Archive for the Radio Communications Category

TAPR annouces availability of Trimble Thunderbolt GPSDO kits.

Posted in Ham Radio, Radio Communications with tags , , , , , , on July 15, 2009 by WA4ZKO

UPDATE:  Looks like these are no longer available from TAPR.

TAPR is announcing the availability of Trimble Thunderbolt GPS Disciplined Oscillator (GPSDO ) kits for $130 here. It looks like they are working with the leapsecond.com folks on this deal.

So with a little effort you can have yourself a super accurate 10 MHz  and 1 PPS reference source. The product data sheet (PDF) here will give you a peak into the capabilities of these neat units.

I have one and it’s a jewel of a device and a very handy addition to your test bench. I didn’t get mine through TAPR and had to come up with my own power connector f or it…so the TAPR kits will save you some time.

Note:  You’ll need a +12 VDC, -12 VDC, and +5 VDC power supply for these units. A small PC power supply is probably the easiest approach, but not so portable. You will also need an appropriate GPS antenna.

NASA – “Mystery of the Missing Sunspots, Solved?”

Posted in Contesting, Ham Radio, Radio Communications with tags , , on July 1, 2009 by WA4ZKO

NASA’s theory on the very slow return of sun spots for this solar cycle:

Mystery of the Missing Sunspots, Solved?”

WA4ZKO – 144 Mhz Spring Sprint wrap up/soapbox

Posted in Contesting, Ham Radio, Radio Communications on April 10, 2009 by WA4ZKO

12 Q’s, 9 grids, 6 states, total score 108.

I did better this time around than last year! The band seemed to be flat, maybe up some to the E and NW.

Worked KA1ZE/3 Stan from Tolland, CT up at his contest site in Pennsylvania (FN01xx) about 420 miles out. This was my farthest contact of the evening.

W9GA Ken in Wisconsin (EN53WE) about 361 miles out.

K4QI with a nice signal from North Carolina, FM06 about 350 miles out.

W8ZN Terry way over in Virgina, FM19bb about 370 miles out.

The continued “silence to the south” is starting to worry me. What has happened to the Tennessee stations? Admittedly I did more “hunt & pounce” this time around, so maybe they were doing the same and we just missed each other. I did spend a lot of time listening to the south and called during a few spells. There used to be several folks routinely active in Tennessee.

The trend of no one on around Lexington and Louisville continues. I think I was the only station on in Kentucky! If others are on the air contesting, I sure didn’t hear them! Kind of glad I didn’t make the Black Mountain run for this one due to weather concerns. With the “silence of the south” continuing, probably best that I stayed in Northern Kentucky.

It’s hard to say for sure if the apparent trend of lower activity is something to worry about. When the solar cycle is low and 6m is only hopping during “easy season” I tend to think a lot of the VHF/UHF weak signal folks pursue other interests and forget about the VHF/UHF activities. Seems like I remember this trend from the 1990’s, but it is worrisome. Today the hobby is also competing against a never ending deluge of new tech/internet “fads” for folks time/interest.

NTIA/IAFC report reveals serious fire service concerns with digital-radio systems

Posted in Ham Radio, Law Enforcement, Radio Communications with tags , , , , , on September 10, 2008 by WA4ZKO

Fringe range performance and spectrum efficiency are often the only advantages to going digital.

A recent NTIA study concerning issues with digital 2-way radio usage in the fire service has revealed some very serious issues.  The study itself can be found here.  MRT’s article on it can be found here.  Some interesting comments on this topic can be found here, take ’em for what they’re worth.

For those that know me, know I’ve preached on this topic for about 2 years now. Just because something is “digital” doesn’t mean it’s automatically better. For sure, digital-radio has it’s place in communications, but it’s not without it’s own pros and cons. You have to weigh these factors in first and not just jump into the “latest and greatest” mindset that is so pervasive in our society today. Often the “latest” is just that and not the “greatest.” The often over-hyped marketing of this technology does not help folks/agencies make wise choices either.

I’ve personally heard vocoder performance failures outside of the fire service. A local city PD in Connecticut had a post vehicle pursuit incident where background noise created a communications mess. As the pursuit ended, they had several officers jumping out of cruisers quickly to contain the suspects. Several units still had their sirens running and you can probably guess what resulted on their UHF digital system.

Yes, the vocoders have come a long ways in the last few years. I’m sure they will improve things even further, but folks there are certain fundamental laws of physics that apply to audio and THEY ARE WHAT THEY ARE.  Without widening the bandwidth, there is only so much sampling and DSP work you can do and keep things contained in a few KHz of channel width. It will be interesting to see how the technology plays out, but for now it is what it is.

Yes user education/training is also needed. From my public safety background I’ve been on both ends of these communication circuits (dispatch & in the field). One of my big radio communication pet peeves is the trend toward “plain language” public safety radio communication techniques, the errors this introduces, and the negative radio discipline that often creeps in. If I had a dollar for every “repeat” or out right misunderstandings caused by poor radio discipline I’ve heard, I’d be retiring at age 40, grin. That’s true even considering I don’t listen to local public safety radio that much anymore as it’s too annoying to monitor daily.

Solar history made – 1st spotless sun in about 100 years.

Posted in Ham Radio, Radio Communications on September 1, 2008 by WA4ZKO

Lot of history made in August 2008. This one will probably fly under the radar of most folks. For the first time in about 100 years, we have an entire month in which the sun was spotless. Safe to say we’re at the bottom of cycle 23 now, grin. Full article here.

Some interesting parts in the article, then some are questionable. This comment struck my eye….

“The event is significant as many climatologists now believe solar magnetic activity – which determines the number of sunspots — is an influencing factor for climate on earth.

Well? The sun and it’s cycles might be responsible for weather changes on earth?? Ah, you think? DUH!