"How to Choose the Proper Coaxial Cable for Your Amateur Radio Station" by Joe Sammartino

Let's start with a simple definition of coaxial cable - A feedline that transports radio frequency energy from your radio to your antenna and from your antenna back to your radio. 

A simple truth: The coaxial feedline is one of the most critical components of your radio station and, as such, deserves careful consideration.

Factors to Consider and Other Considerations 

Length - How much cable do you need? Or, stated another way, how long does your feedline need to be? Why do we need to consider the length of cable? All feedlines have loss and the longer the feedline, the higher the loss.

Frequency - What frequencies do you intend to use?  Loss also increases with increases in frequency. Loss in cable is rated in decibels usually expressed as Db loss per 100 ft of cable. You should be looking for lowest loss in Db per 100 ft for the highest frequency you plan to operate.

Let's stop here for a real world example using RG58 Coax.

 At 75-80 meters, a 100 ft run of RG58 coax is going to exhibit a loss of about 1/2 dB. We are also going to assume that VSWR is low and by that I mean 2:1 or less. That equals about 14 watts of loss from a 100 watt transmitter. The received energy is diminished slightly but modern radios more than make up for that loss.That all sounds very much acceptable to me.

Lets run the same length of RG58 cable to an antenna at 70 cm (440 MHz). This is a huge increase in frequency and the loss now reaches over 9 dB, and this result is with a good VSWR match. That now translates to a loss of 80% of your transmitted power! That is terrible and should not be acceptable to any sane operator!

The solution is to use a cable type that has much less loss for that operating frequency.

Quick snapshot: 

LMR400 Coax by Times Microwave - 3 dB loss at 100 ft, that's still 50% of power loss!

LMR600 Coax - 1.7 dB loss at 100 ft, much better but keep an eye on the cost. It can add up very quickly. 

Note: if your cable length need is very short, such as a mobile setup or maybe even a portable setup where all you need is 10 or 15 feet, higher loss coax (less expensive) may be used because the resulting loss at short distances is much less than at 100 ft.

Another Note: Think about the future. You need to consider the frequencies that you may want to operate in the future when choosing a cable or multiple cable runs.

This is a great time to review your understanding of VSWR and antenna tuners.

I recommend these articles/videos:

Videos: 

SWR - W6LG - https://youtu.be/VcC7j55_xqc 

Using an Antenna Analyzer - K7AGE - https://youtu.be/jOCG6bFGfuE 

Tuners - HamRadioConcepts - https://youtu.be/pdOEiML2XGk 

Audio: 

Selecting Coaxial Cable - ARRL - http://www.arrl.org/files/file/DoctorPodcast/2019/July%204%20-%20Selecting%20Coaxial%20Cable.mp3 

SWR Simplified - ARRL - http://www.arrl.org/files/file/DoctorPodcast/2019/March%2014%20-%20SWR%20Simplified.mp3 

Antenna Analyzers - ARRL - http://www.arrl.org/files/file/DoctorPodcast/August%2031%202017%20-%20Antenna%20Analyzers.mp3

Back to factors and other considerations. 

So, if the solution is to use a cable type that has much less loss for that operating frequency, how do we do that?

RESEARCH!! ( A good ham uses all the tools at his/her disposal to research solutions. An unwitting ham asks their question on social media and gets 100 different opinions from 100 people. The good answers are not easily weeded about by a new ham. Join a club, find an Elmer there or through the ARRL. But I digress.)

To assist you in your selection of the proper coax, use Google search to look up cable losses and cable loss calculators: Here is a typical cable loss table from W4RP's website:

Results are shown in dB per 100 foot and (dB per 100 meters).

A very good cable loss calculator can be found here at KV5R's website: https://kv5r.com/ham-radio/coax-loss-calculator/

This calculator is very comprehensive. The drop down menu for Line Type has all the cable types you will ever need  to consider. The above link is worthy of "Bookmark" status.

Your last consideration is one of economics. Only you can determine the best bang-for-the-buck for your particular situation.

In Summary:

1. Measure the distance between your radio and your intended antenna feedpoint.

2. Determine the highest frequency you will operate now and in the future.

3. Use Google to find an online coax loss calculator. I like https://kv5r.com/ham-radio/coax-loss-calculator/ .

4. Use the calculator to determine the cable that gives you the lowest loss for the frequency and length you will operate. PICK A FEW OPTIONS!. Cost of cable will vary a great deal so prepare a few options to review against your budget constraints. This is a hobby, folks. Feeding your family is a higher priority than feeding your antenna. :-)  Be Practical!

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I hope you or someone you know can benefit from this article.

As always, please provide any feedback you wish.

Best regards, Joe, N2QOJ

Joe Sammartino

24/7:  480.270.4563, Mobile:  480.381.2993

jsammartino@gmail.com  

www.queencreekarc.org  

www.qcecg.org

Everything You Need to Look and Sound Good on a Video Call

 Everything You Need to Look and Sound Good on a Video Call

Eric Schoon @ericpschoon
August 23, 2020, 8:00am EDT

You’ve probably been doing a lot of video calls recently—both business and personal. And while the webcam and microphone on your laptop are fine, you know things could be so much better. With just a few pieces of gear, you can upgrade your video conferencing setup significantly.

First Off, Look Behind You

No one likes a messy room, and the same goes for backgrounds. Keeping the area within view of your webcam clean goes a long way to improving the overall image. You could always use a virtual background if you don’t want to mess with anything in your room, but that requires either a green screen or a decent graphics card to work.

