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Thursday, September 17, 2015

A Cross-Country DXing Story, Fall 2015

Driving from coast to coast is a great opportunity to watch the world go by, to think, and to DX the mediumwaves on your car radio. I admit I am a casual DXer. I rarely do it from inside the home (too much electrical buzz), preferring to take a portable or small ultralight out to a quiet location, or to DX right from the car using its own radio. Twice a year in recent years, I have driven between western New York and southwestern Arizona, staying for six months in each location.

The Ford Ranger pickup I had for eight years had a superb radio. It was extremely sensitive, and its noise floor was very low. A couple of extra feet added to the whip made it one screaming DX machine. It suffered a little from ignition noise under acceleration, but be gentle on the gas and she would quiet.

Click map for larger and more detailed image

For example, cruising east along I-40 out of Flagstaff, AZ last April, I chased Los Angeles' KFI-640 (50 KW) to within an hour of Albuquerque, NM. I started out in Flagstaff at 6 AM and drove for six hours until I lost KFI-640 in the noise just about noon. Of course at the outset their signal was full skywave strength as the sun was just rising. As the sun rose, it faded through steadily decreasing peaks and nulls till about 10 AM when it entered this sort of echo-ey nether-world, the signal just barely above the noise. Then it would fade for longer and longer periods nearing 30 minutes between peaks, in and out of the background noise. Audio would be readable for a few minutes, then enter a long fade again. And then it vanished totally. In the end, it was a daytime reception of 600+ miles. That's a taste of what you're in for.

The newish 2011 Honda CR-V I got this summer doesn't fare as well in the radio department. The noise floor is high, masking ultra-weak DX, and it desenses more readily near big signals. No ignition noise, though. None. Sensitivity is only fair. Overall the radio is a disappointment for mediumwave. I'll carry the recently-acquired RF-2200 along instead.

Now, most of what I report is directed at daytime reception, though much of DXing theory applies to nighttime skywave as well. The key to successful DX, I've found, at least in crossing the wide open western states, is to park yourself on a frequency and just listen. Listen for hundreds of miles if necessary. You will see the progression of fade in to fade out, and the interaction of co-channel stations come and go. Pick a few favorite frequencies, or try some promising new ones, and see what happens. It's kind of like fishing in a stream - don't be too anxious to pull your line out too soon.

One of the main routes I follow when crossing the country is Interstate 70. I-70 runs from near Baltimore, MD through the central US states of Pennsylvania, Ohio, Indiana, Illinois, Missouri, Kansas and Colorado to the I-15 junction in western Utah, about 50 miles past Richfield. From Rochester, NY, our starting point, access to I-70 means a trip southwest to Columbus, OH via the I-90 thruway. I-90 leads you west across the bottom of Lake Erie to Cleveland, OH, then southwest via I-271 and I-71 to Columbus to join I-70.


Notable at the outset right out of Rochester is the massive 50 KW signal of WWKB-1520 at Buffalo, NY, pushing a nicely-formed cardiod pattern slightly north of east from its three-towered array. Sitting perfectly in the cardiod's notch is tiny, adjacent-channel WMCE-1530 (1 KW) at Mercyhurst College in North East, PA, broadcasting AM-stereo, and only 65 miles southwest of the 50 KW monster. Now this is a marvel of pattern engineering, sandwiching a 1 KW adjacent-channel signal right next to a 50 KW blockbuster, both of them sitting right next to huge fresh water lakes! And it works, too. 1530 KHz is filled with horrendous WWKB-1520 splatter as you pass Buffalo. Within 20 miles, WWKB-1520's hash and desense have evaporated to nothing, revealing the oldies-radio format of WMCE on 1530. Somebody should get an award for this engineering. WMCE-1530 is a great station, by the way.

An interesting listen on the Rochester, NY to Cleveland, OH segment is Canadian CHTO-1690, Toronto, Ontario (6 KW), with a variety of international programming and music. The signal is good and propagation is enhanced as it beams across both Lake Ontario and Lake Erie, about 188 miles as we near Cleveland. Here, nearly all of the propagation path is across fresh water, some 140 miles of it. The signal soon dissipates after you make the left turn south, leaving Lake Erie and Cleveland behind as you head toward Columbus.


I overnight at Mansfield, OH, off I-71 and about 60 miles south of Cleveland. In the dark just before sunrise, Denver's KOA-850 is weak, in and out, more out than in, but it does make an appearance. KOA-850 is difficult though not impossible to hear in Rochester, at 1430 miles distant. Here, near Mansfield, at 1175 miles, it makes the trip a little more easily. What's a few hundred miles you ask? Ohio's WKNR-850 in Cleveland (4.7 KW at night) beams north and we are south of them about 60 miles in somewhat of a dead skip zone. But the big difference, and something I stand by after years of DXing, is the single hop skip distance factor. Extreme single hop skip distance at mediumwave is on the order of 1300-1400 miles. We are within KOA's single hop skip distance at Mansfield. Rochester, NY is just barely outside that distance. Beyond that skip distance, signal strength takes a distinct downward turn, making reception that much harder.

