Category Archives: Education and Training

Education and Training information is for folks looking for help to earn or upgrade their license, learn about Amateur Radio, and get help with Ham Radio questions.

My Portable Gear and Organizing for a POTA Event

One of the problems I face when I think of doing a POTA activation is what to bring and how best to organize my gear so I have what I need. The easiest thing to do is consider what you MUST have in your POTA equipment cache. Secondly, list the necessities to get your station on the air in the field. If you forget to bring the manual for your transceiver, some coax adapters, or various lengths of complete jumper coaxial cables, it might make the difference in whether or not you get on the air. I have two ‘bags’ plus my accessory bag containing everything I need to get up and running.

The first ‘bag’ is a hard case for my HF rig, VHF/UHF HT, power source, microphone, keyer, and antenna analyzer. Also included in this case are the operating manuals for the HF rig, the VHF/UHF HT, the power source, and the antenna analyzer.

The second ‘bag’ contains my antenna and coax. Within the confines of this small bag is my “Super Antenna” vertical, the precut-tuned radials from 80m through 10m. A mounting tripod, a ground spike antenna mount, a locking plier with a 3/8” to SO-239 connector welded to it, an HF frequency chart, and a 25’ length of RG-8X coaxial cable with PL-259 for the connection to the antenna end and a BNC connector on the other end for the input to my KX2 Rig. Plus, the tools to set the antenna up and set adjustments.

My accessory bag has various items I have sometimes seen needed on a portable radio setup. Although I am new to the POTA activations and hunting them, I have operated from many field locations in my 66 years as a ham radio operator.

MY GO-BOX CHECKLIST:

  • POTA Gear
    Elecraft KX2

    Elecraft KX2 w/KXPD2 keyer paddle & MH-3 Mic

  • Wouxon UV3D 2m/70cm HT & Whip Antennas
  • FlashFish 200W Solar Generator
  • Heil BM-17 earphones
  • Vibroflex Vibrokeyer CW paddle
  • AA-30 Antenna Analyzer
  • Solar-powered clock/thermometer
  • LED Light powered by Solar Generator
  • Frequency Reference Guide
  • Mini Log Book
  • FCC License
  • Elecraft KX2 Manual
  • FlashFish Solar Generator Manual
  • AA-30 Antenna Analyzer Manual 

MY ANTENNA GO-BAG LIST:

MP1C Super Antenna includes:

  • TM1 Low-Profile Tripod
  • UM2 Universal NVIS Super tilt Clamp Mount
  • SW1 Titanium Super whip

    POTA Gear
    MP1TRDX80 Superantenna
  • SP3 Super Spike Ground Mount
  • MC80 80-Meter Coil
  • MR Super Radial Sets = (40m-10m); (30m-17m); (80m-75m); (6m-4m-2m)
  • FG1 SWR Ruler
  • GB2 Super Go Bag
  • ER1 Extension rods
  • TW1 Telescopic Whip
  • PC1 HF Propagation Chart
  • Clamp and U-Bolt

Tools:

  • Hammer
  • Allen wrenches
  • Long-nose pliers/wire cutters
  • Adjustable crescent wrench

Extra Antenna items:

  • Locking pliers with 3/8”- SO-239 fitting
  • ~ 90’ of Extra flexible antenna wire
  • SIZE: The antenna extends to about 8ft tall. Collapsed Size: 12 inches. Go Bag Size: 13″x9″x3.5″ WEIGHT: The antenna weighs 1 pound. The antenna with accessories in the Go Bag is about 5 pounds. Maximum Power Rating: 500W SSB, 300W CW/DATA.
  • FREQUENCIES: ALL BANDS 80m, 75m, 40m, 30m, 20m, 17m, 15m, 12m, 11m, 10m meters (3.5MHz to 4.8MHz and 7MHz-30MHz) HF, plus VHF 6m (30MHz-54MHz) with a good SWR. Continuously tunes all frequencies: Marine, Government, NGO, CAP, MARS, EmComm, Shortwave, CB, etc. Direct Manual Tuning SuperSlider Coil, with Good SWR.
  • ANTENNA: The MP1C Antenna is at the heart of this high-performance system, with its high Q coil made of military-grade nickel beryllium resulting in repeatable precision.
  • TUNING: The FG1 Frequency Guide SWR Ruler calibrates a rigid polymer card in MHz and meter bands. With it, a good SWR is dialed in on all HF and VHF bands and then fine-tuned with my AA-30 Antenna Analyzer. There’s no need for an autotuner, but it can help extend the frequency range.
  • SUPERWHIP: The included SW1 ruggedized Titanium SuperWhip puts the Super Antenna in a ruggedized durability class beyond most regular ham antennas.
  • TRIPOD: The collapsible TM1 Low-Profile Tripod enables the antenna to be set up on any convenient flat surface, outdoors or indoors. 

