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Published byGeorgia Watts Modified over 9 years ago
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https://www.youtube.com/watch?v=SbHWhvNmbL8
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Washington County ARES February 2015
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Visitors Please leave an email address on the sign up sheet
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Upgrades & Certificates
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Stations – Served Agencies
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New computers for EOCs – _---still waiting… New Templates for Winlink – RMS Express classes Lisa Clark & John Core
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Oregon ARES web site oregonaresraces.org – register and log in ARES HF Net 3.964mhz – 1 st & 3 rd Tuesdays have a message to give Register with “mail chimp”
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Who’s Who OEM ARU : Oregon Emergency Management Amateur Radio Unit OEM : W7OEM SEC : K7VV Vince Vanderhyde DEC : District Emergency Coordinator DEC : KD7WZI James Bryant EC : KE7WKM Emergency Coordinator County EOC : WC7EOC
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WashcoARES.Org
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Coaxial Cable and Connectors 10
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Feedlines - overview Connects the rig to the antenna Most important characteristics are usually: loss (varies with frequency) characteristic impedance power handling (varies with frequency) balanced / unbalanced physical characteristics price There are many types that can be used: selection is a based on a series of trade-offs among these characteristics. 11
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Common Feedline Types Coaxial cable: RG-213 / RG-8* 0.4” diameter 50 ohms RG-8X* / RG-8 MINI* 0.24” diameter 50 ohms RG-58 0.2” diameter 50 ohms RG-174 0.1” diameter 50 ohms RG-6 (TV coax) 0.24” diameter 75 ohms and many, many more… * not a MIL STD cable designator 12
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Dale’s general guidelines Up to 1dB loss - don’t worry about it. 2dB loss - not optimum, but probably usable 3dB loss - find a better alternative if you can Note: feedline loss is much more critical for VHF weak signal work, or trying to be heard through a pile-up. On VHF/UHF no feedline is too long if it runs vertically. The loss due to length is more than overcome by the increase in signal strength due to height. 13
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Coax Loss (dB / 100’) vs. frequency and coax type.
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Coax recommendations RG-58 Good for lower HF bands, marginal at 100’ on 15m and 10m Light and flexible for portable antennas Up to ~25’ on 2m RG-8X / RG-8 MINI Good for most HF use at reasonable SWR Up to ~50’ on 2m RG-213 (and relatives) Best for most uses where weight isn’t important Low loss types such as LMR-400 have slightly lower losses. RG-6 TV cable (75 ohms) Lower loss than RG-8X Sometimes available surplus at very good prices Aluminum shield - use crimp-on connectors 75 ohm impedance needn’t be a major problem RG-174 Very small cable with higher losses - keep it short Useful for backpacking where weight is critical 16
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Coax Recommendations RG-58: Solid polyethylene inner insulation Relatively cheap and commonly available OK up to 200’ on 40m, 80m and 160m. Marginal at 100’ on 15m and 10m Up to about 25’ on 2m Often used for mag mount leads because it can be slammed in a car door. 17
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Coax Recommendations (continued) RG-8X / RG-8 MINI No standard specification Foam inner insulation can be damaged by crushing or sharp bends Smaller and more flexible than RG-213 Lower loss than RG-58 Good for most HF applications Good up to 50’ on 2m 18
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Coax Recommendations (continued) RG-213 / RG-8 types Suitable for most uses where weight isn’t important Low loss types such as LMR-400 have slightly lower losses. RG-6 TV cable (75 ohms) Aluminum shield - use crimp-on connectors 75 ohm impedance needn’t be a major problem RG-174 Very small cable with higher losses Useful for backpacking where weight is critical Small size can fit through small holes 19
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Coax calculation tool: TLDetails Coax calculation program from AC6LA Free download for Windows machines Calculates losses and impedance transformation based on coax type, frequency and cable length. http://www.ac6la.com/tldetails1.html http://www.ac6la.com/tldetails1.html 20
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TLDetail s
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Losses and SWR Feedline losses increase with SWR. (Well, mostly…) This tends to be come more significant when the SWR is over about 5 : 1 or so. Just because you can match it with a tuner doesn’t mean it is very efficient. With high losses, the SWR at the rig will be less than it is at the antenna. The higher the cable loss to start with, the greater the increase in loss due to SWR. 22
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Increase in loss due to SWR
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Coax cable tips KEEP WATER OUT OF YOUR CABLE reduces contact between wires in shield increases losses, which improves SWR Seal connectors, splices, holes Prevent physical damage, especially with foam insulation crushes easily (step on it, bend too tight, tie wraps) foam acts like a sponge if water gets in Run in conduit if underground, or to protect from animals 27
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Connector types PL-259 / SO-238 “UHF” most common type on base and mobile rigs usable up to 450 MHz designed for RG-213 size cable, use sleeve for smaller types Type N Higher quality connector Supposed to be waterproof Better at UHF BNC quick connect/disconnect (push and twist 1/4 turn) used on many older HTs SMA used to save space on small HTs Not as strong Solder vs. crimp-on connectors 28
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Connector tips USE THE RIGHT TYPE OF CONNECTOR FOR YOUR COAX You can use the same PL-259 for RG-8X and RG-59, but you can’t use the same BNC connectors. Crimp connectors must fit just right, and be crimped with the proper tool End of connector shell is the point of maximum flexing / stress Provide strain relief so connectors aren’t under tension Losses in properly assembled connectors and adaptors are quite low. 29
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Common causes of problems Water in the coax broken braid (or center) from flexing at connector braid improperly soldered on PL-259 worn or recessed center pin (especially BNC) female socket splayed out from PL-259 with extra solder stray strand of shield shorting out to center conductor connector insulation damaged by heat of soldering 31
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DSTAR Net N7QQU B @ Synopsis Sundays at 6PM Voice 440.550 8PM Digital 440.550 http://www.dstargateway.org/ https://n7qqu.dstargateway.org/
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DSTAR Class Ronler Fire Station Feb 21 st 9:00AM to 12PM Cue Chris KU7PDX
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Winlink Class – I Want It All!! Location Ronler Fire Station March 14 th 9AM to 12PM TNC’s Radios Packet Pactor Cables Dummy Loads Get your hands on everything
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Task List 1 John Core KX7YT Sam Corbin KF7BUC John Bucsek KE7WNB Kent Powloski N7KPN Pat Flanagan KE7NVB Richard Stack K7TKK Frank Wenzel AE7IS Bob Yolton W7ZXX
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Cascade Rising Quake Ex I April 25th State and Federal CSZ Plans
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A Joint FEMA-OEM Exercise, June 2016 FEMA Region 10 has recently released the Cascadia Rising Exercise Scenario Document which has just been posted at: http://www.oregonaresraces.org/?page_id=559 This is a large file about 7 Mb in size with many maps of expected damage from a CSZ quake based on the most recent research. Our Spring and Fall SETS this year will be based on this document. You will find it very interesting reading. John Core, KX7YT ASEC SET Coordinator
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Run with Paula 5/3/15 Kiezer Volcanoes
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Morning ham radio 440.350mhz Tone 127.3 +5Mhz Offset
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Anything Else
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