[SMCARA] 64 Repeater update

[June Entzi]

Thank you for doing what you do.  It is appreciated.

June

Sent from my Verizon LG Smartphone

------ Original message------
From: Clarke, Frederic
Date: Mon, Oct 22, 2018 5:42 PM
To: SMCARA at mailman.qth.net;
Cc:
Subject:[SMCARA] 64 Repeater update

I have made another adjustment to the audio levels and have a couple of reports that it sounds pretty good.  Turn a critical ear to it and let me know. Just for fun, I checked my frequency counter against a lab quality, Rubidium standard at GEM on base and found it to be less than 60 Hz off!  The Motorola Analyzer at K3NAL, was even closer.  The new card we just received from Bridgecom is 12-20 Hz off, so we are in good shape.

Known issues:

1. Hum in the background. That is the 146.2 CTCSS that is transmitted to accommodate those using TSQ on receive.  This mutes your receiver unless it detects the correct CTCSS tone, and typically is used to prevent interference from another repeater on 146.64 from opening your squelch. Not a big issue, unless you have a high antenna and get the Frederick or Pine Mt (Pennsylvania) during "enhanced propagation" (AKA "skip").  Remember, if someone calls you direct on 146.64 simplex (say, if the repeater is down), you will not hear them. If you go somewhere else and try to use another 64 repeater,  you will not hear it either. At any rate, unless it is desired by users to disable the tone on transmit, ignore it!  For home stations, you can get rid of it by passing the receiver audio through a high pass filter set to cutoff at 300 Hz. A simple HP filter may be made using an Op-amp.  A Google search will bring you lots of hits.

2. The courtesy beep is loud.  Unfortunately, it is as low as it goes.  Any further reduction in the tone will require lowering the deviation of the entire repeater (computer voice and repeated audio.). The deviation is currently set at 3.5 KHz with a max of 5 KHz.  This is the normal setting for wideband FM repeaters. I may experiment with a different tone to see if that helps.

3.  Random announcements for Net Tonight, etc.  The date is incorrect in the controller, so it thinks the Tuesday net meets on Sunday! I'll fix it soon! The random "Message 4" announcement remains a mystery!

4.  The 440 link is ready to test, as is the 100 Watt amplifier (we are currently running 42 watts up the chimney.).  After the audio is satisfactory, I'll move the system to Hermanville to the big tower with the gain antenna and the coverage will go up considerably.

5.  We need to recruit a couple of "control operators".  Basically if a control op detects something going wrong, be it electronic or human in origin, he/she has the ability to turn off the repeater and make other changes, such as disabling CTCSS and Timeout timer (for Nets etc.). This control may be on the input (146.04) or on the link frequency.

6. If history is any indication, Pete and I will probably not live forever, so recruiting a "repeater tech" or 2 might be smart! I am preparing a system manual covering the equipment and all the mysterious wires associated with K3HKI.

Future plan:  At the January meeting, perhaps, I'll bring the Motorola System Analyzer to the meeting and we can check your frequency and deviation.  To check an HT, we will have an rubber duck antenna on the analyzer and you just need to transmit nearby.  For your mobile rig, we will have a coax jumper to run to your vehicle's radio.  A direct connection like this will also read the power output of the rig. To do a home rig, you will need to bring it and a power supply in to the meeting.  FYI, the new repeater is less forgiving of over-deviated (wide) signals.  Chopping and distortion are the usual results of too much deviation. If you are running a microphone that is not designed for your rig (i.e., other than the OEM supplied mike), there may be audio issues.  Whatever you do, don't use a CB "Power Mike"! They just make the distortion louder! <-:

Sorry this has taken so long, but work (albeit part-time, now!) and travel to visit my "geographically diverse" kids/grandkids, has limited my "time on target"!

73 Tom/W4OKW


KBRwyle  |  TRITON NATOPS/NATIP Product Support
22309 Exploration Drive | Lexington Park, MD 20653 | USA
Office: 301-863-4418  |  Mobile: 301-904-2053
tom.clarke at wyle.com [Pri] | frederic.t.clarke.ctr at navy.mil
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