AmateurRadio.com

By John ‘Miklor’ K3NXU

PERFORMANCE  TESTS  –  LMR-450G
The recently announced LMR-450G cable has aroused much curiosity since its characteristics have not been collectively available by any one source.  By multiple inquiries to several manufactures (only three at this time) and numerous lab tests, we hope to put many of the existing questions to rest.

DESCRIPTION
The physical make up of this cable varies slightly from most conventional RF cables.  The center conductor is a semi-stranded copper alloy surrounded by Telfon, which will absorb and distribute cable ‘hot spots’ caused by excessive standing wave.  The double silver braid and foil outer coating which provides a 98.6% shield is what the inverted high frequency loss characteristics are attributed.  The loss is substantially less as the frequency increases, making this cable especially attractive for UHF, cellular, PCS and microwave applications.

Measuring cable loss under lab conditions

LOSS PER 100′
30 MHz     2.4 db
50 MHz     2.1 db
150 MHz    1.6 db
450 MHz    1.1 db
800 MHz    .51 db
1200 MHz  .37 db
1950 MHz  .31 db

The cable’s most unique property is attributed to the outer jacket material Neo-glow, an RF sensitive composite plastic which will visibly indicate RF ‘hot spots’ in the cable.  Adjusting the cable length to the antenna system for the ‘perfect’ impedance match is crucial at high frequency, thus the importance of a low SWR for peak performance.

From 100 Watts and up this cable will brighten up your world.

PROPER  INSTALLATION
The low level emission of light from LMR-450G cable can be enhanced by wearing lightly tinted sunglasses with UV protection, which enhances the light radiation from the cable.  Select an approximate length of cable needed for the installation which must be multiples of a 1/4 wavelength for the desired frequency.  The exact length can be determined by using the formula 467 / Freq (MHz) plus approximately 18 inches.

The initial tests should be run with a 50 ohm dummy load at one end of the cable.  With a minimum of 7 watts from the transmitter, you will see a faint glow from the cable indicating the ‘hot spots’ to be eliminated.  These are the points along the cable where the RF is at its maximum.  It is at these points where the RF connectors should be mounted.  Trimming the excess cable may be required at both ends of the cable to produce the most effective match.  Use caution not to trim too much cable as the loss characteristics improve with longer cable lengths.

SUMMARY
This could be the beginning of the long awaited high frequency “SUPER” cables.  Only available in limited quantities at this time; contact your local cable supplier for more details.

Heathkit announced today they have reached an agreement to acquire the assets of Radio Shack for $300M, blocking efforts from mobile wireless carrier Sprint to acquire a large portion of the struggling and now bankrupt North American consumer electronics retailer.  No further details were mentioned by Heathkit other than they “had big plans” and “everyone should stay tuned to the website for details.”

Radio Shack CEO Joseph Magnacca was quoted in a press release as saying “We are very happy and excited about the pending transaction with Heathkit.  The Heathkit team has shown us they have a more viable business plan than Sprint, and our creditors agree that the Heathkit team brings a higher level of management, leadership, and strategy to Radio Shack, more than the company has ever had.”

Immediately after the announcement amateur radio online forums were alive with discussions and speculation on when closed stores would reopen.  Several commenters reminisced about the days when Radio Shack offered amateur radios and components.  One person noted how difficult it is to get good 68k ohm resistors and Radio Shack could chart a course to profitability if they just stocked these resistors.  Others bemoaned Radio Shack’s practice of asking for customer addresses, claiming it was a front for NSA information-gathering efforts.  Several commenters agreed that Radio Shack should offer a vacuum tube code practice oscillator kit.

Here is the current forecast discussion on space weather and geophysical activity, issued 2015 Mar 31 1230 UTC.

Solar Activity

24 hr Summary: Solar activity was at low levels with C-flare activity from both Regions 2303 (N18, L=065) and 2305 (S10W58, Dho/beta). The largest flare of the period was a C4 at 30/2205 from Region 2303 just beyond the NW limb. Slight decay was observed in the leading spots of Region 2315 (S20W36, Dro/beta) and the trailing spots in Region 2305. No Earth-directed coronal mass ejections were observed.

Forecast: Solar activity is likely to be at low levels with a slight chance for an isolated M-class (R1-R2, Minor-Moderate) flare for day one (31 Mar). An increased chance for M-class activity is expected by days two and three (01-02 Apr) as old Regions 2302 (N12, L=189) and 2297 (S17, L=196) are expected to return.

