2012 memory

This dates from 2012!! It was first posted on Facebook back then.

Lesser Chirpy 10m QRP CW transceiver

This dates back to 2012, but represents a very simple transceiver circuit for 10m CW. Please treat it as a starting point for your own ideas. I was amazed how well such a simple circuit could work.

See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/10m-lesser-chirpy .

10m Lesser Chirpy

These days, many people prefer FT8 or WSPR for QRP. However, it is fun to see where an ultra-simple rig can reach. This has been on before, but with Es so good, it will certainly get all over Europe. As with all simple circuits, it is a compromise.

Although I find it hard to believe, this circuit dates back to 2012!  It is an ultra-simple CW transceiver for 10m. It is capable of improvement, I am sure. Mine was made "dead bug" style.  You can always use the reverse beacon network to see where you are reaching.

See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/10m-lesser-chirpy

Lesser Chirpy

Originally, this was called the XBM10-2. It is probably one of the simplest transceivers you can make. It really works! These days there is less CW activity as people move to modes like FT8, but it is fun to make contacts with ultra simple homemade gear.

See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/10m-lesser-chirpy .

10m QRP transceiver

It is hard to think this is 10 years old! It seems like only yesterday. Maybe you can get some ideas from it. It was called the "Lesser Chirpy" as the original version chirped badly.

See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/10m-lesser-chirpy .

Ultra-simple 10m CW transceiver

The Lesser Chirpy was one of my designs from 10 years ago. It is one of the simplest transceivers you can make. As with all my designs, I  would be very surprised if you could not make it better! It works by FSK so the frequency shifts when the key is pressed. The first version had too much chirp!

See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/10m-lesser-chirpy.

Lesser Chirpy

When I was fitter, I enjoyed designing and building. Sadly this is much harder now. Like all of my circuits, I am sure they can be improved. I make no claims for originality and take inspiration from many sources. My wish is that you use my circuits as the starting point for your own ideas. 

Looking back many years, I designed the Lesser Chirpy for 10m CW. Originally I started with the Chirpy, but it chirped too much! The Lesser Chirpy more or less stopped the chirp. This was a "for fun" rig. It does work, but I was concerned about calling CQ over weaker stations as the RX sensitivity was not as good as modern rigs. My recommendation is ensure that calls are not made over other stations. Fine to call others, but be very mindful of other stations.

The original name was the XBM10-2, but Lesser Chirpy was more meaningful!

See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/10m-lesser-chirpy .

Lesser Chirpy Transceiver

You can guess why this has this name! 

The first version had too much chirp, whereas this has virtually no chirp at all. It is a "for fun" rig for 10m CW with very few parts, that I am sure can be improved.

See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/10m-lesser-chirpy .

10m Lesser Chirpy CW transceiver

It is hard to think I did this 9 years ago! It has been copied across the Atlantic, although as a "compromise" rig I would not use it on the air that much. My main concern is you may miss stations on the channel as the RX is not as good as many. It is all too easy to call on top of a weak QSO.

See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/10m-lesser-chirpy .

Lesser Chirpy (10m)

At the moment, at the depths of sunspot minimum, 10m is not exactly busy! In the late spring and summer 10m can be very good for Es communications up to around 1500km. Often, much further can be reached with 10m Es. Es can be effective at any part of the solar cycle.

Years ago, when 10m was good, I designed the Lesser Chirpy ultra-simple 10m transceiver. Like all simple transceivers, it is a compromise, but it is fun.

In the Es season it is capable of decent QSOs e.g. from the UK into Europe. In decent F2 conditions (may be a few years off yet) it should be possible to cross the Atlantic with it. The main limitation is the RX. Only TX if you know the frequency is clear.

Lesser Chirpy 10m transceiver

Some years ago I designed a very simple transceiver for 10m CW. This was a "for fun" rig, but it does work. Looking at the circuit it could be further simplified. It is already very simple. XBM 10-2 was the original name.

Sadly health issues stopped me fully testing this in the sunspot maximum years.

Maybe I should try it in the next Es season? Got to find it first!

See https://sites.google.com/site/g3xbmqrp3/hf/chirpy

The Lesser Chirpy transceiver

This was designed for 10m when the solar cycle was on the up (rising sunspots). It could still be useful in Es conditions, or it might make the basis of a transceiver for other bands. I can already see how one capacitor can be saved! It uses FSK to eliminate chirp. In the past, I connected an SDR to the earpiece output and this allows much of the CW band to be covered on RX.

See https://sites.google.com/site/g3xbmqrp3/hf/chirpy .

See also https://sites.google.com/site/sm6lkm/saqrx/ for a possible SDR .

How simple?

