free software on to your computer, and have a great display of what’s on the bands:

https://www.sdr-kits.net/Panoramic-Adaptor-Tap-Boards

Jack W6KRK and I bought these folding panels awhile back. Well-made and fold into something close to the size and weight of a laptop computer in a soft bag:

Amazon

George N6GWH bought these portable folding solar panels and likes them. They are about $50 less than the ones I bought, and have another 20W of power as well:

Amazon

Jehu Garcia’s YouTube page. He’s been one of my favorite instructors, as well as a source of parts, for building your own lithium batteries and battery packs. Be sure to also check out his VW Microbus that he converted to a full electric vehicle:

Jehu Garcia on YouTube

Will Prowse has a great YouTube channel that has very informative info on batteries and solar systems:

Will Prowse on YouTube

WebSDR: Listen to Repeaters in Salt Lake City, and Make Other Fun Radio Links

On: By: K7DAA

The Northern Utah WebSDR receiver system has a unique feature that allows you to listen in on local repeater activity in the Wasatch Front area of Utah. Like the other WebSDR receivers, it allows you to listen to activity on the 1.8 to 30 MHz HF bands, but they’ve added another remote receiver for local VHF/UHF activity. This receiver is located southeast of downtown Salt Lake City, on the face of the mountains, about 600 feet above the valley floor. For those of you familiar with the area, it is near the entrance to Parley’s Canyon, where I-80 and I-215 meet. To get from the SLC Airport to Park City, you go right past this area.

Someone has taken the time to mark all of the repeaters that can be heard on the tuning ruler, so all you have to do is click on one of the little brown flags to move from one repeater to another.

NOTE: Before you go any further, if you use the Chrome browser, or any based on Chrome, make sure you remember to click the colored box above and to the right of the tuning dial that says CHROME AUDIO START or you won’t hear anything on any of the WebSDR receivers. Also, please know that if you click these links from an Android or iOS device, you may get re-directed to a different receiver page that might not have the same capabilities. Nothing wrong with your stuff, just a limitation of the design of these awesome receivers. In fact, I sometimes listen to 75 or 40 meter nets with my iPhone, so it works, just a bit differently.

Here are a few web links you can copy/paste (or just bookmark this page) that you can save into your web browser:

This is the 146.62 repeater, the busiest in SLC, and links to one in Park City

Here is the 146.76 repeater, also quite busy, and is my “home” repeater, covering Salt Lake, Davis and Utah (where I am) counties area.

147.12 repeater near our TV towers on Farnsworth Peak (named after Philo Farnsworth, the actual inventor of television), southwest of SLC. This repeater is part of a wide area network of RF-linked repeaters up and down Utah. It is called the Intermountain Intertie system, rivaling the famous Cactus Net for sheer coverage. It also covers southern Idaho (Boise, Idaho Falls), parts of Wyoming, Montana, Yellowstone Park, Flagstaff and Phoenix, AZ, and Las Vegas. Lots of activity here as well. Unlike Cactus, all may use it without fees or membership. Read more about it here

By the way, many of the WebSDR receivers allow you to make your own weblink that you can save or bookmark. It allows you to instantly go to a particular WebSDR receiver, frequency and mode. You can see how I did this by examining the URL’s in the links above. Or, for example, if you like listening to the NoonTime Net on 40 meters from about 10 AM to 2 PM every day, your link would look like this one below. Go ahead and click on these examples if you’d like. I made sure they work:

http://websdr1.sdrutah.org:8901/index1a.html?tune=7284lsb

Note the data after the question mark. Just replace the frequency in kHz with whatever you want, and then add the mode, such as cw, usb, lsb, fm, or am. That’s all there is to it. If you want to listen using a different WebSDR receiver, just use its URL, and add the same frequency and mode data at the end. Here are two more examples of the NoonTime net again, but listening first from the KFS receiver near Pacifica, and right below it is the same net, listening from Phoenix.

http://69.27.184.62:8901/?tune=7284lsb

http://w7rna.com/?tune=7284lsb

Easy, right? Here’s another hint if you’d like to monitor several frequencies or repeaters at once. All you need to do is start one receiver session by clicking one of the above, then open a new browser instance or tab, then either click another link or paste one in, then go. Note that sometimes opening just a tab doesn’t give you audio from both receiver instances at the same time, depending on your browser. It worked OK for my Chrome browser, but your mileage may vary, etc.

