
31 Oct 2009
500kHz - two new reports and a new country

AA1TJ's Code Talker TX

LC Meter - a nice kit

20th station hears me on 500kHz
Last night M0WKR (IO94 at 237kms) reported my 500kHz WSPR beacon bringing the total number of unique reporters up to twenty.
30 Oct 2009
The 500kHz ATU

AA1TJ's "Code Talker TX" - all voice powered
Mike Rainey continues his work on purely voice powered transmitters, in which just the energy in his voice is used to power the RF circuits i.e. no batteries or PSUs at all. He's achieved well over 100kms on 80m this way using a form of CW derived by whistling into a loudspeaker to generate the energy needed. Here is an example of his signal received 109kms away. He can clearly be heard "keying" (actually whistling!) the words of "Mary had a little lamb" in CW.
Labels:
aa1tj,
qrp,
voice powered QSO
29 Oct 2009
A good evening on 500kHz QRPp

A 19th reporter on 500kHz
G4EFE managed to hear my WSPR beacon on 500kHz several times last evening (127kms) bringing the total number of unique stations receiving me to 19 now. I still have work to do to get over the 1000kms distance target.
26 Oct 2009
500kHz - an 18th station hearing me

25 Oct 2009
CQWW contest summary - 10m was great
With darkness falling now 10m is going quiet after an exciting 2 days. In the end, my 5W SSB and halo antenna worked 35 stations in 20 countries. DX from outside Europe was not workable this time but I was hearing CX, PY, ZS, 6W, etc so conditions were definitely not bad. Although there were a couple of stateside stations worked from Europe, I did not manage to hear them. The slight upturn in sunspot activity came just at the right time.
10m - the return of the good days?
The CQWW SSB contest has livened things up on 10m this weekend, but the sunspots are also showing signs of activity again and the band generally has been in good shape. In the last 24 hours I have heard DX from 4 continents and confidently expect it to open to the USA this afternoon. Good signals from 9J2B0 on CW and ZS9X on SSB today as well as wall-to-wall Europeans from 28.38-28.62MHz at times. Could this be a sign of the good times to come? Let's hope so as 10m is one of the best allocations we have on HF and a great band for QRP DXing when conditions really improve.
24 Oct 2009
500kHz TX schematic (5W)
Labels:
500kHz,
qrp,
transverter,
wspr
G0NBD and G4FDD log me on 500kHz
My 500kHz WSPR signal has been logged by new reporters G0NBD in IO83 square (261kms) and G4FDD in IO93 square (212kms) tonight.. This now brings the total number of different stations that have heard me to 16. Not bad with <1mW ERP.
23 Oct 2009
10m - CQWW SSB DX Contest
This BIG HF contest runs this weekend and is sure to make the bands sound busy. I shall be having a go with 5W SSB on 10m only and see what happens.
By 1600z Saturday I'd worked 24 stations in 16 European countries with 5W QRP SSB including C4I, P33W, 4L0A, US5D and TM1O. It is nice to hear 28.4-28.55MHz crowded with stations. Funny how "conditions" magically improve when there is a big contest! In the afternoon there was some decent DX about including LU1HF and PW5G but I did not work them.
By 1600z Saturday I'd worked 24 stations in 16 European countries with 5W QRP SSB including C4I, P33W, 4L0A, US5D and TM1O. It is nice to hear 28.4-28.55MHz crowded with stations. Funny how "conditions" magically improve when there is a big contest! In the afternoon there was some decent DX about including LU1HF and PW5G but I did not work them.
EPAD FETs and low voltage TX
This application note shows a 32uW oscillator using EPAD FETs that works with 0.5V supply and may be useful for "harvested energy" TX circuits. The ALD110800 FETs used has also been used to power an amplifier with just a 0.2V supply.
500kHz ATU
Spent half the afternoon going around in circles trying to measure the antenna current since I rebuilt my tiny ATU with a few more taps on the ferrite rod. For reasons I don't understand it was all over the place with my multimeter connected by about 50cms of wire. Instead I built the current meter around a toroid and a small 50uA meter mounted in the ATU and can now repeatably measure the antenna current which is 50mA. With a 5m effective height this is still way below 1mW ERP.
AA1TJ's Voice Powered DSB TX (El Silbo)