Onward to Columbus, still dark, the famous Grand Ole Opry station WSM-650, Nashville, TN (50 KW) is in solid due to skywave. The sun will rise and it will be with us all day across I-70 almost to the Mississippi River, through the states of Ohio, Indiana, and most of Illinois. 650 KHz is an interesting and somewhat vacant frequency. Only a handful of stations in the lower 48 (seven to be exact) broadcast on 650 KHz, three of them broadcasting under 10 KW power output. From the Mississippi River west, more than 400 miles of dead air reigns until nearly central Kansas, where little KGAB-650 at Cheyenne, Wyoming appears out of the northwest. At Orchard Valley near Cheyenne, still some 400+ miles distant at this point, KGAB-650 commands amazing coverage for an 8.5 KW monopole. The secret here is the excellent ground conductivity of the mid-west, that is, the land west of the Mississippi River. A pipeline of mediumwave signals barrels east out of the front range of the Rocky Mountains across Kansas where ground conductivities hit 30 mS/m and the land is flat and treeless.


WJR-760, Detroit, Michigan (50 KW) hangs with me most of the day too. In fact, it was with me all day yesterday too. It's coverage is incredible. I can hear it weakly in Rochester during daytime hours. Today it hangs in there through Indianapolis nearly to the Illinois state line. Early afternoon, the corn-belt starts to appear, namely, WHO-1040, Des Moines, Iowa (50 KW) at 300 miles.

Overnighting in East St. Louis, this year I veer off I-70 and head south to Springfield via I-44, diverting into the beautiful undulating, treed-hills of central and southwestern Missouri. In this part of the country, roughly the center of the US land-mass, with a quick spin of the dial just before sunrise you can log all four sides of the continent within one minute - WSB-750, Atlanta, GA, WWL-870, New Orleans, LA, WCCO-830, Minneapolis, MN, and KFI-640, Los Angeles, CA. I tried it again. It never fails to impress me. Cuban stations are often in as well. Sunrise in Cuba.

Daylight breaks, skywave is dissipating, and out of Springfield, Missouri this morning the plan is to cross southern Kansas via US 400 to Greensburg, the town 95% destroyed by the EF5 tornado in May, 2007, then northward to Fort Hays. I park my radio on 630 KHz, 650 KHz, and 850 KHz, waiting for something to show up out of Denver or Cheyenne. I didn't have long to wait. In southeastern Kansas, 50 miles east of Wichita near the Butler County line, I hear evidence of carriers on the Honda radio. I pull over and get out the RF-2200. All three stations have readable audio - KHOW-630, Denver (5 KW at 487 miles), KOA-850, Denver (50 KW at 472 miles), and KGAB-650, Cheyenne (8.5 KW at 510 miles). It is late morning, just past 11 AM. KHOW-630 is perhaps the surprising catch. Its two-towered array pushes signal to the southwest into the Rockies and only about 3.8 KW is directed at southeastern Kansas on a beam of 106 degrees.


Nebraska's big-gun farm station KRVN-880 at Lexington (50 KW) is in there all the way across southern Kansas, broadcasting livestock reports. Greensburg is interesting, and gives off an eerie feeling as I pass through. Many new steel buildings, but also many vacant lots, some with concrete steps to nowhere. At Fort Hays, back up along I-70 again, the two Denver stations and Cheyenne are now armchair copy at only at 310+ miles. It is 3 PM in the afternoon. Onward to Denver tomorrow.

Just minutes west of Denver's mile high location lies the continental divide and the massive Rocky Mountains. Relatively poor ground conductivity along the 245 mile path to Utah (2 and 8 mS/m) and towering 14,000 ft. mountains take their toll on westward-propagating signals from the Denver area and east. By Grand Juction, a mere 215 miles, KOA-850 has disappeared, leaving only a weak KLTT-670 (50 KW) and weaker KKZN-760 (50 KW), both Denver area multi-towered arrays that push the brunt of their signal west. 40 miles further along I-70 at the little ghost town of Cisco, Utah, only KLTT-670 remains, extremely weak but readable.

Camp near Cisco, Utah. Quiet!

