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--- radios:ft-2980r [2025/04/24 06:57] – [Tap points] m0mzf
+++ radios:ft-2980r [2025/04/24 11:26] (current) – [Main PCB top side & front panel PCB] m0mzf
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-======Modifying a Yaesu FT-2980R transciever for packet usage======
+======Modifying a Yaesu FT-2980R 2m transciever for packet usage======
-More to follow...
+{{:radios:ft-2980r:ft-2980r-stockpic.jpg?nolink&320|}}
-{{:radios:ft-2980r:ft-2980r-stockpic.jpg?nolink&400|}}
+The FT-2980R is a beast of a transceiver putting out up to 80W FM on 2m. From spending a little time using it for 2m simplex nets and whatnot it is an excellent radio; it's the best 2m receiver I own and (anecdotally) an S-point "better" when compared to my other radios (FT-8800R, FT-857D, FTM-300D etc). S1 stations which were unreadable on my other sets come through clearly on the 2980R as it "seems" more sensitive and selective; impact from local QRM is much reduced. When running full power the case gets extremely hot very quickly and on a 30W rag-chew the case still becomes maximum-touch-hot - but for long runs below 20W it's very happy.
-The FT-2980R is a beast of a transceiver putting out up to 80W FM on 2m. From spending a little time using it for 2m simplex nets and whatnot it is an excellent radio; the receiver is (anecdotally) an S-point "better" when compared to my other radios (FT-8800R, FT-857D, FTM-300D). S1 stations which were unreadable come through more clearly on the 2980R, and impact from local QRM seems much reduced.
+The service manual is excellent; alignment and power / deviation adjustments are made through the front panel in service mode; setting the power levels to 6dB increments (e.g. 1/5/20/80W) or adjusting the power to give 25W ERP is simple. The radio has two crystal filters for wide (-6dB 12KHz) and narrow (-6dB 9KHz) IF filtering; using an IC-705 as a reference receiver the transmitted signal has no horrendous key-up transients (a la FT-1500M) and the wideband PLL phase noise is extremely low.
-I always thought it would make an excellent packet radio, but in their wisdom Yaesu never put a 6-pin Mini-DIN connector on the back - so this article will address that shortcoming!
+For some unknowable reason Yaesu didn't put a 6-pin mini-DIN socket on the back; plenty of folks have used this for APRS via the MIC / speaker sockets but we want flat audio! Plenty of options out there of course but the 2980R is a nice rig, so this article will address this shortcoming :)
-=====Schematic detail=====
+=====Schematic=====
 {{:radios:ft-2980r:ft-2980r-schematic.jpg?960|}}
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   * PTT is achieved by grounding PIN1 of the MIC connector (front panel board)
+=====Disassembly notes=====
+The radio is beautifully designed and assembled; desoldering of the PA and rear RF connector is required to lift out the main PCB. The appropriate tap points are on both sides of the main PCB and the components are mostly very tiny 0402 and 0603 parts. The VCO is contained under a heavily soldered-down metal can so I left that well alone!
+  * A 90W vacuum desoldering gun was used to desolder the SO239 connector from the board, it needed a lot of heat
+  * There is a tiny capacitor on the board next to the SO239 solder points, be careful!
+  * The front panel assembly must be removed before the main PCB as a couple of capacitors on the front PCB prevent lifting out the main PCB
+  * The main PCB must be slid forwards slightly to clear the external speaker jack from its cutout on the rear of the case
 =====Tap points=====
+As there's potentially an awful lot of RF floating around inside the case I decided to use RG174 to tap both the audio inputs. It seems that Yaesu have gone to great lengths to shield and earth-bond this radio internally so it seems prudent to do the same. Unfortunately there's no clear star-grounding point to tap so I used a DPDT switch to switch both the signal and ground for both audio input paths. Receive audio is probably just fine but it may be a good idea to include a few pF from output to ground at the rear connector.
 ==Main PCB underside===
-  * DC-coupled audio input to the VCO was done through a bit of RG178 - there is potentially a lot of RF flying about inside the radio so keeing the audio input well shielded seemed like a good idea. Plus there is a dirty great big ground pad to solder the braid to!
+  * DC-coupled audio input to the VCO was done through a bit of RG178 - there is a dirty great big ground pad to solder the braid to.
   * The de-emphasised audio output appears on the rear side of the PCB too
-==Main PCB top side
+==Main PCB top side==
-  * The flat audio out is tapped from the Q1028 side of C1098, it's an easier solder-job to access the cap rather than the IC pin
+  * The flat audio out was tapped from the Q1028 side of C1098, it's an easier solder-job to access the cap rather than the IC pin.
-  * The MIC audio input is tapped into the test point which appears next to the flat-flex connector to the Front PCB
+==Front panel PCB
+  * The MIC audio input was tapped into pin 1 of the MIC connector on the front PCB.
+  * The PTT line was tapped onto pin 2 of the MIC connector on the front PCB.
 =====Finished mods=====
 More to come
-=====Rear connector=====
+=====Rear connectors=====
-More to come
+Drilling out the external speaker hole provided enough space to fit a mini-DIN socket, held in with a gob of epoxy. The pins on the rear of the socket are close to, but not touching the board and once the front panel is removed the board can still be removed by sliding it forwards (after desoldering stuff of course!). There was also enough space below the DIN socket to drill another hole for the 1200/9600 audio input switch.
+The SO239 socket was also replaced with an N-Female socket, why SO239 sockets are still appearing on VHF / UHF radios is beyond me...
 =====Other tweaks=====
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 More to come
+----
+de M0MZF, April '25