Six Meters Oscar Speech

Last things first.

A capture from the North East. As I was swinging my beam I heard what sounded like a Meteor Ping, they are distinctive things, then another and another and a shower ? on the trace they look fairly evenly spaced but they definitely were not, coming in two’s at times.

Well here is the Capture. Right Clicking and selecting View Image will show a SpecLab image also.

The signal at 15:52 is G0OQK, I am not sure who I turned away from at 15:50 the signal continued merely as pings, then OQK provided the signal for reflections.

Now for the Oscars speech. Tears in eyes, “I would like to thank G8EPQ for just being there for me”. I have struggled with having a reliable local signal for observations and EPQ couldn’t be better placed, the flightpath routing from, or past Heathrow and to Birmingham International, East Midlands or the USA is often dead in line with us.
It would be better if he was running 100% TX cycle but hey beggars can’t be choosers.
Every observation session brings something interesting from Aircraft Scatter and proof of phenomena.

Its almost as if the Air Traffic Controllers know we are here. I am not listening so we have to fantasise. B49 London to Seattle got it a bit wrong. ‘BA49 overhead Bletchley turn Left 10 degrees’ …….. ‘BA49 West of Newport Pagnell turn Left a further 10 degrees’ ……. ‘BA49 that’s better you are bang on track now’.

The flight was doing 407kt when it passed between us, G3ZJO to G8EPQ distance 24Km. In the 110 seconds WSPR Frame it traveled 24.51Km. The Aircraft didn’t get on track until after half way through, the WSPR report averages the signal level across the whole period, the enhancement is only 2dB on my Vertical Antenna but its there and its so nice to see a practical demonstration.

The path G8EPQ to G3ZJO from the WSPR.net Map

Right Click and select View Image for full view

The BA49 Flight Path

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The Signal

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The WSPR report at 15:12 with before and after reports.

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6m WSPR Wing Tip Vortex Reflections

Below is a capture of G8EPQ’s signal on 6m complete with what would be claimed as a Wing Tip Vortex Reflection.

Picture is large please RIGHT CLICK and select VIEW IMAGE to see all. Don’t forget to to click Go Back on your browser after, we don’t want to lose you.

Look at the signal strength reported by WSPR Software. The magic +12dB OVERLOAD the signal level seen on most WTV claims.

If WTV’s were a reality then the next Capture of the same signal would show at least a trace.

Picture is large please RIGHT CLICK and select VIEW IMAGE to see all. Don’t forget to to click Go Back on your browser after, we don’t want to lose you.

It will be of interest to some knowing my love of the IC706 that the Capture showing no false image if from my IC706. The signal level is lower being from a vertical antenna.

The Capture with the inter-modulation product is from my FT897. The signal level is much greater being from my 4 element beam.

I have however today made a Capture of my IC706 putting out a typical double sided spike on transmit so the love hate relationship is still going strong.

Oh and who hasn’t heard their IC706 screeching and scrawbling (technical term) after the tones from the WSPR Software stop and before the PTT drops. Oh sorry, most Hams, because they don’t ever listen to their own signal.
In the top capture at 10:30 can be seen a full 2 minutes of scrawbling, I saw this for several transmission and wondered if it was due to me turning my beam so causing overload of the FT897 when the IC706 transmitted.
No the IC706 was no longer outputting a signal, why, well I had set the TX tone in WSPRX to 1573Hz to move up the band. For some reason after a time the setting had reset itself not to 1500Hz but to 2 Hz. A similar situation to no audio but PTT pressed.
I don’t think there was much RF radiated but if you heard scrawbling, blame Icom and JT it weren’t me Mr.

Six Meters WSPR Aircraft Reflections

This morning I Spotted M0YOU on 6m WSPR, nothing outstanding about that. However I often lurk on 6m and 2m to look for anomalous Doppler reflections from Aircraft. Interpretation of what is seen is an interesting side to Amateur Radio.
Accurate interpretations are essential rather than producing outlandish theory to try and fit some false science.

Here is a Grab of the signal from M0YOU.

Note the 3 curves LF of the signal. I think these are double reflected signal from Airliners of the reflection from a Piper PA34-220T Seneca a private plane out of Oxford.
This morning I e-mailed a local station to ask if he was going to be about for some observations on 2m WSPR as no doubt there would be some Glider activity today. He must be out as he didn’t reply or his XYL wouldn’t let him come out to play.

I had just checked before the above Grab for Glider activity and noted several around Bedford. I looked at the path to M0YOU on WSPR.net

Here is the signal path.

Those Bedford Gliders can’t be responsible unless they have moved, they hadn’t. So was there another Glider on the path. No, but there was the Piper OXF43 he has been on a joyride to Kettering returning via Wellingborough and Milton Keynes. From there he heads South East and then pops up to do 3 circuits of Cranfield.

Here is the situation after the event.