ACCESSORY BAG CONTAINS:

  • 30-watt soldering iron w/solder
  • 3M waterproof Super 88 electrical tape
  • 3’ 50-Ohm BNC/BNC Coax Jumper Cable
  • 2’ 50-Ohm PL-259/PL-259 Coax Jumper Cable
  • AA Battery Pack for Wouxon UV3D HT
  • Assorted VHF/UHF, BNC, and SMA adaptors
  • AC/DC Power supply for KX2 and External Lithium-Ion

Fast Charger for the KX2’s KXBT2 battery

  • Wouxon UV3D battery charger
  • Bongo ties
  • LED flexible lamp
  • Multimeter
  • RCA to twin RCA splitter cable
  • USB to Micro cable
  • 5mm to 2.5mm 6’ audio cable
  • Programming cable for Wouxon UV3D
  • USB cable with AC to 5 VDC adapter
  • 2-Meter flexible J-Pole antenna w/BNC/PL-259/SMA adapters
  • Mini-bud earphones
  • External battery for cellphone – 9.6-watt hours – 5VDC in/5VDC out
  • Wall-wart power supply charger for Solar Generator 110/240 VAC in/15.0 VDC out
  • Transient voltage surge suppressor
  • MFJ Model 281 ClearTone external 8-ohm 4” speaker
  • 25-watt dummy load
  • Extra 2m/440 whip antennas

When building the case for the KX2 and the other items, I chose a hard-sided, oversized briefcase instead of a Pelican Box. I reasoned that I didn’t see the need for that order of protection with the way I operate on POTA activations. History may change my mind, but it has been more than adequate to serve my needs so far. I bought the case at Harbor Freight for $40.00. It came with pre-sliced foam for the bottom and an acoustic-like foam rubber top panel. The precut foam made it easy to make exact-size cuts to insert my Solar Generator and the KX2. The divider strips came with breakable stops to make it easy to make custom-divided sections in the case. I made a door-like cut in the top panel, and with Velcro, it now serves as a storage area for my manuals and paperwork. The total weight is around 15 pounds when loaded. Most of that weight is attributed to the 200W Solar Generator, about 4 pounds alone.

POTA GearThe internal KXBT2 Lithium-Ion battery pack In the KX2 provides 11 VDC @ 2.6 Ah, giving you about 8 hours of operation. It slowly recedes in power as the voltage decreases. The Solar generator plugs into the DC input of the KX2. When the power is less from the Lithium-Ion battery than the Solar Generator output, the KX2 automatically switches to the more prominent voltage source. I have a 100-watt foldable solar panel that inputs to the Solar Generator. However, you can’t charge its battery while it is running. Multiple Charging Outputs on the Generator Provide More Options: Features with AC/ DC/ USB OUTPUTS: 110 VAC output (200W), 2 DC outputs, 2 QC 3.0 quick charge USB ports, and 1 USB port (2.4A auto). It provides 151Wh (40800mAh) to power your transceiver, smartphone, tablet, laptop, camera, light, drones, fans, in-car appliances, CPAP machine, and more anytime. Triple Rechargeable Modes = Efficient Solar Generator: FlashFish power station’s Lithium-Ion battery pack can be charged by a 15-24-volt solar panel (not included), AC wall adapter, and car charger efficiently. There is no memory effect and no worry about battery capacity reduction.

