Re: PL-390 vs. PL-310 & PL-380


jerry popiel
 

Todd, the PL-390 and the PL-398BT which I have does provide a tad better barefoot AM Reception than the PL-380.  The difference is that the Ferrite Bar is bigger in the PL-390 and PL-398BT than in the PL-380. There were some pictures showing this a few years ago but I can’t recall where this info was posted.

Thanks
Jerry

On Dec 9, 2016, at 3:59 PM, toddemslie@... [ultralightdx] <ultralightdx@...> wrote:


Hi,
 
It would be interesting to hear if anyone has compared the Tecsun PL-390 against the PL-310 and/or PL-380. Even though the PL-390 measures some 21 cubic inches, it can be considered virtually ULR size. The PL-390 has 1 KHz tuning steps and variable IF bandwidths. The 2 KHz bandwidth in particular is essential when attempting to resolve trans-Pacific Hawaii and USA signals into east coast Australia. With each signal hop, there is loss along the path. At my Sydney listening location, 590 KHz KSSK Hawaii has been the only trans-Pacific station that could be clearly heard with the default 6 KHz IF bandwidth. This is why earlier ULRs without DSP chip processing, were limited to 6 KHz IF bandwidth, hence trans-Pacific DX was generally not possible.
 
Trans-Pacific signals from Hawaii (mainly limited to KGU 760 KHz) were received by Sydney DXer Robert Copeman in the 1970s on portable radios without any additional antenna. In the 1980s I could only receive 590 KHz KSSK with a 40 inch side length tuned loop. Without the loop there was no trace of KSSK. So in summary, ULRs require narrow 2 KHz bandwidth, and high gain tunable FSL or PVC loop antennas to even stand a chance of hearing trans-Pacific MW DX at my location.
 
This is another discussion topic, but whatever the factors, Hawaii MW reception into eastern Australia was exponentially stronger in the 1970s compared to now. This could be due to reduced evening TX power, modified TX beam patterns, higher ambient local noise, or reduced propagation conditions.
 
This week another Sydney DXer called over and I was able to compare Gary's 40 inch side box loop vs. a PK antennas small loop. [1] The signal difference was night and day. The signal pickup from the PVC loop is very high as expected for a relatively large area antenna. The $65 PK loop barely made any difference to the two radios we tested (Sangean PR-D13, and Tecsun PL-390). One signal tested was 1035 KHz ZB Newstalk Wellington, New Zealand at some 1,390 miles. The PR-D13 indicated full bar LED signal strength with the 40" PVC loop, but barely any improvement with the small Australian-made PK MW loop. The larger size PR-13 portable seemed to provide stronger signal strength coupling when used with the 40" PVC loop. This is probably due to the PR-13's larger ferrite rod.
 
In terms of size (and possibly signal pickup), the $65 PK loop could be a proxy for the Tecsun AN-200 loop. If so, the AN-200 would be of no benefit at my listening location.
 
Regards,
 
Todd

Sydney, Australia
 

1. PK's Loop Antennas for superior radio reception wherever you are
 




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