Some years ago I attempted to see how few components were needed to communicate on 10m. The Lesser Chirpy was the best I could manage. This was a derivative of The Chirpy, which worked, but had far too much chirp!

Looking at the circuit I see I could save 1 component by replacing C1 and C2 by preset C's and shorting out C3. This would allow the TX-RX offset to be set. If one was made a variable rather than a preset the RX-TX offset could be adjustable.

Since being ill I have not tried the rig. A limitation was the limited RX sensitivity, meaning only stronger stations would be workable.  However, the rig does work and is very simple. Another possibility is to switch to an external RX but allow the internal RX to be used when signals are strong enough. The TX power is certainly enough to span the Atlantic and work all over Europe.

The secret to low chirp on 10m is the use of FSK rather than CW. Essentially the TX changes frequency rather than go from RX to TX every time. This means full break-in is not possible in such a simple circuit. Can you do better? If so, I'd love to see the schematic please. I make no great claims for my circuit, which is an amalgam of ideas. Pure fun!

See https://sites.google.com/site/g3xbmqrp3/hf/chirpy .

Lesser Chirpy - a VERY simple 10m transceiver

This design is a couple of years old and evolved from Chirpy. Unlike the original design, chirp on 10m is negligible. This design really works and gives credible results on 10m with just a handful of parts. Sensitivity could be better  with a few more parts, but not this simple!

See https://sites.google.com/site/g3xbmqrp3/hf/chirpy .

Portuguese Lesser Chirpy 10m transceiver

CT5JZX version of the Lesser Chirpy transceiver for 10m CW

In an email from CT5JZX, Pedro tells me he has made a version of my Lesser Chirpy 10m QRP CW transceiver. He has already received some beacons with it - he only has a crystal in the beacon part of the band at present - and hopes to TX with it soon when he has some other crystals. He has made a neat job of it in the plastic casing.

It is some time since I fired mine up and currently it is in a box in the loft after my recent QTH move.

Lesser Chirpy spans the Atlantic (10m QRP)

My 28.060MHz ultra-simple QRP transceiver was copied in the USA this afternoon. K3MM (Maryland) reported me on the Reverse Beacon Network as 7dB S/N at 15wpm on 28.060MHz. K3MM is in FM19JH which is 5886km away.

Initially I was unable to hear any stateside stations to call for a QSO. Still, the rig has now been copied across that big ocean! Power out into the halo is around 70mW.

VE2TH was coming through OK with 5W and might have been workable but the band faded out.

More DX on Lesser Chirpy

Another report via the Reverse Beacon Network from 5B4AGN in Cyprus this morning, but no QSOs and no further RBN spots. A brief outing this afternoon in which I'd hoped to get across the Atlantic proved to be a disappointment. There is always tomorrow....

Lesser Chirpy reaches Cyprus

No QSOs this morning yet but a RBN report from 5B4AGN in Cyprus with the 80mW lesser Chirpy 10m CW transceiver to the Homebase-10 halo. This is the first time I've looked for RBN reports with this tiny transceiver.

Reverse Beacon Network report for 80mW Lesser Chirpy

When I got back from my grandson's birthday party in London in the late afternoon I put out about 10 CQs on 28.060MHz with the rig, but no QSOs or RBN reports. I shall try again during the week.

10m Lesser Chirpy in a new box

Lesser Chirpy (should be No Chirpy!) 10m transceiver

At last I've got around to putting my Lesser Chirpy ultra simple 28MHz CW transceiver in a case. I've added an extra switch so I can listen on another RX if conditions are such that the internal RX struggles, although even with my 64 year old ears I can clearly hear better than -100dBm signals on Lesser Chirpy. Offset is set at about 700Hz between RX and TX. The FSK keying is a bit odd - there is only around 100Hz shift between carrier on and pseudo off (i.e. shifted) but there is zero chirp. This is now a seriously useful transceiver, albeit very very simple. Power out on this sample is around 80mW, so I believe this is certain to span the Atlantic in the next few days, if only to be spotted on the Reverse Beacon Network.

Lesser Chirpy cased

I have not got an internal low pass filter on this model. One should be added between the rig and the antenna to ensure low 2nd and 3rd harmonic levels.

Lesser Chirpy 10m transceiver

You may recall that some months back I did a tiny transceiver for 10m CW ....that chirped. Well, this is the latest version that does NOT chirp! Instead of keying the oscillator current, I now key the capacitor that sets the oscillator frequency instead i.e. FSK keying. The latest version is shown here. Have a go: 10m is is good shape and you may get a few QSOs.

If the going gets tough (the RX audio level is low!) try adding an extra antenna change-over switch so you can receive on an external receiver instead. or add a 100n from TR2 collector and feed the signal into a sound card and SDR so you can use the PC's audio gain to help with copy and tune either side a few kHz.