WISPY RX

One of my Facebook memories today was this photo of my WISPY 10m WSPR RX. I think this was first created in 2011.  Later it formed the basis of a really simple 10m FT8 receiver.

WISPY 10m WSPR receiver

It is amazing to believe that this design of mine is 10 years old!  These days, many have gone on to FT8 instead, but there is a good following on 10m WSPR as well. This used very low cost 14.060 MHz crystals that were pulled, making this a very low cost design. It worked well.

10m WISPY

Although both the TX and RX were built, I never got around to boxing and testing the full transceiver version. It should work, but I have not tried it. You may want to use it for your own ideas.

I have been surprised by the WSPR activity still on 10m. Back in the Es season my beacon was widely spotted most days. The same basic idea would also work on FT8. It depends on finding suitable, low cost, crystals.

Please note there was an error on the schematic: the main winding on the inductor in the oscillator collector should have 22 turns and not 9 turns.

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

Facebook memory today

This photo shows a FB memory from 9 years ago. It later occurred to me that you the same idea would work on FT8 RX so the FT8R was born. See my main website at www.g3xbm.co.uk. 

10m WISPY TX WSPR beacon TX

Many years ago I designed and made this TX beacon for 10m WSPR. You might like to try it as a winter project. 

If you want more power, just add more 2N3904s in the PA. This is far cheaper than a dedicated PA device. Even with QRPP you can expect plenty of spots when 10m is good. It is getting better again now the sunspots and solar flux are climbing.

The photo shows the first breadboard. 

It is a DSB design using low cost 14.060MHz crystals. I was surprised by the vast amount of 10m WSPR this summer.

As I recall, I used matched germanium diodes in the balanced mixer, but I am sure Schottky diodes would be fine. Do not be afraid to experiment! As with all my circuits, use these designs as a starting point. If you can make them better, great.

See https://sites.google.com/view/g3xbm4/home/hf-mf-and-lf/homebrew/10m-wispy for more details and a clearer schematic.

Ultra simple transceiver for 10m FT8

One of my ideas is for an ultra simple crystal controlled FT8 transceiver for 10m probably. Another option is 15m. Crystals can be quite expensive, but bought in quantity the price comes way down. 

I have in mind a simple DSB rig at 28.074MHz only, a bit like my WISPY transceiver.  The full transceiver version of WISPY was never built, but both the RX and TX versions were built. I wonder if there is a low cost source of 14.040 (easily pulled) or 14.037MHz crystals? This would be simpler than a synthesised source. I don't think pulled ceramic resonators would be stable enough, but they might be.

My health rather precludes me designing and building one these days, but I would be more than happy to share my ideas with anyone who could take this on seriously. Ideally, a PCB could be made as a simple kit. 

In my mind this could be a really simple rig that would be able to work the world very soon once 10m really gets going. Don't forget that 10m is always good in the Es season at any part of the solar cycle. Even very low power FT8 would get all across the world.  10m is an excellent band with small antennas and QRP. I can imagine such rigs being incredibly simple and low cost. In this version I used a 2N3866 PA, but I would use paralleled 2N3904s as these are far less expensive.  For greater TX power, further 2N3904s PAs could be paralleled with low value emitter resistors.  This is a very low cost way of getting useful output.

Very few controls are necessary, probably none! It would need a BNC connector and probably something to show it is on RX or TX. I can imagine it fitting in a low cost, small, plastic box.

QRPguys are offering something similar on lower frequencies. Maybe they will offer higher frequencies later as the sunspot cycle gathers pace? 

See https://qrpguys.com/ .

UPDATE 2020z:  Steve G1KQH has told me of some low cost crystals that would certainly work: https://kc9on.com/product/14mhz-hc49u-tall-crystals/

20m FT8 WISPY RX?

A few days ago I showed the schematic for my WISPY RX. The photo shows the actual 10m WISPY RX. 

