Coming: the new 600 meter band

[rtc]

http://500kc.com/

Equipment:

http://njdtechnologies.com/


Build a receive converter for 14 bucks:

(have one;it works)

http://www.wb9kzy.com/lfconv.htm

 

[Darth_vader]

So, it looks like the LW upconverters are meant to be used with a shortwave rig. But the big question is, can (or how can) they be used with/installed in a MW receiver? I have an old two-band boombox (with lots of internal real estate) which would be great to use as a combination LW/MW/FM rig.

Doesn't look like s/he sells them pre-assembled, though. Oh, well.

 

[rtc]

Many consumer grade receivers are not that
efficient below 300 khz.The converter moves the
LW band to HF (usually 4-4.5 mhz) where the
receiver is better.One must take care to use shielded
output cable from the converter to the receiver
to avoid HF feed-through.

It might be possible to use a custom crystal in this
converter to output on AM but the ferrite bar antenna
would have to be disabled in the receiver to avoid
feed through.Also,the web page is not too clear that
the converter now comes with a mod so it will go up
to 530 khz...in fact it goes much higher (mine goes
up to 930 or so) so there would be hets on an AM
receiver.

It is about one inch square and is not hard to build
IF you have such experience.A radio shack aluminum minibox,
standoffs,2-aaa/aa and 9 volt battery holders (for 12v),switch,
and a couple of female F connectors will do it.

Chuck only offers the kit.You may find a Palomar or old
Heathkit converter on ebay.You will need at least a 50 foot
antenna or longwave loop (the PK Loop is excellent).

The easier more convenient (not to mention maybe cheaper)
way would be to get something like a Kaito 1103 or Sony 7600
portable new or used.These cover the 150 to 500 khz band on
their internal ferrite bar antenna.

If you are adventuresome (and have a lot of wire) this Hula-Hoop
longwave (inductive) loop works well:

http://www.youtube.com/watch?v=UHKSYRnVYT8

(Note that the bandwidth will be somewhat narrow compared to an
open-wound type loop.)

 

[Darth_vader]

Here's Chuck's take on it, in his own words (I sent him an E-mail memo yesterday):

"Thank you for the inquiry.

No on the medium wave radio due to the low pass filter (the AM band is adjacent so that the filter wouldn't have enough attenuation, you'd hear the AM stations with the LF stations at the same time), also, there's not much an AM radio would hear on the LF frequencies, a radio with a BFO is what you'd want and finally, I doubt there are 1 MHz crystals that would fit this circuit."

I suppose if I were to do that, the crystal would have to be wired into it and held adjacent the circuit board somehow, but that's not really a problem here, since the boombox has a LOT more internal space for addons (removing its dead tape drive helped.) The whole thing runs on 12 VDC so it already meets the device's power requirement; all I'd probably need to do is tap the power system somewhere in the rig.

But I suppose it's a moot point in the end, since they don't come pre-assembled (and it'd be a waste of money, since I'd almost certainly ruin it trying to solder it together myself.)

It's interesting, though, that he disavows AM usage on longwave. I suppose he must not do much navigation beacon or transatlantic broadcast DX.

 

[WPHA]

A standard AM radio CAN be tweaked down below the AM dial, at least to 490Khz or so. With careful tweaking of the oscillator coil, and moving the loopstick antenna coil, one can do this without ever warming-up a soldering iron!

600 meters is 500Khz... so if you can tune from 480 to 520, I believe you'd have that band covered. Since AM radios use 455Khz as their IF, you don't want to go too much below about 480Khz.

Having a BFO would be a good idea, tho... which is why the suggestion to use an up-converter and a proper HF receiver. A standard AM radio isn't going to do much more than show you that signals exist. Copying them would be difficult.

 

[Darth_vader]

"A standard AM radio CAN be tweaked down below the AM dial, at least to 490Khz or so. With careful tweaking of the oscillator coil, and moving the loopstick antenna coil, one can do this without ever warming-up a soldering iron!"

Yup, I've done that before. Even realigned a couple 530-1620 rigs that way to receive X-band transmissions (well, at least a little bit beyond 1640 where KDZR is, anyways.)

"Having a BFO would be a good idea, though, which is why they suggest using an up-converter with a proper HF receiver. A standard AM radio isn't going to do much more than show you that signals exist. Copying them would be difficult."

Is it possible to add a BFO into an existing AM-only receiver? Are there kits available for that?

 

[KeithE4]

Is it possible to add a BFO into an existing AM-only receiver? Are there kits available for that?

Sure. All you have to do is build an oscillator that will tune +/- 3 kHz or so around the IF frequency of your radio (455 kHz usually, but it might be different on a digital radio). If you place the output of the oscillator close enough to your radio, and there's enough power (Part 15-legal, hopefully), it should work. Connecting it directly to your radio's detector via coax would work even better.

A quick-and-dirty alternative would be to get a 2nd radio and tune it 455 kHz above the frequency you're listening to. That's how I accidentally discovered SSB on shortwave when I was a kid in the '60s (the cheap radio I used for the BFO was rather rich in harmonics). ;D

 

[rtc]

Finally found a link to the new production
Palomar VLF Converter.

(Attn. Moderator:I do not work for them nor receive
anything from them.)

This is the only new-built-ready-to-go VLF converter
available in the country.It performs well and is made like
its predecessors were:

http://k1el.tripod.com/VLF.html