"AA1MY and W1PID met with me on 3686kHz this afternoon. I was operating a new, DSB version of my "El Silbo," voice-powered transmitter. Both Seab and Jim successfully copied my/their calls and signal reports. Jim commented later that I would have been hard pressed to pick a worse day for the attempt. The propagation was producing severe QSB fading and the QRN was all over the place (peaking at S-7 to S-9 at times). I came away nearly dumbfounded that these two operators could pull enough of my 5mW DSB signal out of the mess, at distances of 100 and 67miles, to complete the QSOs."
22 Oct 2009
Antenna measurements at 500kHz
Matching my antenna at 500kHz has been a bit hit and miss: my technique, if you can call it that, has been to match the antenna "by ear" on RX, adjusting taps on the ferrite rod ATU inductor, to give me the best S-meter reading on the intermod product on 504kHz. Then, with a 3dB pad between the PA and ATU, carefully tweek the tap settings on the ATU for maximum antenna current measured using a toroid current transformer. The 3dB pad is to prevent damage to the PA during the adjustment process. Up to now this has been OK, but I could really do with a better way of measuring the antenna parameters. I'd really like to get an antenna analyser, but cannot justify the expense. I need to check out some other simple, low cost, techniques.
Labels:
500kHz,
active antenna,
analysis,
atu,
matching
14 stations hearing me on 500kHz WSPR

21 Oct 2009
Another new reporter on 500kHz
Eddie, G3ZJO, has managed to copy my 500kHz WSPR beacon tonight. He is now the 13th station to hear me on the band. No great DX at 79kms, but pleased to be heard by someone else.
6m WSPRing and aeroplanes

20 Oct 2009
Simple beacon keyer IC: the K-ID2

See http://k1el.tripod.com/KID.html . At $6 each you can hardly go wrong with this. I shall be ordering a few shortly.
Another new country on 500kHz WSPR
My 500kHz WSPR beacon has now been heard in a fourth country: a -26dB S/N report from F5WK who is in the Paris area, a distance of 436kms away to the south. The beacon has now been reported by 11 different stations in four countries so far.
19 Oct 2009
Lambda diode circuits

Labels:
aa1tj,
diode,
fet-1,
lambda diode,
oscillator,
regenerative,
tunnel diode
18 Oct 2009
500kHz WSPR - a summary so far

If I could summarise what this tells me it is:
(a) WSPR works very well at 500kHz allowing weak QRPp signals to be detected.
(b) Very low power (ERP <0.3mW) and electrically tiny antennas do work on 500kHz if weak signal modes are used.
(c) 136kHz is worth a go next, even with the poor antenna and very low ERP.
17 Oct 2009
A map to end a fantastic day on 500kHz QRPp

K1JT, Joe Taylor, thank you for bringing us this wonderful software package.
What next - 136kHz WSPR?
Having now almost achieved more than I could ever have expected on 500kHz WSPR with uWs ERP, I'm wondering if I should give 136kHz a try with the same antenna and transverter. If I could maintain the same antenna current (20mA measured) my ERP would be around 3-5uW on 136kHz. I'm wondering how far that might get. Almost certainly not too far, but probably enough to be detected by some of the nearer stations
Even greater DX on 500kHz QRPp WSPR - 896kms!

International DX on 500kHz WSPR
Just received my first 500kHz report from outside England at -26dB S/N from OR7T in JO20ix which is 337kms away.
Using the formula in the RSGB LF Handbook I just calculated my ERP on 500kHz assuming an effective antenna height of 6m (probably less than this in reality) and a measured antenna current of just 20mA. It works out at 315uW ERP. Based on earlier measurements by M0BMU it should now be around 60uW. I suspect he is nearer than the theory suggests. Anyway, still a long way below 1mW ERP even but getting great results with WSPR.
Using the formula in the RSGB LF Handbook I just calculated my ERP on 500kHz assuming an effective antenna height of 6m (probably less than this in reality) and a measured antenna current of just 20mA. It works out at 315uW ERP. Based on earlier measurements by M0BMU it should now be around 60uW. I suspect he is nearer than the theory suggests. Anyway, still a long way below 1mW ERP even but getting great results with WSPR.
One Laptop Per Child (OLPC)
Good to see that Uruguay has become the first country to provide a laptop for every child attending state primary school according to a report on the BBC News website today as part of the OLPC Initiative. Over the last 2 years 362,000 pupils and 18,000 teachers have been involved in the scheme, which aims to provide low cost, but high specification, laptops to school children across the world.
500kHz paths