Energetic Particle

24 hr Summary: The greater than 2 MeV electron flux at geosynchronous orbit was at normal levels. The greater than 10 MeV proton flux at geosynchronous orbit remained at background levels.

Forecast: The greater than 2 MeV electron flux at geosynchronous orbit is forecast to be at normal to moderate levels all three days (31 Mar -02 Apr) The greater than 10 MeV proton flux at geosynchronous orbit is expected to be at or near background conditions (Below S1-Minor) for the forecast period.

Solar Wind

24 hr Summary: Solar wind speed at the ACE spacecraft for the majority of the period was in the mid-300 km/s range but increased to near 400 km/s after 0730 UTC. Phi was negative. Bz was at or above -4 nT and Bt was less than 7 nT through 0730 UTC when it increased to near 16 nT. The increase in activity is likely due to the onset of a coronal hole high speed stream (CH HSS).

Forecast: Continued enhancement of solar wind parameters is anticipated on day one (31 Mar) and remain enhanced through day three (02 Apr) as the CH HSS becomes geoeffective.

Geospace

24 hr Summary: The geomagnetic field was at quiet levels.

Forecast: Unsettled to active conditions are expected to dominate through day three (02 Apr) due to CH HSS effects. trans-equatorial high speed stream becomes geoeffective.

Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/

Live Aurora mapping is at http://aurora.sunspotwatch.com/

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Amazon announced a new product today called a Dash Button. Amazon sends you a little self-stick wireless pushbutton. When you run out of a product, you just push the button and it sends a wireless signal which triggers your phone to send an order for the product.

With a little creativity, could you “re-purpose” one of these to be a wi-fi doorbell or some other kind of signaling device? A push-button wi-fi panic alarm? I’m sure it would be against the terms of service to open one up and modify it, but geeks like me wonder just what’s inside one of these little buttons.

A lot of the media are reporting that it’s a wi-fi button, but I wonder if it actually uses Bluetooth communication. Basically you press a button and the signal goes to your phone via bluebooth, and then you’re phone places an order via the Amazon app.

I wonder what it contains for a microcontroller? I expect there will be plenty more info to come once these start getting in the hands of consumers. According to their website, Amazon Prime members will be eligible receive three of them at no charge. At the moment it’s by invitation only.

What uses could you think of for a cute little wi-fi push-button transmitter?

5/11/15 Update:
http://www.amateurradio.com/inside-the-802-11bgn-amazon-dash-button/

Daily solar report: Current Sunspot Cycle 24 Activity and Space Weather

Sunspot count: Sun Spots: 56 as of 03/30/2015
10.7-cm Radio Flux: 134 SFU (SFU=Solar Flux Units)
Estimated Planetary A-index (Ap): 5 | K-index (Kp): 2

Solar Wind: 405 km/s at 16.0 protons/cm3, Bz is 2.0 nT
(Mar 31, 2015 at 1820 UT)

X-ray Solar Flares:
6h hi [C4.7][0138Z 03/30] 24h hi [C4.7][0138Z 03/30]

Background X-ray Level, Last Six Days

Mar 30 2015 :: B6.6
Mar 29 2015 :: B9.1
Mar 28 2015 :: B7.9
Mar 27 2015 :: B5.0
Mar 26 2015 :: B4.5
Mar 25 2015 :: B5.4

Global HF Propagation Conditions for 1800Z on 31 Mar, 2015
High Latitude: Fair
Middle Latitude: Normal
Low Latitude: Normal

Geomagnetic Latitude Ranges: High: 60-90 degrees, Middle: 20-60 degrees, Low: 0-20 degrees

For live data and images, visit http://SunSpotWatch.com

Get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!

This report has been prepared by your space weather and radio propagation reporter, Tomas ( amateur radio operator, NW7US, http://NW7US.us )

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Stories you’ll find in our April, 2015 issue:

Scanning North America’s Railroads
By Richard Fisher KI6SN
The good news for the vast majority of railroad scanners is that 95 percent of railroad communication takes place on good ol’ analog FM. So, if you have a scanner capable of covering the railroads’ 96 FCC-assigned VHF channels, you’ve already got everything you need. You’ll be known in the vernacular as a “railfan” – of the radio-operatus specie.

FT-991: Yaesu’s Latest Shack-in-the-Box
By Mark Haverstock K8MSH
The Yaesu FT-991is both a competent rig that has a feature set that will satisfy most hams. Added VHF/UHF capabilities make it a very versatile rig for many applications. Yaesu’s touch screen goes a long way to help demystify menu selections. Find out why Mark thinks the FT-991 is a perfect fit for just about any ham shack, portable and Field Day use.

