On some SOTA summits that are established radio sites, there can be significant RFI on 2 meters. I recently wrote about that here: RFI on SOTA Summits. There have also been discussions from time to time among VHF SOTA activators on which handheld transceiver (HT) has the most robust receiver for use in high RF environments. (Hint: a Baofeng is not going to be your best choice.)

This led me to an excellent web page by Razvan/YO9IRF that tabulates the receiver performance of HTs as measured in the ARRL lab. This is arguably the most objective look at HT performance out there. You can do a sort on a particular parameter and see which models are best.

Probably the parameter to start with is wide 3rd-order intermodulation on the 2-meter band. (I am going to ignore the 70 cm performance because most VHF SOTA contacts are on 2 meters.) The wide 3rd-order intermod performance relates to interference rejection from outside the amateur band.

Here are the best performing HTs for this parameter. (Go to the website directly to see other models listed.)

Interestingly, the Icom IC-V8 jumps to the top of the list. This is an older single-band 2m radio…and I happen to have one hiding somewhere in the basement. I am a bit surprised there are two Wouxun radios near the top of the list but they performed well.  No surprise that the Yaesu FT-60 shows up…it seems to be well-regarded by SOTA activators.

The narrow 3rd-order intermod performance relates to the receiver performance inside the amateur band. Sorting based on that parameter shows these radios at the top:

The Kenwood TH-22AT takes the top position, followed by the Yaesu FT-10R, both older single-band radios. The general trend here is that some of the older radios, especially single-band rigs, have better front end filtering. Newer radios tend to include reception of a wider range of frequencies outside the ham band and have receiver front ends that are correspondingly more open. The Radio Shack HTX-202 gets a lot of positive comments from the SOTA crowd and is on the shortlist.  Again, the well-regarded FT-60 makes the list.

Let’s check a few of my favorite HTs to see how they rate.

My usual SOTA handheld is the Yaesu FT-1DR. The wide 3rd-order intermod is 73 dB, or 12 dB worse than the FT-60 (85 dB). For narrow 3rd-order intermod, the FT-1DR is 58 dB vs 67 dB for the FT-60. This matches my impression that the FT-1DR does OK for most summits but is not the best radio for high RF environments.

Another radio to consider is the Yaesu FT-4XR. I often have this radio on at the house but I don’t use it for SOTA. This radio uses the same receiver IC as the Baofeng UV-5R but has better input filtering. The wide 3rd-order intermod is only 63 dB and the narrow 3rd-order is 61 dB (about the same as the FT-1DR).  The table does not list any Baofeng radios but I would expect them to perform worse than the FT-4XR.

Regular readers of this blog know that I use a Yaesu FT-90 mini-mobile transceiver for most SOTA activations. I looked up the ARRL tests on it. The wide and narrow 3rd-order intermod are 85 dB and 65 dB respectively, not better than the best handhelds but near the top. My experience is that the FT-90 receiver is better than my FT-60 and FT-1DR, consistent with the ARRL lab measurements.

Another radio of interest is the Yaesu FT-818, which the ARRL measured as 96 dB (wide 3rd-order intermod) and 72 dB (narrow 3rd-order intermod) on the 2m band.  This puts the FT-818 at the top of the list with the best handhelds. Actually, I would have expected it to be even better, far superior to an HT, but apparently not.

So I need to dig out that old Icom IC-V8 that is hiding in the basement. It may be a good piece of equipment to have along on SOTA activations.

73 Bob K0NR

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One thing to watch out for when doing SOTA activations is the presence of strong Radio Frequency Interference (RFI) on some peaks. The typical scenario is that the summit is also an established radio site with transmitters that interfere with your ham radio operations.

I use the VHF/UHF bands for SOTA, so I am writing from that perspective. My impression is that HF interference is much less likely because these radio sites don’t usually have any HF transmitters. However, they may have broadband noise sources such as networking equipment, power line arcing or switching power supplies that can create problems on HF. Anyway, this post is focused on 2 meters and higher bands.

In my experience, the transmitters at radio sites may include land mobile repeaters (VHF or UHF), NOAA Weather (162.xx MHz), TV/FM broadcast stations and mobile wireless (cellular) systems. The TV/FM broad stations are really bad news because they run a crapton of RF power.

The worst summit I have encountered is Sandia Crest (W5N/SI-001) near Albuquerque, NM. See trip report here. They even have a sign in the parking lot to warn you that the RFI may wipe out your car’s keyless remote.

Some other notable RFI-heavy SOTA summits are Monarch Ridge South (W0C/SP-058), Squaw Mountain (W0C/PR-082), Terry Peak (W0D/NW-002), and Greentop (W4T/SU-076).

