Archive for the 'Tech info' Category

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Lightning strike

Article and photo link by Mike Walker, VA3MW. Thanks Mike and keep sending us more info.

Last Saturday (May 1st, ), the Toronto FM Communications Society technical committee had the opportunity to take a crane to the top of the ski resort where the repeaters are located (south of Uxbridge Ontario).

The goal was to fix the broken 442.100 (HUB) antenna.  This antenna sits 8 meters above the top of the tower.  It is mounted on top of the 8 bay Sinclabs 224.860 VE3BEG repeater.  For the past year we have discussed how we could easily repair the 440 antenna.  We suspected that it was a bad jumper cable into the 440 vertical.  The HUB has been operating on a much lower mounted UHF antenna which resulted in much less overall range.

With the weather being so dry as of late, we got permission from the ski hill owner to bring the crane to the top since the ground was so hard.  With the use of a man (maybe that should be .. person?) bucket, we hoisted Neil VE3SST to well above the top of the tower.  In short order, he was able to remove the 440 antenna and lower it to the ground for testing.  We quickly determined that it was not a jumper problem, but that the antenna was truly ’busted’.

As Neil installed the spare (doesn’t everyone have a spare 440 vertical?), I took to cutting into the dead antenna housing.  What I quickly found out was that that rod that starts to make up the antenna in had vaporized and the bottom 6″ was totally missing.

What was also missing was the coil that made up the DC ground.  It too had vaporized.    In one of the attached pictures, I have a flashlight shining down the base to the point where the actually antenna rod should have been physically attached.   More pictures can be found at http://www.walkerphotography.ca/Hobbies/TFMCS including the high definition picture of the entire towers that is a blend of 12 static pictures.

That was one amazing lightning hit.  The antenna did die a hero and none of the equipment in the shack was damaged by that hit.

The crane  rental was expensive, however it did allow us to very easily and very safely do the work required on the top of the tower  in a difficult place.  The use of a Gin pole was not practical as we would not be able to get the sling in place above the balance  point of the antenna stack.  There was also risk of more damage to other antennas while lowering or raising the
antennas.

With the new antenna in place, the coverage for the 442.100Mhz HUB has been increased greatly.  As this is a HUB repeater, there is no ‘tail’ on the repeater should you happen to make a call on it.  That doesn’t mean that it isn’t there, it is just being stealthy.

The Toronto FM Communications Society <http://www.tfmcs.com>  has repeaters on 10M, 6M, 2M, 220, 440, 1.2G and D-Star (UHF and VHF).  As well, we are fortunate enough to have 2 repeaters located in the CN Tower on 145.41 – and 444.400 +.  We also provide linking via RF to points north of the repeater site, via IRLP and D-Star.

DX on 2 meters?

This Saturday (8th of May) the Saskatoon Amateur Radio Club is launching SABRE-9 a high altitude ballon that is equipped with a simplex repeater on 147.570. Amateurs in Saskatchewan, Alberta, Manitoba and northern US states should be able to hit the machine when it is at maximum altitude. The launch takes place at 8:00 MDT (9:00 CDT).

Club members expect that the balloon will be aloft for approximately  3 to 4 hours.  What is unique with this flight is that there will be onboard a simplex repeater on 147.570.  This is a store – forward simplex repeater.  You use it by transmitting a short message on simplex at 147.570.  When you unkey you should hear your own communication back.

Anyone else withing range of the repeater will also hear that transmission from the balloon.  They can then respond the same way.  Without flying duplexes etc club members say they should be able to facilitate communication over a very long distance.  In theory once the balloon gets above 30,000 feet ( approximately 3o minutes from launch) stations from Manitoba should be able to hit the repeater and in theory communicate with stations from Alberta and the northern USA.

It may help to direct you antenna towards Saskatoon or Humboldt  Saskatchewan as this is the predicted flight path but it is very likely that a mobile unit with a 5/8ths wave will work especially once the balloon gets above 70,000 feet.

In an attempt to encourage use of the repeater the Saskatoon Amateur Radio club is sponsoring an award for communications through the repeater.

The website for VE5AA has the details of the award under the Sabre 9 link. The club would appreciate it if you would publicize the repeater on the Manitoba nets and encourage Manitoba hams to try and make a contact.

The Saskatoon Web site is for this May 8 Saturday launch is http://ve5aa.dyndns.org/Balloon/sabre_9.html and here’s a link to photos and info from Sabre 1 to 8 flights.

Documentation and images from their previous launches are here http://ve5aa.dyndns.org/Balloon/index.html

Diversity receivers and noise reduction

His post is going to take us down a very technical path. The linked YouTube video is from W9OY and is a demonstration of thediversity properties of the software-defined Flex 5000 transceiver.

