Welcome back – I hope you are ready to get into the swing of another DX season. We’ll pick up this time with some continuation of the discussion on coastal DX.

Mark Connelly <MarkWA1ION@excite.com>: Here are a few coastal DX comments in response to others' recent postings- (Fred Vobbe asked) "Ben, what was the effect from the ocean? If you were in the parking lot and had Algeria on 891 at S-9, would driving a quarter mile back from the lot to the west lose Algeria or just attenuate it a bit?" The amount of difference between strength of a given long haul skip station from shore to inland varies somewhat with season and time of day. At (or before) sunset here on the east coast, especially in summer, differences of up to 40 dB have been noted on early-arrival high-band North Africans at a shore site in Rockport, MA versus my home QTH in Billerica, about 20 miles inland on African bearings. When the Algerian clandestine was on 1544, it routinely hit S9+40 at the shore, but I never saw it get over S9 at my house on equal or better antennas to the same receiver. Late night winter high-latitude signals (from stations such as Norway-1314), when they are in, must be coming in at a somewhat higher angle since the coast versus inland difference on these only seems to be about 10-15 dB.

(Bob Foxworth said) "I remember from my Long Island days that Atlantic City NJ would be well atop 1340 1400, 1450 and 1490 during the daytime all along the south shore. Had to be right on the beach, anywhere from Jones Beach to Montauk was equally good for them. Driving straight inland, e.g. the Moses Parkway, I'd lose them pretty rapidly from about a half mile inland onwards and by about 5 miles inland they were well down in the soup and the dropoff was pretty linear, but this was a non-measured test e.g. no s-meter. Long Island is just a big sandbar and the soil conductivity isn't good." Same deal on Cape Cod. At the southern end of Route 134 near Lower County Road in Dennisport, on Nantucket Sound (water to south), several of the graveyard frequencies have Atlantic City, NJ dominants. Driving Route 134 north through the low-conductivity "sandbar" of the mid-Cape (dry pitch pine/ scrub oak woods) up to the Cape Cod Bay side (water to north) totally flips over the graveyard dominants to be stations from Maine instead. This in about an 7-mile 15-minute drive. "I've never been in a place where afternoon TA's behaved like this however." That's because you weren't using eastward-facing beaches, only southward-facing ones. Come up to the Boston area sometime for a "demo" (as Ben did). George Hakiel noted strong TA enhancement at Greenport, LI, NY: an eastward-facing site similar to several here in MA.

(Russ Edmunds said) "given the differences I've seen between my former Northern NJ location and this one, (a result of the increase of land mass at this end of the signal path of about 150+ miles for much of Europe) the addition of ground at this end in substitution for ocean is very substantial..." The first few miles of sandy or rocky soil kills off most of the signals. Going inland 50 miles isn't a whole lot better than going 150+ miles. If you had high-grade open farmland (instead of rock) between you and the shore, signals would penetrate inland farther for a given amount of loss. For those who haven't seen it yet, Ben Dangerfield's recent Massachusetts visit is documented on the Web (with updates) at "http://members.aol.com/DrakeR8A/dangerfield_visit_2000.htm".

Robert Foxworth <rfoxwor1@tampabay.rr.com>: Another factor too was that I was married when I lived on LI and I would often go to the East End with my wife, usually to Montauk. by the time the TA's might appear it was near sunset and I was then being asked to get dressed for dinner at Gosman's Dock, a place where serious DXing of course was not possible... I did live for 6 years on the LI North Shore a bit east of Port Jefferson, very close to the Sound, across from Bridgeport. The French Canadians from Quebec were always well heard there and it was a very good TA location as well, since the arrival angle from Europe used a lot of the Sound. Greenport would show similar conditions as well, but I never took a good receiver there. I do remember CHSJ-700 could be heard in the daytime in the summer out that way.

Russ Edmunds <wb2bjh@hotmail.com>:The signals bounce off the water somewhere in the mid-Atlantic, then back up and then again down to the rx. I'm more inclined to believe that it is a combination of the completely clear horizon and the excellent ground, although the amount of difference observed shouldn't be as great as it is. It may be that this combination permits a multiplicity of signal paths only minutely different from one another to somehow congregate. I do know that when Ron Schiller DX'ed from Monmouth Beach NJ, he was on an inland waterway and less than a mile from the ocean, and he had that kind of enhancement. I believe that he did the same thing years later from Lighthouse Point, FL. And, given the differences I've seen between my former Northern NJ location and this one, (a result of the increase of land mass at this end of the signal path of about 150+ miles for much of Europe) the addition of ground at this end in substitution for ocean is very substantial....For some as-yet-not-fully-understood reason (s) this occurs. I don't recall anything in any of the literature I've read about this, although it is certainly no coincidence that many of the early radio pioneers used seaside sites for their experiments.