I leave I-70 and camp in the barren desert hills just beyond Cisco at mid-afternoon. The RF-2200 reveals Albuquerque's KKOB-770 (50 KW at 310 miles) with readable signal. One time here several years ago at mid-afternoon I clipped 60 feet of wire to the truck's whip and strained for Los Angeles' KFI-640. It was weak, yet readable, at 600 miles. But talk about quiet, even my cell service has disappeared. Moab is 40 miles to the south. Now camped, both at nightfall and daybreak I listen for WWL-870, New Orleans (50 KW). Nothing. WWL-870 is a medium-tough catch in western Arizona, but absent at this time.

Recent talk has been of defunct Spanish language KXOL-1660 (10 KW daytime, 1 KW nighttime), out of Brigham City, Utah, up by Salt Lake City. The FCC has canceled its license due to expiration of its silent status filing. It has reportedly been heard on the air. I listened on 1660. Nothing on daytime groundwave (a little too far for Brigham City), but skywave at night is strong, particularly right after sunset. They identify as "La Raza", which is what KXOL identified as. I can only conclude that this is indeed KXOL as reported. Further south, near Blanding, UT and beyond, this station and another Spanish station mix. My guess is the other is KTIQ-1660 out of Merced, CA. Not a positive ID, but they mentioned area locations.

Near Moab, Utah

One of the most beautiful drives in the country is the 30 mile drive through the Colorado River canyon on Utah 128. Much of the canyon is narrow, between towering, sheer rock walls, with the road clinging to one edge and the river many feet below. Few signals penetrate. Grand Junction's KNZZ-1100 signal (50 KW and only 65 miles distant) is in and out during the drive. Out of the canyon and into Moab proper, it is strong. One station is in the Moab area, KCPX-1490, a 1 KW graveyarder at Spanish Valley, just south of Moab. Two Grand Junction stations are the next closest, KNZZ-1100 being one of them. We are getting into lonely mediumwave territory here..

While in Moab, the side-trip south along the muddy-brown Colorado River to Intrepid's Potash Mine is always a great experience. At the mine complex the road ends in a dead-ended, washboard mess of rocky jeep trails. I sit down for lunch and listen for Los Angeles' KFI-640 again. Nothing. Two years ago KFI-640 on the truck radio was very readable at the noontime lunch hour. Distance, 570 miles. It was later in the year, though, further into fall. That may have made the difference. A funny place for any mediumwave station to show up, really.  We are still deep within canyon walls. Isn't propagation interesting?


Headed south the next day at the noon hour, we enter Indian territory. Navajo to be exact, the largest Indian reservation in the US. At about 130 miles distant, KNDN-960 (K-Indian), out of Farmington, NM (5 KW) pops up. They broadcast almost entirely in the Navajo language. If you've never heard the Navajo language, listen for it sometime, it is a treat. English words are interspersed where no Navajo word exists to describe the modern noun or action. With us all the way from Cisco is the other Navajo station, blockbuster KTNN-660, Window Rock, AZ (50 KW). Much of their broadcast is in the Navajo language as well. Both stations intersperse Indian pow-wow dance music between their usual country-western format, another listening treat.

I overnight at Flagstaff, AZ. Headed out early the next morning, KFI-640, Los Angeles is prominent on skywave. It is with me the remainder of the six hour, 300 mile drive to southwestern Arizona where Los Angeles is a mere 217 miles distant and Mexico is but 85 miles south. Familiar KBLU-560 out of Yuma, AZ (1 KW) reappears as an old friend south of Kingman, AZ, nearly 275 miles distant.

Settled in my western home, fall and winter DX is at hand! I'll try out the new Panasonic RF-2200 and see what she can do.

14 comments:

Stephen said...

Hi Bill,

Enjoyed reading the report on the trip! :)

Sorry to hear the CR-V's AM radio is lacking, though. :( Now that you're in Quartzsite, what are some examples of midday AM stations the Toyota's radio could hear that the Honda's radio is deaf to?

Just out of curiosity I plotted some approximate reception distances on Google Maps, to see how far beyond the 0.15 mV/m contour (you put on the maps) the stations were heard. I used the Google Maps measuring tool to measure from the transmitter site to approximately where you said they faded (or came in, as the case may be), while having the map file open in another tab scaled & panned as close to the same as possible. I switched back and forth between tabs to eyeball the measurement vs contour. (It'd be nice to be able to use the measure tool directly from within the map file itself, it'd make things a whole lot easier.)

Anyway, some very approximate results in the order they appear in the article ...
(I wonder what the groundwave field strengths would have been? I don't have a good way to calculate it (yet).)

640-KFI - about 3x past contour, near North Acomita Village, NM.

