Anyone Here DX From An AM Radio They've Built?

[Steve_Green]

Years ago, I recall reading about a receiver called the Worcestor. My memory may be wrong, and I never saw one, but I believe it essentially was a homebrew unit built from scratch via a design that would outperform many stock radios in terms of selectivity, sensitivity, frequency determination, etc.

A few questions about that subject :

Does anyone here use one now, or have ever used one?

Are kits for it or similar radios still available -- as a current product, that is?

Deleting the usual upgrades on commercial products for the moment -- Q-multiplier, extra antennae, other additions -- does anyone DX on a rig they've built?

Now that I've retired, I'm more than mildly interested in taking a crack at a project like that. If it's a matter of assembling and soldering a 300-piece jigsaw puzzle, that's one thing. I've etched and drilled some circuit boards already for those small multi-purpose chips, but just for other people (they all worked, somehow :- )

I figure that a tube chassis would be easier to assemble because of the size, but could be wrong.

In other words, I'd like to build something along the line of a good Hallicrafters. Any hope for me? Maybe a starter kit for a good workout?

 

[K6JHU]

Actually I have seen the Hallicrafters show up at antique swap meets and garage sales. Saw one at $25 and was going to leap all over it when I realized that I really didn't need another radio

Ramsey sells the basic AM radio kits. But I doubt that you are going to get real performance out of a $15 kit.

 

[Icangelp]

Indeed there was a Worcester MW radio, but I don't recall it being available in kit form. It was patented. I still have an NRC (or was it IRCA?) review of the receiver, and I think I have a copy of the patent somewhere in my "stuff I'll probably never use again but I'm saving it anyway" area of the basement.

I have a Worcester Space Magnet 2, ferrite antenna, also built by Mr. Worcester, who was a retired from GE.

You might find some receiver building info in the articles available on CD from NRC.

Sounds like fun. Good luck.

 

[ddsparxx]

I used to have a crystal AM radio kit that picked up shortwave broadcasts at night, though the kit's band coverage was only the MW AM band and the diode was the kit's only semiconductor. Of course, the kit wasn't meant for DXing or receiving SWL.

 

[pqgeorge]

I used to have a crystal AM radio kit that picked up shortwave broadcasts at night, though the kit's band coverage was only the MW AM band and the diode was the kit's only semiconductor. Of course, the kit wasn't meant for DXing or receiving SWL.

I built a crystal set back in late '71 (a Christmas present) from Radio Shack. Using a small long-wire antenna and a set of headphones with the kit, I was able to get a couple of local AM stations in the Boston area (namely WBZ/1030 and WMEX/1510). Then for the heck of it, I took the audio portion of the crystal set... connected it to the mic input of a tape recorder. As a result, I was able to pickup CBL/740 from Toronto and WPTR/1540 in Albany, NY. It was very wideband (obviously) but hearing things over 200-400 miles away with very little equipment was amazing to me (at 11 years old). WBZ sounded like FM at the time!

 

[Schroedingers Cat]

Here in Southeast Michigan back in the 1960s, you could use a crystal radio with a long wire and get WCFL and WOWO with a long wire antenna. WCFL and WOWO were both 50 kW (in the good old days when WOWO was 50 kW night) directional and favoring SE Michigan. I also remember adding a couple of tuned RF stages and a one transistor preamp and getting some fairly weak signals on a crystal radio. But then, where do you draw the line and still call it a crystal radio?

The old I-As were all omni except WBZ and WWL, and most have ~195 degree antennas that cut down the skywave signal at the short distances where they most likely could be heard with a crystal radio and a long wire. Some of the I-Bs had slightly shorter antennas and their DAs also concentrated the signal.

The Remco Caravelle got some fairly weak signals and was essentially a crystal radio with an audio amplifier. It could also be used like a tuned loop or Select A Tenna by placing another radio in the right spot. It was essentially omni though with the vertical whip.

The late John Kraus, the all time antenna expert and author, apparently started out just that way-building antennas to DX stations with crystal radios.

 

[pianoplayer88key]

A crystal radio for me consists only of one tuning capacitor, antenna, diode, resistor (unless it's not necessary) and earphones. (Basically, the simple Radio shack circuit would qualify.)

I remember when I built my first one from a Radio Shack 200-in-one kit. (This was the one with the 1-transistor audio amplifier.) I hooked up about 6-8 feet or so of wire that came with the kit, and was just barely able to make out a trace of 1170 KCBQ, whose 50kW transmitter was 6 miles away at the time with a huge lobe aimed right at me (probably with an ERP upwards of 200-300 kW). When I added a longer antenna to make it stronger, KCBQ became listenable.... and could fairly easily be heard across the entire band.

I did inductively couple a Select-A-Tenna to it, which enabled me to bring in a few more stations, like 600 KOGO, 760 KFMB, 910 KECR and 1360 KPOP (now KLSD).