Other items worth bringing along for your activation should include a lightweight, foldable table and a comfortable folding chair. A pop-up canopy is also a good idea if the weather is too sunny or the weather turns to rain. With all this gear, you might want to invest in a foldable wagon to haul it to your chosen spot after leaving your car. They typically cost about $70, but you will also find many uses around your home for them caring for household chores and at hamfests carrying about your newfound ‘treasures.’

A solar-powered 24-hour clock set to UTC gives me the exact time and the corresponding UTC date whenever I log my QSOs in a paper log book.

I now bring a wireless ‘Hot Spot’ from my cellphone carrier on these POTA activations. I can run my logging program on my tablet and use the wireless keyboard. I can still be online because I’ll have an Internet source at a reasonably remote location in the ‘Great North Woods’ of New Hampshire, Vermont, or Maine.

Although not required, legally, having a photocopy of your FCC license handy or mounted somewhere on your Go-Box is a good idea. If law enforcement, park rangers, etc., question what you are doing, it usually alleviates their concern about your presence and actions once a Federally-issued license is recognized. If you are entering a State or Federally-owned National Park, it is always a good idea to ask the person at the entrance about your antenna and whether they have any rules about using the trees as a support source.

Always try your gear at home or a nearby field location before heading out on your outdoor radio adventure. Set it up approximately the same as you will at the POTA event. You will be better prepared after doing so and could benefit from any faux pas you encounter during this practice session.

73 es GL de Jack WMØG

Interpreting S-Meter Readings

Introduction

Most communication receivers and transceivers have S-meters, either analog or digital. We also know that there is a 50-ohm coaxial connector on the back of most receivers. What do S-meter readings mean in terms of the 50-ohm receiver input?

High Frequency (HF) < 30 MHz and Very High Frequency (VHF) > 30 MHz receivers work to different input signal level conventions. In other words, and to confuse matters, an S9 for HF is not the same as S9 for VHF.

Nearly 100 years ago, it was decided that S9 should be 50 uV at the receiver input. However, no input impedance was specified. A signal level of S9 was meaningless until the voltage level was standardized to 50 ohms by the International Amateur Radio Union (IARU) some 50 years later. Different voltage levels at the receiver inputs were adopted at that time for HF and VHF.

While S-meter readings are useful for signal reporting and logging, it is important to remember that S-meter readings are not perfectly linear, and linearity differs from receiver to receiver. It may depend a great deal upon receiver settings.

HF Receivers

Suppose that an HF receiver is displaying a signal of S9. We are told that this signal level is defined as a voltage of 50 uV (50 microvolts) at the 50-ohm receiver input connector. This does not tell us what the signal power is incident on the antenna because we do not know what the antenna gain is, what mismatches there are, and what any other gains or losses might be. We only know that a 50 uV signal is present at the receiver input and that the receiver is displaying S9. If we perform a little calculation, we arrive at the power level at the receiver input connector.

To convert this signal power to milliwatts (mW), we divide by 1E-03 or 0.001 since a mW is 1/1000 of a Watt.

There is another way to do this if we know that there are 1E+03 mW in a Watt. We can use dimensional analysis to arrive at the right answer.

We may now convert this value in mW to dBm.

So, a signal of S9 is equivalent to a signal power level of -73 dBm into a 50-ohm input.

Example 1

Bearing this in mind, what would the power level of a signal be for an S-meter reading of S1 in units of dBm?

The signal level at S1 is 8 S-units lower. If each S-unit adds or subtracts 6 dB by convention, a signal of S1 would be 48 dB lower than S9. Subtracting 48 dB, the signal at S1 would be -121 dBm.

Example 2

Suppose we are told that the signal input to the receiver reads S9+10 dB (10 dB over S9). What would the signal into the receiver be in units of uV?

We know that a signal voltage level of S9 is 50 uV into the 50-ohm receiver input. We already know that the signal power level of S9 is -73 dBm. Thus, if we add 10 dB, the signal power level would be -63 dBm (less negative). All that is left is to convert this power level back to uV.

Let’s convert this -63 dBm input signal level to mW. In order to do this, we must take the antilog of the input signal level.