Digitally Speaking: Battery Considerations for Digital Portables
By Cory Sickles WA3UVV
Digital voice transceivers have more sophistication and complexity going on inside of them than similar analog FM rigs—especially when it comes to portables. That little radio in your hand, and the computer chips driving the extra features needs, additional current to keep everything going.

The Thrift Store Amateur
By Chris Friesen VE4CWF
If money has never been a problem, and you’ve always been able to buy your equipment factory fresh—congratulations—this article is not for you. If however, you have always had difficulty justifying the purchase of a new piece of station equipment, because you need your money to buy groceries, then you might find some encouragement in what Chris is writing about.

2015 Winter SWL Fest Recap
By Thomas Witherspoon K4SWL
Every year at the end of at the first of March for the last 28 years, the North American Shortwave Association (NASWA) has hosted its annual Winter Shortwave Listening Fest. This year saw over 100 devoted SWLers brave severe winter weather to gather in Pennsylvania to share their passion for shortwave.

Scanning America By Dan Veenaman
P25: A Tale of Two Systems

Federal Wavelengths By Chris Parris
Super Bowl XLIX Wrap-up

Utility Planet By Hugh Stegman NV6H
New Use for US Marine Channels?

Digital HF: Intercept and Analyze By Mike Chace-Ortiz AB1TZ/G6DHU
3G Wideband Protocols Are Arriving on HF

HF Utility Logs By Mike Chace-Ortiz and Hugh Stegman

Amateur Radio Insights By Kirk Kleinschmidt NT0Z
My Friend Ferrite: Interference Part 3

Radio 101 By Ken Reitz KS4ZR
The Art and Science of Chasing DX

Radio Propagation By Tomas Hood NW7US
More Sunspot Mysteries Revealed

The World of Shortwave Listening By Rob Wagner VK3BVW
The QSL Card – At What Cost?

The Shortwave Listener By Fred Waterer
Radio, History and Business Today

Maritime Monitoring By Ron Walsh VE3GO
Radio Surprises and Changes

The Longwave Zone By Kevin O’Hern Carey WB2QMY
Tuning in to Natural Radio

Adventures in Radio Restoration By Rich Post KB8TAD
The Real McCoy: A 1957 Novice Transmitter

The Broadcast Tower By Doug Smith W9WI
Stuffing 85 Channels into a 32-Channel Sack

Antenna Connections By Dan Farber AC0LW
Nothing Ventured: Understanding Antenna Gain

The Spectrum Monitor is available in PDF format which can be read on any desktop, laptop, iPad®, Kindle® Fire, or other device capable of opening a PDF file. Annual subscription (12 issues, beginning with the January 2015 issue) is $24. Individual monthly issues are available for $3 each.

Today’s graph, plotting the SESC sunspot number, the 10.7cm Radio Flux, and the Estimated Planetary A Index, for the last 30 days.

The numbers are:

Date | Sunspots | 10.7-cm Flux | Ap

==========================================
2015/03/30 | 56 | 134 | 5
2015/03/29 | 73 | 145 | 14
2015/03/28 | 82 | 146 | 9
2015/03/27 | 109 | 138 | 9
2015/03/26 | 103 | 136 | 8
2015/03/25 | 115 | 138 | 13
2015/03/24 | 127 | 133 | 12
2015/03/23 | 119 | 128 | 21
2015/03/22 | 88 | 122 | 24
2015/03/21 | 40 | 114 | 14
2015/03/20 | 27 | 113 | 24
2015/03/19 | 71 | 109 | 28
2015/03/18 | 44 | 115 | 52
2015/03/17 | 60 | 114 | 117
2015/03/16 | 57 | 117 | 11
2015/03/12 | 56 | 127 | 8
2015/03/11 | 42 | 132 | 9
2015/03/10 | 42 | 121 | 5
2015/03/09 | 29 | 123 | 6
2015/03/08 | 23 | 124 | 11
2015/03/07 | 20 | 138 | 20
2015/03/06 | 37 | 127 | 13
2015/03/05 | 31 | 130 | 6
2015/03/04 | 43 | 124 | 10
2015/03/03 | 38 | 125 | 11
2015/03/02 | 65 | 130 | 28
For complete live data and images visit http://SunSpotWatch.com

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