TFT 450 Mhz "STL" receiver

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jantonuk
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Location: Fairbanks, AK

TFT 450 Mhz "STL" receiver

Post by jantonuk » Fri Dec 02, 2016 5:23 pm

Hi,

I have uncovered an unfinished project from a previous engineering epoch :)

I am the "proud" owner of a TFT 5145 "STL" 450 MHz receiver which was purchased (not by me) to be used as a 450 MHz RPU (Marti) receiver.
It seems that the TFT is still 50 kHz wide even in the narrow mode while the 450 MHz Marti transmitter is only 25 kHz wide.
This seems like I'd be taking a hit on signal-to-noise ratio, not to mention lower audio level.

Am I thinking about this correctly?

John

TPT
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Re: TFT 450 Mhz "STL" receiver

Post by TPT » Sat Dec 03, 2016 9:16 am

Yes, I would suspect so. I saw a Moseley 505 system once that was designed as an STL system--came from Canada. For close hops may not be a problem--and you can always put an EQ on the output to roll off the high frequency "hiss." Given that many stations no-longer have the staff to set up RPU remotes, you should be able to find a Marti receiver on the used market. International crystal makes the crystals for the older models, some newer models are frequency agile. Cheaper in time and money than trying to narrow band this unit.

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Slab Bulkhead
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Re: TFT 450 Mhz "STL" receiver

Post by Slab Bulkhead » Mon Dec 05, 2016 9:00 am

The models for the TFT "Marti" style equipment were 8888 and 8889, I can't remember which end was which. They had DIP switch programmable frequency selection for the 2 channels and the bandwidth on the TX and RX units could be selected to fit 25, 50, or 100 kHz channels.

Had one at an LPFM but it has mostly sat on the shelf since they went to IP over 4G for their remotes.

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