cyberdad said:
BRNout said:
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By the way, I get all this reception on a Sangean DT-400W "Walkman" sized radio! It's WB is a vast improvement over prior versions in older Sangeans and in Sony Walkmans which offer the band.
Yes, as decent a little radio as the Sony Walkman SRF 37 is, the WB is lousy. Here where I am, the Crystal Lake local on 162.500 obliterates all of the other channels. Why, the only thing it's good for is getting the weather! As prone as it is to overloading strong signals (also a problem on other bands), it's also not very sensitive on WB.
Fortunately, the WB in my wife's car is pretty good. Both in sensitivity and selectivity. No overloading, and it does well with distant signals.
Oh yes, I also voice my extreme dislike for the sorry excuses for filters in that SRF 37! I briefly had an SRF-M37W in my (still not yet ended) search for a walkman sensitive enough to get some reasonable several-hundred-mile DX first-adjacent to multi-ten-kilowatt locals, as well as the Sangean DT-400W and a couple other radios. The Sony failed that selectivity test miserably on multiple tests, making it not really worth testing sensitivity. (I did take it, and a few other radios, to a rural location, and it did fairly well on sensitivity, though.)
As a couple examples...
here's a bandscan (530-1710 kHz, 10kHz steps) from the SRF-M37W out in my front yard one evening. I did make it a bit more difficult by using a Select-A-Tenna and utility pole ground wire to boost the signal from 760 KFMB, a local 5kW day / 50kW DA-N station 7.3 miles away, but I still would have expected much better performance than that!
Also last October I
recorded a bandscan also on the SRF-M37W about 0.2 mi SSW of 910 KECR and 1170 KCBQ. As you can probably tell from that recording, it had a heck of a tough time pulling in other stations out from under KCBQ, especially in the upper half of the band.
(I should mention that I
made NO attempt to null KECR or KCBQ (they both share the same transmitter site) when recording that second scan - the M37 was picking them up at
full strength. When I am testing the performance of radios, I prefer to keep the selectivity and nulling tests separate. When testing nulling, I will attempt to null a strong local (one whose signal is completely static free when facing their transmitter location) and try to hear something under it on the
same channel, preferably one not occupied by a 50kW station (if the test is done at night) the local is protecting, unless it's over 1000-1200 miles away. When testing selectivity, I will have the radio
facing the local pest, and try to pull in a weak signal that would be at the normal limit of the radio's sensitivity (which is determined in a location considerably farther from local pests, and based in part on fcc database search, ground conductivity map, radio-locator coverage maps (typically I try to use ones well outside the "fringe" 0.15mV/m contour), etc.), on the first-adjacent channel. I prefer testing selectivity on strong signals - ones that are upwards of 1,000 mV/m or stronger, although I can make do with a pest as weak as about 200 mV/m or so.)
At the time I was looking for a radio that had good sensitivity and selectivity (and still haven't found the one that I'm looking for, although I'm making do for now with a Sony SRF-59 and a Tecsun PL-606). One station I wanted to hear was 1180 KERN Wasco-Greenacres, CA, about 240 miles or so away and I'm about 2x past Radio-Locator's predicted 0.15mV/m contour. Obviously the SRF-M37W had absolutely no chance of pulling it in at that location. I don't recall testing FM much on the Sony, but chances are it wouldn't have been worth it. One station I would want to pull in reliably (24/7, not just during tropo openings) would be KZPO 103.3 Lindsey, CA. Being only 280 watts and 800 meters HAAT at a distance of about 266 miles, having to cross a 4000+ foot mountain range, and with a 100+kW station 212 miles away (KVYB Santa Barbara) pretty much owning the channel when I'm on a ~800-900 foot hilltop about 3/4 mile north of my house, I'm sure KZPO would be a challenge even for a good home tuner (I've heard there's a Sony HD tuner that's fairly decent) with a rooftop antenna.
Also, at the same time I had the DT-400W (and recorded a scan there, but haven't uploaded it). Before I returned the two radios to the store, I asked my dad if he wanted to keep one (he was interested in one with a weather band). He listened to both radios (at home), and found that the selectivity on the Sangean on AM trounced the Sony. Also the Sony had a tough time getting any signal from our local weather station (I don't even remember if it picked it up at all), but the Sangean did just fine - it got a good signal pretty much everywhere in the house, whereas a dedicated weatherradio my dad has could only get it in one or two spots. Needless to say, my dad now has the DT-400W, and the SRF-M37W went back to the store.
I do know of a filter modification that can be done to significantly improve the selectivity on AM to something even better than the DT-400W, but there were other flaws with the SRF-M37W that for me made it not worth even attempting something like that.
KRVN used to be somewhat easier here a few years ago near San Diego, but now it seems there's another station occupying their channel, competing with KRVN. Anyone have any idea who that might be? Another Nebraska station I can also get here is 1110 KFAB from Omaha, but I have to dig it out from under KDIS Pasadena, CA.
I've heard WBAP a few times, but there's a station in Mexicali that usually owns the channel. KRLD was already difficult with stations on 1070 in L.A. and 1090 in Rosarito, but I have heard it a few times. Now with KNX committing adjacentchannelcide with their IBLOCK, KRLD is almost impossible here.
