Report on the SMCARA K3HKI Repeater system.

Please read the follow information provided by Tom Clarke W4OKW about the current and future status of the K3HKI repeater. The club will need to vote on any distribution of monies and the time frame in which any or all of these items will be instituted.

The K3HKI repeater is located on a 150 foot Navy owned tower several miles south of NAS Pax in Hermanville.  We share the tower with some UHF transmitters that support flight testing at the base and enjoy shelter, emergency backup power, and no electric bills.

The repeater is a Motorola MICOR continuous duty commercial repeater with a 6 cavity duplexer that allows the simultaneous use of one antenna for both transmission and reception. The antenna is a Phelps-Dodge Super Stationmaster and is fed with 7/8 inch Andrew hardline.

The transmitter is rated at 100 watts continuous duty and we derate it to 75 watts for longevity purposes.  The controller is a CAT-300 with the phone patch disabled.  The repeater may be controlled via the input frequency or a 70CM link. The telephone line to the site was destroyed several years ago by a lightning strike and never replaced. The club elected not to spend the money to get Verizon to run a new “twisted pair” to the site, as cell phones have relegated amateur phone patches to the dustbin of history!

The repeater is over 25 years old and we do have some spare parts in the event of a failure of a major component, such as the Tx, RX, Power Amp, or power supply. The controller is of a similar vintage, however both are working well.  A backup repeater consisting of a Kenwood TKR-750 repeater (owned by W4OKW) and a CAT-250 controller is available in the event of an unrepairable failure of the main repeater.  The backup repeater is 25 watts, so the range will be down a bit from the main unit. Occasionally I bring the backup repeater up for test and you can recognize the backup as it has no “squelch tail beep”. The tone of the CW identifier is also different.

Last year the club voted to purchase a new controller for the repeater.  In discussing this among the repeater tech committee, it was determined that purchasing a new controller (approx $600) would not buy us any expanded capabilities at this time.  I propose that we defer the purchase of a new controller and commit the funds to a repeater improvement fund to be established.

I recommend that the club establish a “Repeater Fund” starting with the $500 voted for the new controller as seed money.  Periodic and regular additions to the fund can be made from a percentage of the dues, as well as donations and income from club activities such as the 50-50, and the Tailgate Fest.  The details can be determined by the executive committee and voted on by the membership.

Long range plan.

The repeater fund should be used to fund the long range improvements to the system, along with dedicated individual donations and special fund raisers. These suggestions are not original and are based (copied from!) on proven, current state of the art engineering. In view of the current condition of the repeater, the following is for consideration (in order of priority):

  1. Implement a 70CM link.  This will require obtaininig a 70CM transceiver and installing an antenna at the Hermanville site.  The previous antenna was removed by the Navy tower crew due to a misunderstanding. The 70CM transceiver went back to its owner when the previous GE system failed.  Estimated cost is about $300.
  2. Purchase an updated repeater, such as one of the BridgeCom BCR-40V series (Approx $ 1K). This will be a 25 watt repeater, although it can be lowered to provide required drive level for an external amplifier. The Yaesu repeaters have issues with PA reliablility and problems with interfacing an external controller. The Kenwood receive sensitivity is relatively poor at .25 uVolt and the PA will overheat and fail if run at full (50 watt) power.
  3. Purchase a commercial 10 watt in/ 100 watt out continuous duty repeater amplifier such as one of the Henry amplifiers. Estimated cost is about $ 700.  A heavy duty power supply will be needed, approximately $ 200.
  4. Obtain an updated controller, if and when the repeater has access to the internet. Currently internet access is not available at Hermanville. The new CAT-800 controller has many new features including internet interface, a third port, and easier programming.
  5. Way out on the horizon. If we lose access to the Hermanville site and have to move, a new antenna and feedline would be needed.  Estimated cost is about $ 1K.
  6. In the event of a direct lightning strike, a new duplexer could be required. This could be in the $ 1-2 K range.  n.b., the current installation incorporates commercial lightning protection devices and grounding, however Lightning doesn’t always follow the rules!

Tom Clarke, W4OKW

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