1530-WMCE - didn't measure this one, but was thinking, I wonder if they could be heard EAST of Buffalo with a good enough radio, if you're sufficiently far from WWKB or at a 90-degree angle offset?
Also while looking at the 1520 map I noticed that WJMP and WINW in Ohio look pretty closely spaced, and seem to do fairly well at avoid getting in each other's way. And it looks like there's some other closely-spaced 1520s west of there - I guess the ground conductivity is poor enough so they can get away with it? :)

1690-CHTO - about 2.5x past contour, near downtown Cleveland, OH

650-WSM - about 1.3x past, near St. Louis (west IL), OR, 3x, near OH/PA line

760-WJR - about 1.25x or so, near Terre Haute, IN

1040-WHO - about 1.5x, 300 miles from TX, on I-70 midway across IL

I'm guessing the next 3 are on US-400 in KS, northeast of Piedmont, between KS routes 23 (Piedmont Rd) and 528 (L Rd), just west of South Branch Otter Creek...

630-KHOW - 2.5x
850-KOA - 2.1x
650-KGAB - 3x

880-KRVN - about 1.4x, at US-400 / I-44.

850-KOA - about 1.33x, at Grand Junction, CO (about 202 miles from TX)

760-KKZN - (out of range) about 1.6x, at Cisco, UT
670-KLTT - about 1.3x, at Cisco, UT

770-KKOB - about 1.5x, just S of Cisco, UT

1100-KNZZ - about 1/3, on UT-128, abt 1/2 from Dewey to Moab

960-KNDN - about 1.66x, 131 miles from TX, 1/2 from Kane Springs Picnic Area to UT-46 on US-191
660-KTNN - Cisco is right at the edge (0.15 mV/m)

560-KBLU - Kingman, AZ is just outside the 0.15 mV/m contour.



So the Eton E1 gets armchair on KNX, and the Traveller 3 has it barely detectable barefoot, right? What signal level does the T3 indicate under the circumstances?
Also how does the E1, RF-2200 and the CR-V radio compare to my Pioneer's reception on KNX and KFI? The video linked below is an entire bandscan - KNX is at 6:35, and KFI is at 1:25.

https://www.youtube.com/watch?v=1uMF7_awQYs

I also recorded a video of a GE Superadio III bandscan there (in Quartzsite in July - approximately 33.6817, -114.2355), but I need to do some editing before I post it, and idk if I'll get around to it. Also, on the PL-606, KFI was 31/25 with the Select-A-Tenna, and barely registering anything barefoot (too weak to discern program content, about 16/00 or so). Also 810-KGO was weakly readable (about 15/05) with the SAT. KALL was pretty much as good as a no-show, although there was a slight blip in the reading briefly (15/02 then settled back to 15/00) and a slight pump in the audio soft mute, but no program content discerned, with SAT.

I'm hoping someone comes out soon with an improved version of the Traveler III that implements the multiple bandwidths, and has a display that's easily readable outdoors in daylight. (Actually I'd really like a vertical form factor radio, personally. I have the CC Pocket and it's sorely lacking, I think.)

Stephen said...

I was also recently thinking. I've seen various sensitivity shootouts between portables on various sites ... I'm curious as to how well various radios do with just the internal circuits, before any gain from whatever loopstick antenna they include is added. One experiment I'm thinking I might like to do sometime is to take several portable radios, remove the internal loopsticks, then go near a transmitter site. (I'd expect that without the loopsticks they'd not pick much up - I remember one time driving away from 760-KFMB's towers in the evening when they were on 50 kW, my PL-398mp with its antenna disconnected lost KFMB's signal by the time I got to where the Mast Blvd ramp to eastbound CA-52 met the freeway.) I'd note how far from the transmitter I can hear the station on each radio. I wonder how far they'd go?
A few radio candidates include the CC Pocket, Sony SRF-59, SRF-M37W, Tecsun PL-398bt (already has a broken ferrite bar, but I can still hear KOGO, XEWW, KFMB, KECR, KSDO, KCBQ and KLSD at my house on it), maybe a couple others, I'm not sure yet.
As for stations to test, I'd probably either concentrate on multiplexers, or low-power ND stations that aren't too close to other sticks. Diplexer candidates would be KECR/KCBQ, KURS/KNSN, KALI/KAHZ, KTNQ/KEIB, or KAZN/KMRB. The only triplex close enough to me would be KHJ/KYPA/KBLA. (I may go to a camp in December, the route to which would take me by KZSB/KCLU/KSPE, but I'm not sure if I'd stop or not.) The nearest quadraplex is WXYG/WBHR/WVAL/WMIN, and there's a pentaplex too - KHNR/KGU/KHCM/KWAI/KZOO. A single ND stick near me I might consider using as a test station would be 1450-KLSD.

