For decades, Joyce/K0JJW and I have working towards visiting all 63 of the US national parks. We are nearing the end of the list, with just a few parks left. One of the most challenging places to visit is the National Park of American Samoa, located in the only US territory south of the equator. That would be number 61 for us, with only Crater Lake NP and Lassen Volcanic NP left to visit.

Obviously, if we are going to travel to a distant island, we should consider doing a Slacker DXpedition. American Samoa is a US territory, so FCC radio licenses are valid there. It is also a separate entity for DXCC, with the prefix KH8. KH8 is listed at #87 (out of 340) on the Most Wanted list at Clublog, so it is a bit rare in terms of DXCC. Parks On The Air (POTA) has already been set up for KH8 and the national park there has been activated a number of times. I checked into the Summits On The Air (SOTA) situation and discovered there were summits that qualified for the program, but that a KH8 Association did not exist. The next thing you know, I am the KH8 Association Manager working with the SOTA Management Team to establish the KH8 association.

Travel

We usually try to pack light when traveling. On a typical airplane trip, we can generally get by with each of us having one carry-on bag. But once you add snorkel gear, camera gear, binoculars, hiking boots, radio gear, and a few other items, it becomes necessary to check a bag — or two. Still, we focused on keeping the amount of luggage to a minimum so we could navigate the airports without assistance.

To get to KH8, we connected through Hawaii, to catch the main flight to Pago Pago on Hawaiian Airlines. This flight only goes two or three times a week and is the only option coming from the 48 states. We decided to enjoy four days on the island of Kauai, which turned out to be an excellent idea.

Radio Gear

We normally only use frequencies above 50 MHz for SOTA, but given the lack of VHF activity in KH8, we compromised and took along HF gear. Our Icom IC-705 is a good choice for that as it also has the VHF/UHF bands included. We also packed a pair of handheld radios, which were useful for basic communications on and off the trail.

We had two main radio setups: a backpackable station for SOTA and a higher power station for POTA. Scoping out our likely SOTA summits, we definitely needed a compact station that could be carried up some summits that would involve a challenging hike. For this station, we used the IC-705 (10 watts output) driving an end-fed multiband wire antenna from PackTenna, supported by a carbon fiber fishing pole. The IC-705 does not have a built-in antenna tuner, so a small, manual external tuner did that job. A Bioenno 4.5 Ah battery supplied the power to the radio.

The antenna system travels in a small pouch and consists of the Z-match tuner, RG-174 coaxial cable, and the end-fed wire antenna. The antenna can cover 30m up through 10m, using a tuner, so it was an efficient way to cover the bands we planned to use.

With the remote location and QRP power levels, we concluded that SSB might be a limitation. Our solution was to utilize digital modes (FT8 and FT4) to enhance our weak-signal performance. I sometimes operate CW, but I don’t think I can handle the pileups we expected at KH8. Joyce doesn’t do CW at all. Our plan was to use my Windows laptop, running WSJT-X, for digital processing. I would have taken this computer along on the trip anyway, so it made sense to have it do double duty, even though it’s a bit large to carry up the summit—more on that below.

POTA Station

We could have used the SOTA station for POTA as well, and we did in a few situations. However, we opted to take along a Yaesu FT-991, with 100 watts output, thinking that would help us when running SSB and if band conditions are poor. This is our normal POTA radio, powered by a 20 Ah Bioenno battery that can supply 30 amps continuously, providing a decent margin for the FT-991 (max current spec is 23 amps). However, FAA regulations don’t allow large batteries to be taken on an aircraft. I am used to carrying smaller batteries while flying, so this was all new to me. The short story is that you can carry on two lithium batteries, each limited to 160 watt-hours. (Read the regulations carefully yourself to understand the fine points.) For a 12-volt battery, 160 watt-hours corresponds to 13 amp-hours. So maybe I could carry two 13-amp-hour batteries and get by with that. Well, the Bioenno battery, which is the closest in size (12 amp-hour) has a maximum continuous discharge of 20 amps, which is a little light for the FT-991 keyed down at full power. I was also worried about the battery capacity and how long we would be able to operate. (In retrospect, this approach might have worked and deserves further consideration in the future.)

Another option was to take an AC power supply along, which might have been useful, but AC power was not likely to be available at a typical POTA spot. Ultimately, our solution consisted of a power cable with battery clips that connect to the battery in our rental car. We already had our radio gear set up with powerpole connectors, so crafting a cable with battery clips and powerpoles on it did the job. From experience, I know that it is possible to get excited about making radio contacts and overlook the fact that your car battery is now depleted. To avoid this, I inserted a 12-volt power analyzer inline with the DC cable, allowing us to monitor the battery voltage. I was vigilant in monitoring the voltage and running the car engine regularly.

