Differences

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--- radios:tait_tm8100 [2024/06/20 17:05] – [Auxiliary Connector Pinout] m0lte
+++ radios:tait_tm8100 [2026/02/16 21:37] (current) – g5rkt
@@ Line 54: / Line 54: @@
 | 25 | 3.5 |
-TODO: Check idle power
 TODO: VHF / UHF?
+(From Phil M0OFX) - Idle power while receiving and squelched is around 350 to 400 mA for a Band B1 TM8105 data radio. Radios with speakers and more complex control heads will be higher. 500 mA is probably a reasonable rule-of-thumb.
 ===== Pinout =====
@@ Line 77: / Line 77: @@
 The simplified pinout:
-| **Pin** | **Use**                | **NinoTNC pin** | **NinoTNC SMT pin** |
+| **Pin** | **Use**                | ** Standard through-hole NinoTNC pin (9 pin D sub) ** | ** Surface-mount components NinoTNC pin (6 pin mini DIN) ** |
 | 7       | Transmit Audio (Input) | 1               | 1                   |
 | 12      | PTT                    | 3               | 3                   |
@@ Line 273: / Line 273: @@
 {{tag>radio packet vhf uhf 9600 1200}}
+===== Audio frequency response (mV/Hz) =====
+{{:radios:tm8100-af-response-curve.png|}}
+[[https://docs.google.com/spreadsheets/d/1O_LjKFKb_dCBFBqzZ0ZoZNVxEUT5ktLyQf1UXCmehZs/edit?usp=sharing|Raw data]]
+====== Rack Ears ======
+d printable model for 10" rack ears here: https://www.printables.com/model/1334607-tait-tm8110-10-inch-rack-ear
+====== SDR Tap ======
+Tom M0LTE, Eoin M0NVK, Jason G5RKT and Matthew 2E0SIP had [[https://discord.com/channels/715554730323083274/1365420096020807701|some discussion on discord]] on where best to tap the Tait's first IF. An [[https://www.sdr-kits.net/index.php?route=product/product&path=88_84&product_id=162|hupRF buffer board]] from SDRKits will provide a high impedance tap to avoid loading down the IF and a low impedance buffer output to drive the SDR and fits nicely into the radio.
+VHF IF: 21.400MHz\\
+UHF IF: 45.100MHz
+Open up the radio and observe the beauty, it's about to be destroyed forever. First step is to remove the can on top of the IF mixer / filter stage:
+{{:radios:tm8110:t8110-boardlayout.jpg?960|}}\\
+To remove the filter can start snipping away with a small, flat-faced pair of sidecutters towards the corners. The corners are unbonded so you will be left with four flat-sided bits of can which can be de-soldered separately from the board.
+The tap point is after the first IF amplifier filter, XF401. This is in the same location on both the VHF and UHF models:
+{{:radios:tm8110:t8110-ifcan.jpg?960|}}\\
+{{:radios:tm8110:t8110-tapdetail.jpg?960|}}\\
+The buffer board fits in the space left by the can and leaves enough space to solder in the tap wire.
+{{:radios:tm8110:t8110-tapoverview.jpg?960|}}\\
+Adding some extra shielding is probably a good idea. This little bit of copper extends up to the tap board, where the idea is to use the underside ground plane of the tap board to act as the top of the can. Can't hurt... DC / RF ground can be picked up from all over the place so I just soldered in every available spot. The shield can be soldered down to the other shield cans, and the edge meeting the board soldered back down to the pads left by the original can.
+There's a dimple in the casting of the top case / cover which can be drilled out and an SMA installed:
+{{:radios:tm8110:t8110-smaconnector.jpg?960|}}
+And all finished up. I ran a power wire straight from the 12V connector, but there's probably a better place to grab power from!
+{{:radios:tm8110:t8110-tapfinished.jpg?960|}}\\
+(Yes, I removed the blob of solder on top of the tap board's C6 after taking the picture! Check yo board!)
+I took some pains to replace as much of the shielding as possible and properly bond the tap board to every available ground - who knows if it was necessary but the receiver seems to have exactly the same performance as before.