f6irf's blog

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The good news is that a large majority of reporters are within +/3Hz and has a good frequency stability.
You can see how I calibrated my TRX before/after the night.

Nothing really new, but for the newcomers to 80,160m and below bands, I've posted a few new plots, result of last night experiments on 80m. It is on my Picasa web-album.
You may start here:
And move forward using the album arrows.
It shows what kind of improvement can be expected from a simple magn-loop versus a vertical in a noisy environment (if you are lucky enough to have a very quiet location "man-made noise-free", it may not be that effective - A magn-loop is only effective to nul-out a local noise source arriving at low angle).

It is not the first time I am doing such a tests, using a Magn-loop and/or a K9AY. More tests can be seen by following the links at the bottom of the last album picture.
A good start on "low-band receiving" specific problems, and comparison of RX-ant perf. can be found at

Noticing some WSPR activity on 504 Khz band and having 0 experience of bands
below 1.8Mhz I just tuned-in to see. Just using my untuned vertical and
despite my very noisy location I received the SM6BHZ beacon immediately.
Reminded me when I first heard W5UN on 2m EME (just using 4x9 home-made yagis
made from Al recovered from the bin...)... magic !

Knowing the improvement brought by the RX-loop on 160m, I decided to try
quickly something to see if the 160m loop could be tuned down to 504kHz.
A quick calculation, indicated that I needed around 1nF capa to get the loop
to resonnate at 504. in fact 1nF was not enough, the final value was found by
experimentation (just using the band-noise to find the resonnant freq) to be
around 1390pF (2x470pF + 2x220pF silver mica caps + a small 40pF adjustable
cap), which means that my 6 turns loop has an inductance of approx 72uH (and
not 100 as first estimated !). At this frequency, the bandwidth is extremely
limited, just approx +/- 1.5kHz at -3dB.

I then discovered, that the IC756pro2, did not have sufficient sensitivity to

Many of you may wonder what the huge amount of data available in the WSPR-DB may be used for...
Just for the newcomers, I am spotting here again some work I have done using the WSPR-data.
http://mangafight.free.fr/index_eng.htm (just updated)
You may find ideas for you own work. Please spot any propagation, antenna or other related study you may have done using WSPR.

Thanks and best regards - Patrick

Although I sometimes decode OK2SAM's WSPR signal, it always need to be strong...
On the attached file, OK2SAM signal is around -10 but getting no decoding. On the other hand the upper signal at 11:40z got decoded at -26 (the stronger one in the same period is 7L4IOU at -10.)
OK2SAM, if you ever read this post, please explain what kind of settings you are using to produce such a signal, resisting to WSPR decoder ! (You may also want to fix it !)


As I already mentionned, the WSPR DB is far too unreliable to attempt any serious propagation study or to trigger any propagation alert (ie for multi-hop E's on 10/6m)...

Here is an example among many others

The following may give ideas to the WSPR'ers interested by 80m.

I built a RX loop - quick dirty job with plumber / electrical PVC - let say 2 hours work.
- The main loop is a single turn, made from 5mm diameter coax (only the shield is used). It is "diamond shape" 1m by side. It is tuned by a 358pF silver mica capacitor + a 5-60pF ceramic trimmer.
- The coupling loop is also "diamond shape" ; 25 cm by side inside the main loop.
- The SWR at resonnance, measured with the MFJ249B is 1.1

The WSPR 80m distance record which was held by W1CDO and ZL1ANY with 14529 kms on March5 fell 3 times today...

- The first one today was N2JR with VK7KRD with 16311 kms at 0612z
- Then followed by myself at 1612, also with Bob VK7KRD at 1612 with 16929 kms
- Finally G3SUY is the current record holder (once again with Bob) with 17326 kms at 19:10...

A special mention for Rich N2JR, who has the only 2xways and with 1 W !!!
Now we are looking for 80m long path !!!

73's Pat

See attached recorded on F5RRS 17m signal... (F5RRS is 35kms away, but behind the mountains)
Anybody has an idea on what could cause such a doppler? plane, meteor trail, or something else (ESS, UFO ? ;-)
Anybody is able to calculate the speed of the object ?

PS Sorry, have exceeded my 1Mb limit. The file is here

Great activity thanks to all participants;
However this was a bad day for me, at least on RX side, due to non-stop heavy rainfalls. For those who may be interested to compair actual reports to predictions, attached is a noise map, done on 20m with rain. I have 2 clear noise sources which correspond to the power lines towers at 270 and 130 degrees. Of course the noise level is a bit lower on 17m (about 3dB according to the CCIR model).
With rain, my quieter direction is 30 degrees, and the SNR degradation is some

See the attached showing W1CDO signal as received here in EU.
The path from NM to SE France, passes near the "aurora oval" and the effects of the frequency spreading (aurora effect) are clearly visible, although it is not strong enough to affect decoding, as it was the case on K7EK 40m signal.
This explains why it is so hard for EU -stations to get WSPR spots from US west-coast stations.
By the way this screen shot was taken today with quiet geomagnetic conditions (k=1 A=1). I guess that W1CDO signal will become unreadable, with perturbed conditions.

I've been asked twice in the last 24 hours, if 7038.6 was the official WSPR frequency
here is my answer:
Although it is far from being ideal (mainly due to Pactor BSS's) we choose this frequency after several tests with 7L4IOU, mainly because, the JA's are not allowed to transmit digi above 7043. It became "de facto" the center of activity, thanks to the participation of several stations from the region 3 (ie VK/ZL)


I am adding the plot of this morning 40m test, involving VK7KRW (RX), DG0OPK and myself... (TX).
We were both using 5W; DG0OPK uses a G5RV at 4m AGL and I am using a ground mounted 17.5m vertical (tuned with an AT130 auto-tuner).

Please see forum topic "WSPR-DB data vs VOACAP model" for more details, comments and plots.

For those who are interested to compair antenna performances (TX/RX) over a long period using WSPR, and who own an ICOM transceiver, my friend F5LEN wrote a little software, which allows to switch TRX antenna 1/2 according to a predefined timing... (of course you need a TRX with 2 ants ports; ie IC756, 7800, etc)

Just discovered the JT65 Reverse Beacon mode (thanks Gary K7EK). After 2 days of activity here is a quick summary: