472 khz

Not sure about the Challenge? Details can be found here. The MF Systems m converter is at the far right on the top shelf. Here, in his own words, is his description of progress to date on m:. Remote tuned using a gear motor and controlled by a battery powered switchbox in the shack. Guess what, it worked! The K3s is a great receiver on MHz with the general coverage filter but sports only a half milliwatt 0.

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Getting that tiny signal boosted is the job of the MF Systems converter. The converter was modified to use only the amplifier portion and puts out about 20 watts. Plans for station improvement include a variometer to replace the fixed tuned coil and more power. James is an avid m operator with a nice location in Chesterfield, MA. His station consists of a Kenwood TS and various wire antennas.

He has been receiving signals on and MHz since the beginning of the challenge. James has tried to work a few local stations but his 1mw signal is just not heard, at least so far. Frandy added a general coverage filter to his K3 and is using a G5RV for receiving. He has obtained an MF Solutions converter and hopes to get on the air soon feeding an Inverted L antenna.

This wraps up our mid-Challenge activities. Winter months are great for these frequencies with little atmospheric interference.

Many ham transceivers and most general coverage receivers can receive below KHz. How many or how far can they be heard? Give it a listen and use one of the links below to see where they are located. Interested in digital modes? The links below have proven very useful for our members. They concentrate on the basics and will get you QRV on m quickly.

472 khz

Unfortunately that guy does not currently have transmit capability. I have been licensed since and this has really been an exciting project forcing me to get back into building stuff. I have learned a lot about RFI with my smoke detectors, the importance of proper grounding, impedance matching and a bunch more. Really gets you back to basics. I tried cranking up the power supply voltage but nothing would do it.

Now that I have remote antenna tuning I might have been able to do a quick tune and put him in the log. It is amazing that even a Hz frequency change will require re-tuning.I value your comments and suggestions.

Post Please click link to read the full article. Accessed on 04 Julyhrs, UTC. If you're curious about what the new band means for radio amateurs and the type of equipment needed to get on meters, then this simple tutorial from Dr. The report is divided into four separate pages, each with supporting photos, graphs, reception reports, and other operating data: kHz antennas kHz receive preamp kHz transverter kHz transmitter Dr.

Smart also provides a helpful youtube video discussing individual pieces of hardware needed to get on meters. I found the tutorial easy to read and fully illustrated with diagrams, schematics, photos, and performance data.

Be sure to check the blog sidebars for more antenna and propagation articles. Opinions expressed in this blog are mine unless otherwise stated. Thanks for joining us today. No comments:. Newer Post Older Post Home.

Subscribe to: Post Comments Atom. Amateur Radio Bicycle Mobile Setup. An Meter Vertical Helix. Like many amateur radio operators, I live on a small lot surrounded by neighbors, utility lines, and civic-minded citizens concerned aboutThe transmitter would be grounded to the mast earthing point, and we would run the 10w transmitter at the base of the mast overnight.

The antenna slops down from 42m towards the ground. With a little bit of tinkering, we had a resonant antenna on KHz. Here you can see the tower and yellow wire making its was up from the base, and then into an adjacent field. As previously described the setup has been operating for a couple of weeks now, and its a good time to review the WSPR spots. The problem is trying to find a transceiver, computer, antenna combination that will allow this with minimum fuss.

Low power consumption, and low noise with many running on 12v. I opted for a second-hand minicomputer, silent running and powered from 12v. These are good value and should provide a reliable machine, with a very small desktop footprint.

Stations completing at least one QSO on 630 meters:

You can read more about receiving loop antenna on this page. SW listening and the ability to receive stations many thousands of miles away on HF has always fascinated me. The doublet antenna at home while working well on 7 to 30 MHz, is a poor performer below 3 MHz. This coupled with the high noise floor makes reception of all but the strongest signals very difficult. In part the answer is a dedicated antenna for low frequency reception. The answer for many of us comes from a surprisingly small antenna.

Receive only active antenna may provide a solution, the active part providing some amplification in the receive path. I was lucky enough to spot a second hand Wellbrook loop on ebay, reasonably cheap and this gave me a chance to compare the performance with my other HF antennas.

