Posts Tagged ‘vhf/uhf’
Best VHF SOTA Antenna?
Charlie/NJ7V and Gaston/KT1RUN did a comparison of VHF antennas during a SOTA activation. Specifically, they compared a rubber duck antenna, a J-pole antenna on a tall mast, and a 3-element Yagi antenna. Spoiler Alert: the rubber duck sucks (they all do) but the Yagi and J-pole performed about the same.
Joyce/K0JJW and I use the Arrow 3-element Yagi antenna for most of our SOTA activations, so I am very familiar with that one. We also have a rollup J-pole that we use once in a while.
Charlie used the Yagi the same way we do: handheld at ground level. The J-pole was on a mast, maybe 12 feet (?) in the air. Although they were on a summit, there is some performance improvement getting the antenna higher than the surrounding terrain. The gain of the Arrow 3-element Yagi has been measured at about 6 dBd. The gain of a J-pole, being a halfwave radiator, is 0 dBd. The additional height of the J-pole has to make up this 6 dB of gain difference to be roughly equivalent.
A big difference, though, is that the Yagi antenna has to be held and pointed. The J-pole is always pointing in the right direction so you can just focus on operating and logging. We may have to consider using a omni antenna instead of the Yagi.
Good stuff!
73 Bob K0NR
The post Best VHF SOTA Antenna? appeared first on The KØNR Radio Site.
North America Adventure Frequency: 146.58 MHz
Recently, on the nasota group, there was a discussion about designating an alternative 2m FM frequency for Summits On The Air (SOTA) use (instead of 146.52 MHz). The main driver for this is that 146.52 MHz can get busy with other radio traffic and/or a busy SOTA activation can tie up the calling frequency for a long time.
Rex KE6MT (SOTA W6 Association Manager) kicked it off with:
A friend of mine, George KJ6VU, has been talking with me and several others about the idea of an FM “Adventure Frequency.” It would be for more than just SOTA – other *OTA’s could also use it. There are other ideas to layer on top of it, such as tone signaling so that you don’t have to hear traffic you don’t want to hear, and repeater infrastructure for announcing someone’s on the frequency with a given tone, etc. But the core thing would be to decide on a frequency and really get it in use. The National Calling Frequency (146.52) can be great for a few contacts sometimes, but other times it’s problematic either because it’s being hogged or because nobody’s listening. Of course, this Adventure Frequency could have the same issues present themselves differently, but would alleviate some and pave the path for future additions mentioned above.
I have previously written about the challenges of using 146.52: The Use of 146.52 MHz
One important idea is to include the other “OTAs” in adopting this frequency, most notably Parks On The Air (POTA). Hence the name “Adventure Frequency,” and not “SOTA Frequency.” It is really about hams operating portable in an outdoor setting. Of course, like all amateur spectrum, this frequency must be shared with other users.
It may seem like a simple thing to choose a nationwide simplex frequency but VHF band plans are managed regionally. In particular, there is a mix of 15-kHz and 20-kHz channel spacings. (For more background on this see Simplex Channel Confusion on 2 Meters.)
After some discussion, the group settled on 146.58 MHz. There was some dialog around using CTCSS for signaling but nothing specific surfaced.
Some key points:
- The NAAF is 146.58 MHz.
- This frequency is in addition to, not a replacement for, the National Simplex Calling Frequency 146.52 MHz.
- Local usage will likely vary depending on needs.
- Program 146.58 MHz as The Other Simplex Frequency in your radio.
What does this mean to you?
Program 146.58 MHz into your radio and have it available. If you are doing SOTA (or POTA) activations, consider using this frequency, especially if you are in an area where 146.52 is used a lot. (I’ve already started using this frequency for SOTA activations near urban areas.)
73 Bob K0NR
The post North America Adventure Frequency: 146.58 MHz appeared first on The KØNR Radio Site.
Recommended Colorado Hotspot Frequencies
A big trend in ham radio activity is the use of internet-connected transceivers commonly referred to as hotspots. These devices often use one (or more) of the popular VHF/UHF digital formats (DMR, D-STAR, Fusion) but analog FM is also used. They allow a radio amateur to have a local RF connection into one of the extensive radio networks (e.g., Brandmeister).
Unfortunately, there have been situations where radio amateurs arbitrarily chose hotspot frequencies that caused interference with existing radio activity. For example, a hotspot showed up on the 70 cm SSB calling frequency, 432.100 MHz. One of the worst examples of interference was a hotspot sitting on the input frequency of a satellite transponder. Not good.