OK, here is one last bonus link. If you would like to practice listening to CW, here is a link to 7047.5 kHz. It is the ARRL’s station W1AW. Every day it sends plain text from a recent issue of QST magazine at varying speeds. Very good practice, but don’t freak out if you happen to arrive while it’s sending at 35+ WPM! Yeah, I can’t copy most of that either. If you look at the web link, note that I inserted the frequency as 7046.75 kHz to get to 7047.5. I don’t know why, but on CW, it’s 750 Hz higher. Maybe a quirk. I dunno. I’ll come back and edit this if I figure out why.

There you go–you’ve got lots of cool receiver power all over the planet for the price of…nothing. Can’t beat that!

What Are Those Weird Tones?

On: By: K7DAA

Contestia Signal

If you tune around the HF bands, you’ve very likely heard strange-sounding tones, squawks or beeps, and wondered what they are. Here is a link to a very well-done Wiki that gives you audio samples you can listen to, and a brief explanation of all sorts of different modulation types found on the Amateur bands to help you identify what you’re hearing:

https://www.sigidwiki.com/wiki/Category:Amateur_Radio


Take 5 Minutes to Comment on USFS Fees That Will Ruin Your Repeater Fun!

mountain covered with fog under cloudy sky
On: By: K7DAA

The Federal government is at it again–this time they are proposing that all repeaters and radios on US Forest Service sites–and there are lots of them–pay an exorbitant (to us hams) $1400 yearly fee to be able to stay where they are. Many repeaters we use in the Bay Area are on USFS sites. The Feds say that there are thousands all over the US.

Here is a link to the ARRL website with their summary of the impact of the proposal:

http://www.arrl.org/news/arrl-to-oppose-forest-service-administrative-fees-for-amateur-facilities

Annoyingly, the ARRL doesn’t have this very important item shown prominently on their front page, nor do they provide you with a direct link to where you should post your comments. I’ve added a shortcut to where you want to go. The comment window will close on Feb. 22, 2022, so do it now! Just click on “Comment” to leave your own thoughts:

https://www.regulations.gov/document/FS-2022-0001-0001

I posted my own a few hours ago. It was quick and easy to do. You can do it anonymously if you’d like.

I suggest a few things to have the best effect:

1. Please avoid histrionics, name calling, or off-topic rants. Keep to the issue at hand, which is the proposed fee problem for hams, who can be an important emergency resource to government.

2. Double- and triple-check your spelling and grammar. You’ll make a better impression if you sound reasonable and thoughtful.

3. NO CAPS LOCK! Don’t shout with your keyboard.

4. Keep it short. A few lines are more effective than 10 paragraphs that no decision maker will take the time to read.

Even if you don’t use any repeaters, please do take the time to comment! If you are a repeater user, think of what life would be like without it, or worse yet, how it would be to get a monthly or yearly bill to continue using it.

If you leave an email address, you’ll get an acknowledgement that your comments were received, along with a copy of what you wrote. Here’s mine:

———————————————————-

Your comment was submitted successfully!
Comment Tracking Number: xxx-xxxxx-xxxx

Your comment has been sent for review. This process is dependent on agency public submission policies/procedures and processing times. Once the agency has posted your comment, you may view it on Regulations.gov using your Comment Tracking Number.

Agency: FOREST SERVICE (FS)
Document Type: Proposed Rule
Title: Land Uses: Special Uses; Annual Programmatic Administrative Fee for Communications Use Authorizations
Document ID: FS-2022-0001-0001

Comment:
I am strongly opposed to this proposal to charge an administrative fee, if it includes Amateur Radio (FCC Part 97) repeaters and radios. Amateurs have a long and rich history of working directly with the Federal government, as well as local government agencies, in times of disaster or other emergencies. One of the primary tools Amateurs use to enable emergency communications is mountaintop repeater systems. The proposal to charge such a relatively high fee for Amateur Radio repeaters will effectively drive them off most of the USFS sites. This is due to the fact that they are maintained by individuals or small club groups, not corporate entities that can include the proposed fees in their budgets as a cost of doing business. Please consider amending this proposal to exclude repeaters and radios licensed under FCC Part 97 from being required to pay the proposed site fees.

