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Search found 857 matches
- Wed 24 Mar 24 2021 7:29 pm
- Forum: General Discussions
- Topic: SARTS Repeaters
- Replies: 19
- Views: 3664
- Tue 23 Mar 23 2021 4:26 pm
- Forum: General Discussions
- Topic: SARTS Repeaters
- Replies: 19
- Views: 3664
Re: SARTS Repeaters
VHF Duplexers Telewave TPRD-1444C Min. separation: 600kHz Insertion loss: 1.5dB Rejection: 70dB Weight: 8.7kg USD2267.33 https://www.tessco.com/product/135-151-mhz-compact-pass-reject-duplexer-517711 https://www.talleycom.com/viewProduct?rlProdNum=TELTPRD-1544C Telewave TPRD-1554 Min. separation: 6...
- Fri 19 Mar 19 2021 7:18 pm
- Forum: General Discussions
- Topic: SARTS Repeaters
- Replies: 19
- Views: 3664
Re: SARTS Repeaters
Tuning procedure 1. With all cabling harness in place - connect VNA port 1 to TX port and port 2 to the Antenna port. 2. Disconnect the RX-side and the connection to cavity 1 (TX) 3. This leaves only cavity 2 (TX) connected On cavity 2 (TX) 1. Adjust the flange rotation to get exactly 600kHz separa...
- Fri 19 Mar 19 2021 6:07 pm
- Forum: General Discussions
- Topic: SARTS Repeaters
- Replies: 19
- Views: 3664
Re: SARTS Repeaters
Retuning the Cavity (again)
1. It looks like all cavities affect the final tuning. The TX cavity can be perfectly tuned but the moment the RX cavities are connected - everything goes off.
1. It looks like all cavities affect the final tuning. The TX cavity can be perfectly tuned but the moment the RX cavities are connected - everything goes off.
- Mon 15 Mar 15 2021 7:29 pm
- Forum: General Discussions
- Topic: SARTS Repeaters
- Replies: 19
- Views: 3664
Re: SARTS Repeaters
Cavity Inspection and Tuning 0. Duplexer model is Telewave TPRD-1554 Screenshot 2021-03-15 215846.jpg spec-18.jpg desc-16.jpg http://www.telewave.com/product/tprd-1554-pass-reject-base-station-duplexer-144-174-mhz/ [yt]https://www.youtube.com/watch?v=tD1upx4-DDI[/yt] 1. Cavity #2 (TX) coupling loop...
- Sun 14 Feb 14 2021 8:33 pm
- Forum: Radios
- Topic: ICOM IC-7300 and IC-9700
- Replies: 2
- Views: 831
Re: ICOM IC-7300 and IC-9700
The IC-7300 uses an MP7741 audio power amplifier IC in quite an elaborately filtered configuration.
- Sun 14 Feb 14 2021 8:23 pm
- Forum: Radios
- Topic: ICOM IC-7300 and IC-9700
- Replies: 2
- Views: 831
Re: ICOM IC-7300 and IC-9700
Documents for the IC-9700.
- Sun 14 Feb 14 2021 8:22 pm
- Forum: Radios
- Topic: ICOM IC-7300 and IC-9700
- Replies: 2
- Views: 831
ICOM IC-7300 and IC-9700
Approved for use in Singapore. The following are the documentation and service manual.
- Sun 14 Feb 14 2021 11:55 am
- Forum: Radios
- Topic: Yaesu radios' audio output stages
- Replies: 2
- Views: 812
Re: Yaesu radios' audio output stages
Interestingly, ICOM also uses the LA4425A in the output stages, for example in the IC-718 (pg.16 of attached file). This has been confirmed to exhibit that hiss at zero volume as well.
The FT-DX101MPD, on the other hand, uses the TDA2003 power amplifier chip.
The FT-DX101MPD, on the other hand, uses the TDA2003 power amplifier chip.
- Sun 14 Feb 14 2021 10:47 am
- Forum: Radios
- Topic: Yaesu radios' audio output stages
- Replies: 2
- Views: 812
Noise in output
The noise in the output of the amplifier does not change with volume, so it must be inherent to one of these three parts - the M62364FP, NJM2737 or the LA4425A. The NJM2737 is specifically a low noise part so I'm not suspecting it as a noise source at the moment. The M62364 has only 8-bits so it is ...