The Colorado Council of Amateur Radio Clubs (CCARC) is the VHF/UHF frequency coordination body for the state of Colorado. Included in its spectrum management role, the CCARC maintains a detailed set of band plans (called Frequency Use Plans) for the 144 MHz, 222 MHz, 420 MHz, 902 MHz and 1200 MHz bands.
The CCARC recently decided to provide some guidance on what frequencies should be used for hotspot operation. Previously, the operator of a hotspot had to scan through the Frequency Use Plan and figure out where hotspots fit in. It wasn’t very obvious, so the CCARC now recommends 10 specific frequencies on the 70 cm band for hotspot use.
Hotspot Channel | Frequency |
---|---|
1 | 438.4500 MHz |
2 | 438.4750 MHz |
3 | 438.5000 MHz |
4 | 438.5250 MHz |
5 | 438.5500 MHz |
6 | 438.5750 MHz |
7 | 438.6000 MHz |
8 | 438.6250 MHz |
9 | 438.6500 MHz |
10 | 438.6750 MHz |
These frequencies are available for simplex hotspot use. However, for each of these simplex frequencies, there is also a corresponding frequency 5 MHz lower that can be used for hotspots that operate duplex.
Unlike repeaters, hotspots are not coordinated by the CCARC. With 10 frequencies available, it should be easy to find one that doesn’t have any co-channel interference from other users. See the complete CCARC hotspot guidance here.
These guidelines won’t solve every problem but it will help people find a hotspot frequency that plays well with others. These frequencies are valid for Colorado only. Check your local VHF/UHF band plans for more information.
73 Bob K0NR
Disclosure: I contributed to these CCARC guidelines but I don’t speak for the CCARC.
The post Recommended Colorado Hotspot Frequencies appeared first on The KØNR Radio Site.
The Truth About Tiny SOTA Transceivers
After seeing some videos about small HF transceivers for Summits On The Air (SOTA), I feel I need to set the record straight.
The following video shows the World’s Smallest SOTA Transceiver in use. Of course, it uses the UHF spectrum because shorter wavelengths enable smaller ham radio stations.
The radio shown in the video is the NKTech NK-M1 UHF transceiver.
This radio is a 16-channel UHF transceiver, available from multiple online vendors. I programmed it to operate in the 70 cm band on 446.0 MHz.
73 Bob K0NR
The post The Truth About Tiny SOTA Transceivers appeared first on The KØNR Radio Site.
Top Five K0NR Blog Posts for 2020
Closing out 2020, here are the top five blog posts at k0nr.com during the year. Some people may see this as a lazy way of creating one more blog post for the year without much work. This is definitely true. I hope you enjoy it anyway.
Leading the list is this blog post…a perennial favorite that seems to make the top five each year.
This is another popular article that explains some of the details behind the 2-meter band plan. This particular article is tuned for Colorado but there it also provides a link to an article that covers the topic for the USA.
New on the blog this year, I wrote this article about the Yaesu FT-4XR handheld transceiver. Spoiler Alert: Buy this one instead of the Baofeng.
Coming from nowhere, this article talks about an alternative firmware package for the popular Tytera MD-380 transceiver. I don’t know why this is getting so many hits but it might just be people searching for the TyMD380toolz, which seems to have disappeared.
The fifth-place post is one of my personal favorites that talks about proper kerchunking of repeaters. It even introduced a new Q-signal for kerchunking, although I must admit it may not be catching on.
Editor’s Choice
I am going to add one more post to this list. No extra charge. This one announced that Joyce/K0JJW achieved Mountain Goat status in the Summits On The Air program. You Go, Grrrrl.
The post Top Five K0NR Blog Posts for 2020 appeared first on The KØNR Radio Site.
POTA: Arkansas River Headwaters State Park (K-1208)
The Arkansas River Headwaters is a unique recreation area that follows the upper Arkansas River in Colorado, extending roughly from Leadville to Pueblo. POTA has it listed as the Arkansas River Headwaters State Park, but the Colorado Parks and Wildlife website shows it as the Arkansas Headwaters Recreation Area. This area is a bit unique, a cooperative effort involving Colorado Parks and Wildlife, the Bureau of Land Management, and the US Forest Service. See map here.

Joyce/K0JJW and I decided to activate this park earlier this week, enjoying a nice sunny day. We operated from the Collegiate Peaks Overlook, which has a picnic area and an excellent view of Mount Princeton and adjacent peaks.