In a high RFI environment, your radio receiver gets overloaded such that you can’t hear stations calling you but they can hear you just fine. This results in the SOTA activator calling and calling while the chasers get frustrated that the activator never hears their call. Not good. It may not be obvious that this is happening. This blocking of the receiver may come and go, depending on which transmitters happen to be active.

Mitigation Strategies

There are a few things that you can do to deal with the RFI:

Move Away From The Source

Probably the first thing to try is just moving away from the source of interference. This may mean moving away from the highest point on the summit but it may be better overall to give up a few feet of elevation to not have the interference. You’ll need to stay in the activation zone to be a legitimate SOTA activation.

Use A Better Radio

Some radios are better than others when it comes to receiver performance including the ability to reject unwanted signals. The low cost radios from China (Baofeng or similar) generally have lousy receivers so they are a poor choice for operating from an RFI-intense summit. Many people report better results with the Yaesu FT-60, a solid performer. Commerical radios from Motorola are even more robust. I’ve been using a small mobile radio for SOTA (Yaesu FT-90) which outperforms most handheld radios.

Change Your Antenna

Using a directional antenna can help…just point it away from the source of the interference.  Oddly enough, using a worse performing antenna can help improve your ability to communicate. For example, a rubber duck antenna on a handheld radio will allow less of the interfering signal to get into your receiver which may improve your ability to receive. As long as the antenna is “good enough” to complete the radio contact, it may be the way to go. One trick I’ve used is to deploy two radios, one for receive with a crummy antenna and the other for transmit with a better antenna. That way, you still radiate a stronger signal while reducing the interference into the receiver.

Use A Bandpass Filter

You can insert a filter into your antenna feedline to reduce the interfering signal. The best approach is to use a bandpass filter that passes the frequency you are operating on but attenuates other signals.  SOTABeams offers a compact bandpass filter for the 2m band. (Note that it has a 5W power rating which is fine for handheld radios but not more powerful transceivers.) DCI Digital Communications offers higher power filters but they are much larger in size.

Change Frequency

Sometimes a small change in frequency might help a bit if the interference is limited to certain frequencies. Another tip is to try another band. That is, if you are getting interference on 2 meters, you may find that the 70 cm band is better. Or vice versa. It all depends on the transmitters at the site.

73 Bob K0NR

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Congratulations to my wonderful spouse and favorite hiking partner, Joyce/K0JJW, for achieving Mountain Goat status for Summits On The Air (SOTA).

On August 10th, she reached 1000 activator points while activating Pikes Peak (W0C/FR-004).  She had quite the pileup on 146.55 MHz.  Her best DX for the day was WY7ATH near Cheyenne, WY at a distance of 167 miles. Not bad!

Early on, she always hiked with me on SOTA activations but didn’t start pursuing activator points until the middle of 2017. All of her SOTA contacts have been on the VHF/UHF bands, lots of 2m FM along with 2m SSB, 70 cm and 23 cm FM.

Joyce has activated 181 summits, 112 unique in 19 associations.
She is the second female Mountain Goat in Colorado (after Lynn/KC0YQF) and is the eighth female goat in North America.

73 Bob K0NR

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The QSO Today Ham Expo is an exciting event that takes the fun of an amateur radio convention online!

Congrats and thanks to Eric/4Z1UG who conceived the idea and took the initiative to make it happen.

I was pleased to participate in the event, talking about Having Fun With VHF. In case you missed it, here is the video of my presentation.

Slides are here: Having Fun With VHF – Bob K0NR slides

73 Bob K0NR

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I often get asked questions about the band plan for 2 meters (144 to 148 MHz). Usually, this is about choosing a suitable simplex frequency, because the repeater frequencies are already coordinated and visible.

I’ve written about 2m band plans before. This article attempts to cover the topic in a way that applies to all of the US. This is actually a challenge because VHF/UHF band plans are regional in nature.

What Frequency Do I Use On 2 Meters?

I also wrote this article which is specific to the state of Colorado.

It is always best to check your local VHF band plan, usually supplied by the frequency coordinating body for your area. Typically, their main focus is coordinating repeaters but simplex frequencies are also listed.  Most frequency coordinating bodies kind of follow the ARRL 2m band plan, while adapting it for local use.

Channel Spacing: 15 kHz or 20 kHz

A big issue for the 2-meter band is that some areas have adopted a 15-kHz channel spacing while others use a 20-kHz channel spacing.  A typical FM signal is about 16 kHz wide, so the 15 kHz channel spacing is a bit tight but does allow for more channels (resulting in more adjacent channel interference issues). The 20-kHz spacing is “cleaner” but with fewer channels.

This map from the ARRL web site shows the channel spacing in use across the various states.