73, Stephen

RADIO-TIMETRAVELLER said...

Hi Stephen,

Glad you liked he article. Lots of hard work you did, plotting those distances. Thanks. Where do you find the time?

Haven't done a thorough Quartzsite bandscan on the Honda yet. When the weather cools off a bit at mid-day I'll do that. KNX was pretty poor today, though. KFI-640 is down some from the truck as well. I never caught a signal strength reading of KNX on the Traveler 3. Too late now. Yesterday I gutted it and stripped the ferrite out of it. I've got it directly wired to an air core loop now, 18 x 18 inches by 13 turns. I'm going to rewind it to 17 turns in the next day or so. I'll do an article on it soon. Signal strengths are nothing less than mind boggling. I'm receiving KTNN-660 all day now. Also KKOB-770 Albuquerque pops in now and then. The San Francisco stations are there too, weakly. KALL-700 of course. You should try one.

Watched your bandscan video again. Your reception of KNX-1070 comes across pretty good. The RF-2200 and Eton E1 sound like they have a little better signal strength, but not by much. On the CR-V towards mid-day, KNX is audible and listenable, but very weak. Certainly the truck would have done a whole lot better. I just don't remember tuning KNX with it.

Yes, with a better tuning encoder, better display, and the ability to select bandwidth, the Eton Traveler 3 would be the rig to have. By the way, have you tried a CCrane Skywave yet? I understand that soft mute is turned off on it as well. The only other rig I know of that has soft mute turned off (or the ability to disable it manually), is the Tecsun PL-880. Too expensive at this time though, at $159. I doubt if the price will be coming down any time soon, either.

73s,

Bill

RADIO-TIMETRAVELLER said...

Hi Stephen,

Re your other question about removing the loopsticks in certain radios. I'm not sure you'd hear anything at all beyond 100 feet if that. It stops becoming a radio with the coil removed. You might get something like people say they receive radio on a bad filling in their teeth. :-)

Pulling the loopsticks out of the DSP radios is one thing. Pulling them out of normal superhet radios like the SRF-59, SRF-M37W, etc., is another thing. There are extra windings there for the oscillator stage. Be careful. You will destroy them. Also in their case, you pull all those coils out and you definitely have no radio. No tracking oscillator. No signal.

73s,

Bill

Stephen said...

Hi Bill,

First off, a few possible typos in the article that I'd seen earlier, but forgot to mention...

1: caption of map of route: "Clcik map for larger image"
2: at end: "new Panasonic RF-2200 and she what she can do"
I also thought there was another spot where 2 short words were duplicated and 1 should have been a different word, but can't remember now.


Also, reading through the article again, a couple more thoughts... :)

I wonder if WWKB has the deepest null relative to the TPO of any AM station in the USA? Or do you know of any that have deeper actual nulls? (It doesn't count if it has a huge null on paper but in real life is a lot less, for example I've seen some stations where the FCC pattern data says the theoretical field is like 0.6 mV/m, and the augmented field is like 30 mV/m or something like that.)
Also one of my far-out radio-related dreams (which I realize is pretty much 100% likely to NOT happen) would be to own/build a 50 kW station using Franklins in southern California below 600 kHz, with the transmitter site on the beach, such that at least one or two of the towers would get its base splashed at high tide. My "dream station" would have a null over the water so deep that if surfers went out to wait for waves to surf on (maybe around 800-1200 feet or so, I'm not sure), with something like an RF-2200 and a 72-inch loop, they wouldn't hear any trace of the signal. :)

On hearing all 4 sides of the country simultaneously ... it reminded me of something I would like to do as far as trans-oceanic DXing. Some day I would LOVE to hear simultaneous co-channel stations from, say, Australia, mainland Asia, Europe and/or Africa, on AM (not shortwave). :) Another big wish would be to be able to hear India, England, Iraq, etc, on 1071 kHz from the southwest corner of Columbia Park in Torrance, CA (where KNX's tower is). Now that would require some pretty impressive selectivity, I'm sure. :)

Also mentioning Greensburg (95% destroyed by tornado) and Cisco (ghost town) reminded me of another thing ... You probably are aware of the exclusion zones around Fukushima and Chernobyl, right, where people generally aren't supposed to live within like a 30-40 km area or something like that? I'm curious, if someone built an AM station on 540 with a Franklin antenna at the center of those locations, and adjusted its power so the 614 volt/meter contour (per FCC 1.1310, the max signal strength allowed for public exposure at that frequency) is at the edge of the exclusion zone, I wonder how far that signal might be heard? :)

I looked at KKZN and KLTT's patterns, comparing your maps to the FCC patterns. They definitely look quite different, due to the ground conductivity. :) Another one I think deviates significantly from "on paper" is KNWZ. Also an interesting ND one to look at is 560 KBLU - apparently the coverage west over Mexico is significantly less than over USA territory. And of course, small ND coastal stations in areas with poor ground conductivity but massive saltwater conductivity are interesting to see, too.