My new 500kHz DX record - 210kms

Incidentally, this is the transverter at the moment very ugly style. Will add the RX part soon so I can use CW.
Dave's G0YMC's report:
153000 15 10 2.6 -62 0 G4JNT IO90 23
153000 8 -20 5.2 8 1 G3XBM JO02 0
Wow, only 30dB down on G4JNT! Well done Roger.
(sorry cannot upload as I am copying with WSJT7 which doesn't support
the internet upload - but has an auto soundcard calibrator).
73 Dave G3YMC
IO91PJ
5W (from the PA) on 500kHz
With the arrival of some IRF510 FETs I've built a small PA to go on the end of my WSPR beacon transverter. The output (from the PA) is now 5W, so my ERP should be up by around 10dB to around 50-60uW. Already I have been spotted by G7NKS some 10dB stronger than ever before - most encouraging!
The first transistor - read Shockley's lab notes

Labels:
bell labs,
shockley,
transistor
15 Oct 2009
500kHz WSPR - last time before improving the station
This evening and overnight I am running my 500kHz WSPR beacon for the last time in its unmodified state before beginning to make improvements to the antenna and PA. I am still hopeful that I'll get another one or two new stations spotting my signal. Once the ERP starts to be increased by up to 20dB my "sphere of influence" on 500kHz should increase.
Do listen on 500kHz WSPR and upload any spots you get.
POSTSCRIPT: I did actually fire the "old" setup again last night (Friday evening) for a few hours but was only reported by G7NKS. I'm now thinking of practical and relatively unobtrusive ways of making the signal a bit more potent on 500kHz without the garden looking like Droitwich or GBR Rugby.
Do listen on 500kHz WSPR and upload any spots you get.
POSTSCRIPT: I did actually fire the "old" setup again last night (Friday evening) for a few hours but was only reported by G7NKS. I'm now thinking of practical and relatively unobtrusive ways of making the signal a bit more potent on 500kHz without the garden looking like Droitwich or GBR Rugby.
14 Oct 2009
A new station hears my 500kHz WSPR QRPp
This evening I received reports from G0BPU in Ipswich on 500kHz WSPR, This is now the 5th station to have heard my 6uW ERP signal. I am still hopeful that I will beat the 100kms barrier before I start the station improvements. Other reports today came from M0BMU and G7NKS. My best DX remains at 69kms.
500kHz WSPR restarted - please listen

If you are able to listen on 500kHz WSPR set you receiver to 502.4kHz in USB mode and click "upload spots" on the WSPR screen so that your SWL reports will be added to the database on the internet automatically.
It really would be good if more people listened on 500kHz WSPR even if they can't TX. WSPR is very easy to use especially on RX and the WSPR software can run in the background whilst you get on with something else. The WSPR software can be downloaded from http://physics.princeton.edu/pulsar/K1JT/WSPR112.EXE
All reports really would be most welcome.
13 Oct 2009
161kms voice powered QSO by AA1TJ
Just got an email from Mike Rainey AA1TJ describing his TX powered only by his voice. He achieved a distance of 161kms with a germanium transistor oscillator putting out a few mW of power. The power for this was generated by rectifying the audio signal from the loudspeaker used as a microphone. In the end Mike resorted to a sort of MCW mode shouting CW into the LS but W1VZR copied this and made a recording. Mike is also looking at a receiver using "RF harvesting" to allow a receiver that requires no DC power source other than that derived from off-air RF.
Mike's amateur radio pages are at http://mjrainey.googlepages.com/radio
Mike's amateur radio pages are at http://mjrainey.googlepages.com/radio
Labels:
aa1tj,
qrp,
voice powered QSO,
w1vzr
Free power QRPp transceiver or beacon?

See also Ben Tongue's crystal set pages for a circuit using a supercap to store harvested energy which is then used to power a micropower op-amp.
A "harvester" QRPp transceiver or beacon which derives its energy from stray RF, storing this is in a supercap and allowing brief periods of transmission at very low power is worth developing I think. I have not seen such "harvesting" circuits used to power a transceiver or beacon before but for a uW level beacon this should be feasible.
GQRP Club SPRAT 140