For POTA, our standard station configuration is the Yaesu FT-991 transceiver driving an end-fed halfwave antenna, usually on 20m or 15m. We have a collection of end-fed halfwave antennas that cover 40m and up. We have bigger and smaller transceivers available to us, but the FT-991 is small enough to be portable but includes an antenna tuner and has 100 watts of output available. (Typically, we run about 50 watts of RF output on battery power.) Our power source is a Bioenno 12V 20aH LFP battery. This battery is lightweight and compact, capable of running the FT-991 for hours.
Bob working VE4RBH and AG7KO on 20 meters.
We set up our station on a convenient picnic table. We had hoped to lash the mast to a conveniently-located post or tree, but none were present. Our backup plan was the drive-on mount, held by the front tire of the truck. The 20m band was alive so we just set up on that band and never looked back. We also worked some of the locals on 2m FM. It is always fun to see who shows up on that band.
Here’s Joyce working AA5UY in Louisiana.
I don’t think we have really optimized our POTA setup but we have found an approach that works well. Never underestimate a properly-fed halfwave antenna up in the air.
73 Bob K0NR
The post POTA: Arkansas River Headwaters State Park (K-1208) appeared first on The KØNR Radio Site.
More On SOTA and POTA
Recently, I commented on participating in the Parks On The Air (POTA) program: How About Parks On The Air? Since then Joyce/K0JJW and I have done a few POTA activations, including a few combination SOTA (Summits On The Air) + POTA activations. We are starting to sort out how SOTA and POTA work for us. I am sure this will evolve over time as there are many operating options with both programs. But here is what we’ve done so far.
Recall that we’ve been focusing on VHF/UHF operating for SOTA, although I did break down and actually made some HF contacts from a SOTA summit recently. VHF/UHF is a good match for SOTA (Height Above Average Terrain). However, for some remote summits, it can be a challenge to get enough radio contacts (4) to qualify for the SOTA points. Using HF can be a big help in generating contacts. POTA can also be done with VHF, some parks have high elevation, but many of them are not attractive VHF locations. POTA requires 10 radio contacts to qualify for points, so that raises the bar a bit, too.

Yesterday, we decided to hike up Mt Herman (W0C/FR-063) for a short afternoon VHF/UHF activation. I posted both a SOTA alert and a POTA alert. We made plenty of radio contacts (40 total) and submitted logs to both the SOTA and POTA websites. I know there were SOTA chasers out there but I’m not sure if anyone worked us specifically for POTA. As usual, a lot of hams give us a call just because it is fun to work someone on a summit (without any SOTA or POTA interest).
The majority of our SOTA activations in Colorado are in national forests, which count as “parks” for POTA. So it is easy to tack on a POTA activation when doing SOTA.
Vehicle-Based POTA
Joyce and I also did some POTA activations from a vehicle. It is pretty easy for us to get to Pike National Forest (K-4404) or San Isabel National Forest (K-4407) and set up a portable station.

We used a Yaesu FT-991 and endfed halfwave antennas for 20m and 15m, supported by a SOTAbeams pole. This is the same configuration I’ve used for portable operating from many locations, including some Caribbean islands. I recently purchased a 20 Ah LFP battery from Bioenno Power to use as a power source so that we don’t rely on the vehicle battery.
We focused on HF for these POTA activations and were pleased to have decent pileups of stations calling us on the 20m and 15m bands. Fifty watts to a halfwave antenna works just fine. We also made it a point to call on 2m FM and usually picked up a handle of contacts on that band, too.
What’s Next?
At this point, our outdoorsy portable operating is looking like this:
- SOTA Summits – if the summit is in a park, we will probably go ahead and submit a POTA log along with the SOTA log. Many of the W0C SOTA summits are in national forests, national parks or state parks. VHF-only activations will probably have less impact on POTA…those chasers/hunters tend to be on HF.
- POTA Parks (day trip) – another option is for us to just stop by one of the national forests or a state park and get on the air. (Pike National Forest is about 2 miles from our home.) This will be focused on the HF bands but we can always make a call or two on VHF.
- POTA (RV camping) – we’ve been RV camping in state parks and national forests this past year. An obvious additional activity is to set up on HF for a POTA activation. We haven’t done this yet.
I’ve already done a combination VHF Contest and SOTA activation, so this could be extended to include POTA. Three Things In One. In fact, some locations qualify for more than one POTA park, so maybe it is time for a Four-In-One.
73 Bob K0NR
The post More On SOTA and POTA appeared first on The KØNR Radio Site.