In the signal Grab we see him on the South West turn of one of the 2 full circuits circuits which have a long side of approximately 10Km.
Taking a typical maneuvering speed for the Piper, during the capture we see him cross the signal path make the turn cross again and fly up the Eastern side a total of some 7Km.
Some will say that this defies ‘gravity’ as far as Doppler is concerned but it is not that simple.

Ham Radio Ten Years Ago

I very rarely update my Website now, Blogging has taken over. Whilst updating some meta tags my TT site came up with a typo on METEOR, Its in the html Title text obviously I might correct it one day.

On that page at least Ten years ago I wrote this.

The Hobby has been downgraded by the repeater user only brigade.

I am an odd ball, there now you have it in writing. I am not very interested in operation via repeaters. Yet I built circuitry for the first repeater, GB3NH in town. I have been actively involved in tests on various other repeater projects and ongoing tests. As a technical project per se, fine, but their usage is rarely within the original concept of their purpose.

It saddens me to see new and old operators who’s sole achievement on V.H.F. is to get a poor signal into the local V.H.F. or U.H.F. repeater, and there be daily battered by the antics of the low ignorami scum who lurk upon it. Only to declare that “Amateur Radio has gone down hill”.

When I first came on 2 meters my locals were in the next two adjacent counties. Yes we chatted in our lunch hours , using home made or modified P.M.R. A.M. rigs and no more than 10 Watts. I carried an 8 ele beam in the car and a 4 section mast which I slipped up before the lunchbox came out. A regular net member was in Nottingham (only 95Km away).

Down hill, I should say so. Now locals abound, pay fortunes for their rigs and put a scratchy signal into a well sited repeater at 2Km. What do they have to talk about, well, how much they spent on the radio, and who puts their antenna plugs on for them.

Hmm looks like that was prior to the “come round and break your windows” AND DEATH THREATS on the local repeater. Down hill needs replacing with to the dogs.

Also on the same page I had an appeal to Hams to contact me for AS tests.

There is much talk about Aircraft Scatter working. G3PPT has developed SlowfeldXPAS to utilise this. I have tried the Slowfeld on H.F. and the mode works well. As yet no VHF signals have been heard. Sked times and frequencies are needed from suitably equipped and sited stations.

6m,2m,70cm,23cm SSB,SSTV,PSK,WSJT Skeds drop me an e-mail please. If you cannot hear stations in Northampton but you can see the North South UK air corridor I would like to try Aircraft Reflection skeds on 2m SlowFeld. I can see the aircraft reflections on the Angus beacon GM3ANG.

I did some Slowfeld with a Dutch station. I have learned the ropes of HF, VHF and UHF Aircraft Scatter, but never was I contacted due to the above plea.

2m VHF Aircraft Reflections NOT WTV’s but an interesting Capture

In my last post I promised something interesting NOT WTV’s that we were looking at. Below is the 2 by 2minute windows from the start of the WSPR capture.

I have carefully placed Yellow dots on the Doppler trace of an aircraft which approaches the TX and RX stations from the rear, East, at roughly 90 degrees, it can be seen that it turns upon reaching the stations, something that will happen often if the two stations are close to and in line with an Airport.
The aircraft then I believe lands in around 2 minutes, in this time it could travel 5Km or more depending when it throttles back.

Seen in Light Blue dots going downwards is an AGC induced image of the approach trace, it is a signal that didn’t exist it was caused in the Receiver. Likewise in Light Blue there is an image above the signal path, also a false Receiver induced image of the turning aircraft.

Now for something interesting, I have highlighted in Light Purple dots two curves above and below the center line. These are spaced at approx. + and – 75 to 80 Hz from the center line. This confirms the conjecture of a light propeller aircraft. As the aircraft is at its closest to the two stations it starts its turn so presenting its propeller in an ideal position to reflect the 2m signal.

Can this effect be demonstrated. Yes thanks to G3PLX I have the means to generate a simulation of a 144 MHz 1.5KHz modulated signal being reflected by a propeller of the proportions of a typical light aircraft at a typical rotation speed.

Below is the simulator output. Peaks of reflected signal can be seen at the appropriate spacing. There are multiple possible variables for propeller speed and size which conform to the 75 to 80 Hz spacing.

As mentioned before G3PLX has been a great help whilst analysing the possibilities of correct interpretation of the traces, its great to have someone who understands to discuss the theories with.
These stations are obviously ideally sited for some serious study aircraft reflections.

VHF 2m Aircraft Wing Tip Vortex Reflections No Evidence

I have once again put the theory of Aircraft Wing Tip Vortex Vectors to bed.

The latest claim showed no such phenomena at first glance, but did raise some more queries with me.

1)Despite vehement claims that it is not due to AGC action, can it be shown that it is the cause.

2)Can observed spikes from PLL’s in the TX or RX cause any odd phenomena.

I have made observations, conducted tests and conferred with other knowledgeable persons on the subject.
My final conclusion is still the same, WTV’s do not exist.

Here is one more analysis of the last claim with annotation.