Rounding out the POTA station were two 25-foot lengths of RG-8X coax and an end-fed long wire antenna from MyAntennas. This antenna was needed to handle the higher power level of the FT-991. For antenna support, we used a SOTABeams 32-foot Travel Mast.

The National Park of American Samoa is POTA AS-0001. This park had already been activated 33 times, primarily by KB2FMH and KH8RRC. There are two other POTA parks in KH8 (both unactivated), but we did not operate from them.

Alerts and Spots

Our operating schedule was fluid, so we used the SOTA and POTA websites to post our activations once we decided to go out,  and to spot ourselves once we were on the air. Some of this could be done from our hotel room using an internet connection but at the operating location, we typically did not have a network connection.

We did have a Garmin Inreach satellite communicator that works anywhere on the planet, so we sent messages via the SOTAmat system. This requires some preplanning to set up access and learn the system but it performed well. The only disadvantage to this method is that Inreach messages can take 5 or 10 minutes to send, depending on when the satellite passes over.

Summits On The Air

Complete KH8 SOTA information can be found here in the Association Reference Manual:
https://www.sotadata.org.uk/en/association/KH8

There are 11 SOTA summits in KH8. Many of these are not accessible due to rugged terrain and dense tropical vegetation. The most accessible summits are listed below. See the SOTA database for more information and specific activation tips. In all cases, assume the trail condition can change and inquire locally for the latest information.

Tutuila Island

Olotele Mountain (KH8/TI-004) – Drive Up Summit.
Olotele Mountain is a developed radio site with multiple towers on it. There is a single-lane paved road to the top, making this a drive-up summit. This is the easiest summit in American Samoa. It is NOT in the national park.

Mount Alava (KH8/TI-003) – 3.9 miles one-way, 1300 vertical feet, in the national park.
This is a well-known summit and hiking trail, promoted by the national park. The trailhead is relatively well-marked, starting at Fagosa Pass. This trail used to be a road, generally wide but overgrown in spots.

Matafao Peak (KH8/TI-001) Steep trail, 1500 vertical, 1.5 miles one way
The highest summit in American Samoa. There are widely varying reports on whether the trail to the summit is hikeable or not. Trailhead is at Fagosa Pass. We did not attempt this summit.

Ofu Island

Tumu Mountain (KH8/MI-003) 3.0 miles one-way to the summit with 1500 feet of elevation gain. This trail used to be a road, generally wide but overgrown in spots, rope assist in one spot.

Let’s Go!

So that was the basic plan. Fly to Hawaii, hang out there for a few days, then continue on to American Samoa. Activate a few summits on Tutuila and then travel to Ofu Island to activate one more. Interspersed would be POTA activations, lots of snorkeling, and sightseeing.

More to follow in Part 2.

73 Bob KH8/K0NR

Side Note: Kauai SOTA

We were not focused on SOTA in Kauai, but I looked up what summits were available and discovered the answer to be quite straightforward. Out of the 11 SOTA summits on the island, only one has been activated: Nounou Mountain (KH6/KU-011). The rest are very difficult to access.

So Joyce and I decided to do the summit. As advertised, the trail turned out to be muddy and had some difficult sections requiring some minor rock scrambling. The weather was hot and humid, making this a good warm-up for KH8. In particular, I discovered that my SOTA station had serious EMI problems. I thought I had worked this out back home, but my notebook PC was producing a high level of noise that was interfering with the receiver, and the RF from the transmitter was disrupting the USB data connection. This messed up the activation of Nounou, but it caused me to work on the problem before arriving in KH8.

The workaround I came up with was to use my iPhone with the SDR-Control Mobile  app, connecting to the IC-705 via Wi-Fi. This eliminated the need for the USB cable, which was acting as an EMI radiator. The iPhone display is relatively small for running FT8, and the app has a few anomalies, but it did the job. On the plus side, the iPhone is a lot less to carry up a summit.

The post KH8 SOTA/POTA (1) – The Plan appeared first on The KØNR Radio Site.

Today, Joyce/K0JJW and I activated Kaufman Ridge (W0C/SP-081). This was my 10th activation of this summit and the 8th for Joyce. Kaufman is an easy summit near our cabin, so it is a favorite when we want to do a Summits On The Air (SOTA) activation. I’ve posted about how to activate this summit in the past, but a few things have changed over the years, so this update seems appropriate. Because of the off-trail hiking, we always seem to take a different route each time, but the specific route is not critical. We have learned a few things to avoid on the hike, which are reflected in this post. The one-way hiking distance is about 1.4 miles with 1000 vertical feet.