Besides keeping the area clean, you should also watch out for the lighting and camera angle. The major things to avoid are sitting in dark parts of your room or having windows and bright lights located behind you—those all look pretty bad on camera.

When it comes to the camera angle, try to make sure you’re not looking down at the camera. Preferably, your webcam should be at eye level or slightly above, depending on your setup. When it comes to raising your camera, you could get a simple camera tripod (make sure it’s compatible with your webcam), or just stack some books on your desk.

 A Dedicated Webcam

Logitech

This will be the most “bang for the buck” upgrade. Jumping from a bad to even just a decent webcam is a major improvement, and there are plenty of quality options out there.

• Logitech C920: This is the webcam everyone knows, and that’s for good reason. It’s a simple webcam, but the quality for the price is great. It records in 1080p at 30 FPS and even includes a privacy shutter for when it’s not actively in use. You can also use Logitech Capture to pan the camera and adjust the zoom level.
• Logitech StreamCam: If you want to take a step up from the C920 in features and quality, the StreamCam is the way to go. Not only does it record in 1080p at 60 FPS, but it also features automatic face-tracking, exposure, and focus through Logitech Capture. The camera itself is versatile, allowing you to switch it between vertical and horizontal modes, and the included clasp can easily fit onto a monitor or camera tripod.
• Razer Kiyo: The Kiyo is an interesting camera with a couple of tricks up its sleeve. The first thing you’ll notice about the Kiyo is the light ring around the camera. This light ring will illuminate your face on camera and can be adjusted in Razer Synapse 3. Synapse 3 is also where you can adjust the brightness, white balance, contrast, and saturation settings of the camera itself. It can record in 1080p at 30 FPS (or 720p at 60 FPS), and includes a stand that can either sit on a desk or clasp onto your monitor.
• Your Phone (Android/iOS): It can be difficult to get your hands on a webcam right now, and even then, you might not want to spend the money on a decent option. In that case, you likely already have a quality webcam near you right now: your phone. Phone cameras are pretty great nowadays, and by using a simple app you can turn it into a wireless camera for your computer. Epocam is a great option for this; all you need to do is make sure your phone and computer are on the same Wi-Fi network and install the corresponding apps for each platform.

Lighting

Neewer

A dark room is obviously harder to see in, but it also heavily affects the quality of your webcam. When webcams have to record rooms with dark lighting, the image appears grainy—proper lighting can fix that.

• Whellen Selfie Ring: This is a simple ring of LED lights that can be clamped around your monitor. You can adjust it between three levels of strength to ensure everything looks nice and bright when you turn on the webcam.
• Neewer LED Light: For a more professional option, these LED light panels from Neewer will provide you with all the lighting you could ever need for a video call. The tripod is adjustable, there are four included color filters, and you can change the lighting’s strength with the simple push of some buttons. It’s powered via a USB-A cord, so you can either plug it into a brick on the wall or your computer. You can also get these lights with a taller tripod, in case you want to set them up on the floor instead of your desk.

A Proper Microphone

Samson Technologies, Blue

Your video is covered, so let’s switch over to audio. No one wants to use a bad microphone—it’s unpleasant to listen to and makes understanding what you’re saying difficult. While most webcams will come with a microphone built-in, these are rarely above passable and often experience echo. It’s worth it to get a dedicated microphone if you want to be heard loud and clear.

• Samson Go Mic: This tiny microphone has been around for a while, but it’s still one of the best mics you can get for the price. The included stand can rest on a desk or clasp onto a monitor, and there’s even an included carrying case if you need to take it on the go.
• Blue Yeti: The most popular USB microphone in the world, the Blue Yeti is renowned by YouTubers, streamers, and podcasters for its high-quality audio and simple setup. The Yeti is easy to use, as is the Sherpa software for adjusting the gain and sample rate of your audio. There’s also the Blue Yeti Nano, which is a smaller and more affordable version of the standard Yeti.
• Antlion ModMic (Wired/Wireless): The ModMic is unique, as it attaches directly to any pair of headphones turning them into a headset. The ModMic attaches via an adhesive strip (don’t worry, it won’t leave behind any residue), and comes in either a wired or wireless model. The quality won’t be as good as the desk mics previously mentioned, but it will still be far superior to a webcam mic.

Headphones

Sennheiser

When you’re using a dedicated microphone, wearing headphones is important. After all, your microphone might pick up the sound coming from your speakers over your voice.

• Panasonic ErgoFit: This no-frills pair of earbuds won’t blow away anyone with its audio quality. It’s a basic pair of earbuds to be sure, but the price reflects that. If you don’t care about audio quality and just want something simple and cheap, these are the headphones to get.
• 1MORE Triple Driver: If you prefer in-ear headphones but want something that can actually produce quality audio, then these are a great option. There’s nothing too special about them, but what they lack in unique features they make up for in audio quality. They also come with a huge selection of ear tips and a traveling case.
• Jabra Move: Wireless is always a nice feature to have in a pair of headphones, and the over-ear Jabra Move is an excellent choice. They last for about 14 hours on a full charge, and have volume and media controls on the headphones themselves for quick access.
• Sennheiser HD280PRO: If audio quality is the main concern for you, these around-ear headphones from Sennheiser do a great job balancing audio quality and price. They don’t sound as good as a high-end pair of headphones, but for video calls, they’re more than enough.

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Just a couple of pieces of gear are enough to boost your video conferencing game from passable to fantastic. And those improvements not only help you, but the people you’re talking to as well.