RIGHT CLICK and select VIEW IMAGE to view full size.

The WSPR signal trace is 100% duty cycle. The approximate path of Flight 474 taken from the information provide is shown in Khaki Green. The TX station is shown by the Red/Green circle, the RX station by the Blue/Yellow circle.

My final conclusions are :-

a) Flight 474 has little if anything to do with the observed traces claimed to be WTV’s.

b) The Mauve arrow indicates the path of an aircraft to the North of both stations which crosses from approx. East to West or West to East and turns North. AGC action causes mixing creating an image of the path, below the main trace, ending near the point of the arrow. During the turn there is something else of interest which we are holding judgment on awaiting evidence, NOT WTV’s.

c) Indicated by the Red arrow the same aircraft (a propeller plane most likely) heads away from both stations and most likely lands, 11 minutes before Flight 474.#
Because the Doppler shift produces a near zero beat signal, the RX ACG starts to pulsate causing mixing, the upper part of the C shape trace is a result of this mixing. Flight 474 is heading toward both stations at this time.

d) Indicated by the Green arrow another aircraft heads away from both stations, we may also be seeing it faintly approaching from the East. Flight 474 fits the criteria now. Although I think it is in fact another plane which then lands 5 minutes before flight 474, or less likely takes off and rapidly goes out of range. The reflected signal sets the ACG pulsating producing the upper part of the C shaped trace by mixing action.

e) Indicated by the Blue arrow an aircraft approaches both stations and goes out of range after crossing the signal path, the signal is within the ‘beat zone’ of the AGC action and sets the AGC pulsating causing mixing and producing the lower part of the > shaped trace. Flight 474 is heading away from both stations at this time.

# My thanks go to Peter Martinez G3PLX for pointing out the true happenings here, I miss read one part of the trace. I listened to the originator, didn’t look close enough and didn’t apply enough scientific reasoning .

VHF 2m WSPR Wing Tip Vortex Reflections WTV’s

I have still not managed to provide a reproduce-able 2m WSPR wing tip vortex vector demonstration of the X type. I stand by my theory that they are related to PLL Spikes, overload due to high power TX’s and station proximity, RX AGC, plus inter-modulation distortion in the receivers.

I have seen X’s with plainly no aircraft involvement and half X’s at the start of transmissions. Below I have pasted, at the same scale, some overload from a high power local station prior to the WSPR capture, used for another WTV claim. The similarity is enough to cause some serious concern.

RIGHT CLICK and select VIEW IMAGE for full picture.

When the K1JT WSPR software shows +12dB signals you are overdoing things and you are going to be peering at the Spikes on the TX and the anomalies in the RX due to overload.

In the example above there remains an un raised question. Where is the reflection from the body of the Aircraft which would be much stronger than the “WTV’s”.
Saturated by the strength of the huge direct signal which clearly has many Spikes to cause the AGC to back off in a cyclic manner is one theory.

Such pulsing of the AGC will produce the ‘mirror’ image of the trace shown above. Examined carefully there is a blob visible on the curve s which is repeated in the image signal.

Another strong possibility is that the two signals Direct and Reflected zero beat and thus cause inter-modulation.
Lets take another look at the signal path.

RIGHT CLICK and select VIEW IMAGE for full picture.

The TX station is shown as the red/green circle he is beaming at 90 degrees to the RX station shown blue/yellow (up the page if you wish to visualise) “to avoid overload”. Not a bad idea but if you want to illuminate an Aircraft with your signal and prove WTV’s, which will be extremely weak, beaming away from it is not too wise. The RX station is beaming toward the airport.

The stations are 9Km apart I have taken a landing speed for the aircraft type on flight 474 and placed the stations on the time line. Projecting the time line to the end everything fits the plane hits the runway on schedule.

I have placed blue circles as reference points also 9Km apart. from the left labelled B C D H I.
The khaki green line will be the WSPR signal reflected from the body of the aircraft, positioning may not be exact but within a few Hz it must be near actual. As previously stated it will not be seen due to the vastly overloaded direct signal, red would show overload pink is OTT to the extreme.

Taking a look at the claimed second aircraft and possibly a third The near vertical trace at D I think is a plane not to the West but North or South of both stations, it looks weak but to show in the presence of the swamping direct signal it is strong, could it be flight 474 coming out of its last hold pattern, reflecting some signal from a side lobe on the TX beam, the strongest the reflection gets.
HF and shortly after is what I previously labelled ‘s mirror’ (although its not actually a mirrored image) I think this could be another aircraft or the last bit of flight 474’s maneuvering and what I labelled ‘s’ is in fact the image caused by RX inter-modulation. The image is broader (it obtains WSPR modulation in the mixing) which is the same phenomena that the artifacts in the complete capture have. The C shape at D also has this feature as do the other two claimed X type instances of WTV’s.

Why the last claimed WTV is manifested in the start of the X ie >, a signal starting at 60Hz, the mains hum sideband, and falling to 0Hz, and not the last part ie