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Anyone do 900 MHz?


RCM

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Lately I've been perusing some of the 900 MHz commercial radios for sale, and thinking Hmmm... :unsure:

Repeaterbook lists lots of 33cm repeaters, including several in my area. Maybe now's the time to make a move into a new band.

Anyone here using the band?

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I've been running multiple 900mhz repeaters for years. It is a great band. Similar to 440mhz but with sharper nulls etc... The trick is finding clear input and output freqs...my machines are on odd splits because of that but since everyone is on commercial radios it doesnt matter.

 

Motorola GTX and MCS2000 are my preference.

KENWOOD TK-981 my other preference.

 

For at home base antennas comet makes a really well performing fiberglass vertical.

 

LMR-400 or better is damn near mandatory.

 

Thats my 2cents. FYI nyc based.

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The rig I just picked up is a TK-981. I have a dual band cellular Yagi that I might be able to use for mountaintopping, if I had any way to check the match. I plan to put a mobile antenna on my van, too.

33cm operation from my home would probably be an exercise in futility.

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  • 1 month later...
  • 6 months later...
  • 1 month later...

There is a new 900 repeater fairly close to me, and I have worked it a couple of times to verify its existence. I've also been in contact with the repeater owner.

I have more 900 rigs now, too. TK-981s and a couple of TK-481 portables. Both are awesome radios that use the same programming software.

 

The TK-981 is a mobile that is the same platform (and uses the same software and cable, accessories etc.) as the TK-880 that is popular with GMRS ops. The 481 is the same platform as the TK-380.

 

Anyone who is at all interested in 900 MHz should look on ebay and possibly elsewhere; TK-981s are kinda' flooding the market right now at prices as low as $50 shipped. A year ago they were $140-$200. Next year you might not be able to find one for any price. That's how it works.  Apparently one or more sizeable entities are replacing their 900 MHz system(s) with something else.

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I'd be using it if the Part 15 stuff weren't.

 

XBScZWJ.png

 

You know... In looking back at this, I am wondering if that wide mess centered at 927.5850 isn't an IF image on your monitor.  That 150KHz wide signal doesn't look like anything part 15, but it sure does resemble the pattern of an analog Stereo-Composite FM signal used to relay programming from a studio to a transmitter site for broadcasting.  STL (Studio to Transmitter Link) signals are normally 150KHz wide, and are in the 940-960MHz range... the bottom end of L-Band microwave.  If it's on 24/7 and never moves, that's likely your answer.

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You know... In looking back at this, I am wondering if that wide mess centered at 927.5850 isn't an IF image on your monitor.  That 150KHz wide signal doesn't look like anything part 15, but it sure does resemble the pattern of an analog Stereo-Composite FM signal used to relay programming from a studio to a transmitter site for broadcasting.  STL (Studio to Transmitter Link) signals are normally 150KHz wide, and are in the 940-960MHz range... the bottom end of L-Band microwave.  If it's on 24/7 and never moves, that's likely your answer.

 

That's just a short blip. The only analog STL is up at 947.00 MHz and doesn't come in particularly strong. There's a few FLEX pager signals bleeding in and they show up pretty weak on that spectrum display, but they're coming in around -60dBm just about 2 MHz up. All of the rest of that junk is real signal, and it's getting worse as the smart meter deployment continues.

 

Here's a current look, with interference sources labeled:

PNsm5IGl.png

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The rig I just picked up is a TK-981. I have a dual band cellular Yagi that I might be able to use for mountaintopping, if I had any way to check the match. I plan to put a mobile antenna on my van, too.

33cm operation from my home would probably be an exercise in futility.

 

Quoting myself because I was just reading back over this thread and thought an update to this statement might be in order.

I searched the web and found the manufacturer's data for the dual band Yagi I have. It indicates coverage of the 902-928 (and beyond) band.

Because I didn't have a way to check the match on 900, I bought a Bird 43 wattmeter and a Coaxial Dynamics 400-1000 MHz (at 50 watts) slug. As it turns out, that Yagi is a near-perfect match.

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