"Talk about quiet, even my cell service has disappeared." I wish there was some way for cell service to work over wider areas like AM radio does. I can understand not doing high-speed data from transmitters 400 miles away in the daytime and 1300 miles at night, but I think it'd be interesting to see voice calls and text messaging (which should only need minimal bandwidth), at least in rural areas, use some spectrum below 25 MHz.

Stephen said...

Speaking of some of the remote places near four corners, some day I'd love to go visit that location, also Durango, Silverton (both in Colorado), other places where my paternal grandfather grew up. :) Also visiting Moab, Cisco, etc. in Utah might be interesting. :) Hey I wonder if there are any places in the mainland USA where at midday at anytime of the year you would get absolutely NO reception on an RF-2200 with a 4-foot box loop? Or would you have to go to north central Canada during summer for that?



Now replying to your comments... :)

Time? What time? :D Well not having employment helps with that, but also doesn't help with income. Having some limited income related to disability is better than nothing, but I would like to be able to find some work in an area I can do.
Now where YOU come in, is: what are the groundwave field strengths for those stations at the locations you noted in the article? And if possible, midday skywave field strengths?

I guess it'd need to cool off a little more then to do the bandscan in the Honda? :) (Today it's about 100 at my house and fairly dry (humidity in the low 20s). I think it was like 110 or so in Quartzsite when I was there in July and I thought it felt fairly nice.)

Interesting, I look forward to seeing the report on the updated Traveler 3 antenna. :) I wonder how it'd do close to a transmitter for selectivity and desense, compared to the original antenna?
That also reminds me, what kind of antenna would you have to use with the RF-2200 so that a station that is unreadable (other than a faint het by tuning a superhet radio 452 kHz below next to it) on the built-in stock ferrite would be full quieting with the external antenna, like the S/N ratio that HD is when it's enabled, with the external antenna?

https://youtu.be/BwL47Y_WjMI?t=18m7s - my Pioneer at home on KNX, which is in and out of HD with the engine off. One of the segments later (still on 1070) shows the engine noise, and KNX never comes in HD although its call does eventually appear on the display.
Also at 13:18, XEKAM starts off with some engine noise but soon the HD kicks in.

I'd like to make a couple improvements to my car radio setup, one would be eliminate the engine noise (and the noise caused by my cell phone charger when I plug it into the 12V socket), another would be to put on a better antenna (I'm thinking a whip, but I've been looking some online and have no idea what to look for), and a third is to add a way to route the audio output directly to a recording device. (I think there are a few unused RCA jacks on the back, I wonder if I could route those around? I already have a microphone (for the phone function) and USB cable routed, and there's provision for a second USB port on that model.

I guess your definition of "armchair copy" and mine are a bit different :) To me, armchair copy isn't just a signal that you can hear every word that's said, it's one where the volume is just as loud as it'd be on a local station, even if there's a little noise in the background, and/or it stops a scan or indicates at least half approximately on a signal scale or something like that. An example would be my reception of KNX at home when it's not in HD.

No, I haven't tried the skywave. I'd like to, maybe when it comes down to about $60 or 65 or so. :) Also I think radiojayallen has done a review of the Sangean ATS-405, which has a button to defeat soft mute (as well as defeating tuning mute and adjusting squelch). If the PL-880 was down to below $100 I'd consider one of those maybe, too. Speaking of other recent radios I've tried, I wish the PR-D15 would have been a lot better. The volume dropped dramatically on weak signals, which for me is a deal breaker. I'd rather hear louder noise on a weaker signal than have the audio level drop when the station gets weak.

Stephen said...

I was able to manually defeat the squelch (is that what the volume drop on weaker signals is called, or is that soft mute?) on the PL-398mp in this video...

https://www.youtube.com/watch?v=4SbWavMLxm4

Unfortunately I managed to zap the DSP chip in that radio somehow. I'd disconnected the antenna lead for an experiment, then one day I happened to be in an area with some static (like a carpet/rug) with the lead disconnected, and somehow it accidentally connected just in the wrong way to overwhelm the DSP chip. Last I remember, turning on the radio and attempting to tune would have it take a few seconds to respond to my button presses or something like that.
I have the PL-398bt now, but that one has a broken ferrite bar, so that KCBQ reads about 06/18 at my house. It reads under 15 dBµ when I do the aforementioned defeat squelch function, which is shown near the beginning of the video, also it doesn't indicate 41/00 or 50/00 or whatever on "empty" channels near strong signals. I believe the Traveler 3 is also like this, but it still quiets down on weak/blank signals, or does it? How does yours behave?


