ETH036 – Don’t Skimp on the Coax

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Hello everybody and welcome back to the Everything Ham Radio Podcast! In this episode we are going to be talking about Coax

 


Tech Corner – Coax

Coax is probably one of the main components of your station that you should NOT skimp on the cost of. You should always get the best coax that you can afford! You can have the best radio and the best antenna but have crappy coax and your neighbor could have a crappy radio and antenna but awesome coax, and your neighbor will nine times out of ten have a better signal than you do.

 

Let’s do some math…

 

For easy math, let’s say that your coax has a line loss of 3 dB per 100 feet and you have a 100 foot run, your radio has a transmitter power of 100 watts and your antenna has a 3 dB gain.

 

100(w) – 3 dB(coax loss) = 50(w)

50(w) + 3 dB(Antenna Gain) = 100(w)

 

In this example, you didn’t gain anything but you also didn’t lose anything. Let’s take it one step more now and say that you have 200 foot run now.

 

100(w) – 6 dB(200 ft coax loss) = 25(w)

 

*every 3 dB, your sign either doubles or halves; so at 3 dB you have 50 watts and for the next 3 dB you are down to 25 watts

 

25(w) + 3 dB(antenna gain) = 50(w)

 

By doubling your coax length, you cut your radiated power in half.

 

In this example, we are also assuming that you have perfect 1:1 SWR on your antenna. If it is more than that, you have even less being radiated. You also have to take into account what frequency you are talking on. A coax that has a loss of 3 dB around 100 MHz or the 2 meter band, might have a 6 dB loss around 400 MHz or or the 70 cm bands.

 

Coax dB Loss per 100 Feet using common coax types:

dB Loss / 100 feet

Frequency Mhz

Cable Type

1.0 10 50 100 200 400 900 1000 3000 5000
6A, 212 .26 .83 1.9 2.7 4.1 5.9 6.5 9.8 23.0 32.0
8 MINI, 8X 1.1 2.5 3.8 5.4 7.9 8.8 13.0 26.0
LMR -240 .24 .76 1.7 2.4 3.4 4.9 7.5 7.9 14.2 18.7
8, 8A, 10A, 213 (RG8/8A hard to find ) .15 .55 1.3 1.9 2.7 4.1 7.5 8.0 16.0 27.0
9913, 9086, 9096 0.9 1.4 1.8 2.6 4.2 4.5 13.0
4XL8IIA, FLEXI 4XL 0.9 1.4 1.8 2.6 4.2 4.5 13.0
LMR-400 .9 1.2 2.5 4.1 4.3
LMR-500 .7 1.0 2.0 3.2 3.4
LMR-600 .6 .8 1.4 2.5 2.7
8214 .60 1.2 1.7 2.7 4.2 7.8 14.2 22.0
9095 1.0 1.8 2.6 3.8 6.0 7.5
9, 9A, 9B, 214 .21 .66 1.5 2.3 3.3 5.0 7.8 8.8 18.0 27.0
11,11A,12,12A,13,13A, 216 .19 .66 1.6 2.3 3.3 4.8 7.8 16.5 26.5
14, 14A, 217 .12 .41 1.0 1.4 2.0 3.1 5.5 12.4 19.0
17,17A,18,18A, 218, 219 .06 .24 .62 .95 1.5 2.4 4.4 9.5 15.3
55B, 223 .30 1.2 3.2 4.8 7.0 10.0 14.3 16.5 30.5 46.0
58 .33 1.2 3.1 4.6 6.9 10.5 14.5 17.5 37.5 60.0
58A, 58C .44 1.4 3.3 4.9 7.4 12.0 20.0 24.0 54.0 83.0
59, 59B .33 1.1 2.4 3.4 4.9 7.0 11.0 12.0 26.5 42.0
62, 62A, 71A, 71B .25 .85 1.9 2.7 3.8 5.3 8.3 8.7 18.5 30.0
62B .31 .90 2.0 2.9 4.2 6.2 11.0 24.0 38.0
141,141A, 400, 142, 142A .30 .90 2.1 3.3 4.7 6.9 13.0 26.0 40.0
174 2.3 3.9 6.6 8.9 12.0 17.5 28.2 30.0 64.0 99.0
178B,196A 2.6 5.6 10.5 14.0 19.0 28.0 46.0 85.0 100
188A, 316 3.1 6.0 9.6 11.4 14.2 16.7 31.0 60.0 82.0
179B 3.0 5.3 8.5 10.0 12.5 16.0 24.0 44.0 64.0
393, 235 .6 1.4 2.1 3.1 4.5 7.5 14.0 21.0
402 1.2 2.7 3.9 5.5 8.0 13.0 26.0 26.0
405 22.0
LDF4-50A .06 .21 .47 .68 .98 1.4 2.2 2.3 4.3 5.9
LDF5-50A .03 .11 .25 .36 .53 .78 1.2 1.4 2.5 3.5

Note: These tables are typical specifications for comparison only.

Values may not be exactly as quoted by a specific mfg.