Wellbrook Communication have a number of versions available, comparison of models here. M1GEO has recently repaired a Wellbrook loop antenna, his website includes a detailed teardown. LZ1AQ has detailed design notes on his website for his wideband active loop antenna.

You can see and hear the difference for yourself. How well does the Wellbrook work on KHz. Well it outperforms my doublet antenna by some considerable margin. I had never tried kHz before, as the combination of local noise and poor antenna has always put me off.

The signal to noise ratio of received stations has improved dramatically, and the screen was soon populated with stations all over Europe. Although I didnt transmit this type of set-up works well if you intend to use a separate receive antenna.

Radio user completed a review of the Wellbrook antennaand you can read that on-line. Its a SDR that can be run standalone, and works like a normal radio with a front panel and VFO or connected to a computer. Dial freq for WSPR is After 24 Hrs I had received the following stations.

This data can be represented on a map. Tag: khz. Dave M0TAZ. How well does the Wellbrook work on KHz Well it outperforms my doublet antenna by some considerable margin. Here is a screen shot showing stations received.Please click on images and schematics for a larger, clearer version.

This page details the build of a transverter for the m amateur band, released in the UK Jan 1st On a recent evening it was just the 6m vertical coax to my 10m halo tuned against the copper waterpipe ground! The latest version of the transverter saw me go back to a design using a double balanced mixer. I had issues with a transistor mixer stability problems that were hard to fix, although these may have been simply decoupling weaknesses and with the double balanced mixer the circuit is working very well.

I have built a couple of samples with almost identical performance. The whole unit is currently housed in a small plastic box but I think a larger metal box is advisable so that the PA heatsink heat does not cause the LO crystal to drift. There would be no problem with CW. The transverter described here is based on an earlier design for the kHz band now withdrawn in the UK. There is a video of this earlier design on my YouTube channel. The band could definitely do with a few more stations, especially on TX.

Please, if you can, get on the band. You will not be disappointed. Some months ago I was sent a kHz preamp by an anonymous doner. It was very kind. To this day I have no idea who this kind person was. The preamp brings the FT up to full sensitivity, but I find I am copying the same stations with or without the preamp. In theory, the preamp should allow very weak stations to be copied but I am copying no more stations! Search this site. Sub Pages Start Page. Buying A New Radio.

Codar AT5. Early Voice Recordings. G3XBM History. Homemade Recordings.So look around as your rig may have a rigorous mod available to allow operating at and There have been a number of questions recently received via email asking about modifying existing amateur rigs for use on kHz or kHz. While I cannot provide you information on doing this for your specific rig, there are a few warnings that need to be stated and heeded by the prospective operator. Often times following the modification of an amateur rig, the operator sees anywhere from 15 watts to 50 watts of output into a load and there is an assumption that the RF is at the frequency of interest.

This could not be further from the truth! This fact becomes apparent when an external low pass filter is used as the RF output will drop considerably. Dirty signals can often be observed on a scope while transmitting into a ohm load. You will either see multiple waveforms or a waveform that is ragged and not smooth.

A properly filtered sine wave output with be smooth and show symmetry. Modified rigs do not have low pass filters at these frequency and assuming that a high-Q antenna system will perform the filtering function is asking for trouble. If you are planning on using a modified rig on meters, be sure to add an external low pass filter using values like this one or this one.

While some are designed to work for MARS and CAP with modification, those frequencies are much higher in spectrum than those of meters.

Persistent high power operation at kHz will likely result in PA or other component failure.

472 khz

Consider an MF or LF-specific meter or consider building a scopematch system. A simple meter loop: a receive antenna implementation described by W5DFN.

472 khz

A simple antenna dipper for 80 m - m and possibly also meters. Menu setup for the TSSG for use on m and m digital modes. A meter transverter, amplifier and switching arrangement by Wayde, K3MF. Problems with RF triggering alarm systems or fire suppression systems at your station?

WB4JWM meter non-linear amplifier. Beware of modifying amateur transceivers for kHz or kHz!We got the new KHz band in Jan So it nice to have a new playground to run around that has new, shiny and different toys to play with.

