2200m beacon

This was my LF beacon, before I managed to blow it up last year! It could do QRSS and normal speed CW. I may have a go at trying to replace the FET.

There is a YouTube short of it.

2200m beacon

Looking through some old photos, I spotted this one from 2012 showing my beacon for 2200m (137kHz).

As I recall it produced about 8W although the ERP was in the microwatts as my antennas were not very good.

137kHz QRSS3 test - aborted

Last night I tried some local 137kHz tests using my 137kHz beacon. Then it blew up!!  I could smell burning and the transmission stopped. 

This means I cannot do my test unless I can repair my beacon. Also, to be so badly damaged it suggests the match is poor and the heatsink inadequate. 

I think this puts an end to my tests at 137kHz.

UPDATE 0929z:  In a vain hope, as my FT817ND was widebanded when I bought it, I tried directly TXing on MF and LF. It said "TX err", so no luck!

137kHz QRSS test

On my ‘to do’ list are some QRSS tests at 137kHz using my earth-electrode ‘antenna’ in the ground and SpectrumView software on my iPhone.

2200m transverter

Last night I gave the latest version of Google's AI tool (now called Gemini) a try. I tried various family names, without being impressed. Basically, compared with ChatGPT4, it was hopeless. They have a long way to go to catch up in my view.

I then tried G3XBM and it came up with a French site that had a copy of my 137kHz transverter from 2011. I think it was a prototype (no RX preamp) and I cannot even remember producing the circuit. The schematic is the best I have. It shows the loop antenna that I used. Zooming in on the schematic makes it a bit clearer. As I recall, the furthermost I got was the Netherlands on QRSS3.

11 years ago on 137 kHz

This was in 2013 at the old QTH.  At the time I was seeing how far away I could be spotted on that band. Not much later, I got to the Netherlands.

2200m activity

 Apart from an unsuccessful test last year with my CW beacon, I have not tried TX this LF band. As my only suitable antenna is my earth-electrode "antenna" in the ground, I am rather hampered with my poor health. It is this or nothing.

Some years ago, I made a video of my LF transverter.

At some point I must repeat my test with my 2200m CW beacon.

137kHz (2200m)

It is a very long time since I was on this LF band. 

On TX, I have used my earth-electrode "antenna" in the ground and a loop in the garden made with 0.2mm diameter multi-strand wire.  Thicker wire would have been better.

On TX I used a QRSS beacon or a transverter, both home designed. I have been copied overseas. My transverter is shown on my video channel and on my main website.

For RX only, the antenna can be very small e.g. an e-field probe, also described on my main website.

137kHz experiments some years ago

The photo shows the screen shot of my 137kHz experiments some years ago. I used the earth electrode antenna buried in snow with a small E-field probe on the car. ERP was just a few microwatts. This was January 2013.

136/137kHz - which modes?

A few days ago I tried spotting on 137kHz WSPR. Nothing was copied. 

I am wondering what modes are used mostly these days on this band?   Perhaps WSPR is less popular on 137kHz than it once was.

137kHz WSPR

At the moment I am on 137kHz WSPR with the Wellgood active loop. It will stay on overnight. It would be a miracle if I copy anything! As usual, lots of stations on RX, but very few on TX.

UPDATE 2044z:  Still no spots, although I am not surprised.

137kHz transverter

 

This photo, taken about 10 years ago, shows my 137kHz TX transverter. I still have it...... somewhere.

See  https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/2200m-137khz-transverter .

137kHz tests with an E-field probe mobile

Before my stroke, I did some mobile tests on 137kHz QRSS QRP using an EFP with an FT817 RX. The EFP was mounted on a mag mount.  Results totally exceeded my expectations. After I reached 24km, I gave up. This was with a very low ERP (uWs).

See https://sites.google.com/view/g3xbm4/home/antennas/137khz-efp-rx-antenna .

137kHz

At the old QTH I was active on 137kHz. The photo shows my 140uW ERP QRSS signal at 101km. With a "proper" antenna and decent powers, who knows what is possible? I have not (yet) been on 137kHz TX from this QTH.  

You may find this link of interest. Do not try the links on the side. This was my old site that has not been maintained for many years.  

See https://sites.google.com/site/g3xbmqrp/Home/136k

137kHz transverter

From this QTH I have never tried 137kHz. At some point I really should. It is an interesting allocation. From the old QTH I copied a station in Sweden with just an E-field probe antenna. The transverter below was used on TX (see link below).

With QRP ERP from my old QTH it allowed me to be copied 250km away on WSPR. I forget the actual ERP but it was low mW at most. The antenna was either my earth-electrode antenna in the ground or my 80m square loop.

See https://sites.google.com/site/g3xbmqrp3/mflf/137khz_tvrtr

137kHz E-field probe

Several years ago I made this mag-mounted 137kHz e-field probe to see how far away I could detect my QRPP 137kHz beacon. At about 24km I just stopped!

Both the EFP and the 137kHz beacon clearly worked.

See https://sites.google.com/site/g3xbmqrp3/antennas/137efp

137kHz transverter

Because of my poor health, it is some years since I have done any serious experimentation or building, so I hope some of the ideas on my main website inspire others to have a go. In many cases, the designs can be further optimised. If you can make a better circuit I shall be very pleased. Treat my ideas as starting points and don't be afraid to experiment!

See https://sites.google.com/site/g3xbmqrp3/mflf/137khz_tvrtr

137kHz

Last winter, I tried 137kHz WSPR and OPERA even though my FT817 is very deaf on LF.

In the past, when I was fit, I put my 137kHz beacon on QRSS3 and looked for the signal with a mag-mounted E-field probe on the car. Even though the ERP was low milliwatts at most, I got good copy the far side of Cambridge at about 24km.

At some point I should try 137kHz TX again. It was good fun. Maybe I should resurrect my 137kHz transverter. It is somewhere around.

137kHz E-field probe on the car mag-mount

Many years ago, I tried looking for my tiny 137kHz beacon with a small E-field probe mag-mounted on the car. After seeing the signal quite well on the far side of Cambridge at about 24km, I stopped the test. As you can see, the EFP used readily available parts and was very simple.

At some point I should rebuild this and try from the QTH we moved to almost 5 years ago, maybe using the earth-electrode "antenna" on TX. I have felt too unwell since my stroke.

See https://sites.google.com/site/g3xbmqrp3/antennas/137efp

137kHz Transverter

One of my videos describes my transverter for 137kHz, a band on which I had no suitable antennas. Best DX was a WSPR spot by G8HUH at 250km. This is also on my main website at www.g3xbm.co.uk  where you can also find a better quality schematic.

In the end this was converted into a RX-TX transverter, although the FT817 was very deaf on 137kHz!

See https://www.youtube.com/watch?v=QHGLkA25MQA