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- Subject: KiwiSDR's / other remote receivers, comments welcomed
- From: Mark Connelly <markwa1ion@xxxxxxx>
- Date: Mon, 2 Oct 2017 01:02:06 -0400
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For over 10 years now, online receivers, like station webstreams, have been a useful tool in getting a clearer listen to stations you get at home or on DXpedition in scratchier harder-to-analyze form. It's a good way to get a better feel for announcer voices, jingles, local place names in news or advertising, and the sound of different languages (and English dialects).
Online receivers also offer the advantage of showing what propagation is doing at another location. That, I feel, is the most valuable contribution of this resource. Hams like to use these to see how their own transmitted signal is "getting out" to intended target areas and to compare the performance of different transmitting antennas so they'll have the best set-up selected the next time they try to crack a big pile-up.
Hearing how one's locals sound at a great distance is always interesting. I've had the opportunity to do that myself in person on trips taken to Ireland, Newfoundland, Florida, and Texas. Online tuners can do this and save you the airfare.
DXTuners / Global Tuners was among the first networks of online receivers. Way back in 2006, I used a DXTuners online receiver in Ilfracombe, Cornwall, SE England to listen to one of my Boston locals during a reasonable TA opening. A demo mp3, at " http://www.qsl.net/wa1ion/audio1/WWZN-1510_home_v_uk_tuner_20060222.mp3 " exhibits a WWZN-1510 reception on (UTC) 22 FEB 2006 in stereo: left channel = audio from Drake R8A at Billerica, MA and right channel = audio from the UK online receiver. Delay of web is about 9 sec. relative to live Drake R8A.
At one time there was even a site "Five Below" that hosted complete SDR band capture files for download. These were from an interesting variety of worldwide sites. Most were medium wave though there was also some tropical band and shortwave available. That site is no longer active.
The online receiver in the Netherlands (Univ. of Twente) has been around several years and is quite useful for checking out what's going on in western Europe.
A more recent development has been the KiwiSDR network. This is accessible via " http://sdr.hu/ ". I have extracted a representative list of receivers. It is posted at " http://www.qsl.net/wa1ion/doc1/kiwisdr_list_20171001.txt ".
One thing that must be remembered is that the interests of the different receiver hosts are quite varied. Some are VHF / UHF oriented (copying air traffic etc.). Many are aimed at good HF ham band reception. There are some that are competent on medium wave and lower but, since those parts of the spectrum are more "niche" interests and also harder for the attainment of high gain / low noise / no spurious images performance, you find that many of the receivers don't "cut the mustard" for MW DX. Some are as deaf as a post. The KiwiSDR in Iceland does not hear UK 909, 1089, 1215 etc. as well as I can hear them in MA at the same time. The one in the Canary Islands can barely find Algeria 549 when it's knocking the house down on this end. A South Africa one is rather deaf, barely delivering locals - nothing at all like the recent DXpedition report from there with zillions of Brazilians.
Receivers at some "drool-worthy" locations are simply spoiled by doggy antennas and bad local noise. These are probably fine for copying aircraft comms or other stuff above 30 MHz. MW ... not so much.
There are some decent receivers on there though. They aren't always at the best coastal sites for pulling in real long-haul DX however. The ones in Sea Girt, NJ and South Dennis, MA should be DX monsters. They aren't. Cuba 670 that you can get on your teeth here barely makes it over the noise. On the other hand, a couple of ones in VA and the Mt. Airy, MD one seem good in terms of overall sensitivity and lack of noise. There's also one in Indiana that's supposed to be optimized for MW and LW reception. Those radios aren't close enough to the coast to do much in foreign DX though. Domestics pretty much covered TA's and LA's I get here. I couldn't raise Absolute Radio UK 1215 on any of them and that is certainly not tough DX. The Concord, NH one, although reasonably sensitive and noise-free, was also short-skip centric: much less Latin American and TA activity than here closer to the shore.
In Europe, the western flank of countries are those that are going to have the best North American "reverse TA" reception. The farther south and west the country, the lower chance that aurora is going to disable propagation from the USA and Canada. Northern and Central Europe have the most receivers. These can be quite useful for evaluating European, North African, and Middle East stations but they often don't show much on typical reverse-TA frequencies such as 590 (VOCM), 660 (WFAN), 850 (WEEI), 880 (WCBS), 930 (CJYQ), 1010 (WINS), and 1130 (WBBR): stations that were not at all difficult just before dawn on my unaided Realistic TRF portable at sites in western Ireland during my 1977 trip.
Yesterday evening the Carlow, Ireland receiver did produce weak 590 VOCM. Not that TA's were that good last night coming the other way either. A Lisbon, Portugal receiver (along with the aforementioned Canary Islands one) should have been even better than Ireland for the stateside route but not really. Sensitivity at MW was not DXing grade. 549 Algeria came in OK on the Lisbon RX but // 531 was surprisingly weak and noisy. It should have been tearing the roof off the sucker.
What stimulated this latest round of my interest in remote receivers was a posting on Facebook about one situated on Bonaire not far from the 800 PJB (TWR) site. The Caribbean is a region which has typically been poorly represented in the realm of competent online receivers. Reception from there is very relevant to what I hear at my home QTH here on Cape Cod, especially on my south SuperLoop aided by only about a 3 mile / 5 km overland run before crossing West Dennis Beach en route to the eastern Caribbean and South America. A quick scan of the band on the Bonaire receiver indeed showed a high correlation to what I log on the south loop during aurora, maybe over 50% of 10 kHz multiple channel occupants being the same in the 530 - 1220 kHz stretch of the band. Some US stations did come in there. 610 WIOD Miami was strongest followed by 940 WINZ, also Miami - not exactly surprising. Some northerly stations including 660 and 880 NYC made it too, though with quite a bit of co-channel Cuban + other Latin American interference. 700 WLW was the farthest inland US signal noted. It was duking it out with Colombia pretty much as it does here around midnight.
There is also a fairly good receiver near Miami, FL. Interestingly Cubans and other Latin Americans didn't seem that much louder or more dominant than they usually are here on the south loop. In fact mainland US domestics on some channels were doing better there than here versus Latino QRM, possibly because the paths going from those stations to FL were less aurorally reduced than the paths from those stations to MA. That meant that some Latin Americans may be missed in FL but heard in New England because of the greater suppression of northerly domestics. Maybe not the result you'd initially expect but "it is what it is" as Patriots' coach Belichick likes to say.
What I could really use would be receivers in Bermuda, Newfoundland, Barbados, north coast Brazil, Azores, Ascension Island, and Falklands (as well as having significant performance upgrades made at existing Iceland, Portugal, Canary Islands, and South Africa sites). That upgraded Caribbean / Atlantic Basin coverage could answer a lot of "mystery het growl" questions. Sometimes I wonder if weird off frequency carriers are actual broadcast activity or just something spurious in/near the house. Remote receivers along with helpful DXers on email lists, Facebook, etc. can get to the bottom of such things quickly.
I didn't even begin to explore all the KiwiSDR resources in the Pacific area ranging from the western US and Canada to Siberia, Japan, China, Philippines, Australia, and New Zealand since they aren't relevant to what I can hear. But I'm sure they're a great resource to the large contingent of DXers in OR, WA, BC, etc.
Any comments by others about how they use or have used online receivers will be appreciated. That includes comments by those who host such a receiver..
Mark Connelly, WA1ION
South Yarmouth, MA
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