Most amateurs get by with smallish antennas but when KHz has a wavelength of m, everyone has small antennas! Even a 40m tower is only a 0. I am lucky to have the room to spread out some long beverages for receive. To work well beverages need to be over a wavelength at least. I had a m roll of electric fence wire and I decided to try to use it all.

I left this beverage unterminated as with would allow me to receive from both directions that the wire runs. My first transmit antenna was not the best. I shorted the ohm feed of my 86m long Vee-Beam. All connected to my existing radial system.

VK1SV 472 kHz small loop experiment

Testing a new antenna. Added a little bit of a horizontal top wire to my 80m quarter wave 21m long. Added a large coil, 80 turns of 6mm wire on a mm form and wound up an impedance transformer. Being heard in 5 states and New Zealand. Had 10 decodes in one cycle. So it was a vast improvement as can been seen on this picture. So I am all the time throwing down a few more radials. For transmit I launched off into finding all the bits to make a transmitter. The spectral output is really bad with harmonics all the way through HF.

So a Low Pass Filter will be needed with it. I knocked one up with some 25mm conduit and a hand full of caps. Need to build a better filter but it will do for now. And I am keeping the radio on low power. On high power it was making So not to bad considering it was never designed to work this low in frequency.

Not Grahams normal stomping grounds so you can see the microwave pedigree. It has an on board 28 MHz oscillator for a 10m IF, but can also inject any external oscillator of about 7dBm. IF power level can be anything up to 4 watts. Works a treat! Well some! Almost half of Australia because of the Timor beacon. Amateur Radio - DC to Light.The m band is only 7 kHz wide, so signals shouldn't occupy too much space.

CW signals are found in the lower part of the band kHzwith most activity below Most CW activity is in the evening. Depending on your location, your equipment, the propagation and ERP of the transmitting station you can expect to be able to hear CW signals up to km distance. Intercontinental contacts in CW are possible, but rather rare. Signal "decoding" is not done by ear but on screen, using dedicated DSP software. The SNR signal to noise ratio of a signal can be improved by reducing the receiver bandwidth.

But the minimum receiver bandwidth is determined by the spectrum of the signal. A SSB signal for example has a spectrum of 2. By slowing down the keying speed to 0. This will result in a SNR improvement of almost 15 dB. The main disadvantage is the larger bandwidth. All transmitted information such as call signs and reports is efficiently coded and a very strong FEC protocol forward error correction is used to improve the SNR.

JT9 is transmitted in sequences that always start at 1 second into the minute and take about 50 seconds. Depending on the submode a TX or RX cycle takes 1, 2, 5 10 or 30 minutes.

Beware of modifying amateur transceivers for 472 kHz or 137 kHz (MARS AND CAP mods)!

The slower submodes have a lower SNR treshold, but are also more vulnerabe to frequenct instabilities of any kind including ionosperic doppler shift. And of course: the slower the bitrate the longer it takes to complete a QSO. But on m and m frequency stabilities are far less a problem than on HF and signals are usually much weaker, so the slower JT9 submodes can be very useful. SlowJT9 can be downloaded here. From the operators side FT8 is pretty similar to JT9, but it is 4 times faster.

With a 15 seconds transmision cycle a basic QSO can be completed within 1 minute. Compared to CW however FT8 is very competitive, in regard with speed as well as sensitivity although the true CW operator might prefer the "gusto" of CW. Furthermore it uses varicoding to achieve high text efficiency. The typical character throughput is about 5 WPM. A detailed description of WSQ can be found here. DL4YHF's version of the software can be downloaded here. More information about WSPR, including download of the software, can de found here.

It also uses forward error correction and a compressed data format in order to improve SNR. The advantage is that any CW transmitter can be used, the inherent disadvantage is a 3 dB lower average power compared to FSK modulation. The "deep search" functionality of Opera, that takes advantage of information exchange over internet as an aid to decode very weak signals, is rather contested.

Opera can be downloaded here. Register as new user. Popular modes The m band is only 7 kHz wide, so signals shouldn't occupy too much space.

CW CW signals are found in the lower part of the band kHzwith most activity below CMS: WebsiteBaker.


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