With a couple of low cost GQRP 7030kHz crystals in parallel this could probably allow a very low cost 20m FT8 RX to be made using the same idea and pulling the crystals upwards. 

If you have a source of low cost 7040kHz crystals, just one will probably allow you to get to half 14.074MHz. A 14.074MHz simple DSB based FT8 RX would be a fun winter project, guaranteed to spot lots of DX every day.

Just think - for the cost of a couple of coffees out (those were the days!) and you have a low cost way of spotting DX from across the world.

Come to think of it, a full 20m FT8 transceiver could be made for the price of a bag of fish and chips! Surely someone is up for the challenge. 

WISPY

It is some years since I designed this TX. At the time I needed a quick and low cost way to TX WSPR on 10m.

I opted for a DSB TX using low cost 14.060MHz crystals and doubling. The PA used low cost transistors. These days many prefer FT8, although WSPR works with much lower signal levels.

You may find some useful ideas in the circuit even if you do not use it for WSPR. The site below also has a transceive option. This was breadboarded as separate RX and TX units but never tried as a full transceiver. It should work.

The same circuit (and the transceive option) should also work on PSK31. Just think of it: work the world for a few pounds!

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

WISPY on 10m WSPR

Some years ago I designed and used this very low cost rig as a beacon on 10m WSPR. Even the crystal is low cost. With 10m in decline, this is an ideal time to try 10m WSPR. More power can be had by adding more low cost transistors in the PA. 2N3904s are very inexpensive.

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

WISPY WSPR beacon

Some time before my stroke in 2013, I designed a simple WSPR beacon for 10m that used low cost 14.060MHz QRP crystals doubled. These pulled up sufficiently.

This beacon was copied all across the globe. It uses a DSB transmitter, so the power goes out on two frequencies so the power in the WSPR slot is half. With the Es season approaching you may like to build it. 10m should be fun May-September in the Northern Hemisphere.

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

The PA could be replaced by paralleled 2N3904s instead of the 2N3866 to get more power for a few pence. 2N3904s are very very cheap. If you look at my Tenbox (also on my website) you will see the idea. Don't forget the emitter resistors so power is shared!

WISPY 10m WSPR rig

Some years ago (in my fit days) I build a simple DSB WSPR rig for 10m based around a low cost 14.060MHz crystal bought from the GQRP club.  The idea was to pull and double this crystal and use it in a simple DSB TX and direct conversion RX.  Both TX and RX have been built separately, but I was ill before I got around to combining the 2 into a 10m WSPR transceiver. Both parts worked well.

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

Back on 10m WSPR with WSPY TX

Unique 10m WSPR spots using WIPSY TX today

Having given up on 20m CW this morning, I fired up the 10m WISPY beacon TX running around 250mW to see what spots I got. During the day I caught a couple of Es openings. 4X1RF seems to spot me whatever I do/run and on most days!

I have still to put the TX and RX parts of this project together (both parts have been separately tested) as a full WSPR/PSK31 transceiver for 10m.

WISPY reports

For the first time in a few weeks I set the WISPY 200mW 10m WSPR beacon running to see what reports I got whilst getting on with jobs.

It is fascinating that G8KNN who is just 12km away often gets me at similar levels to the reports I get from K1OF who is 5455km away, all due to the vagaries of HF propagation.

More WISPYs on 10m

The G4SFS version of WISPY

Yesterday I received a nice email from Peter G4SFS who told me that he and Dave G6WZA had made a couple of WISPY 10m WSPR beacon TX units using the schematic on my website. A few values changes were needed - not unexpected - but that they are now working well and receiving spots from distant monitors. This is a photo of one of them. WISPY is a simple QRP WSPR beacon for 28MHz using a low cost 14.060MHz crystal and inexpensive 2N3904 transistors throughout.

