Like all commercial transceivers, FT-847 has many "pluses" and some "minuses".

Reading the manual, it was obvious that this is not an "entry level" transceiver or a contesting machine. Certain features are not available as: tone generator for CW practice, VOX, SWR-meter. But, this does not necessary means that FT-847 can not be easy operated by a beginner or that can not be successfully used for contesting.

In order to save time, I wanted to see what already others have found about FT-847, what are the necessary modifications that could be made in order to improve its performances. Searching with Google, I discovered a huge amount of redundant information, but very few pages sharing really valuable info.

When I bought mine, the dealer told me that my unit it is from Yaesu's last production lot of FT-847.
According to the serial number, which begin with 5J020, it seems that my unit was produced in 2005, month August, production lot number 20.
For instance, one of my good friends, Ion YO7IV, bought a FT-847 just one month before. His unit was produced in 2005 June (serial beginning with 5H0)...

Now the Yaesu FT-847 is a discontinued transceiver. And since the first half of 2006 even its accessories are no longer available.

Until now, I used it on HF, VHF and UHF, working on CW, SSB and some digital modes. It is a good transceiver!

FC-20 is the companion antenna tuner; it is a microprocessor controlled by FT-847, through a cable. When you change the operating band or the frequency, the antenna tuner make automatically the necessary tuning adjustments and you don't have to care anymore about your antenna impedance matching.
But, FC-20 can not be used when the transceiver is controlled by a computer (CAT), this being in my opinion the biggest "minus" of the FT-847.
That's why, when I want to enjoy the CAT control, I'm using a manual antenna tuner and an external SWR-meter.

Yaesu MH-31B8 is a dynamic hand microphone supplied with the transceiver. Its impedance is 190 ohms @ 1 KHz. Many other dynamic microphones used with ham radio equipment have an impedance of 600 ohms. The switch on the back side of the microphone, on the position "tone 2" reduces a bit the lower audio frequencies by -14dB @ 100 Hz.

Rx chain

double superheterodyne, 1^st IF = 45,705MHz, 2^nd IF = 455 KHz.... 

- Front end stages

• HF

The HF front stage uses a 2SC3356 low noise amplifier transistor.
• VHF

2SC3356

• UHF

The UHF front stage uses a 2SK2685 GaAs HEMT.

- Mixer stage

Quad-FET mixer GN2011-Q

TX chain

Filters

The muRata ceramic filters

The FT-847 comes from factory with two CFJ455K14 ceramic filters: one within receiver chain and one within transmitter chain.


Part number	Center frequency (KHz)	6 dB Bandwidth (KHz) min	Ripple (dB) max	60 dB Bandwidth (KHz) max	Spurios 0.1-1MHz dB (min)	Insertion loss (dB) max	Input/Output impedance (Ω)
CFJ455K14	455	2.2-2.6	2	4.5 (total)	60 (40 at 600-750KHz	7	2000

Note: Ripple definition range is within 3 dB bandwidth mentioned in the standards list whenever the 3 dB bandwidth standard is provided.
It is within a 6 dB bandwidth mentioned in the standard list whenever 3 dB bandwidth is not provided.

One of the sources for the above numbers you may find here.



 

The Rockwell Collins symmetrical torsional mechanical filters for SSB used as replacement for the ceramic filters

These filters are optional. They can be installed in the  transceiver, replacing the ceramic ones, having an input/output impedance is 2000 ohms//30pF and a shape factor better than muRata CFJ455K14 shape factor. This means a better selectivity to the skirts level (-60dB), helpful during the crowded band conditions.

Yaesu Collins YF-115S-02 2,4 Khz @ 3 dB SSB Mechanical filter is used in the FT-847 and FT-1000MP Mark V (maybe some others, too).

Carrier	Filter Bandwidths (KHz)						Loss	Number of Resonators	Case Style	Part Number
Frequency (kHz)	Min. BW	@	dB	Max. BW	@	dB	Max (dB)
455.00	2.40	@	3	5.20	@	60	5	8	PS	526-8694-010

Plots for this filter are available here and the specifications can be downloaded from here.

 

There is also available a bit wider filter, with 2,5 KHz @ 3dB, which has written on the label YF-115S, as shown in the following picture.

Carrier	Filter Bandwidths (KHz)						Loss	Number of Resonators	Case Style	Part Number
Frequency (kHz)	Min. BW	@	dB	Max. BW	@	dB	Max (dB)
455.00	2.50	@	3	5.50	@	60	5	8	PS	526-8700-010






 

The Rockwell Collins symmetrical torsional mechanical filters for CW

The CW filter, YF-115C, has a bandwidth of 500 Hz @ 3 dB and it is a must when you like operating CW.
After my opinion, is one of the options which worth all the money.

Carrier	Filter Bandwidths (KHz)						Loss	Number of Resonators	Case Style	Part Number
Frequency (kHz)	Min. BW	@	dB	Max. BW	@	dB	Max (dB)
455.00	0.450	@	3	2.00	@	60	5	7	PS	526-8686-030






 

Where to read about FT-847

One of the places containing good information and almost all links about FT-847 is the DH1NGP - Peter's web site.

 

Software control

To control the FT-847, I'm using an IBM laptop (which hasn't a serial port), a USB to serial adapter followed by a RS-232 null adapter and gender changer. The set-up can be seen here.

 
One simple “plug and play” soundcard interface for the Yaesu FT-847 is the one designed by Bill Ellis N5ZTW. It allows a full PTT switching and CAT functions from a single serial port. The schematic is available on the internet. Few other designs are available.

A convenient free software package is the well known Ham Radio Deluxe which initially was written by Simon HB9DRV and Peter PH1PH (SK), This provides the basic control of the transceiver.
Unfortunately, HRD has not yet a graphical interface for FT-847.
Are also other available software packages for CAT, but until now I had not any opportunity to use them.  

 

 

under construction......

 

December 2011