Barry McLarnon VE3JF <bm@lynx.ve3jf.ampr.org>: The effect is known as "sea gain", and it often appears as one of the factors in empirical formulas for estimating the field strengths of MW skywave signals. Essentially, a skywave signal coming in at a low angle becomes a groundwave signal for the last part of its travel (and the first part near the transmitter site too, of course). Attenuation of the signal over these segments of the path is therefore much the same as for groundwave signals - very low over salt water, and much higher over land (especially land with low conductivity). The difference is the "sea gain" factor for receivers located close to the coast. A book I have ("Propagation of Radiowaves", from the IEE in the UK) shows the sea gain plotted as a function of the ground distance for the path. Since the gain is greatest when the skywave is at a low angle, it peaks when the distance is near the maximum for one hop propagation (about 2000 km), two hops (~4000 km), and so on. In between it dips a bit lower - e.g., near 4000 and 6000 km it's about 10 dB, but it's only about 4 dB at around 2700 km and 6 dB around 4800 km. According to the book, ITU-R Recommendation 435 gives a procedure for calculating sea gain in more complex situations (receiver located inland, irregular coastlines, etc), but I don't plan to delve into it that deeply, since I'm nowhere near a coast.:-)

Marc Delorenzo <Marc.Delorenzo@rcp.dph.state.ma.us>: Barry, Thanks for sharing! That explanation makes it very clear to me. I have wondered for years why skywave is better at the beach. Groundwave was obvious but skywave had me puzzled. I have DX’ed from Cape Cod beaches since 1964.

Russ Edmunds: That makes sense, certainly. And that is another reason why some of the Spanish, Portuguese and Moroccan stations seem to be more common. I don't recall if I was aware of that element before or not. It would be interesting to know just what kind of distance on that first or last segment of the signal path typically (if there is such a thing) acted like groundwave.

I know nothing about grounding. But the following helps explain a lot of it.

Patrick Martin <mwdxer@webtv.net>: Hi: As many of you know, I have several beverages and antennas I use. Here on the Northern Oregon coast we generally get a lot of rain 60-100 inches a year. This Summer has been a "dray" one to say the least. Does anyone know what the best type of grounding I could use? Right now I am using a series of several rods (copper pipes) with #14 bare copper wire connecting them. It isn't all that easy to put 8-10 foot rods in the ground, so I use 4 foot ones. Most of the year the pipes are under water. Oh course in the dry part of the Summer the grounding is in very sandy soil. I notice this Summer when we get a bit of drizzle or light rain, the noise level goes down and the antennas work better, as they should. What would be a reasonable ground system that would work pretty well even when the soil is dry? Also should I increase the number of rods at all grounding points, including the matching transformer grounding points and the termination points? I am just trying to make the system work better, as we are trying to do. Getting that 1/2 dB signal can make the difference of logging the rare catch. Thanks.

Lee Freshwater <LFreshwate@aol.com>: Patrick, One thing I have learned in 30 years of radio is "deeper the better" I was just up to a transmitter site in the NC Mountains. They have driven ground rods up to 50 feet deep in places. Ground "radials" are also good, but you will find that your signals improve the deeper your rods are. Of course you do get to the point of "diminished returns" I would say that 10-12 ft would be a minimum, but I do not know your area or the "ground" conductivity of your site. We have very poor "grounds" in FL while the upper midwest had extremely good ground. I'll have to dig out my FCC rule book, as they have a good map.

Patrick Martin: The ground conductivity here is rather poor too, but the salt water from the ocean connects to the land mass. In other words the water in the nearby field (Non salt water), is salty at times. Much of the year the fields where the beverages run are under water. However this Summer has been dry.

Bruce Conti <BACONTI@aol.com>: Ground radials work great here. I use radials buried just a couple of inches underground. Just use a garden shovel to pry up the lawn and stuff the wire underneath. Textbooks recommend ground radials of about 1/4 wavelength minimum. I have 100-ft antenna wires, and the ground radials are about 50-ft long. I use the same wire for ground radials that I use for the antennas; insulated THHN type from the hardware store. Solder the radials to your ground rod. To get the best performance from your ground rod, I've read that you can dig a deep hole and replace the soil with a mixture of rock salt, cow manure, and top soil, before pounding in the ground rod.

Russ Edmunds: Reminds me of what a ham buddy of mine several years back did - he built a pit, filled it with a mix of topsoil, sand, loam and some clay, and then ran all of the downspouts from his house and also his sump pump discharge into it to augment the dampness during dry times...

