I have been using the Tecsun 660 for over a month now so I guess it's time for a short review. If I encounter any problems, I will update.
This is Tecsun's latest offering and possibly their best to date. It is a Dual-Conversion radio with a myriad of features including synchronous detection. My sample was a first generation unit meaning the display light will only stay on for 3 seconds after a control is activated. Newer units will have lights that stay on for thirty seconds. Other new alterations involve tuning speed.
Layout and Operation:
Layout is very straightforward. The tuning knob BFO and non-digital volume control are located on the right side. Antenna jack (FM/Shortwave), antenna gain switch, tone bass switch, headphone and external power jack are all located on the left side. All other controls are located in front.
After turning on the radio and selecting a band, you can choose 1 of 3 modes to utilize: VF,VM or scan. If you choose VF (frequency mode)tune as you would any radio or input frequencies directly using the keyboard. If you choose VM (memory mode) use the tuning knob to "scroll"through memorized stations. If you choose scan mode the receiver will stop for 5 seconds on each station and move on to the next. Memories can be stored manually or automatically using ATS (auto tune system). This is a very useful feature which automatically stores stations.Two modes are available but I'll use mode A as an example. Choose the AM band and hold down the same button for a second and let up. The radio will go silent and the dispay will literally start counting out received stations until it reaches the end of the band. The tuning knob can now be used to scroll through all perceived stations bypassing "dead frequencies". The threshold or squelch is set low enough that even the faintest stations are counted as valid. In the past I have had radios with this feature made useless because the squelch was set to high causing even strong stations to be missed. These memories will stay in place until using the ATS again which will overwrite previously stored memories. What makes this feature even more interesting is it literally gives you an indication of atmospheric conditions from day to day. Some nights during a scan you might get 70 stations,,,,the next night 85.
The radio has two selectable bandwidths. I would guess 6khz. and 3khz? These are shown on the dispay as upside down brackets of differnt widths. Plus it has a selectable sync detector which helps separate stations; If you are listening to a weak station say 800khz and find strong interference from a powerhouse at 790 activate sync and choose USB (upper side band) , which will eliminate most of the interference. This does change the sound tone a bit too but it works well! If the signal becomes too week for sync to work, SYNC will begin to flash on the display.
Sync can reduce fading a bit but works better as a station separator. Selectable SSB with BFO is included for shortwave enthusiasts. Find a Ham operator and select the appropriate sideband (usually LSB below ten Megs and USB above 10Megs) and fine tune the BFO to decode these transmissions. It is quite stable in use.
MW sensitivity is quite good owing to a almost 5" internal antenna but I'd like to further enhance reception with a tuneable loop... From WA state I have easily received CKMX Utah as well as well as KFI Los Angeles. CKNW New Westminster BC, which is always tough, comes in quite well at night with little fading.
I have compared it to a Super Radio 3 and couldn't tell any difference in sensitivity. I use the 17 foot included plug in antenna to receive many shortwave stations although it works very well on the whip to. I rarely listen to FM but did try to receive some known faint stations and was able to get them fairly easily. I noticed some videos on You Tube comparing Tecsuns earlier model the 600 with the 660 on FM and the 660 was less sensitive. Also includes an air band and LW neither which I have tested extensively yet.
From pictures of the internals the radio appears to be heavily shielded which helps minimize electrical interference ect. I checked Long wave 470Khz. for a local strong station (1380) and found no image so the dual-conversion seems to be doing its job. Sound quality is adequate for a DX machine but don't expect it to compare with a Tivoli or Super Radio. It is very clear and crisp. Speaker output is rated at 450mW. The manual claims power consumption between 50 and 70 mA so 2300mA rechargeables should last somewhere around 40 hours. Build quality appears solid. I have had this radio for about 1 month now and like it very much. I would rate it a 5 out of 5 for funability. It cost about $100 with shipping from eBAY. Included is a nice case with a velcro flap, external FM/shortwave antenna (for clipping on curtain ect.), rechargeable batteries (four 1000mA) and a wall wart.
As we all know it can be risky ordering from China as you might get a dud. Then you have to decide whether or not it's worth sending back. Too bad Tecsun doesen't have service center in the US. Long-term quality can be a concern but as of yet I haven't had any problems except a prematurely worn volume control on a Kaito. Careful of that flimsy collapsible stand too. I always support the radio with my hand when depressing buttons (which by the way are rather stiff). Hope this review is helpful and happy listening.
Craig-. WA State.