10m DX in 2012

One of my Facebook memories today was of a report from the USA 🇺🇸 when I was using my ultra-simple CW transceiver on 10m.

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

Tenner - QRP CW on 10m

This rig is many years old. It is simple, but it worked lots of DX. 

As I recall, it produced about 500mW of CW.

See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/10m-tenner-qrp-cw . 

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 .

Learning CW

Some enjoy CW. Jason M0NYW has been learning it recently and has used some of the 10m CW beacons to improve his skills. CW can work with marginal signals far weaker than SSB ones. You might like to try too.  As these beacons repeat, they can be good for practice. No PCs needed! Just ears!

These are the stations Jason spotted:

        28201.5    SV2HNE/B KN10LL 5W ANT GP 73

        28243       F5ZWE "just repeats callsign"

        28244.6    SV2FQNB KN10FC 5W ANT GP

        28265.3    SV2RSS KN10LO GP/3W 73

        28268       VK8VF "repeats callsign and something else but hard to copy due QSB"

        28269       SV6DBG "V V V DE SV6DBG BEACON KN09KQ"

        28271.6    SV2HQD/B

Often CW rigs are far simpler to make than SSB ones.

Best ever QSO?

Way back in 2007, I achieved what I had thought impossible - a real QRP 6m QSO across the Atlantic. The antenna at the far end must have helped, but Lofty must have had good ears!  My antenna? Just the V2000 vertical omni fed with CB coax. My power? 1W ERP.

21MHz (15m) QRP CW - my homebrew "Pipit"

Many years ago I designed and made this QRP (800mW) CW rig of 15m. 

It worked remarkably well and worked some impressive DX. 

For several months it was the only rig I used, out of choice. Every QSO was so satisfying. It appeared in GQRP SPRAT. It was in the days before schematic drawing packages, so the schematic was hand-drawn. I used Neosid toroids as these were at hand, although I am sure Amidon ones would be suitable with turns adjusted.

Values are on my webpage. As with all my designs, please use this as a starting point for your own ideas and do not be afraid to change things if this makes the design better! The SBL1 mixer can certainly be replaced by similar double balanced mixers or a homebrew version.

See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/15m-qrp-cw-pipit .

Learning CW

With modes like FT8, many people may question why we still need CW. My answer is with CW it is possible to build very simple rigs that can work a very long way.

As an example my recent article in RadCom shows 2 simple circuits and my 15m CW Pipit transceiver (on my main website) was used for a first contact with the USA many years ago despite only having an output of just 800mW. This was with just a simple, low, wire dipole.

Pipit - 15m QRP CW transceiver

Way back in the 1980s I designed and built this tiny transceiver for 15m CW. For months it was the only rig I used. It worked remarkably well with just a simple, low dipole. Output was 800mW. The very first contact was over 4000 miles! Later the case was used to house another transceiver, the Tenner for 10m CW. Looking back, I should never have got rid of this rig. If my health was better, I should rebuild it.

See https://sites.google.com/site/g3xbmqrp3/hf/15m_pipit

Miracles do happen on 6m

This is probably my most treasured QSL card. It is for a transatlantic 6m CW QSO in 2007 when I was running about 1W ERP. That evening 6m sounded like 20m and was filled with stateside SSB and CW signals. That was before FT8! The propagation was summer Es.

More recently, I have been mainly looking on 6m FT8 RX with the occasional TX period. I am using my FT817ND (at 2.5W out) and the V2000 vertical omni antenna fed with cheap CB coax.

How much better is WSPR compared with 12wpm CW?

It is very hard to calculate this as you have to compare "apples with apples". A calculation by PA3FWM suggests this could be 17dB!!

See http://www.pa3fwm.nl/technotes/tn09b.html .

Valves

Facebook regularly shows memories of years past. One popped up yesterday showing a CW valve TX that G6ALB build some years ago.

He did not feel confident on the key, so I operated.

On 15m this little 400mW rig got a response to the very first CQ call from a W. We nearly all fell off our seats.

I have to confess that I have never built a valve rig. Andrew G6ALB keeps trying to persuade me.

Learning CW

It is some time since I tried CW - I use JT65 and WSPR mainly because of my health - but this can be a very effective mode with simple gear. Learning CW can be hard for some. An on-line resource that may help is http://lcwo.net/en/cwsettings .

600m DX QSO

Steve, G1KQH has brought my attention to a Southgate News item about a DX QSO on 600m CW across the Pacific.

See http://www.southgatearc.org/news/2016/february/greater_distance_achieved_on_600m_band.htm.

CQWW CW this weekend

Usually I don't do this contest as CW is often sent at breakneck speed, but the CQWW CW contest is on this weekend. If you enjoy CW and contests, this one may be for you?

Elecraft K1

One of my least used rigs (it has still to be used at this QTH!) is my 4-band Elecraft K1 CW transceiver. This covers 40m, 30m, 20m and 15m CW at up to about 7W. It has the auto-ATU built in so just needs a 12-13.8V supply, CW key and end-fed antenna to be on the air.

At my old QTH it has worked lots including the USA on all bands with a simple end-fed wire antenna down the garden.  I really should consider selling it or trading it in as it is not being used.

Tenner - a 500mW CW transceiver for 10m

This was a rig I built and used a few years ago for 10m CW.  As you can see, the design is simple but it worked across the Atlantic many times. Pull the crystal too much and the RX-TX offset becomes too great. Ideal as a simple rig for 10m CW.

See https://sites.google.com/site/g3xbmqrp3/hf/10m_tenner .

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 .

First 40m Pixie QSO

At 1000z this morning I exchanged RST 579 reports with G6ALB who is 3km from me on my 40m Pixie on 7.023MHz CW. This was my first on-air QSO. Netting was perfect and I used the rig directly into my low Par triband antenna. An ATU might have helped. Andrew G6ALB said the channel was pretty busy but that I was a good RST579 with no hint of chirp. This afternoon we'll put the rig on his spectrum analyser. I gave Andrew 579 probably reflecting the poorer MDS of the Pixie. I have no idea of his power or antenna.

My initial goals have been met: I built the kit and have managed a QSO on the air with it. With the fatigue associated with my brain bleed still very apparent (I am well and truly shattered currently), I was well pleased. A few more QSOs with the 40m Pixie would be good, HI.

$10 well spent. Excellent little kit. FB little transceiver. Works surprisingly well.

Tenner 10m CW transceiver

Click for bigger image.

The Tenner is a very simple CW rig for 10m. It produces about 500mW output and has worked across the Atlantic on many occasions. Offset RX-TX seems to work out at about right, although no special circuitry is employed. This simple circuit just works. Although I used an "at hand" SBL1, any double balanced mixer is likely to be OK. Although I did not try it, a homebrew DBM would be fine. Google it.

QRP 5W CW transmitter from SM0VPO

Many years ago Harry SM0VPO worked at Pye Telecom. I had no idea back then that he was such a prolific and good designer.  This is his design for a simple HF 5W CW transmitter. His website has loads of great ideas.

See http://www.qsl.net/qrp/tx/5wtx.htm .