In this demonstration we start off listening to the basic noise floor on 160 meters (which is pretty much how I hear 160 meters all the time) and then Lee walks us through how the Flex 5000 can make the signal so much more intelligible by introducing filtering and diversity receiving.

But there’s more. The Flex 5000 has two software defined receivers that Lee is feeding with two vertical antennas separated by about 3/8 of a wavelength. The software allows for the operate to “steer” the two vertical antennas for better reception. As Lee puts it: “Beam steering is accomplished by changing the phase and gain of one antenna relative to the other.”

This is likely the future of radio.

Thanks VA3MW for this link.

Canadians get 137 kHz!

RAC Bulletin 2010-007E – Canadian Amateur Radio Access to 137 Khz.

2010-03-10

Industry Canada has approved access by Canadian radio amateurs to the Low Frequency (LF) band 135.7 ? 137.8 kHz, subject to certain conditions. The Revised Canadian Table of Frequency Allocations, promulgated in December 2009 to incorporate changes arising from decisions taken at World Radiocommunication Conference (WRC) 2007, permits amateur use on a Secondary basis subject to Footnote 5.67A.

The Footnote states: “Stations in the amateur service using frequencies in the band 135.7-137.8 kHz shall not exceed a maximum radiated power of 1 W (EIRP) and shall not cause harmful interference to stations of the radionavigation service operating in countries listed in No. 5.67. (WRC-07)”. Industry Canada has advised that Canadian radio amateurs may now use the band and that Schedule I of RBR-4 Standards for the Operation of Stations in the Amateur Radio Service will be amended in due course.

Richard Ferch VE3IAY/VE3KI

Vice President Regulatory Affairs RAdio Amateurs of Canada

Bulletins RAC 2010-007F – Accès à 137 kHz. pour la radio amateur au Canada

2010-03-10

Industrie Canada a approuvé l’accès par les radioamateurs canadiens à la bande basses fréquences (BF) de 135,7 à 137,8 kHz, sous certaines conditions. Le Tableau Canadien Révisé des Allocations de Fréquences, promulgué en décembre 2009 pour incorporer les changements découlant des décisions prises à la Conférence Mondiale des Radiocommunications (CMR) 2007, permet l’utilisation radio amateur sur une base secondaire sous réserves de l’annotation 5.67A.

La note se lit comme suit: «La puissance rayonnée maximale des stations du service d’amateur utilisant des fréquences dans la bande 135,7-137,8 kHz ne doit pas dépasser 1 W (p.i.r.e.) et ces stations ne doivent pas causer de brouillage préjudiciable aux stations du service de radionavigation exploitées dans les pays énumérés au numéro 5.67. (CMR-07)». Industrie Canada a annoncé que les radioamateurs canadiens peuvent maintenant utiliser la bande et que l’Annexe I des Standards IPR-4 se référant aux opérations de stations dans le service radio amateur seront amendées en temps opportun.

Richard Ferch VE3IAY/VE3KI

Vice-président Affaires Réglementaires – Radio Amateurs du Canada

(Traduction par Serge Langlois, VE2AWR)

500 kHz activity

Did you know that there is amateur radio activity on 500 kHz? This is a frequency that is below the AM radio band. Antennas at this frequency are HUGE and not all countries allow amateur radio operation (Canada does thanks to a RAC initiative back in 2008). Here’s a link to a website that’s filled with great information about this new initiative (well really it’s an old band).

Why aren't you on 6?

The April 2010 issue of QST, the ARRL’s monthly magazine came in today and the lead editorial is all about the excitement of operating on 6 meters. For those of us who lived in cities where TV channel 2 was active (here in the Toronto area we had to contend with a weak signal from Channel Two Buffalo, New York), there was little to no 6-meter activity. There’s a famous story about one Toronto ham who back in the 60′s ran a kilowatt on six and caused TVI for miles around.

With the re-allotment of analogue U.S. TV to the higher UHF digital bands, 6-meters is pretty safe for hams across North America.

So what’s so great about 6?

As David Sumner, K1ZZ, ARRL CEO says in his editorial, we don’t call 6-meters the “Magic” band for nothing. Six is famous for its unpredictable openings thanks to sporadic E propagation which can allow for transmissions over 1,000 miles using relatively small antennas. Most new HF rigs include the 6-meter band. If your rig has a squelch, it’s easy to leave it on full time at 50.125 mHz (a calling frequency) and wait for the action.

Conditions get really good in May so now is the time to get your 6-meter antenna up.

And more good news: Modest 6-meter antennas work really, really well. At VE3HG, I’m using two square-halo antennas (in photo) on a 16′ mast on top of a TV tower at 30′. So no rotor needed and I can easily work into the U.S. and the Caribbean when the band is open using 100 watts.

Welcome to the future Elmer

If you’re active at all on the HF bands you’ve likely struggled with configuring popular software programs like Writelog or N1MM. Maybe the complexities of the computer to rig interfaces have been frustrating? How about how to erect a vertical antenna for 160 meters?

