New MF/LF ham bands - with a catch...

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eaf1956

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Here is what the link brings up:


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QDP2012

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---
Here is what the link brings up:


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The article linked above references this link. Maybe it will work for you.

CQ Amateur Radio:FLASH! FCC Approves New MF/LF Ham Bands
...and gives the link to the .pdf file:
the full Report and Order from the FCC (PDF)

Hope this helps,


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Interesting. Is this new frequency-range something that hams in other countries already use, or is it something that functionally will be US-only, for now?

Thanks,
 

nd5y

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Interesting. Is this new frequency-range something that hams in other countries already use, or is it something that functionally will be US-only, for now?
Some other countries have LF/MF allocations but I don't know off hand which ones or if they are the same frequencies as here.
 

ka3jjz

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With the very low power and antenna restrictions, these are no doubt going to be used for narrow band digital modes, likely slow speed stuff like QRSS. Might be able to squeeze PSK31 if it's narrow enough

Mike
 

N4GIX

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With the very low power and antenna restrictions, these are no doubt going to be used for narrow band digital modes, likely slow speed stuff like QRSS. Might be able to squeeze PSK31 if it's narrow enough

Mike
Speaking of antennas...

LF amateur 2200 meter band 135.7- 137.8 kHz (2.1KHx wide). FYI a dipole would be nearly a ½ mile long, maximum power would be 5 watts EIRP.
MF 630 meter band for US amateurs 472-479 kHz. FYI a dipole would be a mere 635 feet long. A non-loaded vertical would be 32 stories high (to say nothing of your ground radials). Maximum EIRP would be 5 watts. :lol:​
 

SCPD

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This will be nice addition to the ham bands, though a bit long in arriving.
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There has been a de facto, pseudo hammish band of frequencies for a long time between 160-190 Khz - but with quite severe restrictions. Some may be familiar with it-- **
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My father played around with this band over 25 years ago- and I remember quite well some the equipment he used. He conversed with ham friends using a ~50 foot guy’d vertical with a HUGE top mounted loading coil and umbrella-like ‘top hat’ capacitor… The mode was CW, though they tried voice not too successfully… the transmitter resembled more something Tesla would have approved of than the average ham. It used a 186Khz crystal oscillator feeding a large audio frequency transistor’d PA.
In the years that followed and my experiences in VLF long had eclipsed this, my memories centre as a teenager, amazed, that the audio circuit work’d in RF... the only tuned circuit was the PA's output tank.
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My father would tune the system by dipping that tank circuit to resonant the PA, as indicated by a large glowing Neon bulb. A pencil lead placed at the bottom of the well isolated antenna would draw a healthy +½” spark, and should you brush against it, a painless, nasty RF burn. He'll probably still swear this was 1 Watt input , but…..:)

With this transmitter, my father routinely chatted 50-80 and more- miles to other “Low-Fers” using made up callsigns- usually their ham call prefixes. I was intrigued, but never liking CW, I wasn't intrigued enuff.
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I mention all this, because while it seems that 5 watts ERP (630 metre’s), 1 Watt (2200 metre’s) are paltry- the regulations state ERP; not input or even transmitter output power… For the average ham to achieve this with even a 60 metre antenna, the transmitter output will need to be in the hundreds of watts- for a shorter antennas?.. Maybe at 0.5% efficiency?? well- do the math.
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...One of my favorite LF examples is the former Naval Station NSS- with its 20Khz signal feeding an antenna system centre’d around a 1200 foot tower- with a curtain array covering acres-- One Million Watts! into it, 30 Kilowatts ERP… and this could talk to submarines submerged on the other side of the world.
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While I'm on the subject, forget any antenna that isn’t vertically polarized…. Nothing horizontal. Everything at these frequencies will be vertically polarized ground wave- this is true ground wave, not what many hams think of when they use this term- and this will be especially true for 2200 metre’s.
There is a lot to profit by looking at the old low frequency stations-- going long wave is to step back in history.
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These bands poise a great departure/challenge from the standard ham bands. They won’t lend themselves to the causal operator- pretty much forget voice (Bandwidth too large)-- CW will be the easiest mode- digital most like will dominate, but again, it will be BW issue. They will be for the exotic experimenter.
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Hmmmmm , would I take the bait?
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………………….CF
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_________________________________________-
**
Part 15.217 Operation in the 160-190 Khz Band