Apollo 11: How NASA Got All That RF From The Moon Back To Earth

space research science astronaut
On: By: K7DAA

This is a very good article that we hams might enjoy reading! It’s about the first moon landing in 1969, and how video, voice, and astronauts’ heartbeats were all sent back to Earth using frequencies and modes we are familiar with today. It was all analog stuff back then, and communications were sent “in the clear” without encryption. Of course, that meant some hams got to listen in!

Read all about it here:

https://www.rfcafe.com/references/electronics-world/communications-moon-electronics-world-august-1969.htm

Note that the “S” band microwave frequencies mentioned in the article are just a hair outside of our present 13 centimeter ham band that covers 2300 to 2450 MHz. A chunk of our 13 cm band (2310-2390 MHz) got taken away a few years back, and is now used by, among others, Sirius/XM satellite radio. If you’re one of their subscribers, it might be fun to know that the music coming out of the speakers in your car is from a satellite transmitting inside of an Amateur Radio band. Think about that while you’re driving around, listening to the Beatles Channel (Ch.18)! Oh, and of course, we also share almost half of the 2.4 GHz Wi-Fi and Bluetooth band with the world. Ask me sometime how we got there…

Talking About 10 Meters

On: By: K7DAA

In last month’s Tech Net, we talked quite a bit about the fact that 10 Meters has been open. In fact, Jack, W6KRK, told us that he had been able to check into a 10 Meter net being held by the Utah County hams earlier that evening, covering a distance of about 850 miles.

10 Meters is typically described as a daylight-only band that is more often than not closed. If we stop right there, we may not realize that we’re missing out on some big fun and possibly some very interesting contacts.

Another thing of great interest is that 10 Meters contains the only sub-band that allows Novice and Technician licensees to transmit data and SSB voice signals. This gives Techs a good chance to experience the fun and technical challenges of operating on the HF bands. Technicians have unlimited operation on 6 Meters and higher, but most of the time, those high-frequency signals behave more like a beam of light, where contacts can be made locally as long as antennas can “see” each other. There is more to it than that, but I’ll leave that description to be expanded upon in another post.

Being able to get a taste of HF operation, meaning operating in the shortwave bands from about 1.8 to 30 MHz, can be both exciting and challenging to a Tech who has not had any previous experience. When I say “challenging”, I don’t mean that it represents an unpleasant or insurmountable task, only one that is new and unfamiliar. You’ll have to decide on an antenna and transceiver to use, and also learn a bit about how signals on 10 Meters behave so that you don’t waste lots of time trying to make contacts when the band is not open.

Before we talk about antennas, radios and how signals bounce around the globe, let me briefly mention some of my own experiences with the 10 Meter band. On the net, I mentioned one of my favorites being a station from French Polynesia that came on 28.410 MHz, as I recall. I had a mobile station then (about 2010), and I was on 10 Meters only because I was checking the SWR of my antenna, a Lil’ Tarheel HP “screwdriver” antenna. This antenna covers 40 through 6 meters, and uses a motor to expose more or less of the internal inductor coil, tuning it to a particular frequency. In the earliest versions of these antennas, the motor from a battery-operated electric screwdriver was used because it was cylindrically-shaped and had high torque, hence the name “scredriver” applying to all motor-tuned mobile antennas.

Anyway, as I was checking my SWR on 10 Meters in the early evening, I heard this very strong S9+10 signal that I found was from French Polynesia. Interestingly, I couldn’t hear any of the stations calling him, but he was very strong. I gave him a call on my 100-watt Yaesu FT-857 transceiver, and he answered me on my first call with an S9 report! Cool! Interestingly, his signal persisted strong and clear until he finally said he was closing down for the night, at about 9:15 PM California time. Wow! That’s unusual, but not unheard of.