Just £6 annually gives you GQRP Club membership with 4 article-packed issues of SPRAT magazine a year, as well as access to the GQRP QSL bureau and club sales items such as toroids, QRP frequency crystals, transistors and ICs at good prices. As a GQRP club member, you can get a CD with all 140 editions of SPRAT magazine for just £4. It's worth joining just for this alone. If all other magazines had to go then SPRAT would be the one I'd still get as it is the best.
12 Oct 2009
Rybakov Wideband Vertical Antenna
"Multiband NO TRAP NO GAP Antenna. This Antenna is a small wonder, easy to build and allow you to work all HF spectrum with your TRX and it's internal ATU. It consist of a matching device at it's feed point to enable lowering the impedance of a randow wire. Winding 14-18 turns of twin insulated wire 1.75mm over an AMIDON T-200-2 RED Toroid type and wiring as the image on your right will enable you to perfectly feed the radiating element . Once finished, place it in a waterproof plastic casing used for electrical wiring suitable for UV radiations. Complete it utilizing a SO 239 socket and two Stainless Steel Bolt to ensure long life under external condition. Connect, to the Wire Terminal, a lenght of wire ranging from 7,6m onwards depending the frequency range we would like to obtain. With 7,6m we can easily cover from 7Mhz upwards, for better performance we suggest to leghten the wire up to 8,6 > 12m so to have a better performance staring from 3.5 Mhz. The Antenna will perform well in vertical position utilizing a retractable fiberglass pole ( we use a 9m fiberglass fishing rod ) so to deploy the Antenna in seconds just hook the wire to the top part and extend the elements fully. You are now ready to operate ALL BAND NO GAP making use also of the internal ATU of your TRX for portion of band where SWR is above 2:1. See Below the Antenna fully extended and in Action during a short Portable Expedition."
See http://www.iv3sbe.webfundis.net/html/Rybakov806.htm
10 Oct 2009
IC703 TX failure
After many years of excellent service my IC703 decided to expire on TX last night: power started to drop when running 5W on 30m then 80m (good matched load), then nothing, although I could detect a signal on the FT817, probably at mW levels.
I believe this is a common IC703 issue. Does anyone have data on how to fix this and where I get the spare parts? I believe it is either a driver or PA failure.
Incidentally Martyn Lynch quoted £45/hr plus parts and shipping to do a repair. I don't expect I'd see any change from £100.
This is the first time in 42 years of operating that I have had ANY piece of amateur gear fail, confirming that generally equipment is reliable if used carefully, so I cannot complain.
I believe this is a common IC703 issue. Does anyone have data on how to fix this and where I get the spare parts? I believe it is either a driver or PA failure.
Incidentally Martyn Lynch quoted £45/hr plus parts and shipping to do a repair. I don't expect I'd see any change from £100.
This is the first time in 42 years of operating that I have had ANY piece of amateur gear fail, confirming that generally equipment is reliable if used carefully, so I cannot complain.
Labels:
failure,
ic703,
power,
reliability
Genesis Q5 QRP kit from Australia

Labels:
genesis q5,
qrp
8 Oct 2009
Ferrite rods as transmitting antennas?
Assuming one is running very low powers (milliwatts) and use (say) 10 ferrite rods "in parallel" for the core is there any reason why a single thick turn on a ferrite rod, suitably tuned and matched, would not make an effective transmitting loop antenna on the lower HF bands or 500kHz? As long as the core doesn't saturate I cannot think why this would not be feasible.
I have just been told about a Yahoo group for people experimenting with ferrite rods. The owner, John Popelish, experimented some time ago with stacked ferrite toroids to make a ferrite rod.
http://groups.yahoo.com/group/ferriterodantennaexperimenters/
I have just been told about a Yahoo group for people experimenting with ferrite rods. The owner, John Popelish, experimented some time ago with stacked ferrite toroids to make a ferrite rod.
http://groups.yahoo.com/group/ferriterodantennaexperimenters/
Labels:
ferrite rod antenna
17m WSPR
Just put the WSPR beacon on 17m and received 3 reports from W8LIW at 6105kms when using 5W to the 15m end-fed wire. Activity on 10m WSPR is very low today with no reports of signals.
7 Oct 2009
Sound powered transmitters

There is a patent for this sort of sound powered transmitter - see United States Patent US2981833 dating from 1955 which has some schematics. This is available to view at http://www.freepatentsonline.
Labels:
6m qrp,
patent,
sound powered TX
DXTV - 1938 style!

See http://www.youtube.com/watch?v=4SniB0JEDGs
Labels:
bbc,
dxtv,
f2,
sporadic-e,
tv
5 Oct 2009
Back from holiday - WSPRing soon
Just got back from 2 weeks in Greece visiting the ancient sites. Hope to get back WSPRing on 500kHz within a few days after I've caught up on things at home.
Subscribe to:
Posts (Atom)