SARTS Repeaters

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Daniel Wee
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Re: SARTS Repeaters

Post by Daniel Wee »

SLR-5500 Auxilliary connector pinouts

Current settings
GPIO1 - External PTT
GPIO5 - CSQ
SLR5500-aux.jpg
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Attachments
3459501-75.png
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Daniel Wee
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Re: SARTS Repeaters

Post by Daniel Wee »

18 Sep 2021

CPS 2.0 finally connected to the repeater after installation of the RNDIS drivers. The following are the current settings:-

1. Power at 35W (25W into antenna after 1.5dB cavity loss)
2. CTCSS 156.7Hz
3. Time out timer at 300s (5mins)
4. Hang-time 1s
5. Analog only mode
6. Voice de & pre-emphasis on
Attachments
18Sep2021-478IVY2431.zip
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Daniel Wee
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Re: SARTS Repeaters

Post by Daniel Wee »

Lightning protection classes:-
Table-8-Maximum-values-of-rolling-sphere-radius-corresponding.png
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2-Figure1-1.png
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Daniel Wee
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Re: SARTS Repeaters

Post by Daniel Wee »

Antenna choices:-

Daniel Wee
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Re: SARTS Repeaters

Post by Daniel Wee »

X50 was put in place and, as expected, the performance was worse than the X200 and noticeable though not that great. For fringe stations, it was more noticeable.

Now looking at LNA candidates to insert between cavity and RX port of the repeater.
https://www.downeastmicrowave.com/product-p/l144lna.htm
http://www.advancedreceiver.com/page5.html
https://vhfdesign.com/lnas/lna-eme-atf5 ... bands.html
https://www.ebay.com/itm/173854373799

LNA's need to be 0.5dB NF or less. We may need to use in-line attenuators to bring the gain down to something more reasonable? 10-12dB?

A site noise survey should be done to see how much local noise there is. This can be done with an SA to see if the noise floor is high. Alternatively, connect a radio to see if the noise floor is louder.
Daniel Wee
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Re: SARTS Repeaters

Post by Daniel Wee »

LNA and 2m Bandpass filter

20211006_184857.jpg
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20211006_184952.jpg
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Daniel Wee
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Re: SARTS Repeaters

Post by Daniel Wee »

2m Bandpass filter performance

Insertion loss @145.025MHz = 0.80dB
Attachments
2mBPF.png
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Daniel Wee
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Re: SARTS Repeaters

Post by Daniel Wee »

LNA144 performance

Gain @145.025MHz = 20dB
Attachments
LNA144.png
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Daniel Wee
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Re: SARTS Repeaters

Post by Daniel Wee »

Retuning Telewave TPRD-1544 for second repeater (145.075/145.675MHz)

TXANT4.png
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RXANT4.png
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TXRX4.png
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TXSWR4.png
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Final results:
TX insertion loss = 1.24dB
RX insertion loss = 2.87dB
TX-RX isolation @145.675MHz = 84.43dB
TX-RX isolation @145.075MHz = 73.44dB
TX SWR = 1.31
Daniel Wee
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Re: SARTS Repeaters

Post by Daniel Wee »

Attachments
R1-2020 User Manual-V1.7-September 15, 2020.pdf
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