Ben Dangerfield <BEN-DANGERFIELD@email.msn.com>: Bruce, just what are these ground radials supposed to do? Improve ground signals? Improve skywave signals? Reduce noise? I have a short ground wire buried about a foot down just outside my den window. I use it off and on with my phasing units and it does reduce some of my noises. Not sure if it improves any signals.

Bruce Conti: Ground radials improve the electrical conductivity of the ground plane. According to Victor A. Misek in "The Beverage Antenna Handbook," a low loss ground system tends to suppress locally generated noise. In addition, confirming suspicions expressed by Patrick Martin and others, Misek states, "A lossy ground can cause seasonal and even daily variations in antenna impedance as soil conditions change from dry to rain-soaked to snow and ice covered. The impedance is always changing and never stays matched. The use of parallel ground conductors or wire mesh to increase the effective ground conductivity short circuits the variations due to weather and minimizes the effects of ground conductivity anomalies under the antenna." For the noise-reduced system I've installed, the use of ground radials has significantly improved the effectiveness of the noise reduction. The ground radials act as an effective counter-poise for the wire antennas. Visit any AM tower installation, and the engineer should be able to tell you about the ground system, which often includes ground radials. (During a visit to the WKBR site during the 1994 NRC Convention, we found many exposed ground radials on top of the soil.) 1/4 and 1/2 wavelength towers depend on the ground to extend the electrical length of the antenna. I believe that it's the same for end-fed wire receiving antennas. For wires at less than a wavelength, the ground becomes part of the antenna's electrical length. In Misek's discussion of wave antennas (end-fed wires or Beverages), a poor ground "results in shortening the electrical length."

Mark Durenberger <mark@durenberger.com>: If you're not a tecchie, stay with me and I'll 'splain further what Bruce is talking about. If you are a tech-naut, please forgive me as I take some liberty with terms. Whenever you deliver "power" to a load, you pass current through that load. The load requires two terminals (an "in" and an "out" if you will), so current can flow through it. For example, a lamp can be a load, but it won't light if you connect a battery to one side of the lamp, but don't connect the other side of the lamp back to the battery. There are in fact no "one-terminal" loads. A one-terminal load is impossible, since the current needs to flow through the load, to deliver power to the load. A radio transmitter is a source of power, delivering that power to a "load" that in our over-simplified case may be described as the "ether", or the path to the receiver. (Now don't beat me up guys, I'm trying to keep it simple). No matter how you describe this radio "load", it's still a two- terminal load. The two terminals of the radio load are the transmitting antenna and the ground system. The transmitter delivers power to the load by providing an electrical current in the form of a radio-frequency signal. Disconnect the transmitter from either the antenna or the ground? Current will not flow, and no signal will be radiated. Most broadcast engineers will tell you the tower is only slightly more important than the ground system. Since the 1930's the FCC has sanctioned "transmitting systems" consisting of an insulated vertical radiator and a complementary ground system. The ground system is usually composed of 120 wires fanned out in a circle. In a good design, each wire is at least as long as the tower is tall. Without a good ground system, the signal simply will not get out. A better ground system is one of many reasons that some stations do so much better than others, even when they're the same authorized power level. On the receive side, the "radio load" is the receiver. In the ideal system, maximum current will flow when one side of the "load"/receiver is connected to the antenna, and the other side of the "load"/receiver is connected to ground. This arrangement reduces inherent noise, as Bruce points out. And if the receiver is properly matched to antenna/ground, the increase in signal level reduces the noise even farther. Enough already. Thanks for reading

Lee Freshwater: Mark, Well said. I had an engineer friend in Alabama that had a set of railroad tracks behind his site. he grounded his AM system to the tracks and boy did his signal improve!!! A perfect example of what you are talking about. Grounding is as important as the antenna(if not more)

Frederick R. Vobbe <fredv@nrcdxas.org>: Very good description, Mark. One only has to look at the radiation angles/field-strength of two stations on the same frequency, one with a good antenna system and one with hardly any ground and a tower shorter than 1/4 wave.

Russ Edmunds: Mark - since I plan to use some of this discussion in an upcoming column, I am most grateful for your simplification as it's better than I could have done, and for the non-techies, it needed to be done - some guys who are very technically inclined somehow aren't able to bring the discussion down to a lower level, which you've done. That said, I'd appreciate your supplementing your comments by addressing the following items in similar fashion also, if you'd be so kind-

1) the ground system and variations in conductivity or moisture content within the area of the ground field

2) does the depth of the radial system need to vary with local ground conductivity and/or composition (sand vs. clay for instance)

3) what can one do to achieve optimization of the ground system to the antenna for a receiving site

Thanks!