The channel spacing is driven by factors associated with repeater coordination, and simplex usage tends to adopt the same spacing. (There is no technical reason that simplex has to use the same channel spacing as the repeaters but that’s what usually happens.)

Some repeater coordinating organizations have done a good job of prescribing FM simplex frequencies. The Colorado 2m band plan (called the Frequency Use Plan) lists each simplex frequency individually.  The Illinois Repeater Association uses a similar approach: Illinois 2m Band Plan. The Southeastern Repeater Association (SERA) 2m band plan is also very specific. Note that the SERA band plan indicates that some of the usual 2m simplex frequencies may be used as repeater pairs — an example of a local decision on frequency use.

The Arizona 2m band plan shows a range of frequencies to be used for FM simplex, such as 146.400 – 146.600 MHz along with a note that says the Even 20 kHz Frequencies should be used. So that means the preferred simplex frequencies in this range are 146.40, 146.42, 146.44, 146.46, 146.48, 146.50, 146.52, 146.54, 146.56, 146.58 and 146.60 MHz. Some repeater coordinating bodies just give the frequency segment allocated to FM simplex and don’t mention the channel spacing. And some organizations don’t say anything about FM simplex so you have to figure them out on your own.

Recommendations

So what do we make of all of this? When it comes to 2m FM simplex frequencies, try to find your local band plan. If it recommends 2m FM simplex frequencies, then follow that guidance.

If that doesn’t work, look at the map above to determine if your state uses 15 kHz or 20 kHz spacing. Then follow the guidance in the HamRadioSchool.com article: What Frequency Do I Use on 2 Meters?

In all cases, remember that these are shared frequencies so you need to cooperate with other radio hams. If you bump into existing activity, go ahead and try another frequency. There are usually plenty of quiet simplex channels around.

The one simplex frequency that everyone does seem to agree on is the National Simplex Calling Frequency: 146.52 MHz. For some thoughts on how to use that frequency see: The Use of 146.52 MHz.

I do think that frequency coordination bodies would be wise to provide guidance on simplex channels. This is not frequency coordination but it helps the amateur radio community be more effective in using the spectrum.

73 Bob K0NR

The post Simplex Channel Confusion on 2 Meters appeared first on The KØNR Radio Site.

McQuaid Butte (W0C/SP-019) is a 9043-foot mountain near our cabin in Park County. Joyce/K0JJW and I activated it for Summits On The Air (SOTA) way back in 2013 but for some reason, we had not been back to it. The access road (Salt Creek Road, FS 435) is gated closed from January 1 to June 15 to protect wildlife habitat, so I suppose that is a factor.

Today, we decided to make a return trip to the summit and activate it on VHF/UHF. I remembered that Salt Creek Road can turn into a muddy mess but today it was dry and easily drivable with most vehicles. Salt Creek Road is accessed from Highway 285, south of Fairplay but north of Antero Junction.

There is a good parking spot shown on the map above at 38.95791, -106.00790. A trail begins here, heading east. It used to be 4WD road but it is now closed to motor vehicles. This trail/road heads east and then curves to the north and eventually disappears. About that time, you’ll encounter a fence that needs to be crossed as you make your way towards the summit (approaching from the west). There are pieces of a trail here and there but its mostly bushwacking up the side of the summit. In places, there is substantial downed timber that can be stepped over and around but its mildly annoying.

Our route turned out to be 1.3 miles one way with 650 vertical feet. We both quickly made enough QSOs to qualify for activator points, working W0BV, KD0MRC, K0MGL, WZ0N on 2m FM (and some on 70 cm). The weather was excellent, resulting in a fun SOTA activation in the Pike National Forest.

We will probably return again to this summit because it’s a nice hike that is easy to get to from our cabin.  It would also be a great choice for someone passing through on Highways 24 or 285.

73 Bob K0NR

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In 2018, Joyce/K0JJW and I did a trip to the Black Hills area of South Dakota to do some SOTA activations:  Dakota SOTA Adventure.   We really enjoyed that part of South Dakota and figured we would be back. The Black Hills top out at ~7200 feet and the climbs are usually interesting but not very difficult. There are plenty of SOTA summits to choose from and the scenery is beautiful.

This summer we found ourselves on a road trip returning to Colorado from Wisconsin, so we decided to swing by South Dakota for a couple of days. Joyce is getting close to achieving the coveted SOTA Mountain Goat award (1000 activator points), so we were looking to add to her activator score. I’m not saying we only did easy summits but we pretty much did easy summits.

Looking at the SOTA database, we scanned for summits with 6 points or higher that also had a significant number of activations. On this trip, we were driving our Class B RV (basically a big honkin’ van with RV gear in it). This limited our choice of SOTA summits to ones that can be accessed via reasonably good roads. We were fine with the typical gravel US Forest Service road in good condition but not anything worse.