(a) The total input power to the final radio frequency stage (exclusive of filament or heater power) shall not exceed one watt.
(b) The total length of the transmission line, antenna, and ground lead (if used) shall not exceed 15 meters.
(c) All emissions below 160 kHz or above 190 kHz shall be attenuated at least 20 dB below the level of the unmodulated carrier. Determination of compliance with the 20 dB attenuation specification may be based on measurements at the intentional radiator's antenna output terminal unless the intentional radiator uses a permanently attached antenna, in which case compliance shall be demonstrated by measuring the radiated emissions.
 
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SCPD

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A follow up to the closing of my last comment:
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"Hmmmmm , would I take the bait? "
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I did... I just order'd a JUMA TX136 ....... a 2200 metre transmitter/ transverting receiver.
It will be awhile before I have this system together- together, as in: the antenna poses a challenge.
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This is going to be Fun.... :)
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.....................CF
 
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majoco

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Most of the aircraft beacon transmitters and antennae that I've had anything to do with used "Twin-T" type antenna. Some had the transmitter hut directly under the antenna which meant you could have the tuner in the hut, others had the transmitter in one hut fed by coax to the tuner in a smaller post mounted box with the tuner in it. Whatever the system, the antenna was the weak link as usually just not big enough. Currents at the base were quite high, often run in copper tubing out to some large ceramic insulators.

Here's some info...
http://cdn2.hubspot.net/hub/90253/f...eet_60ft_sym_t_low_power).pdf?t=1481584649058
 

SCPD

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This 2200 little experiment will provide me with plenty of entertainment, Majoco. I cut my teeth, so to speak, on E/LF radio in grad school, so I am under no illusions about what I have embarked upon. Thank you for the web site info....;)

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One of the antenna I have consider’d is exactly what you mention’d; the Double T, although I won’t go that direction because of the mechanical issues in maintaining one (where my Colorado home is- this radio’s future site-- we can get over 20 feet of snow in the winter… which has taken down every one of my wire antennas.)
So far, the plan is something vertical, --and sturdy. I have a friend who has been trying to get me to take off his hands a 50 foot section of an old AM broadcast radio tower. What’s attractive is this is the bottom section with the insulator and base…. plus I have some cowboys who owe me a few favors whom I’ll enlist to place it. The bigger task I see, however, is going to be the ground matrix beneath it.
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I have attached a picture of Radio NSS, the naval station in Annapolis Maryland, dated just before the demolition of all but the three Eiffel (seen to the right.) The central tower was 1200 feet high, forming the core of a huge Goliath array. What isn’t seen is the massive spider web of copper lines that cover the point of land this array was built on. This winter I got to walk about the old site, beneath the three 600 foot remaining towers. Over the years erosion has exposed lots of that matrix, and I tripped twice over some large gauge copper wires. My feeble ground system will be a mockery of NSS’s, I’m afraid.
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The matching circuitry will be mounted directly at the base, and I don’t envision that tower going taller than 50 feet- with a top loading coil and capacitive ’hat.’ This morning, in my enthusiasm for this project, :) I ran a computer model of several verticals at 136Khz, and confirm’d there isn’t much advantage making it taller than 50 feet unless it goes a lot, lot higher- and with my limitations, it won‘t. At very-best, it will radiate approximately 0.2% of the input RF**… With the 60 watts or so from my transmitter I can expect, maybe, a whopping 120 *milliwatts* ERP. Breath taking, No? (laffs)
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What will be breath taking will be the RF voltages generated at antenna matching circuit at the tower base. Tuning will be easy:, just dip the circuit until the thing stops sparking (just kidding.) I can feel Telsa looking over my shoulder, smiling.
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But sparking is not something I take lightly. The Q of this array will be so high, and thus the bandwidth so narrow, that +1Khz deviation will likely cause it to arc… hence I plan on a slow speed digital data mode..
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I am lucky to have access to several remote receiver sites, so I can listen for my signal. So far I haven’t heard any ham activity on 2200- though I hope to hear myself- lots of hope, any way. I have a friend who says she’ll try it out too, if it can be heard in New Mexico- but neither of us are holding our breaths……
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It should prove an interesting summer, however ……… :)
…………………..CF
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** NSS, at 20Khz was 0.3%
 