On removing the loopsticks, I would not intend to hear anything beyond 100 feet or so. My intent would be to measure how far from the station's tower each radio on its own without an antenna could hear the signal, and not having to drive several hundred miles to find out would greatly help, as well as not having other signals present to muck things up. :)

I'd want to find out how much the internal circuit affects AM reception, before you factor in the antenna. I wonder if a better way would be to transplant the exact same antenna into each radio one after the other? For testing radios, though, I'd want it to be a weak antenna, for example one that can't hear KNX outside of Columbia Park, or something that isn't going to be affected by off-channel desense (except if caused by the station I'm monitoring, but I'd prefer it be weak enough on sensitivity so that doesn't happen) or co-channel interference (including GY channels at night). On not getting desensed by a strong signal, the PL-398mp with disconnected antenna leads and 398bt with broken ferrite I remember wasn't desensing even standing about 50 feet from a 50 kW station.

As far as removing the loopsticks goes, I'm hoping that just desoldering them from the circuit connections, while still leaving them physically intact, would be sufficient. That's what I did with the PL-398mp (before I fried it), and was able to hear KFMB at night partway down the onramp from Mast Blvd to CA-52. *IF* I was to attempt to pull the antennas out, I'd want to try to pull them all out in one piece if possible. I hope I won't need to remove them, though, just disconnect them.

73, Stephen

RADIO-TIMETRAVELLER said...

Hi Stephen,

I'll tackle your comments one at a time. :-) There may be a time delay between some of my returns.

Thanks for the typo corrections. I'll make the changes. It seems no matter how hard one checks, an error or two always sneaks through.

WWKB I'm sure doesn't have the deepest null. Theoretically, at least, I had a station somewhere down around New Orleans that had a perfect cardoid. It was so perfect it caused a "divide by zero" error in my program. I had to fudge around it. I'll look for it again sometime.

Augmentations might add or subtract from a signal, depending, either enhancing a null or further reducing it.

Hearing all the continents... yes, hearing all at one sitting would be exceptional, wouldn't it. I suspect daylight might interfere on one side or the other.

Exclusion zones... don't know how far a signal of that magnitude might be heard. Of course it could be calculated. Would need a way to introduce a test station. Haven't done that yet.

KKZN and KLTT patterns... yes, the FCC patterns are theoretical. The M3 ground conductivity will greatly distort them. Check some stations at the coast and see what sea water does. The effect is huge.

KNWZ pattern distortion... yes, that station's daytime pattern is greatly distorted. Lots of different ground conductivities in play. Nighttime is closer to the theoretical, at least on my latest rendition. My latest nighttime patterns are much more accurate than the last set of maps I did.

Cell service has disappeared... nice to make use of the spectrum below 25 MHz, but cell wouldn't be advisable much below 200 MHz due to the chance of E-layer skip and other low frequency annoyances. Many years ago the FCC authorized the CB band at 28 MHz and they have been sorry ever since. :-)) They hadn't intended for skip operations. Skip can occur clear up into and above the FM band frequencies. rare, yes, but it does happen pretty frequently at certain times of the year.

73s,

Bill

RADIO-TIMETRAVELLER said...

Hi Stephen,

The four corners area is one of my favorites. Over by Mexican Hat, UT, you are fairly remote from AM broadcasts. Looking at a map of all AM locations, it looks like south central Nevada is about the most remote. I suspect that even there you'd hear something, especially on a big loop. A barefoot ultralight might be dead, though.

"Now where YOU come in, is: what are the groundwave field strengths for those stations at the locations you noted in the article?" We're back to time again. That would take about an hour or more. :-)

Temperatures here hovering about 100. 108 day before yesterday. We had huge rain yesterday afternoon though. Maybe only 96 today.

The Eton Traveler 3 is likely to choke very badly in the near field of a broadcast antenna with the hardwired loop. I also don't have an input capacitor on the loop. In any event, I'd be afriad I'd fry the chip with the direct connection.

"What kind of antenna would you have to use with the RF-2200 so that a station that is unreadable (other than a faint het by tuning a superhet radio 452 kHz below next to it) on the built-in stock ferrite would be full quieting with the external antenna, like the S/N ratio that HD is when it's enabled, with the external antenna? In the case of the RF-2200, it is already so sensitive, that attaching a huge antenna to it would probably just amplify the noise floor. The signal is likely below the noise floor, so you still wouldn't hear it. It's generally not possible to extract a signal that's too far below the noise floor.

