看国外爱好者Allen艾伦的文章，链接在上面，有这样的记录：

Two Versions: There were some relatively minor circuit revisions made after serial number 30,000 which have a rather major affect on performance. Models with numbers higher than 30,000 are referred to as the “Orange” version as the model name at the bottom of the front panel was now printed in orange lettering instead of the original white. The orange series had one transistor removed from the pre-selector stage which slightly reduced RF input gain but greatly reduced overloading in the presence of stronger signals. Also new IF filters were used. Most owners agree the orange is the more desirable version…the radio has slightly reduced but still higher than typical gain and it can still overload when used with external antennas, although the flexible user controls allow one to compensate for this. Both of the 6800′s I will discuss here are orange versions.

Description: The ICF-6800 is a large shoebox sized AM/FM/SW portable, approximately 18″ v 7″ x 9″ and weighing about 13 pounds with batteries. It is completely self-contained and able to be powered by 6 D cells and incorporating internal antennas for all bands. It is PLL tuned via an analog-feeling knob with both analog and digital readouts and can demodulate SSB broadcasts. It covers standard AM and FM broadcast bands (no expanded band AM except in the SW mode but at reduced sensitivity), plus SW from 1.6 to 30 MHz in no less than 29 spread bands. It can also be powered by AC power from 120-240 volts via a rear panel voltage selector switch (only the Canadian model does not have an external voltage selector), 6 D cells or an external 9 volt source via a DC input jack. There is also an input jack for a timer and output jacks for record, earphone and stereo headphones (although even FM is output in mono…the stereo jack is a convenience to allow both earpieces to be driven from the mono sources).

There is a telescoping rod antenna for FM and SW, a large internal ferrite rod for AM and external antenna inputs – SO239 and spring clips for SW and spring clips for AM…all  low impedance -c50-75 Ohms. The AM spring clips are connected to a few turns of wire around the ferrite rod which means the ferrite rod cannot be disconnected when an external AM antenna is used. There is a rear panel switch to select Rod or External antennas for SW. The SW spring clips are in fact tied directly to the SO 239 connector and so are of low impedance…this is the first time I’ve ever seen this type of arrangement…again, spring clips or screws are used for bare wires which are generally indicative of a high impedance input. The most important point is to know the impedance so you can get the most out of external antennas with any radio.

There is also a pre-selector which aids in front end selectivity and an effective variable RF Gain control as well as a rear panel Local-DX switch, although this switch only affects signals incoming through the external antenna jacks. Two well chosen bandwidths (nominally 9 and 4 KHz) make program listening pleasant in Wide mode and tightly-spaced DXing possible in Narrow mode. The filters have rather broad ranges yet with steep skirts and excellent ultimate rejection the 6800 seems to have sufficient real-world selectivity for the situations I encountered during more than two months of listening…the improved filters of the “orange”seem to have excellent characteristics.

两个版本:在序列号30000之后,出现了一些相对较小的电路修改,这些版本对性能产生了相当大的影响。数字高于3万的型号被称为“橙色”版本,因为前面板底部的型号名称现在以橙色字母形式打印,而非原来的白色。橙色系列从预选器阶段移除了一个晶体管,略微降低了射频输入增益,但在信号强度更强的情况下,其过载程度显著降低。还使用了新的IF过滤器。大多数用户都认为橙色是更理想的版本......无线电的降幅虽小,但仍高于普通增益,且在与外部天线配合使用时仍可能过载,但灵活的用户控制功能使其能够弥补这一效果。我将在这里讨论的6800两种版本都是橙色版本。

ICF-6800 是一款大尺寸的 AM/FM/SW 便携式鞋箱,约 18 英寸 对 7 英寸 × 9 英寸,电池重量约 13 磅。它完全独立,能够由6个D单元供电,并为所有频段集成内部天线。PLL 通过模拟感应旋钮进行调音,同时支持模拟和数字读数,并能对 SSB 广播进行调和。它涵盖标准AM和FM广播频段(除SW模式外,未扩展频段AM,但灵敏度较低),以及不低于29个扩音频的SW频段,频率从1.6至30 MHz不等。也可通过后面板电压选择器开关(仅加拿大型号没有外部电压选择器)、6个D单元或直流输入插孔,从120-240伏的交流电源供电。还有一个用于录制、耳机和立体声耳机的定时器和输出插孔的输入插孔(尽管单声道输出的接口也相同)......立体声接口是一种方便,方便两个耳机从单声道电源处驱动。

有一款用于调频和SW的伸缩杆天线,这是一种用于AM和外部天线输入的大型内部铁素杆——用于SW和弹簧夹的SO239和弹簧夹,适用于AM......所有低阻抗 -c50-75 大七烯。AM弹簧夹连接在铁氧体杆周围的几圈导线上,这意味着当使用外部AM天线时,铁氧体棒无法断开。后置面板开关可选择用于SW的Rod或外部天线。SW弹簧夹实际上直接与SO 239连接器相连,因此阻抗较低......这是我第一次看到这种排列方式......再次使用弹簧夹或螺钉用于光线,通常表示高阻抗输入。最重要的一点是了解阻抗,以便使用任何无线电都能充分利用外部天线。

还配备了前置选择器,可辅助前端选择性和有效的可变射频增益控制,以及后面板Local-DX开关,尽管此开关仅影响通过外部天线接口进入的信号。两个精心选择的带宽(名义为9和4 KHz)使程序在宽模式下听音愉快,在窄模式下能够实现紧密间隔的DXing。滤镜范围较广,但带有陡峭的裙子,而6800的极致防爆效果似乎具备足够的现实选择性,能够满足我在两个多月聆听过程中遇到的情况......改进后的“橙色”滤镜似乎具有极佳的特性。