I can give you many examples of contacts I’ve made on 10 Meters when the band appeared to be shut down. The usual thing to do is to tune around, and if you don’t hear anyone, set your dial to 28.400 MHz, the SSB calling frequency, and call CQ. Like me, you might be surprised to get someone calling you back! If I had just listened instead of calling CQ, I might have not made any contacts because everyone else was just listening also. So by all means, get on the mike and call if you don’t hear much.

Even in “down” times, when the 11-year sunspot cycle is at a low ebb, there are contacts to be made. Each year, from about May through September in the Northern Hemisphere, the band tends to open up, sometimes allowing even daily contacts. This will happen mostly from late morning through to early evening, but there are plenty of exceptions to that timetable as well, such as my hours-long connection to French Polynesia.

As we are now climbing up the 11-year sunspot cycle roller coaster, things are heating up on 6 and 10 meters. Especially if you are a Technician class ham with a shiny new HF transceiver, this is your moment! You can work the world when these two bands are open. 10 meters should be your “go-to” band right now, as it will open more reliably, possibly on a daily basis. 6 meters is a bit more tricky, relying most on what’s called E-Skip propagation. But when it’s open, fun things can happen as well.

Something else to listen for on both bands are the beacons. Hams have put up simple CW beacons all over the world, and they provide an easy means of telling when the band is open. Have a look at these two links to get you started with understanding how to listen for and identify what frequencies to use, and where the beacons are calling from:

https://www.youtube.com/watch?v=5uk2tC18mOs

https://en.wikipedia.org/wiki/Amateur_radio_propagation_beacon

Build a Super-Simple Radio, Get it on the Air, and Learn CW Along the Way

Tuna Can QRP Radio
On: By: K7DAA

One of our group is working on a very simple little one-transistor low-power 40 meter transmitter. No, the picture above is not it, although this is a fun little receiver kit you can build if you want to start with a simple kit.

Anyway, when he’s done with his little transmitter, he then faces his next hurdle: The dreaded CW monster!

The CW Monster!
Does that maybe ring true for you as well? Let me give you some encouragement, and maybe we can shine some light on the monster. You may find that he doesn’t actually bite, and is even friendly!

I’m re-posting some comments I made to Bob just tonight, and I thought I’d pass this along for you to consider:

When you get a simple radio put together, you might find that CW is your biggest challenge. I’ve always had a love/hate relationship with it–mostly love. The hard part, of course, is in getting started.

There are lots of QRP clubs around to offer encouragement and also even on-air schedules. I know I’ve mentioned the QRPARCI club on our net nights before. You may also find lots of encouragement in learning CW with the SKCC, the Straight Key Century Club: http://www.skccgroup.com/membership_data/opfreq.php

This page shows their “watering hole” frequencies. I’m listening to two SKCC members right now on 7055 kHz. They are going along at about 7 words per minute or less. The idea, of course, is to use a simple hand key instead of an electronic keyer, and to (usually, but not always) slow down. They usually call “CQ SKCC” and then exchange numbers and pleasantries. The two guys I’ve been listening to are in Florida and Rhode Island. I can hear them easily with my G5RV dipole antenna, so they’re probably running 100 watts. You don’t have to use QRP power levels if you don’t want to.

It’s fun to sit here and hand write each letter on the back of a piece of junk mail I received today as they send them. I get to think about other things for a moment, and then write down the next letter sent, etc. Very pleasant actually. Kind of like taking a slow ride through the back country roads instead of zipping down the interstate highway.

Anyway, just thought I’d pass that along to you. It’s always a bit intimidating to get on the air with CW for the first time. By the way, Jack, W6KRK, can be counted on as a helpful guy when it comes to CW. He just decided last year to dig in and re-learn CW. So if you can get him to take a few minutes on the air with you, it might help to get over the “first call” jitters. Oh wait–I could do that, too, from here in Utah! Just ask. I can be as sloooow as you’d like! We could try 20, 40 or 80 meters just about any time you want to try.

Maybe you could find some of our other friends to try, too. Building radios and then putting them on the air, at least for me, has been a lifetime passion. The “putting them on the air” part usually means CW for the simple gear, of course, and it can be tremendously satisfying when you make a contact with your little radio. Remember, too, that your first attempt does not have to be a full-on transceiver. A one- or two-transistor, crystal-controlled peanut whistle transmitter can be used just fine with your “big” HF transceiver.