New 147.000 Repeater Antenna

As you may have heard, the 147.000 repeater had been experiencing sporadic crackling noises on weaker signals over the past year.  It was determined that the cause of this problem was not in the repeater itself, but in the antenna system.  This finding is of no surprise, due to the fact that we had this same issue almost 5 years ago.

The repeater antenna is a commercial grade Super Stationmaster that is built to withhold the toughest conditions and comes with a price tag of over $1,000.  SEMARA originally installed this antenna model in 1999 when the current 180 foot tower was built.  Unfortunately, that antenna had to be replaced in 2006 due to the same recent crackling problem.  Faced with the fact that we must replace the antenna once again, it appears that our average life span with this antenna is only about 5 years (it is advertised to be 15-20).

The repeater committee received a recommendation from Tony, NN1D to purchase a consumer grade Tram 1481 (a Diamond X-500 equivalent).  This low cost $100 antenna has been in use on Tony’s 146.805 repeater for a few years now with positive results.  SEMARA recently purchased this same antenna and on the morning of Tuesday, July 20, 2010, NETCOM arrived at the tower site make the antenna swap (the receive antenna for the Dartmouth Police Department‘s new 450 MHz P25 digital system was also installed).

The end result?  A very clean sounding repeater with improved coverage!  Repeater committee member Dave, W1DJG is now able to hold the repeater (without help from tropo) until the end of MA Route 24 in Canton at the I-93 split during his commute to Boston.  The current plan is to keep this antenna in place until any future issues arise.  Even if we had to replace this antenna once per year after a harsh New England winter, it is still half of the overall cost of replacing a $1,000 antenna every five years.

Cable Modem Replaced

Around 12:15pm during yesterday’s severe thunderstorm that passed through the South Coast, the internet at the SEMARA clubhouse along with the repeaters’ IRLP nodes, APRS and the scanner feed all went offline.  It was determined today that the cable modem at SEMARA’s clubhouse suffered a power surge and went dead.  The Comcast SMC Business IP Gateway was replaced today by a Comcast technician around 2:00pm.  Special thanks to Marcel, W1MLD for going down to meet the technician at the clubhouse before I was able to join in.

Programming Party – Sunday, July 11th

On Sunday, July 11, 2010 at 11:00am, there will be a programming party at the SEMARA clubhouse.  Jeff, N1ZZN and Rick, W1RJC will be on hand to reprogram anyone’s Motorola 900 MHz radio.  Radios that can be programmed include the Motorola GTX mobile and MTX9000 hand-held.

Whether you need your radio reprogrammed to work with the recent changes on the two Dartmouth 900 MHz repeaters, or you would just like to get the most up-to-date memory “codeplug”, be sure to bring your radio(s) and stop on by!

900 MHz Repeater Now Linked!

The wait is over!  I am happy to report that as of Saturday, June 26, 2010 at approximately 4:30am (after spending hours at the site), SEMARA’s 927.8375 repeater is now linked full-time to the New England Amateur Radio 900 MHz (NEAR-900) network.  Larry, W1DBX stayed up all night to witness the moment when the link was activated and made the first transmission over the network.

I again must thank everyone that helped me make this happen, including Ho, KC1HO and Jeff, N1ZZN.  They both came down on two prior occasions to help wire up the repeater controller and make changes to the PL tone and Hear Clear settings.  I still owe them a nice big meal at Wright’s Farm!  In the upcoming week, we will be finishing up some minor work, including permanently mounting the repeater controller inside of the repeater rack and adjusting the repeater deviation.

Some of the other 900 MHz repeaters that you can expect to be linked in full-time with us include Boston, Hingham, Marlborough, Marshfield, Salem and Wrentham.  You can always check to see who is currently connected to the network in real time by visiting the IRLP Status Page for the New England Reflector.  Channel 5 (9125) is the NEAR-900 channel and all stations listed under this channel are linked together.


Richard J. Cabral, W1RJC
SEMARA Repeater Committee

Changes to the 900 MHz Repeater

SEMARA’s 927.8375 repeater has changed from DCS (DPL) to CTCSS (PL) access.  The new tone is 67.0 Hz.  Motorola Hear Clear technology has also been disabled.  These changes were made to facilitate the upcoming linking and to fix a problem in which the repeater would falsely key-up on random noise on the input.

Please note that these same changes have also been applied to the “Dartmouth North” SCMARG repeater on 927.6500.  A big thank you goes to Ho, KC1HO and Jeff, N1ZZN for once again donating their time to assist.  A radio programming party may be scheduled in the near future so that local users can have their Motorola mobile and handhelds reprogrammed.

