CNHARC  on  6-meters

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Click here for the official CNHARC web site


         Latest update as of Wednesday April 29, 2009


CNHARC  -  Six-meter repeater at Gunstock

Update 8-3-2008 After a summit trip to fix a power surge, the repeater is back on the air.  Details here:

Update 7-30-2008 : All Gunstock repeater output traffic is now mimicked on 51.74 from Hopkinton, MA. A Hopkinton remote receiver on 51.24 will be installed later this summer to enable extended southern coverage down to the Cape Cod Canal. This will enable NWS Gray ME to communicate with NWS Taunton, MA as well as many other Skywarn spotters.

Update 4-27-2009:  Hopkinton, MA  southern node is permanently on the air


rptr TX: 53.77 PL 100.0(user RX, PL not required)
rptr RX: 52.77 PL 71.9 (user TX, PL required)

also Hopkinton, MA southern linked node for Gunstock
(extends mobile-mobile coverage from Franconia Notch to Cape Cod Canal)

rptr TX: 51.74 PL 100.0(user RX, PL not required)
rptr RX: 51.24 PL 71.9 (user TX, PL required)

TX site pix:
RX site pix:

This project involved dozens of people with diverse skills.  It took several years to transition from just an idea into central New Hampshire's first wide coverage 6-meter linked repeater system.

Net Thursdays at 8PM     NY1H, Net Control




The existing, on-site Rohn-25 was purchased from WMEX radio which was recently sold. The antenna base is only 5-feet above the building roof.

The very rare lowband duplexer was previously used by Boston Gas.  It was purchased at Hosstraders in 2005.  Original list price:  $4500

The lowband GE MASTR-II repeater was acquired via eBay and was previously used by the Arizona Highway Patrol on Roof Butte on an Apache reservation in northeast Arizona.  The repeater is now going from baking to freezing !

The heavy duty backup batteries came from a retired UPS system formerly used at the ch-5 Doppler RADAR site.  The new UPS uses different voltage batteries so these "old"  batteries were only six months old!

The brand new Heliax cable came from a new microwave system being installed by ch-9.  These were the leftover short ends and the length was perfect for our needs as we had a short run.

The Motorola cabinet that holds the GE repeater was part of Operation Wolfpack. Click here for details.

Different TX and RX PL's are used to prevent the repeater from talking to itself.  The user transmits on a PL of 71.9Hz. The RX PL of 100.0 Hz is optional and is only used to reduce unwanted noise on the channel.  This is very important in the Boston area due to the ch-2 TV transmitter but may be of little use in New Hampshire.  Not all ham-built radios can support different TX & RX PL tones (some do) but all commercial radios can.

Testing on day-one reached south to Framingham, MA using a non-directional antenna (full quieting) and later in the day, Rhode Island. A coverage map is below.

Repeater Voice ID's by:

  • Long ID with "Gunstock":  Peter Mehegan, ch5 Chronicle reporter
  • Short ID: JC Monahan, ch5 meteorologist
  • PL ID:  Natalie Jacobson, ch5 former anchor
  • timeout:  Mary Richardson, ch5 Chronicle host

The previous "audio crunchies" issue was traced to a few loose connections that have been corrected.





Pictures by K1VE, N1LT and K1RJZ

KB1JCL is now NY1H              




Due to the highly skilled mechanical work (actually major surgery) of N1VE, NY1H and N1LT, this now-shortened commercial duplexer could be properly tuned up on ham freqs.  This gives the phrase "duplexer tuning" a whole new meaning !

Without CNHARC's amazing and highly-diversified skill-set, none of this would have been possible!








This is an extremely rare six-meter duplexer.  It was originally set-up by K1RJZ but some pesky repeater receiver desense symptoms remained.  Rick's work was double-checked by W1BRI and was already found to exceed factory specs at 53.77 MHz.  The culprit was that most testing of the repeater and duplexer was performed at a safe 20-watts.  However, the 110-Watt GE PA did not like to operate at 20-watts and thus created spurs. Increasing the power to a full 110-Watts made the problem go away.   None of this could have been proven without a 90-minute proof of performance battery of tests by Bryan, W1BRI using some fairly exotic borrowed test gear.  (HP 8712C Network Analyzer and Agilent 4407B Spectrum Analyzer... about $70,000 worth!)





Installation  day  is  finally  here....   Sunday  July 6, 2008


Gunstock management required very detailed information about what CNHARC was all about, how the non-profit 501(c3) corporation was insured, and what our plans were.  Gunstock employees also checked references or were the references.  Once their due diligence was satisfied, Gunstock was extremely helpful in facilitating the club's needs.  Both entities call Gilford home and that certainly helped to grow our relationship.










The repeater cabinet was a perfect fit... fortunately!  
The chair is designed to support 1200 lbs.






Rick-K1RJZ     Ed-N1EO     Tom-K1LQN    Mark-W1DDI
















High-tech meets no-tech...
Surprisingly, the duplexer is factory spec'd for optional horizontal
installation with no detuning down to -40-degrees F.  
Check back in January to see how well it works!




To save on rare interior space, the duplexer was installed outside.






The duplexer enclosure was designed and built by K1LQN and W1DDI






Lee, KB1GNI took a trip to Needham, MA to pick up the very heavy sealed batteries.





















N1XBD and KB1QOX spent several hours on top
with no break. They get a gold star!

















Some final tie-wraps by K1RJZ.  Although the effort may
look impressive, Rick was only 2ft off the ground.





Every successful project needs one special local person to push, cajole and
otherwise play cheerleader to motivate members to join in on the project.
Meet Bob Carollo, NY1H










N1LT, Dick
N1EO, Ed
KB1OCE, Dick
KB1MGL, Doug
K1RJZ, Rick
W1DDI, Mark
K1LQN, Tom
N1XBD, Jim
Ben Craver, N1XBD's son
KB1QOX, Greg
NY1H, Bob
KB1ESJ, Gary
NU1S, Bernie
N1MAZ, Frank

plus hiker Klaus Buttinger 's dog



Surprisingly, real-world coverage seems to follow this computer projection quite well.
Bob, K1IW is also President of which is our frequency coordinating agency.


Click here for the log of the first 6M net held via Gunstock (but 6M net #223)


For the wider picture from Gunstock...

Gunstock Mountain as seen from Paugus Bay, Laconia, NH












 rptr TX:   53.77    PL 100.0    (user RX)
 rptr RX:   52.77    PL 71.9      (user TX) 

Net Thursdays at 8PM






From Gunstock Summit looking south








Update 8-3-2008:   Repeater is back on the air after a power surge. 
Details at this link:


 rptr TX:   53.77    PL 100.0    (user RX)
 rptr RX:   52.77    PL 71.9      (user TX)

Net Thursdays at 8PM


last updated: Wednesday April 29, 2009

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