*http://www.hamuniverse.com/coaxdata.html

Connectors

 

The other aspect of coax that you need to pay attention to is the end connectors that you use. While it is tempting to use the cheap $0.25 to $0.50 a piece PL-259 connectors that you can get at most hamfests, it is better to use a more high quality version of them. The cheap ones that you find are often very cheaply made and can be damaged easily while you are trying to solder it onto the coax. Often while you are soldering these ends on you can very easily get too much heat in the center point and melt the insulation before you are able to solder the shielding to the sides of the connector.

 

Check out this page,  K0BG.com – Coax and PL259 for more information about coax and connectors. It is a very nice article written by Alan Applegate, K0BG. He was the guest on episode 28, where we talked about mobile installations.

 


 

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GigaParts has graciously given one of these cases as a giveaway. Tune in next week to find out how to enter to win it! Until then, head on over to GigaParts.com and check out their wide selection of cases. If you decide to buy one, enter the coupon code of…

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Amateur Radio Club Spotlight

sara_logo_color - CoaxSocorro Amateur Radio Association

 

Website: http://www.socorroara.org/
F
acebook: https://www.facebook.com/SocorroARA/

About SARA

Amateur radio has been part of the landscape in Socorro since the 1930’s. By the mid-1970’s, informal meetings of members and their families were occurring and SARA made the transition to a formal association on May 1, 1976.  Although participation in the association has ebbed and flowed since, SARA has remained a vital element of both the amateur radio and Socorro communities since its formation.  Although a smaller southwest community, Socorro is very high tech.  The ARRL featured Socorro and SARA in the QST article, “Socorro, New Mexico — Ham City, USA? (QST, December 1996, pp. 43-45),” an article by Dave Finley (N1IRZ) that highlighted the area’s high per capita interest in amateur radio.   New Mexico Tech is a high quality, Socorro-based university offering bachelors degrees through doctorates in science, mathematics and engineering disciplines.  The NSF-funded National Radio Astronomy Observatory is located on the NMT campus and coordinates activities of the Very Large Array and Very Large Baseline Array.  Employees from diverse research endeavors ranging from the geophysics to defense make Socorro and SARA home.

 

Repeaters

  • 146.680 – 100 or 123 input tone, 123 output tone – Socorro Peak
  • 444.500 + D-Star Repeater

 

Netsp

  • Weekly Socorro ARES Net – Wed 1930 – 146.680 Repeater
  • Weekly Tri-County ARES Net – Thur 1930 – URFMSI System via the 146.680 Repeater
  • New Mexico D-Star Net – Thur 2000 on DStar REF055A

 

Meetings

  • SARA Club Meeting – Second Wed @ 1930(Except December) – Socorro County Annex, 198 Neel Ave.
  • Burger King: Coffee every Saturday ~8:00 to 9:30 hrs at Burger King.
  • Capitol Bar on the Plaza – Weenie Wednesdays (on the patio in good weather) beginning in late afternoon.
  • Twisted Chili – Friday Happy Hour beginning at 5:30 PM (on the patio in good weather).

 

Activities

  • DX
  • QRP
  • Digital Modes
  • Community Service
  • Hamfests – Oct 15 8a-2p
  • Field Day

 


Upcoming Events

Contests

 

*Information taken from the ARRL and WA7BNM Contest Calendar


Hamfests

09/23/2016

 

09/24/2016

 

09/25/2016

 

10/01/2016

 

10/02/2016

 


News

Amateur Radio Parity Act Passes in the US House of Representatives!

09/14/2016
“The bill is passed without objection.” With those words, Amateur Radio history was made on September 12, when the US House of Representatives approved the Amateur Radio Parity Act, H.R. 1301 on a voice vote under a suspension of the rules. The focus of the campaign to enact the legislation into law now shifts to the US Senate. The House victory culminated many years of effort on ARRL’s part to gain legislation that would enable radio amateurs living in deed-restricted communities to erect antennas that support Amateur Radio communication. The measure calls on the FCC to amend its Part 97 rules “to prohibit the application to amateur stations of certain private land-use restrictions, and for other purposes.” While similar bills in past years gained some traction on Capitol Hill, it was not until the overwhelming grassroots support from the Amateur Radio community for H.R. 1301 shepherded by ARRL that a bill made it this far. The legislation faces significant obstacles to passage in the US Senate, however.

“This is huge step in our effort to enact legislation that will allow radio amateurs who live in deed-restricted communities the ability to construct an effective outdoor antenna,” ARRL President Rick Roderick, K5UR, said. “Thanks to everyone for their help in this effort thus far. Now we must turn our full attention to getting the bill passed in the Senate.”
RARRL Hudson Division Director Mike Lisenco, N2YBB, who chairs the ARRL Board’s Legislative Advocacy Committee, has been heavily involved in efforts to move H.R. 1301 forward. “This has been a multiyear effort that is finally seeing some light,” he said. “The passage of the bill in the House is a major accomplishment, due to the hard work of so many — from the rank-and-file member to the officers and directors.”

