FCC Grants ARRL Request for Emergencies, Hurricanes

The FCC has granted ARRL’s request for a temporary waiver to permit amateur data transmissions at a higher symbol rate than currently permitted by section 97.307(f) of the FCC Amateur Service rules. The FCC acted to facilitate hurricane and wildfire relief communications within the US and its territories.

Read the full story here.
73 de KE2YK
Ham Shack Battery Equipment

How Long Will Your Backup Battery Last?

Somewhere in my travels across the Internet I ran into a formula for calculating transceiver usage and associated battery consumption. The formula has been a fairly accurate way to estimate my shack’s backup battery consumption. Draining 100% of a battery is obviously unworkable so transceiver run time is calculated at 75% of total battery amp hours. I have examples of the formula with both a 100 watt and 10 watt transceiver below. Plug in your own numbers and check your results.

Formula: %BAh / (((R%h x RI) + (T%h x TI)) = rt

  • %BAh – 75% of total battery ampere hour usage
  • R%h – percent of hour in receive mode
  • RI – radio ampere rating in receive mode
  • T%h – percent of hour in transmit mode
  • TI – radio ampere rating in transmit mode
  • rt – approximate transceiver run time

I keep an Optima Blue Top high performance AGM (sealed absorbed glass mat) battery on a CTEK Battery Minder Charger in the Ham Shack.

The AGM design holds the electrolyte in suspension and keeps the electrolyte in constant contact with the lead surface on the plates. AGM batteries are superior to flooded batteries in a number of ways. AGM batteries are spill proof, can be used in rugged environments, charge faster and have a much longer life to name a few.

Battery chargers are generally broken down into two general categories, smart chargers and trickle chargers. Smart chargers offer an efficient design to prolong battery life. Using trickle chargers for long term battery maintenance will actually destroy batteries because they cycle on and off which eventually overcharges and dries the battery out.

CTEK’s chargers switch to a pulse mode after the battery is fully charged. Pulse mode allows a battery to self discharge to a predetermined level and then another charge cycle is initiated. Pulse mode avoids overcharging and effectively exercises the battery as if it were in use. As a result, pulse mode greatly extends battery life.

I found that keeping my 5 year old Optima Blue Top maintained with the CTEK battery minder has done a great job in keeping my Optima Blue Top in peak condition.

50Ah battery with 100 watt transceiver

  • %BAh = 50Ah * .75 = .37.5Ah
  • T%h = 25% of hour = .25 x TI of 20 amp TX rating = 5 amps per hour
  • R%h = 75% hour = .75 x 3 amp RX rating = 2.25 amps per hour
  • 5 + 2.25 = 7.75Ah consumed hourly
  • 37.5Ah / 7.75Ah = ~ 4.8 hours transceiver run time @ 100 watts

50Ah battery with 10 watt transceiver

  • %BAh = 50Ah * .75 = .37.5Ah
  • T%h = 25% of hour = .25 x TI of 2 amp TX rating = .5 amps per hour
  • R%h = 75% hour = .75 x .25 amp RX rating = .15 amps per hour
  • .5 + .15 = .65Ah consumed hourly
  • 37.5Ah / .65Ah = ~ 57 hours transceiver run time @ 10 watts

What kind of Ham Shack backup battery system do you use?

COVID-19 How To Make A HomeBrew Face Mask

At the ripe old age of 71 and one who has to fend for myself, I have recently become increasingly concerned about the rapid spread COVID-19 around here during this crazy crisis.

Venturing out for supplies and fuel is a real problem. As we all know by now the virus can survive for very long periods of time in colder temps and on certain types on types of surfaces.

What perplexes me most is the lack of discipline folks have. Here on Long Island, few wear gloves and fewer people wear masks when out in public.  Now I’m not one to be paranoid about such things or listen to the prophets of doom in the media circus or hang on every word the CDC pushes out but there truly seems to be a real lack of concern about this virus where I live.

One of my pet peeves is gas pumps. IMHO, gas pumps are probably one of the most  dangerous surfaces to come in contact with. Yet, I see very few people with any form of protection against a surface that can be held by hundreds in a single day!

I have had limited success finding disposable gloves in the supermarket but masks are nowhere to be found.

To circumvent  the mask problem, I have Googled around for reasonable ways to make homebrew masks. Of course none of these masks will ever measure up to an N95 mask but making a homebrew mask appears to be worth the effort.

The New York Times offers a step by step guide on rolling your own. https://www.nytimes.com/article/how-to-make-face-mask-coronavirus.html

From Googling around, I also found out that face shields made from 100% polyester microfiber have a reasonable density for protection. Alpha Defense Gear sells a wide variety of face shields for both men and women. https://alphadefensegear.com/


Ham Radio will always be the ultimate way to perform Social Distancing

72 and 73 Be Well Be Safe de KE2YK