Hi there, here is part 2 of my reception videos taken in the tropical rainforest of Pará, Northern Brazil. As I mentioned in my previous post, I took a Tecsun PL-680 with me on the trip because I didn’t want to risk losing or trashing one of my precious vintage portables but also because of the following:
It can handle a longwire very well without overloading (I actually only used a 5 metre wire)
An excellent synchronous detection circuit and audio bandwidth filtering options
Excellent sensitivity, as demonstrated by the many DX reception videos on YouTube
If it got lost or damaged it would be a pain, but not difficult to replace
So, what can you hear in the jungle? Part 2 of my group of reception videos follow below – I hope you enjoy them.
Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.
“The basic idea of the diode clipper is that for signals with an amplitude within ±0.7 Vpeak (less than about +7 dBm over 50 ?) the diodes are just open circuits and do not interfere; for higher amplitudes, the diodes clip the signal to about ±0.7 Vpeak limiting the maximum power that reaches the receiver at about +10 dBm over 50 ?, which the vast majority of receiver circuits can easily tolerate. If you wonder why I specified +7 dBm for unclipped signals and +10 dBm for clipped ones of the same peak to peak amplitude, it’s because unclipped signals are supposed to have a nice sinusoidal shape; once clipped, they become more square and their RMS voltage is higher, explaining the 3 dB difference.”
Thanks for sharing this, Mehdi! I’m happy to see that the PL-680 has some built-in ESD protection.
I just noticed that Universal Radio is featuring the following used Tecsun PL-680 in their used receiver collection. Here’s the description:
The Tecsun PL-680 receives longwave, AM, FM and SW bands plus VHF Airband. It features a backlit digital display, stereo FM (to ear jack), SSB, clock timer, 2000 Memories, Sync. Detection, ATS and keypad entry. The left side features earphone, external antenna and input voltage jacks. The right side features a variable BFO and tuning knob. The rear panel has a battery compartment for 4 AA cells (not supplied). This PL-680 system includes: box, nice carry case, printed manual and earphone.
Jay has also reviewed the Sangean ATS-405 on his website and Keith Perron tells me he will include a review of the ATS-405 on today’s episode of Media Network Plus. Keith has informed me he was very disappointed with the ATS-405, but Jay’s review is mostly positive, focusing on its great AM (medium wave) performance and new tuning/muting functions.
I thought you would like to know this. I bought PL-680 few days ago and I noticed that mine has the display about 1 khz off. I contact Anna on Anon-Co and got a quick reply:
“I have received a response from the supplier regarding the 1 kHz deviation issue of the PL-680 radio. Unfortunately they consider this to be within their tolerance standards for SW reception. Overall, their standard is set to be +/- 0.5 kHz, which translates to 1 kHz on the LCD display. They understand the effect it may especially have for SSB listening, which is why fine tuning has been added as a feature.
For MW/AM the situation is a bit different. According to the supplier this is an issue that both the PL-680 and PL-660 radios have and cannot be avoided. As they indicate, unfortunately only the PL-880 has a special function for MW frequency calibration.”
I just checked my PL-680 and did a zero-beat in SSB against WWV on 10 MHz. If the BFO adjustment is correct when in the middle position, I can confirm that mine is almost 1 kHz too high as well.
For AM listening, a 1 kHz deviation isn’t noticeable. If you’re using ECSS, though, you’ll certainly have to fine tune the BFO accordingly. If locating a CW or SSB signal (in the ham bands, for example), you’ll also need to adjust the BFO fine tune control in advance.
Most importantly–and fortunately–when you turn on the PL-680’s synchronous detection, the receiver is exactly on frequency (at least on my early model PL-680).
Many thanks, Olli, for sharing this information! I’ll note this negative in the PL-680 review.
Spread the radio love
Please support this website by adding us to your whitelist in your ad blocker. Ads are what helps us bring you premium content! Thank you!