Lisenco said it’s not a time to rest on our laurels. “We are only halfway there. The focus now shifts to our effort in the Senate,” he said. “We are beginning a massive e-mail campaign in which we need every member to write their two Senators using our simplified process. You will be hearing from President Roderick and from your Directors, asking you to go to our ‘Rally Congress’ page. Using your ZIP code, e-mails will be generated much like our recent letter campaign. You’ll fill in your name and address and press Enter. The e-mails will be sent directly to your Senators without you having to search through their websites.”

Lisenco said getting these e-mails to members’ Senators is a critical part of the process. “Those numbers matter! Please help us help you by participating in this effort,” he said.

As the amended bill provides, “Community associations should fairly administer private land-use regulations in the interest of their communities, while nevertheless permitting the installation and maintenance of effective outdoor Amateur Radio antennas. There exist antenna designs and installations that can be consistent with the aesthetics and physical characteristics of land and structures in community associations while accommodating communications in the Amateur Radio services.”

During this week’s limited debate, the House bill’s sponsor, Rep Adam Kinzinger (R-IL), thanked ARRL and the Community Associations Institute (CAI) for reaching an agreement to move the bill forward “in a bipartisan and very positive manner.” He pointed out to his colleagues that Amateur Radio antennas are prohibited outright in some areas.

“For some this is merely a nuisance,” Kinzinger said, “but for others — those that use their Amateur Radio license for life-saving emergency communications — a dangerous situation can be created by limiting their ability to establish effective communication for those in need.”

Kinzinger said that in emergencies, hams can provide “a vital and life-saving function” when conventional communication systems are down. He also praised the Military Auxiliary Radio System (MARS), a US Department of Defense-sponsored program, comprised largely of Amateur Radio volunteers, that also supports communication during emergencies and disasters.

Cosponsor US Rep Joe Courtney (D-CT) also urged the bill’s passage. “This is not just a feel-good bill,” Courtney said, recounting how Hurricane Sandy brought down the power grid, and “we saw all the advanced communications we take for granted…completely fall by the wayside.” Ham radio volunteers provided real-time communication in the storm’s wake, he said, saying the legislation was a way “to rebalance things” for radio amateurs who choose to live in deed-restricted neighborhoods by enabling them to install “non-intrusive antennas.”

Courtney noted that he spoke recently with FCC Chairman Tom Wheeler, and said that Wheeler “strongly supports this legislation.”

Leading up to the vote, Rep Paul Tonko (D-NY) also spoke in support of the legislation, calling it a commonsense approach that would build “fairness into the equation for Amateur Radio operators” in dealing with homeowners associations.

The earlier U.S. Senate version of the Amateur Radio Parity Act, S. 1685, no longer is in play, and the Senate is expected to vote by unanimous consent on the version of H.R. 1301 that was adopted by the House on September 12.

 


New Section Manager Appointed in Northern New Jersey

 

09/16/2016

Steve Ostrove, K2SO, of Elizabeth, New Jersey, has been appointed as ARRL Northern New Jersey Section Manager, effective September 16. He takes the reins of the Northern New Jersey Field Organization after Richard Krohn, N2SMV, announced that he was stepping down. Krohn, of Manalapan, has served as the Northern New Jersey Section Manager since July 2008.

ARRL Field Services and Radiosport Manager Dave Patton, NN1N, received Krohn’s resignation and recommendation for his replacement. He then consulted with ARRL Hudson Division Director Mike Lisenco, N2YBB, before making the appointment.

Ostrove will complete the current term of office that extends until June 30, 2017.

Ostrove has served as Assistant Section Manager in Northern New Jersey since 2009, and was the Section Emergency Coordinator from 2001 through 2008. He is currently a District Emergency Coordinator, Official Emergency Station, and Official Relay Station.

 


SKYWARN Youth on the Air Net Debuts

 

09/14/2016

The SKYWARN Youth on the Air Net is on the air, encouraging young radio amateurs to get on the air and learn about the SKYWARN weather-spotting network and basic weather facts.

The SKYWARN Youth Net meets on most Southwest Missouri SKYWARN repeaters Sunday evenings at 7:30 PM CT and is open to all hams via EchoLink.

The net will first take check-ins from young hams aged 25 and younger. The net also will offer an opportunity for participation by unlicensed young people in ham radio households who may be interested in obtaining a ham ticket.

“As this net grows and evolves, we hope to create and present brief educational segments,” said George Sfair, KJ6TQ. “We invite all young hams, their families, and the Amateur Radio community in general to check into this net. Young hams are the future of this hobby, and we encourage them to get involved, to get out on the air and talk, and to invite their friends to become hams as well.”

The SKYWARN Youth Net is held on Missouri linked repeaters in Fordland/Springfield, 145.49 MHz (136.5 Hz tone); Joplin, 145.35 MHz (91.5 Hz tone); Walnut Grove, 147.33 MHz (162.2 Hz tone); Buffalo, 147.18 MHz (136.5 Hz tone), and Branson, 147.15 MHz (162.2 Hz tone), as well as on EchoLink node 291849 or NNWS-R. — Thanks to George Sfair, KJ6TQ

 

Source:

ARRL News

 

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73 de Curtis, K5CLM

 

 

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