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Re: SARTS Repeaters
Posted: Sat 18 Sep 18 2021 11:03 am
by Daniel Wee
SLR-5500 Auxilliary connector pinouts
Current settings
GPIO1 - External PTT
GPIO5 - CSQ
- SLR5500-aux.jpg (220.59 KiB) Viewed 89677 times
Re: SARTS Repeaters
Posted: Sat 18 Sep 18 2021 5:45 pm
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
Re: SARTS Repeaters
Posted: Mon 20 Sep 20 2021 12:03 pm
by Daniel Wee
Lightning protection classes:-
- Table-8-Maximum-values-of-rolling-sphere-radius-corresponding.png (17.6 KiB) Viewed 89670 times
- 2-Figure1-1.png (30.13 KiB) Viewed 89670 times
Re: SARTS Repeaters
Posted: Mon 20 Sep 20 2021 3:26 pm
by Daniel Wee
Antenna choices:-
Re: SARTS Repeaters
Posted: Sat 25 Sep 25 2021 8:38 pm
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.
Re: SARTS Repeaters
Posted: Wed 06 Oct 06 2021 6:52 pm
by Daniel Wee
LNA and 2m Bandpass filter
- 20211006_184857.jpg (2.33 MiB) Viewed 89555 times
- 20211006_184905.jpg (2.11 MiB) Viewed 89555 times
- 20211006_184952.jpg (3.64 MiB) Viewed 89555 times
Re: SARTS Repeaters
Posted: Wed 06 Oct 06 2021 7:11 pm
by Daniel Wee
2m Bandpass filter performance
Insertion loss @145.025MHz = 0.80dB
Re: SARTS Repeaters
Posted: Wed 06 Oct 06 2021 7:35 pm
by Daniel Wee
LNA144 performance
Gain @145.025MHz = 20dB
Re: SARTS Repeaters
Posted: Thu 07 Oct 07 2021 8:44 pm
by Daniel Wee
Retuning Telewave TPRD-1544 for second repeater (145.075/145.675MHz)
- TXANT4.png (14.89 KiB) Viewed 89537 times
- RXANT4.png (15.19 KiB) Viewed 89537 times
- TXRX4.png (14.63 KiB) Viewed 89537 times
- TXSWR4.png (16.76 KiB) Viewed 89537 times
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
Re: SARTS Repeaters
Posted: Wed 20 Oct 20 2021 8:14 am
by Daniel Wee