- UHF/VHF/HF Allmode Tranceiver YEASU FT-847 -
2006.03.23 First look - I got this radio used from AFR Electronics in Sundsvall / Sweden. @ the first look 2006.03.23 i notice the alarming noice level from the 40 x 40 mm fan on the back of the station, i will try to reduce the noice with a new Papst 412. I return with the result a.s.a.p
2006.06.05 Now used the radio for some weeks, replaced the noicy fan's, one 60x60mm inside and one on the rear 40x40mm. Noice levels now a little lower. Looking forward to start using the rig on 50MHz and up.
I think the rig mainly is intended for higher frequenzy usage! On HF i got big problems to pick out stations when noice levels is high, and when signals is strong and other stations close by on frequenzy.
Now also running my Timewave AF-DSP filter with the radio, i always liked the Timewave's;-) - I'm looking at the roofing filter mod done by W5VIN. Also loking at some ssb-filters (1,9-2,5Khz) but have notdecided yet.
DSP TIMEWAVE DSP-599zx
2007.09.17 Made som mods to resolv fan-noice problems. I earlier replaced the rear fan and it helped. Now i replaced both the internal and the rear fan with computer grade low-noice fan's. I used this type of fan's inside my computers and is quite satisfied with the performance and the obtained low noice levels.
The used fan's is made to operate at 12V DC - The rig is supplied with 13,8V DC, this is a problem, the fan's need to be operated att the correct voltage, or slightly less to obtain the low noice levels wanted. Operating them with at higher voltage makes loots of fan-noice.
In order to make about 2-3volt dropp i placed a 47ohm resitor in series with the fan on the plus lead in the fans, when doing sow i also remove the blue lead, (used for rpm messure in computers) it's not needed in this case.
FAN Specifications ======================================== Rear fan ............ ADDA 40x40x10 AD0412LX-G76 Varv/minut (RPM) .... 4800 Luftflöde (CFM) ..... 5,6 Ljudnivå ............ 14 dB Main fan ............ ADDA 60x60x25 AD0612LX-A76GL Varv/minut (RPM) .... 2500 Luftflöde (CFM) ..... 12,2 Ljudnivå ............ 16 dB Tillverkare http://www.addausa.com/
 New rear fan in place! |
 47ohm resitor in series on plus lead |
 Remove blue lead from the fan |
 New main fan in place! |
- Documentation -
FACTORY SPECIFICATIONS
========================================
Receive:
Frequency coverage HF ..... 100kHz - 36.99 MHz
Frequency coverage VHF1 ... 37 - 76 MHz
Frequency coverage VHF2 ... 108 - 174 MHz
Frequency coverage VHF2 ... 420 - 512 MHz
Sensitivity ............... 1.8 - 28 MHz 0.25 uV
28 - 30 MHz 0.25 uV
50 - 54 MHz 0.20 uV
144 / 430 MHz 0.125 uV
Transmit:
Frequency coverage HF ..... 160 - 6 / 2 Meter / 70 Cm
Amateur bands only
Power Output .............. 160 - 6 m 100W (25W AM carrier)
2m/70cm 50W (12.5W AM carrier)
Emission Modes ............ USB, LSB, CW, AM, FM, F1, F2, AFSK
Antenna Impedance ......... 50 ohm
Antenna Connector ......... HF / VHF 3 x SO239
UHF N-Chassi Female
Dimensions ................ 260(W) x 86(H) x 270(D) mm
Weight .................... 7 kg
Go Back!
©2006 SM2YER Goran