The IC-7850 at APDXC 2014, Osaka, Japan

and IC-7851 Information

by Adam Farson VA7OJ/AB4OJ

Hot News! IC-7850/7851 Firmware Update V1.40 is now on the Icom Japan World site.  Click link below.

The IC-7850 at Icom Inc. HQ, Osaka. Photo: VR2XMC.
The IC-7850 at Icom Inc. HQ, Osaka. Photo: VR2XMC. 



On 14 November 2014,  Icom Inc. hosted a presentation on the new IC-7850 for attendees at APDXC 2014 (Asia-Pacific DX Convention, 2014). We were also treated to a hands-on preview of two IC-7850's which were set up in the conference room. Icom engineering managers and staff were in attendance to address questions posed by the audience.

The following is a summary of the PowerPoint presentation material. For the first time, we can present some technical insights and performance figures for Icom's new flagship transceiver.


The IC-7850 and IC-7851 received FCC and IC certification on 15 January 2015. FCC ID: AFJ361500, IC: 202D-361500.

VFO Tracking Feature:

Allows the operator to tune the Main and Sub VFO's synchronously by rotating the MAIN tuning knob. This feature facilitates diversity operation.

Firmware Update Ver. 1.40 now available:

Firmware Ver. 1.40, released 30.04.2021, is now downloadable from the Icom Japan Global website.

The Ver. 1.40 Release Notes describe the features added by V1.40 and previous firmware releases.

Salient points from Icom HQ IC-7850 presentation, 14.11.2014:
  1. Extremely low phase noise

  2. Effectiveness of Optimum Roofing Filter (64 MHz, Bandwidth = 1.2 kHz).

  3. 15, 6, 3 and 1.2 kHz roofing filters fitted to both receivers

  4. FFT spectrum scope is much faster, much wider and has higher sensitivity (and much narrower minimum RBW).

Impact of RMDR (reciprocal mixing dynamic range):
IC-7800 8 kHz
TS-990 5...7 kHz
IC-7850 300 Hz


Examples of weak and strong signals on IC-7850:
Weak signal at 14200 kHz.
Weak signal at 14200 kHz.


Strong signal co-channel with weak signal.
Strong signal co-channel with weak signal. 


Strong signal offset from weak signal. Noise sidebands do not degrade weak signal.
Strong signal offset from weak signal. Noise sidebands do not degrade weak signal. 
Comparing phase noise of various flagship radios: 
Phase noise curves of IC-7850 and competitors.
Phase noise curves of IC-7850 and competitors. 


RMDR Table  RMDR dB 
Offset kHz  20 
IC-7850   111.6   115.9  118.6  122.9
IC-7800  78.2  87.2 99.2 112.2
TS-990  83.0  88.4 100.8 117.9


Icom Optimum Roofing Filter:
64 MHz 1.2 kHz roofing filter. 

FL-483 and FL-484: Bandwidth = 1.2 kHz at 64 MHz. This filter has been optimized for low passive IMD.

Manufacturer  Purpose of filter  Reason 
Others  To improve RMDR  Poor LO spectral purity 
ICOM  To improve IMD  -- 
DR3 at Spacing 
Radio  Filter BW 1 2 5 20 kHz 
IC-7850  15 kHz  100 101 104 114 dB 
1.2 kHz 99 105 111 113
TS-990  15 kHz 75 79 90 108
270 Hz  87  91 100 106


Salient points of spectrum scope:
  1. Displays finer resolution

  2. Displays information faster

  3. Lower noise floor displays weaker signals clearly

  4. Dual scope for Main and Sub receivers

  5. Narrower minimum resolution bandwidth (30 Hz)

Radio  IC-7850 IC-7800 TS-990
Analysis method  FFT Swept/filter FFT
Span range kHz 5...1000  5...500 5...500
Max. resolution, pixels 1 20 11
Max. sweep speed, sweeps/sec.  29 4 11
Display dynamic range, dB  100  80 80
Noise floor, dBm  -137 -126 -117 
Operation on display  Mouse Mouse Touch panel
Dual scope (Main/Sub)  Yes N/A N/A


IC-7850 calibration marker, 2.5 kHz span, slow sweep. Photo: VA7OJ.
IC-7850 calibration marker, 2.5 kHz span, slow sweep. Photo: VA7OJ. 


IC-7700 calibration marker, 2.5 kHz span, slow sweep. Photo: VA7OJ.
IC-7700 calibration marker, 2.5 kHz span, slow sweep. Photo: VA7OJ. 


Key features for amplifier interfacing:
  1. ALC input (0 to -4V nominal, negative-going, adjustable,  identical to ALC port on IC-7700/7800) and compatible with amplifiers supporting this voltage range

  2. Selectable reed-relay or MOSFET SEND Relay (keying-line) interface, identical to that in IC-7600/7700/7800

  3. Adjustable TX Power Limit by band

  4. Adjustable TX Delay (RF onset delay), identical to that in IC-7800 V3.00/3.01, IC-7700 V2.00/2.10 and IC-7600 V2.00

  5. Dedicated, private CI-V port for IC-PW1 (by unlinking REMOTE and USB/LAN CI-V ports and assigning separate CI-V addresses) - no more IC-PW1 data collisions!


My full IC-7851 Test Report (including NPR with 1.2 kHz roofing filter)

Replacing the PA FETs in the Icom 7851, by Dave Wilson AA0RS

IC-7850/7851 Firmware V1.40      Cumulative Firmware Release Notes

RS-BA1 V2.40 with link to manuals

RC-28 Firmware V1.02 (prerequisite for use of RC-28 with IC-7850/7851 Firmware V1.10 & higher, and RS-BA1 V2.XX)

IIcom America IC-7850 Page

Icom America IC-7851 Page

Icom Japan IC-7851 Page

IC-7300 and IC-7850/51 USB Port Setting Manual V1.0

Introducing the IC-7850 50th Anniversary Edition - video

The IC-7851 on 20m - video

IC-7850 vs. IC-7800 RMDR characteristics - video

All data and images courtesy and copyright  2014-2021 Icom Inc. (except where noted). Editing & page creation: A. Farson VA7OJ/AB4OJ.
Last updated: 04/30/2021

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