A question from the DDXD-West Editor:

Bill Hale <phantom2@eaze.net>: Here's another subject I'd like to hear comments on...I do a lot of listening in bed, lights out, ear buds in, waiting for slumber. Next morning, I wake to whatever frequency was there when I conked out. Then I tune around for awhile listening for DX. If I don't push one of the 32 memory buttons on the -2010, I don't know where I am on the dial. So...can a synthesizer with a limited vocabulary of "zero", "one", two", etc through "nine" be integrated into a radio so as when a button is pushed the 'voice' says "seven-six-zero" or whatever frequency you're on? If not, why not? This would be especially valuable to a sight-impaired DXer. Let's hear from you tech types.

And some more receiver talk:

Jerry W. O'Dell <jwodell@ameritech.net>: I'm just getting interested in this again, and I haven't heard WWL, New Orleans, for many years. Wonder what happened to them. Just got a CCRadio, and it's pretty good, but not like my old NC183! Ah, to recapture the excitement of the late 40's.

Mark Durenberger: Jerry if you like good AM sound, get on ebay and watch for a Sony 7600 analog slide-rule-dial receiver. IMHO one of the best-sounding AM radios in captivity!

Kevin Redding <lwdxer@juno.com>: Really Mark? How is it on reception? I am not saying much about the SRIII except I sure like the way they sound. That big speaker does a nice job. I would like to hear one of those 7600's someday.

Mark Durenberger: Very good. Because it's "wide", its selectivity isn't quite up to some of the digitally-tuned radios, but I think Sony did an excellent job of design on this one. Only drawback is no external antenna jack but if you're into loops, it works well with an external loop coupler.

Bruce Conti: Regarding Jerry O'Dell's comments about the CCRadio, the bandwidth of the CCRadio is purposely limited to 4 kHz, to reduce interference from adjacent channels. This is a requirement these days for any serious MW (AM) DXing. The 4 kHz bandwidth is fine for long distance news/sports/talk radio, which the CCRadio was primarily designed to receive on AM. To hear the transoceanic signals often requires reducing the bandwidth to around 2 kHz. When using a narrow bandwidth, sound can be sharpened simply by tuning slightly off-frequency. A receiver that is reported to have good sound will typically have a bandwidth of 10 kHz or greater, perfect for airchecks of strong stations, but not useable for "hardcore" DXing. The Drake R8A/B is a favorite among MW DXers, with selectable AM bandwidths of 6, 4, 2.3, and 1.8 kHz. If you can't afford the $1000 price tag for the Drake, then the Sony ICF-2010 is another favorite, but needs to be upgraded with Kiwa filters for improved DX performance. The Palstar R30, a newcomer, is also a good DX receiver when outfitted with a Collins narrow filter.

Mike Pietruk <pietruk@shellworld.net>: Mark - Amen on the 7600. I have one of them in the closet -- nonfunctioning sad to say -- which I'm about to discard as preparation for a move later in the year. Had both great AM and FM reception with good sound, selectivity and sensitivity on AM, and fm. While I'm thinking of it, are their businesses that can work on these receivers to get them functioning again?

Jerry W. O'Dell: I got interested in radio because my dad had one of those big old RCA console radios. I'd go up on 75 meters, and the most awesome signal there was W8UM, the U of Michigan station. Super quality, and I think they built it all. I fear that if things had been SSB I would have taken up another hobby. I really hate that mode -- although there is no reason that it has to sound as awful as it does. But that's another story!

Jerry W. O'Dell: "watch for a Sony 7600 analog slide-rule-dial receiver." Will do -- but I'm an old person, and a really good sounding radio (not very selective) with a Zenith table radio with FM and about an 8 inch speaker on it. Man that thing sounded good. Haven't seen one since about 1958

David Coons <davidcoons@webtv.net>: I am one also who returned a ccradio. I feel it is inexcusable to have terrible audio since it was designed with a 4k limit at least provide low distortion sound without hiss, and a usable treble control.

Paul Smith <sunray@gate.net>: If you will contact me off list, I might be able to help, I'm in the business.

Jerry W. O'Dell: On the shelf in front of me is a big old Sony, about 10 inches long, and 8 inches high, and it used to sound wonderful. It still works, although the band switch needs a good shot of cleaner from time to time. Wonder if that is the 2600. FM and shortwave + BC. I don't see any numbers on it, and about 9000 CDRoms would fall down if I moved it!

See you in two weeks.