Getting There

There is no trail and no trailhead. To reach the recommended parking spot, turn south at the top of Trout Creek Pass and follow Windmill Drive (also marked as County Road 318) southeast to San Isabel National Forest. As you enter the forest, you will be on FS318, which has a gate normally closed from Dec 1 to Apr 30. You can still activate the summit when the gate is closed, but you’ll have to hike in on the road.

Pass through the gate going south on FS318 and take a sharp left (almost a U turn) onto FS308. Later, turn right onto a side road, FS308B, which should be marked. Drive a short distance on FS308B until the road is closed to motor vehicles. These roads are easy 4WD and high clearance 2WD will probably work fine. The FS road continues but is closed to motor vehicles at this point. There is a dispersed campsite here, so you may encounter campers. Park here at 38.85979, -105.93318.

The Hike

The hike up Kaufman starts on the old Jeep road, which is easy to follow. Later, this road ends, and the off-trail hiking begins. In the past, we’ve tried just heading straight for the summit (which works), but it can take you into significant downed timber and difficult rocky areas. It is better to head due south, hook around to the west and approach the summit from the east/southeast as shown on the map. This avoids the large aspen grove directly NE of the summit, with lots of downed timber.

There is a medium-sized rock (maybe 2 by 2 by 3 feet) sitting in the open that is a useful landmark to aim for. This waypoint (The Rock) is particularly useful for orienting yourself on the descent. Keep heading south past The Rock and turn slightly southwest toward a ridge that runs NW/SE from the summit. A good place to intersect this ridge is marked as the waypoint Trail on Ridge. Here you will intersect a game trail that runs along the ridge, which you should follow to the summit. This waypoint is also useful on the descent, to let you know when you need to leave the game trail (which continues on SE for a while).

Once you get onto the ridge, you will have a fantastic view of the Collegiate Peaks to the west. A cairn is at the summit with the typical summit register in a jar.

We had a fantastic time today on the summit. Great spring weather, blue sky with a few clouds. We worked a number of stations on 2m and 70 cm: KF0RIG (On Spinney Mountain, W0C/SP-118), KD0MRC, K8QWR, W0XC, K0MGL, K0LTH, W5PYB (mobile), W0BV, K0PF (mobile), and KD0RRD (mobile).

73 Bob K0NR

Waypoints
End of Old Jeep Trail (38.85545, -105.93519)
The Rock (38.85545, -105.93519)
Trail on Ridge (38.84937, -105.94055)
Summit (38.85050, -105.94280)

The post Activating Kaufman Ridge (W0C/SP-081) appeared first on The KØNR Radio Site.

Its a big issue, and great articles, along with our regular columnists.

Now read in over 165 countries, this issue brings you 120+ pages of Amateur Radio content from the Southwest corner of Canada and around the globe. With less fluff and ads than other Amateur Radio publications, you will find Amateur Radio related articles, projects, profiles, news, tips and how-to's for all levels of the hobby.

Download the May-June 2025 Communicator in 
LARGE or SMALL format, or read it on-line like a magazine

Previous Communicator issues:

Search for past Communicator issues

We now have a comprehensive searchable index back to 2007
HERE.  

As always, thank you to our contributors, and your feedback is always welcome. 

The deadline for the next edition is June 15th.

If you have news or events from your club or photos, stories, projects or other items of interest from BC or elsewhere, please contact us at [email protected]

73,

John VE7TI
'The Communicator' Editor

The Table of Contents for the May-June 2025 Communicator issue:

Planning for the special event stations commemorating the life-saving food drops to NW Netherlands near the end of World War II is now in full swing. 62 nationalities were part of Bomber Command in WW2.

Please visit Operation Manna @ 80 for a full list of stations around the globe. Here are the Canadian stations participating:

VB7MAN Surrey Amateur Radio Communications

In Canada, Surrey Amateur Radio Communications (SARC) has been granted special event callsign VB7MAN from April 1^st to May 10^th. We will be on the air from our training station and elsewhere prior to, during, and after the event and will seek involvement of the high school students from our RF Communications class. Contacts with Europe can be sporadic from our location but we are generally able to contact North and South America, Asia, and Oceania. We have created a QSL card to commemorate the event. The card bears the $100 Royal Canadian Mint gold and silver coin struck in 2020 for the 75^th anniversary. 