Recently I built the basic crystal set with the 300-in-one kit, and by inductively coupling to a Select-A-Tenna and utility pole grounding wire, I'm able to bring in 600 KOGO, 690 XEWW, 760 KFMB, 910 KECR, maybe 1130 KSDO, 1170 KCBQ, 1360 KLSD, 1470 XERCN and 1700 XEPE. The tuning is entirely done with the Select-A-Tenna - the built-in capacitor on the kit has virtually no effect.

Here is the strongest signal I've ever heard on a crystal set. There's no audio output jack on the RS 300-in-1 kit to hook up to my Zoom H2's line input, so I hooked up the kit's speaker instead.
That was 1170 KCBQ, recorded right outside their transmitter site, with the crystal set and Select-A-Tenna held up to a utility pole. (There was basically no trace of it using only the set once i was more than a few feet away from the pole.) Here's a pic of the PL-380 & Select-A-Tenna at the same location tuned to 1170's 60th harmonic. The 4 towers in a line behind the pole carry KCBQ's 50kW daytime signal, and throws a lobe right at where I was standing. (The tower off to the side isn't used by KCBQ in the daytime, also due to the angle from which the photo was taken you may only see 2 or 3 towers in a line.)

 

[BobOnTheJob]

Not AM, but I still have the Heathkit AJ-15 tuner that I purchased in kit form exactly 40 years ago...and yes, it still works fine.

 

[K6JHU]

I have a single digit Heathkit SR AR-29 that I also built back in to 70's. Still using it. I also built their colr TV kit. Nolw that was an experience.

 

[Schroedingers Cat]

A crystal radio for me consists only of one tuning capacitor, antenna, diode, resistor (unless it's not necessary) and earphones. (Basically, the simple Radio shack circuit would qualify.)

I would say anything passive like tuned RF stages are permissible and still be a crystal radio, but no power or amplification.

 

[pianoplayer88key]

A crystal radio for me consists only of one tuning capacitor, antenna, diode, resistor (unless it's not necessary) and earphones. (Basically, the simple Radio shack circuit would qualify.)

I would say anything passive like tuned RF stages are permissible and still be a crystal radio, but no power or amplification.

Personally I'm a bit wary of tuned RF stages, unless it's a tuned loop inductively coupled to the crystal set, and even then I'd specify that a tuned loop antenna was used. IIRC, when I built the RS kit crystal set, I'd estimate it having a selectivity of maybe -10-15dB at +/- 500-600 kHz, if not worse. Basically, if a local is loud enough to recover enough audio to ID the signal, it seems that there would be at least some trace of their signal across the entire MW band.

 

[ddsparxx]

I used to have a crystal AM radio kit that picked up shortwave broadcasts at night, though the kit's band coverage was only the MW AM band and the diode was the kit's only semiconductor. Of course, the kit wasn't meant for DXing or receiving SWL.

I built a crystal set back in late '71 (a Christmas present) from Radio Shack. Using a small long-wire antenna and a set of headphones with the kit, I was able to get a couple of local AM stations in the Boston area (namely WBZ/1030 and WMEX/1510). Then for the heck of it, I took the audio portion of the crystal set... connected it to the mic input of a tape recorder. As a result, I was able to pickup CBL/740 from Toronto and WPTR/1540 in Albany, NY. It was very wideband (obviously) but hearing things over 200-400 miles away with very little equipment was amazing to me (at 11 years old). WBZ sounded like FM at the time!

That is something I had never thought of doing--connecting it to the mic input. I did remember when one local station sounded good through the earphone and I remember it playing Fleetwood Mac's "You Make Lovin' Fun."

 

[BobOnTheJob]

Prior to the mid 1990's, AM stations were permitted to broadcast the full audio spectrum (today they are limited to 10khz). The sound quality of some AM's truly rivaled and sometimes even sounded better than FM. Today that quality still exists north of the boder...AM 740 in Toronto has amazing sounding AM audio to this day.

 

[N4GBK]

Check out Xtal Set Society on Google.

 

[Schroedingers Cat]

I remember hooking a crystal radio up to a phonograph through the auxiliary input, in an area that only got one strong signal. It did sound pretty good. It was a 1 kW station about a mile away.

 

[K4WRF]

Living in rural Mississippi, the crystal set was a disappointment but just  about the time I was going to give up,  I heard a noise late one night and picked up the headphones much to my delight, a weak WWL New Orleans. Inductor was wound on old cylindrical oatmeal container. It took a lot of fiddling, winding, unwinding, antenna lengths and just plain luck then later, WLAC was discovered. The five-tube superhet kit was a Christmas gift, much better results and more to hear after understanding the right and wrong way to use electrolytic capacitors. Parental intervention following that learning moment almost ended the hobby along with the incident where my father discovered the antenna wire with a lawn mower. Time period, late 1950's. That was about good as it got...
memories....