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zz0468

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This 2200 little experiment will provide me with plenty of entertainment...

That looks like a fun little toy. I may have to get me one. I've been chasing LF and MF beacons for many years. Becoming the DX to be chased is a blast.


The bigger task I see, however, is going to be the ground matrix beneath it...

... My feeble ground system will be a mockery of NSS’s, I’m afraid

Check back issues of QEX magazine from the last 7-8 years. There was a pretty good article with some empirical data on radial ground systems that might be of some use. It did some comparisons of things like many short radials vs. fewer long ones, and so on. Might give you some ideas.

But sparking is not something I take lightly. The Q of this array will be so high, and thus the bandwidth so narrow, that +1Khz deviation will likely cause it to arc… hence I plan on a slow speed digital data mode.

Do what the LF beacon transmitters do... Key the antenna matching network along with the transmitter.

It should prove an interesting summer, however ……… :)
…………………..CF

Let us know when it's on the air. I have some pretty mean RX capability below 500 KHz.
 

majoco

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Some years ago I had to visit Rugby Radio in the UK which broadcasts the MSF time signal on 16kHz at 0900 and 2100z. At that time the station used those low freqs for submarine comms too. The whole place was eerily quiet with just a very slight breeze to make the wires hum a bit. I asked the guy I was going to see about 'why no birds outside' and he said the RF scares them off. 4 masts 820ft high and from this bit of info, 160Amps RMS into the base of the antenna system - the final ERP was only 15kW!

mb21 - ether.net - 'MSF' Rugby
 
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SCPD

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Thank you for the suggestions, ZZ. I had not consider’d an active antenna tuner… a neat idea. At this stage it is probably too exotic for what I have the energy for, but I have filed the idea away, carefully under Active Consideration. For now it will be a large coil.
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So far, my meager plans are to get that section of tower placed ( turns out its only 40 feet instead of 50- but I don’t look gift horses in the mouth) as soon as I can get a concrete base pour’d for the insulator assembly, and the anchor points for guy lines. I’m going to do this full-out “industrial”- heavy cables, ceramic insulators- the whole business. I’ll have all the parts largely because I have to take the whole Magilla from my friend- he wants what’s left of this former broadcast tower gone from his ranch. He’s never has told me why he came to own it.
But before all this, the snow will have to melt and the ground thaw.
If this doesn‘t make it for 2200, I figure it might work out for 630... or something else- but I remain 2200 optimistic..
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I have a place for the tower, out in a pasture where there is a hut for the transmitter and AC power. My plan is to run it by wireless link.. and listening remotely. The ground system remains an enigma- it will be, in essence, non existent. Anything that resembles effective is beyond my ability (and finances) to construct. Not that I won’t do something, but it will be very minimal, considering the wavelength involved… far more effective for lightning protection than RF return- for after all, even a 1/8 quarter wave radial is over 825 ! feet long.
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So far all this is just plans- I haven’t even received the transceiver yet, let alone touched the antenna…
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……………. I appreciate the comments and suggestions :)
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…………..CF
 

SCPD

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Nice photos, Majoco. It really puts into perspective what it takes to put a signal successfully on these frequencies.
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Your mentioning of the birds reminded me of this attached photo.
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While I didn’t take it (no cameras allow’d then) …it sticks in my mind as one of the impressive memories of a tour of operational NSS shortly before it was decommissioned.
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“Keep Moving”…. (laughing) like a bowl of chile revolving in a microwave oven. :)
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……………CF
 