Conditions on 10m have not been too great of late, although I did exchange reports with PY2SDR at 9616km and 4X1RF. Interestingly, there have been a few early evening WSPR reports from DL which I assume are probably a result of wintertime Es propagation.  At this time of year there is a mini-peak in sporadic-E propagation, so it is worth keeping an eye on 50MHz and 70MHz too.

WISPY 10m WSPR beacon video

A few people have requested a video of WISPY, my QRP WSPR beacon for 28.1246MHz. This video shows the TX beacon only. I have a companion RX breadboard that works well and at some point these will be combined into a small 10m WSPR transceiver.

WISPY spans the globe

Today WISPY, my little 10m 200mW WSPR beacon, excelled itself getting spots from 5 continents with the best being a spot from Australia late this morning. 

Conditions in the last few days have been excellent. I keep reminding myself that if, as some are now saying, cycle 24 has already peaked and we are on the way down, conditions in my lifetime (and probably most of those reading this) are unlikely EVER to be as good again.  It is just possible there may be a second peak next year which is stronger, but I somehow doubt this now.

Unique 10m WSPR reports with 200mW and a halo today

WISPY reports and a red kite

For the last month we seem to have been away from home half the time. The last few days we have been in Yorkshire for a sibling reunion with my wife's brothers.

On the way back home we had a REAL surprise driving along the Leeds ring road. I could not believe my eyes when I saw a red kite flying quite low overhead. These fine forked tailed raptor birds were once confined to a small part of south central Wales but following selective reintroduction they are making a comeback all over the place. We see them near Newmarket quite often, but I was totally surprised to see one driving through urban Leeds!

When I got back home I switched on the WIPSY beacon and was rewarded with a string of reports including a +6dB S/N from Germany - not bad for 100mW. The now regular  report from EA8FF was not long coming as was a report from F5VLY and several other DL stations and G8KNN not far away.

WISPY TX gets better (and even cheaper!)

Today I did a rebuild of the TX only version of the WISPY 10m WSPR beacon to improve it in several ways.  Switching to germanium diodes helps produce a much better looking DSB signal out of the mixer. With silicon diodes there was not quite enough drive. The second change was to remove the 2N3866 PA and replace it with a couple of paralleled up 2N3904s (each with a small emitter resistor so they share current properly). A 2N3866 is around £1.50 whereas a couple of 2N3904s are about 6 pence.  Output is now a clean DSB signal, even without the low pass filter, with a conservative 200mW DSB out (100mW equivalent SSB signal in the WSPR band). This is now a very pleasing little design that can be built for even less.  Within 5 minutes of turning it on it got a remarkable -3dB S/N report from EA8FF over 3000kms away.

TX only WSPR beacon

UPDATE 11.9.12: see later post for improved version

WISPY is a full 2-way WSPR transceiver but there may be occasions when just a simple WSPR TX is needed. This is the (current) schematic of the WSPR TX beacon for 10m, but the very same schematic with a different crystal and values should work on any HF band. On lower bands the doubler could be removed and a simple on-frequency crystal substituted.  The doubler approach was the cheapest way for 10m WSPR.

The schematic needs rationalising and some further simplification, so treat this (as always) as a design starting point.

WISPY now transmitting!

Breadboard of WISPY TX - 50mW pep WSPR (100mW DSB)

Very pleased with my little 3 transistor DSB 28MHz WSPR transmitter. Since turning it on at 11.34am I've received around 30 reports from stations in Europe despite the power being just 50mW pep ...and as I write my first spot from Africa: -14dB S/N (a good report) from EA8FF in the Canary Islands!

Schematic to follow tomorrow. OK, I know - there is no low pass filter on the breadboard. As the circuit is linear throughout and there is filtering on both stages the output is pretty clean, but I will add a 3-section LPF on the final transceiver version.

This is a very simple, all discrete parts, design using 2 x 2N3904s, 1 x 2N3866 (may be overkill) and a couple of 1N4148 diodes in the mixer.  Again, I use a cheap 14.060MHz crystal, pulled a bit and  doubled, as the LO.