900 MHz Repeater Update

On Saturday, September 19, 2009, SEMARA’s new 927.8375 repeater was placed on the air.  The repeater is a Motorola MSF-5000 with its antenna on top of the 180 foot tower along with the 147.000 repeater.  The plan was to add IRLP to the repeater in order to link it to a growing eastern Massachusetts repeater network known as New England Amateur Radio 900 (NEAR-900).  As of Saturday, June 12th, we are now one step away from linking the repeater to the network.

At 2:00pm, Rick, W1RJC met up with Jeff, N1ZZN and Ho, KC1HO at SEMARA.  The crew started at the clubhouse with Jeff programming a few Motorola 900 MHz mobile radios (including one that is to be mounted on the wall).  Rick reconfigured the underground CAT-5 cable that runs between the clubhouse and repeater site to carry two ethernet connections.  This will be necessary so that the 2 meter and 900 MHz repeater’s IRLP can be on two different Comcast IP addresses.

About an hour later, the crew headed out back to the repeater site.  In order to link the repeater to NEAR-900, an external repeater controller is required.  A repeater controller is the brain of a repeater which tells it when to transmit and routes the audio, courtesy tones and IDs accordingly.  The repeater’s receive and transmit audio along with logic control for the receiver carrier operated squelch (COS), receiver PL decode and transmitter push to talk (PTT) needs to be wired to the controller.

After a few hours work and a trip to Rick’s house to pick up some parts, a DB-9 port was added to the repeater.  Our brand new repeater controller, the Arcom RC-210, was then connected via a shielded patch cable to this port.  After adjusting the squelch and audio levels in the controller, the installation was a success!  The crew then headed to Texas Roadhouse in Dartmouth for some well deserved food.

Following dinner, Jeff and Rick headed back to SEMARA.  The Kenwood TS-570 HF/6m radio was fired up to check out this weekend’s VHF QSO Party.  There was a fairly decent 6 meter E-skip opening which allowed Jeff to log at least five contacts in the SEMARA logbook.  Most of the stations were from 4 land including Florida and Kentucky.

The final piece of work in linking the 900 MHz repeater into NEAR-900 will occur in the upcoming week by Rick.  A patch cable will need to be modified to allow the new IRLP computer to be connected to the repeater controller.  The computer must also be tested to make sure that it can acquire a separate IP address from the cable modem (a router will be added later).  Audio levels for the node need to be adjusted via the repeater controller as well.  A second update will be posted here when the link is complete and up and running.  Stay tuned! 🙂

SEMARA Computer Access

For SEMARA Members:

The Technical Committee has decided that we will use call signs and a password (password cannot be your call sign) to gain access to the SEMARA computers.  If you would like access, please send an email with your username and password to technical [at] semara [dot] org.

This access will be for computer and internet use only.  You will be responsible for any content that passes through the SEMARA network.  There will be zero tolerance for anyone abusing the SEMARA PC Code of Conduct, posted next to the computer.  This access will not allow you to install programs.  If you need a program installed, you will need to get in contact with a Technical Committee member.

Thank you for your cooperation.

ARRL Field Day – June 26th – 27th

ARRL Field Day is always the fourth full weekend of June, beginning at 1800 UTC Saturday and running through 2059 UTC Sunday. Field Day 2010 will be held June 26-27, 2010. The objective is to work as many stations as possible on any and all amateur bands (excluding the 60, 30, 17, and 12-meter bands) and to learn to operate in abnormal situations in less than optimal conditions.

SEMARA will be participating in this year’s Field Day. Ben, N1WBV is coordinating the event and is open to suggestions. He writes:

Current plans are for us to be active Sunday as a 2A station running off the club’s batteries and a generator I will bring. I plan on being at the club around 6AM. I know last year we petered out around noon, but lets try to run later this year!

If more folks would like to bring equipment and operate: PLEASE DO! Just let me know before hand so we can ensure a spot for you to operate and we can ensure that we are kosher with our transmitter count.

Currently, we have needs for tarp or something else for shade (or shelter if mother nature decides to pull a fast one on us) on the operating positions.

I have heard that in years previous, we have had a cookout. I think this is a great idea. Does anyone want to volunteer to cook?

Since this is only my 2nd time running a field day (admittedly, this is the 1st time I actually have attempted to plan one) and I know that W1AEC have done this many times before, suggestions are most welcome.