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SCPD

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A brief update...
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I received my Juma 2200 transceiver and I have assembled it. The kit is nicely straight forward,- for those that maybe interested in following my foot steps- but it is surface mount technology- so good soldering techniques/skills are paramount.
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Curious as to what it would do, and unwilling to wait for spring to break back home in the mountains-- I ran a 50 foot vertical wire up the side of a Ponderosa pine here on this New Mexico mesa. A BIG coil and a huge 2000uuf variable capacitor serve'd as the matching circuit at is base-- there was no capacity 'hat' or coil at the top of the wire.... don't bother asking what served as its ground....
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In a "beacon mode" of 4 WPM CW, ~ 60 watts out of the transmitter- it could be heard 599 ---at 1 mile, the nearest remote site to my house. At 50 miles-- Nada-- and this second site has the advantage of directional LF loops and virtually zero noise by diversity cancellation. (In all fairness to the TX136, this Mickey Mouse'd antenna model'd out at a spectacular 0.03% efficiency.)
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Oh well
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I have hardly written 2200 off-- but I throw this out to anyone who may also be considering it. If you try 2200, using nothing better, or similar to my little hasty experimental antenna-- maybe, like- you might wish to... reconsider ?!
I can for see this band breaking a few hearts out there.
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So, until the snow melts back home, this little jewel will sit awaiting its day this summer to shine...... hopefully
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:)
.......................................CF
 
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prcguy

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I recently upgraded the synthesizer in my Elecraft K3 and did some mods to extend the receive down to these new bands, which should be a really high performance receiver for down under. Plus the K3 puts out 1mw on 2200 and 630m all mode to feed an amplifier and whatever down stream.

I need to relocate my VLF/MW/HF AMRAD active antenna for receive and come up with some kind of antenna for transmit. Since I'm in the big city a large ground plane is not practical but I can easily insulate one of my 40ft crank up towers and experiment with that as a vertical with top hat.

Anyone in the So Cal area able to get on these new bands?
prcguy
 

SCPD

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This week I am going home to Colorado, and while there I'm going to look over the proposed site of this "noble experiment"--stuff that's been rattling about my brain.
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-- It'll be in a mountain meadow horse pasture, with a deep irrigation well, a metal well casing -- and an AC wired hut. That well casing and the extend'd metal water lines, so far, is about as advanced as I have planned a ground plane-- The more I think about it, and the more I look at my computer models, the more dismal the prospects (I would advise those that want to try 2200 to not research it too much least you become dishearten'd..... :) )
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One thing that is glaringly clear- I will want/need all of that 1W EIRP.
So--
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I have access to (can borrow) -- a Harris amplifier that covers 50-500Khz that can output up to 2500W --. Its a little over kill at this stage, not to mention heavy... but I am going to hold it in reserve just in case 60 watts doesn't cut it. At my theoretical calculated 0.2% antenna efficiency I should be able to achieve that 1W EIRP with 5-600Watts into it.**
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Boggles the mind, doesn't it...(laughing)...500 Watts in, 1 Watt out.
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I don't like doing field strength measurements, but I will have to--- maybe I'll need to goose that 5-600 watt up a bit--- if I should go the amplifier route.
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But there's still too much snow up there-- this remains only 'on paper' for now. .
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......................................CF
___________________________________________________________________________
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**
§ 97.313 Transmitter power standard
(k) No station may transmit in the 135.7-137.8 kHz (2200 m) band with a transmitter power exceeding 1.5 kW PEP or a radiated power exceeding 1 W EIRP.
(l) No station may transmit in the 472-479 kHz (630 m) band with a transmitter power exceeding 500W PEP or a radiated power exceeding 5W EIRP, except that in Alaska, stations located within 800 kilometers of the Russian Federation may not transmit with a radiated power exceeding 1 W EIRP.
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