Car radio noise. The Honda is pretty good for lack of ignition noise. The base noise level of the radio is high, though. It tends to mask the weaker signals. I want to investigate the antenna. It has one of those angled 6 inch stubby antennas at the back on the roof center. It's so hard to get behind the dash in these cars.

Armchair copy. An old Ham radio term, actually. It generally means a booming signal. But my meaning is at a little less strength than your meaning. Basically, 100% copy without effort, but enough out of the noise that it's not in the "weak" category.

On eliminating soft mute. I forgot about the ATS-405. Now that I've successfully made the hardwired loop surgery on the Eton, maybe there are others that might be appropriate candidates. I would want no soft mute, selectable bandwidth ability, good sensitivity.

Sorry about the PR-D15. It's not DSP is it?

73s,

Bill

RADIO-TIMETRAVELLER said...

Hi Stephen,

I think by squelch you are referring to soft mute. I'm not sure what you're doing in the video with the yellow gadget. I have no idea what it is.. another radio?

Okay, some definitions. There is soft mute (who's practical implementation has only been in existence since the DSP chip in 2009), and there is AGC, or Automatic Gain Control, which has been around maybe since the 1930s. It's in all receivers even today.

A little history. Automatic Gain Control, or AGC, was first implemented in radios many years ago for the reason of fading propagation, which required continuing manual adjustments of the receiver’s gain. The idea is that the AGC circuit will automatically maintain a constant signal level at the output, regardless of the signal’s variations at the input of the system. Besides the depth of its interaction, AGC has two other characteristics, attack rate and decay rate. The attack rate is the speed in which the AGC is applied, the decay rate is the speed in which it is relaxed. All three are important design considerations.

Soft mute. The chip processor analyzes the signal-to-noise ratio of the signal (in the DSP ultralight radios, the carrier-to-noise), and when it reaches a certain low level threshold, the processor reduces the audio volume to the speaker or headset. It's for a "more pleasant listening experience" (the consumer), but it masks weak signals.

I could never understand why they would combine AGC with soft mute. One intends to increase the receiver gain so you can hear weak signals and the other masks the receiver output for weak signals. They are mutually-exclusive.

I don't notice any soft mute at all on the Eton Traveler 3. Tune between stations and all you hear is noise.

I find the Eton's AGC to be a bit heavy handed. It's decay rate is extremely slow in reaction, especially for the DXer. Tune off a moderate or strong signal to a nearby weak one, and it seems seconds before the AGC relaxes and brings up the volume of the low level background signal and attended atmospheric noise. This is simply a programmatic adjustment on the DSP chip. It probably works for the intended consumer crowd, but not for the DXer. I prefer a relatively fast AGC.

Removing the loopsticks. In the case of the DSP sets, by removing the loopstick connection you basically have an untuned front end. In a superhet set, by removing the antenna side of the loopstick (and leaving the local oscillator side), you would have a similar result. The best thing to do would be to substitute an antenna coil wound on a ferrite core doughnut. This would isolate the tuned circuit and wouldn't tend to receive signals. Then you could do your comparisons. In other words, you need to replace the loopsticks with a tuned entity of some sort that does not receive signals. That would be a ferrite doughnut core. An untuned front end, one with the coil missing, doesn't test anything. If you hear anything, it's like the guy who hears radio off his tooth filling. It's a quirk of nature.

73s,

Bill

David W9819 said...

I live in Ogden, UT and I'm located close enough to KXOL's transmitter that I can receive faint images of the station on 760 AM. Therefore, I can assure you that KXOL 1660 is still on the air as of this writing despite the fact that the station's license was cancelled back in August 2015. I can only assume that either no one has filed a complaint against Inca Communications (owner of KXOL and several other radio stations in Utah), or that the FCC just doesn't care about shutting down a 10 KW/1 KW pirate broadcast station. The lack of FCC enforcement action up to this point is baffling, since KXOL received an NAL in August 2013 for not notifying the FCC that the main studio had been relocated, and the phone number listed for KXOL when a field officer attempted to inspect the station had been disconnected.

RADIO-TIMETRAVELLER said...

Hi David,

Thanks for your comments on KXOL-1660. Since getting to southwest Arizona last September, I've not been able to log them, so wasn't sure they were still on the air.

Yes, FCC enforcement is sorely lacking. I am told they only are responding to complaints at this point.

We shall see how long this goes on.

Bill

MI said...

Great post! Very inspirational to get out and dx. I very much enjoy your site, review, and commitment to radio. I'm an amateur radio operator but in the last couple of years have really been bitten by the SWL and MW dxing. Keep up the great work!

Mike

RADIO-TIMETRAVELLER said...

Thank you Mike! Glad you like the site.

Bill