We will update this page as plans progress but hope to make a QSO with you in April or May. Any certified amateur in BC may operate the special event callsign, as long as it is only used in one location at a time. If you wish to use the call on any band or mode, a Google calendar has been set up to reserve the call for your use between April 1st and May 10th. If you wish to book an operating time for VB7MAN, please contact [email protected].

John VE7TI
Coordinator [email protected]

> 

VB6MAN Calgary Amateur Radio Association

CARA will be operating from the Bomber Command Museum of Canada in Nanton, Alberta. They will activate on April 25, 26, and 27th and May 9 and 10. The final dates and hours of operations will depend on the radio amateur operators participating.

> 

VE1MAN Nova Scotia

The Canadian teams closest to Europe will be operating from their club station as VE1MAN. They may be activating from a former WW2 air base or another location of significance to tie in with the event.

Radio Amateurs of Canada published an article about MANNA@80 in the March-April issue of The Canadian Amateur, as did the Radio Society of Great Britain in their national magazine RADCOM.

~

At first, I was just looking around on the web for some simple Rules of Thumb that compare the weak-signal performance of commonly used analog and digital modulation types. I was mostly focused on FT8 and FT4 but I also wanted to compare SSB and CW. I failed to find a simple comparison of these modes but I did find a number of good articles that compared some but not all of them. This article is my attempt to aggregate the available information into something easy to understand.

Disclaimers

I decided to leverage the work of others and to not try deriving everything from basic principles. I am telling myself that I am perfectly capable of doing the analysis but that I would never find the time to actually complete it. (Yeah, that’s my story, and I’m sticking to it.) Where the articles disagree, I tried to identify which one(s) had the most convincing analysis or rationale and used those values.

My goal is to compare common modulation types primarily in terms of weak-signal performance. This means focusing on how well a signal can be detected with low signal-to-noise ratio (SNR). I have ignored other factors, such as signal fading, frequency drift, multipath distortion, etc. Also ignored are factors such as the information rate provided by the modulation type and the required signal bandwidth. This is focused on having the ability to pass just enough info to make the contact.

Literature Survey

Searching the internet provided me with a number of good articles that have examined this topic, listed below in the References section. My approach is to compare the results of these articles and aggregate them into a concise summary. These minimum SNR values are listed in the table shown below, along with my aggregated conclusions in the righthand column.

Most of these articles presented SNR data in terms of a 2500 Hz bandwidth, with the goal of providing an easy comparison between modulation types. SSB is the widest signal discussed, and it roughly fits into a 2500 Hz bandwidth, which is often the IF bandwidth of the receiver being used. Some authors make this explicit by tagging this SNR as SNR2500.  It is common practice in communications work to normalize the bandwidth to 1 Hz, which indicates the modulation’s bandwidth efficiency. However, we’ll stick with SNR2500.

I started with the article by PA3FWM [Ref 1], which provides a look at many of the modes I was interested in comparing. Unfortunately, this article does not include FT4 and FT8. N6MW [Ref 2] has a good treatment of FT4 and FT8 as well as minimum SNR values for SSB and CW. These lined up well with the PA3FWM values, so that was a good sign. N6MW referenced the foundational article about FT4 and FT8, published in QEX, written by the FT4 and FT8 developers [Ref 3]. The KB9II article [Ref 4] focuses on VHF weak-signal performance and provides minimum SNRs for SSB, RTTY, CW, and PSK31. He introduces the concepts of SNR (average) and SNR (peak). I used the SNR (average) numbers in the table. The KF6HI [Ref 5] article provided another set of SNR values that lined up pretty well. Finally, I came across a presentation by K0LB and KK4SNO [Ref 6] that includes a slide summarizing SNR performance. Because it is slideware, it does not include much about the sources of their numbers, but it seems useful to include them in the table.

The authors have somewhat different approaches to determining their SNR2500 numbers, mostly related to the assumptions used. You may want to read through these papers to gain a better understanding of the fine points. Overall, there is good alignment on results, with a few exceptions.

SSB

The single-sideband SNR2500 values are a mix of 10 dB and 6 dB. Frankly, I think 10 dB is a bit high for “minimum SNR” because I’ve spent quite a bit of time making weak-signal VHF/UHF contacts with the signal right at the noise level. I’ve squeezed out radio contacts with SNR much less than 10 dB. I looked at the rationale supplied in the articles for this value and it is mostly just assumed. So I went with my own experience and chose something smaller, 6 dB, aligning with KB9II and KF6HI. Even this number might be a bit conservative.

RTTY

I found only four values for RTTY, and they vary quite a bit. After studying the articles, I judged KB9II to have the best justification, so I went with -9 dB. I suspect that the actual decode performance may vary depending on the type and quality of the detector.