We connected up with Don/K0DAJ who we met at a hamfest in Loveland, CO earlier this year. Don reviewed my list of potential summits and provided valuable feedback and additional summit suggestions. Don also alerted the local hams that might want to get on the air to work us. We use VHF/UHF exclusively for SOTA, so it is easy to get skunked if there isn’t anyone around. (I found out later that Gary/KT0A also passed along the word for us.)

The SOTA Summits

We identified seven summits that we wanted to activate, which would provide 56 new activator points. They ended up being clumped into three northern summits, around Deadwood, and four southern summits southwest of Rapid City. We camped at a USFS campground in between the two clumps, activating the northern three on the first day and the southern summits on the second day.

Terry Peak (W0D/NW-002)

Terry Peak is a drive-up mountain with a short hike up to an observation platform.  We approached Terry Peak from the south on Terry Summit Road, off of Hwy 85/Hwy 14A. The Black Hills National Forest map is very helpful for finding all of these summits.

We discovered that Terry Peak is quite the tourist spot and several groups of people showed up while we were there.  It is also a big radio site with over a dozen towers and many more transmitters. When we parked, I noticed that the VHF/UHF mobile transceiver in the RV had both S meters pegged at full scale on all frequencies. Rut Roh, there is probably some RF around here. As usual, we had the Yaesu FT-90 transceiver which has a robust receiver in it, and it performed well. Still, I noticed that strong signals would abruptly drop down to being almost unreadable when some transmitter on the site turned on.

Mount Theodore Roosevelt (W0D/NW-023)

Mount Theodore Roosevelt turned out to be a pleasant surprise with a really good trail to the summit (0.4 miles one way, less than 200 feet elevation gain).

Also, at the summit, there is a tower that was built in honor of President Roosevelt. This is a fun little hike with a monument at the summit.

We climbed the stairs leading to the top of the tower and operated from inside it. The tower reminds me of the many lighthouses we’ve been inside, but it’s not nearly as tall, and no light.

Unnamed Summit – 5110 (W0D/NW-038)

For a third summit, Don suggested an easy-to-access unnamed summit (5110), W0D/NW-038. We got there by driving south from Sturgis on Vanocker Canyon Road (26), then west on Galena Road to USFS 171.1. Driving a short distance north on 171.1 got us to an open area where we parked. Then it was just a bushwack up the hill (no trail), 0.3 miles one way with an elevation gain of 400 feet.

Day 2 was a repeat of summits that we did in 2018, so I won’t repeat all of that here: Odakota Mountain (W0D/BB-002), Bear Mountain (W0D/BB-029), Coolidge Mountain (W0D/BB-012) and Rankin Ridge (BB-089). Refer to the 2018 trip report for more info.

This time, Odakota Mountain was extra special because Don/K0DAJ joined us on the summit.

There is an actual summit marker for Odakota, so I had to get a photo of me standing there.

Most of the contacts were on 146.52 MHz, a few on 446.0 MHz. Joyce’s log and my log are pretty much the same but I did work a few more stations. In summary, we had QSOs with these stations during the two days: AD0HL, K0DAJ, KB0QDG, KC0WC, KD0AYN, KF0AFX, KF0ARA, KF0XO, KF7ZQL, NC0K, W0LFB, W0NIL, W0SEB, W0SSB, W5LJM, W7LFB, WN6QJN and WS0V. Thank you to each and every one of you for getting on the air!

In Colorado, we pretty much work Colorado stations on VHF from the summits, so it was fun to contact other states on this trip. From Bear Mountain, we worked W0NIL and W0SSB in Chadron, NE, about 90 miles away.  Not too shabby. From Terry Peak, we worked Clem/KF7ZQL in Carlile, WY at a distance of 50 miles. Not as far, but another state in the log.

We caught AD0HL and KF0ARA on unnamed summit 6167 (W0D/BB-008) from both Odakota Mountain and Bear Mountain, for two Summit-to-Summit (S2S) contacts. We also got two S2S contacts with Don/K0DAJ:  Crooks Tower from Terry Peak and Terry Peak from Mount Theodore Roosevelt.  It was kind of an S2S festival!

Don/K0DAJ and Terry/AD0HL worked us on 6 of the 7 summits, so they were our most prolific chasers. Thanks, guys! Finally, special thanks to Don for the helpful advice and joining us to play radio in the Black Hills.

We were able to get our minimum 4 QSOs on each summit and usually had many more. This resulted in 56 activator points, so we are quite happy with that.  We have just sampled a few of the many SOTA summits in the Black Hills area, so I suspect that we will be back for more.

73 Bob K0NR

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