Next, let’s convert mW to Watts by dividing by 1000

Finally, we convert to Volts using the formula

We can convert Volts to uV by multiplying by 1E+06

Since the impedance level for the 50 uV and the 158.3 uV input signals are both 50 ohms, we can check the result to see if it is 10 dB higher than our S9 signal of 50 uV. We notice that the 50-ohm impedance cancels when we take the ratio of the two power levels in

Example 3

What is the 50 uV signal in dBuV?

Receiver specifications are frequently written this way.

VHF Receivers

VHF uses a different standard for S9, notably –93 dBm (5 uV) into a 50-ohm receiver input. A value of 6 dB still represents 1 S-unit. All of the calculations are similar to those for HF receivers.

Example 4

Prove that 5 uV is equivalent to an input signal level of -93 dBm into a 50-ohm VHF receiver input.

Again, there are several ways to proceed. Let’s begin by converting 5 uV to Volts.

We can convert this to power

Convert to mW by multiplying by 1000

We convert to dBm using

Example 5

Convert the 5 uV signal to dBuV

Conclusions

The reference levels for S9 are defined differently for HF and VHF receivers. In this article, it has been shown how one would convert between voltage and power levels at 50-ohm receiver inputs.

When discussing S-units, some receivers are more linear than others, and linearity may depend upon receiver settings. Nonetheless, S-units are useful for signal reporting and logging because everyone agrees on the same standards.

Title Photo Credit: Photo of Ten-Tec Orion S Meter, author: Martin Ewing. Public Domain, https://commons.wikimedia.org/w/index.php?curid=1575140

 

 

 

 

Nashua Area Radio Society at HMS STEM Night on March 13th

Dan Pooler (AC1EN), a teacher at Hudson Memorial School in Hudson, NH, and a Nashua Area Radio Society member, worked with the school and other NARS members to present an exhibit to students and their families promoting HAM Radio and highlighting some of the activities of our club to them. Dan reported that “STEM Night at HMS was a big success.

HMS Steam Night
HMS Steam Night

We had over 100 5-8th graders attend the HMS STEM Night, with over 400 people attending the event. Students and their families could watch SubZero Ice Cream demonstrate how they created ice cream, learn how pickles are made, program robots, shoot off Alka Selzer Rockets, make math art, and play games with family and friends along with visiting the NARS booth.”

Lining up for HAB Exhibit
Lining up for HAB Exhibit

Fred Kemmerer (AB1OC): shown here explaining aspects of our High-Altitude Balloon activities to some students. Anita Kemmerer (AB1QB), Mackenzie Pooler (KE1NZY), and Sam Hergenhahn (KC1PVZ) also participated at the event .

HMS STEM Night
This big

Dan Pooler (on the left) at the High-Altitude Balloon exhibit.

Morse Code Exhibit
Morse Code Exhibit

NARS Exhibits at Hudson Memorial School STEM Night

Our exhibits included:

  • A Fox Hunting display
  • A remote HF Radio Station, where students heard amateur radio operators from Australia, Greece, Lebanon and other countries.
  • An ISS /Satellite exhibit including a Raspberry-Pi based video of the HMS ISS contact video,
  • A Morse Code display with keys and practice exercises.
  • A High-Altitude Balloon display
Remote HF Radio Station
Remote HF Radio Station

Special thanks and appreciation to NARS Vice President Jamey Finchum (AC1DC), who worked with Dan and the school to plan NARS’ participation in the event.. Thanks also to Fred (AB1OC) and Anita (AB1QB) Kemmerer, who graciously took the time to provide the displays and attend and share their love of the hobby with the students and their families.

HMS Principal Keith Bowen told me in an email after the event, “It was great having your group participate in our STEAM night. Students and families enjoyed their experiences.”

Hudson Memorial School will also be the location for NARS Summer Field Day 2023. Please check the forums on n1fd.org for updated info.

SUMMER FIELD DAY WEEKLY PLANNING MEETING THURSDAY NIGHTS AT 7:00 PM – Nashua Area Radio Society (n1fd.org)

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