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Author Topic: Hamtronics Repeaters  (Read 3350 times)
K5OO
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Posts: 7




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« on: June 13, 2002, 09:13:43 AM »

Anyone using a Hamtronics receiver for a 2 meter repeater? How well is the sensitivity and rejection? Does anyone reccomend them? I have been using the old surplus radios that are 20-30 years old for repeaters like alot of others. They are really hard to find around here as well as alot of the parts are obsolete (that's why they wound up at a ham's shack instead of still in service in a police car somewhere). I am wandering about anyones reviews other that the great praises that are on their website about how they surpass all the old "mobile transceivers" that everyone homebrews repeaters from.
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WB2WIK
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Posts: 20611




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« Reply #1 on: June 14, 2002, 04:54:46 PM »

I've used them several times, beginning back in the 1970's (the Hamtronics receivers-transmitters-preamps-controllers are very old products that have not changed much).

Sensitivity is fine.  Selectivity isn't too bad, but immunity is not as good as most commercial repeater equipment.  By "immunity," I suggest resistance to overload, desense, noise, adjacent signals and out-of-band signals.

Transmitters are sufficiently clean for amateur work, although if greatly amplified, could create problems due to noise bandwidth.

The biggest obstacle to a successful repeater installation remains with the Hamtronics products exactly what it is with converted commercial gear, those being shielding, decoupling, filtering, and more shielding!  The system is only as good as its TX/RX isolation, a lot of which is in the enclosure design, use of feedthrough filters with sufficient attenuation, use of N connectors or better (rather than UHF) to take advantage of their 120dB shielding, use of all 100% shielded or at minimum double-shielded interconnect cabling, excellent duplexer tuning, and use of 100% shielded or at minimum double-shielded transmission lines.

If building the boards from kits, having a very well equipped test lab is a huge benefit in tuning these units for best signal-to-noise performance, and I don't mean receiver sensitivity!  Without a spectrum analyzer to tune the transmitter, it's impossible to know its output noise spectrum, which must be well controlled for repeater use.

WB2WIK/6
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W0AV
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Posts: 10




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« Reply #2 on: June 20, 2002, 09:22:57 AM »

Hi OM,

Well, my Hamtronics 2M repeater has been in service for 9 years now.

The only failure was a $2.00 IC, the Quad OpAmp audio filter.

I am very happy with the performance of the Hamtronics xtal repeater.

73 de George/W0AV

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KA4WJA
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Posts: 704




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« Reply #3 on: July 12, 2002, 11:14:42 AM »

I can echo everything that Steve, WB2WIK, said!!!!

I currently have two repeaters on the air using Hamtronics Rec. and Trans.
One at 146mhz and one at 224mhz.....

They both work VERY well.
The 2m one replaced an old GE MasterII  which replaced an even older MastrPro.....

BUT I needed to add additional Bandpass cavities upstream of the rx pre-amp, inorder to keep out intermod.... when I had some NEW vhf pager transmitters go up on a nearby tower.....
Other than that, NO problems in over 8 years of service....(except for a lightning strike that took out the old autopatch....)

73,
John,   KA4WJA
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W0MAS
Member

Posts: 2




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« Reply #4 on: February 25, 2013, 12:52:15 PM »

I built a 2M repeater using Hamtronics receiver and transmitter kits.
and RLC Club controller &150 watt repeater amplifier cruising @ 75watts.
after completing the kits and fine adjustments it was a very crisp and clean sounding repeater. way better than the muddy sounding old converted comercial systems
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