Back in the “old” days newcomers to amateur radio would team up with an “Elmer”.

I don’t know for sure where I first heard ham radio mentors called Elmers but it was a long time ago. I can remember going to “Uncle Ray” Hunter’s (VE3UR SK) Etobicoke, Ontario shack as a wide-eyed 13-year-old. Ray took great delight in showing my Dad (who would later be licensed as VE3FWR) and I the wonders of DX. I was especially enthralled by the big black box that sat on its own stand at the end of the operating table. It might have been a Model 19 as shown. Fifty years ago, this was “high technology” at its best. Big, noisy as heck and smelled of machine oil. But it worked. Uncle Ray had over a couple of hundred confirmed RTTY DX QSOs back then.

These days, it seems to me, that there aren’t that many Elmers kicking around. So where do you go to get technical help if you’re new? Well online of course! Many organizations (RAC and the ARRL) have tons of information available on their websites. And with the availability of virtually no-cost bandwidth it’s now possible to post audio and video files.

The Northern California Contest Club has posted almost a dozen webinars online for you to download. Subjects include “How to set up a Microham keyer” (It’s easy if you read the manual but if you’re like me it took me weeks to get it running just right. This would have been so helpful.) or how to set up and configure Writelog (which I use) or the free and very popular N1NN contesting software. There’s a webinar on RTTY and several on antennas.

We’re going to see many more clubs and associations offering tons of online help.

RTTY Contesting

According to the Contest Club of Finland, RTTY contesting is the fastest growing contesting mode in the world. I love RTTY contesting. The emphasis of RTTY contesting is more on the equipment and less dependent on the the ability of the operator to decode the information in his or her brain.

As I grow older, this fact alone makes my RTTY experiences very positive. CW not so much and I don’t know about you but listening to a band load of contesters yelling in my headphones for 48 hours isn’t my idea of a great time (although it’s a lot of fun if you’re part of a multi-operator effort). Having said that, I do intend to be on this weekend’s ARRL DX SSB contest.

Today, some rigs, (notably ICOM’s newer equipment) can send and decode RTTY right in the rig thus eliminating the need for a computer and interface. Cool.

If you’re interested in learning more, Contest Club Finland held the world’s first RTTY Contesting School. Thanks to the ARRL Contesting Newsletter here’s a link to a PDF presentation that was part of the school.

Grounding

Newcomers to amateur radio often find grounding a very confusing subject. Even the “experts” can disagree.

A discussion about grounding a high-frequency contest station has taken place on the Contest Club of Ontario’s email reflector and it got me thinking about how I ground my own station here at VE3HG.

To complicate matters, there are two reasons to ground your station and high frequency (H.F.) antenna systems. First is for safety. All antennas erected outside are capable of being struct by lightening. That lightening needs somewhere to go. It’s best if the termination point isn’t your expensive radio. The second type of grounding is an radio frequency (R.F.) and here’s where there can be some confusion. Antennas cut for the precise frequency and feed with perfect feedline terminated with perfect mechanical connections at the optimum height do not require an R.F. ground as 100 per cent (okay there are some losses due to heat) of the signal gets radiated. In fact, at some frequencies such as VHF (6 meters and up) an R.F. ground can be more a problem than a solution. So why do so many hams think they need an R.F. ground? It’s because most of our stations are not equipped with perfect antennas at optimum height radiating 100 per cent of the R.F. being created by the transmitter. R.F grounding can help tame stray R.F. in the shack when used in conjunction with ferrite chokes.

Here’s a link to W8JI’s webpage that includes information on ground systems.

K0BG’s site has some useful information about R.F. and D.C. grounds.

Finally here’s another link from Hamuniverse.com on grounds by N8SA.

Webinars for hams

Webinars, online lectures, have come to amateur radio. This thanks to the ARRL Contest newsletter:

The Potomac Valley Radio Club announces another pair of its popular Webinar series: Jan 14 at 8 PM EST - K3LR on Contest University and Jan 20 at 10 PM EST - K9LA on 160 Meter Propagation. The hyperlinks will take you to the registration page for each free event.

BTW if you’re looking for an easy way to get into CW contesting this weekend is the North American QSO Party. Starting at 1800Z on Saturday and ending 12 hours later (of which operators can operate for only 10 hours out of the 12) this somewhat easy going CW contest is one of the more civilized contests where the objective is to work as many North American stations as possible. Everybody who can radiate a signal into a dipole is welcome. CW speeds rarely exceed 22 wpm and most contesters will come back to you at your speed. The exchange is your state/province and name. BTW there are no rules against using somebody else’s name. A few years back a famous and much respected contester died just before the NAQP and strangely, to those of us not in the loop, we were very surprised to work so many guys named “AJ” all from the same state.