CW

The SNR2500 numbers for CW varied significantly, over a range of 10 dB. One way to estimate CW performance is to use the bandwidth of the receiver and compare it to 2500 Hz. Using a typical CW filter bandwidth of 200 Hz, SNR2500 = 10 log (200/2500) = -11.0 dB. However, it is well-known that the human ear/brain combination provides additional signal processing. The classic article by W2RS [Ref 7] covers this topic quite well. Using actual on-the-air tests, the article explains that the skill of the operator can introduce a variation of 3 to 6 dB. Another interesting note is that if the operator knows in advance the type of information they are expecting (such as the callsign of the other station), it provides a 3-dB advantage.

We can and probably will debate the SNR2500 value for CW until the cows come home, but I decided to adopt -12 dB in the right-hand column. This is probably conservative for a highly skilled operator.

FT8, FT4

For FT8 and FT4, I used the N6MW values, which come directly from the FT4 and FT8 paper [Ref 3]. I rounded off to the nearest decibel to be consistent with the rest of the column.

JT65

The JT65 values are quite consistent. An article by K1JT [Ref 8] says JT65 SNR is “roughly -28 to -24 dB in 2500 Hz,” so I put -24 dB in the righthand column.

WSPR

WSPR is a popular beacon mode and the king of weak-signal reception. Signal reports are collected worldwide and shared via WSPRnet.org. WSPR performance will vary depending on the specific settings used on the software and we have some variation in the table. The K1JT & W1BW article [Ref 9] says, “The WSPR protocol is effective at signal-to-noise ratios as low as –28 dB in a 2500 Hz bandwidth, some 10 to 15 dB below the threshold of audibility.” So I used -28 dB in the aggregated column.

Conclusions

The rightmost column in the table provides a reasonable comparison of the listed modulation types. I don’t claim that the values are perfect, but they should be helpful in understanding the performance of these modes. These data show that SSB is the least sensitive mode, followed by RTTY and PSK31. As mentioned earlier, the CW number is open to debate but it performs better than RTTY and PSK31. This brings us to FT4 and FT8, which are commonly used WSJT protocols with reasonable throughput. (FT4 and FT8 using 7.5 and 15-second transmit/receive intervals.) JT65 operates at lower SNR, but it is really in a different category, It is designed for Earth-Moon-Earth contacts, using one-minute intervals. WSPR is also unique as a beaconing system and not designed for two-way radio contacts, but it does have the best SNR performance on the list.

When using this data, keep in mind that most of these modes degrade slowly so there may not be a sharp cutoff at an exact signal level. The values are Rules of Thumb, accurate to within a few dB.

Thanks to Jim/K5ND and Bob/WØBV for reviewing this article and providing feedback.

73 Bob K0NR

References

1. Signal/noise ratio of digital amateur modes – Pieter-Tjerk de Boer, PA3FWM

2. FT8 Modulation and Decoding – A Dive into SNR interpretation N6MW

3. The FT4 and FT8 Communication Protocols – Steve Franke, K9AN- Bill Somerville, G4WJS – Joe Taylor, K1JT

4. A Comparison of Common Digital Modes for Weak Signal VHF Communications – John Matz, KB9II

5. Signal to Noise Ratio, definition and application to Radio Communications – KF6HI

6. Digital Modes in Amateur Radio – Larry, K0LB and Scott, KK4SNO

7. The Weak-Signal Capability of the Human Ear – Ray Soifer, W2RS

8. EME with JT65 – Joe Taylor, K1JT

9. WSPRing Around the World – Joe Taylor, K1JT, and Bruce Walker, W1BW

The post Weak-Signal Performance of Common Modulation Formats appeared first on The KØNR Radio Site.

You will find some great articles in this issue, along with our regular columnists.

Now read in over 165 countries, this issue brings you 115+ pages of Amateur Radio content from the Southwest corner of Canada and around the globe. With less fluff and ads than other Amateur Radio publications, you will find Amateur Radio related articles, projects, profiles, news, tips and how-to's for all levels of the hobby.

Download the January - February Communicator in 
LARGE or SMALL format, or read it on-line like a magazine

Previous Communicator issues:

Search for past Communicator issues

We are working on providing you with a comprehensive searchable index,
but in the meantime a searchable topic index is HERE.  

As always, thank you to our contributors, and your feedback is always welcome. 

The deadline for the next edition is April 15th.

If you have news or events from your club or photos, stories, projects or other items of interest from BC or elsewhere, please contact us at [email protected]

73,

John VE7TI
'The Communicator' Editor

The Table of Contents for the March - April 2025 Communicator issue: