As an experiment, I have reduced my TX so that the FT817 ALC is now barely moving. This is a bit lower than the usual setting. TX power as indicated on the FT817's meter is unchanged.
I'll monitor to see if reciprocity. is affected. I suspect not. The ALC was set at a lower setting at 1038z.
21 Jun 2014
40m WSPR overnight
As you will recall, my antenna on 40m is very low and not that efficient: it is just a 10/20/40m Par end-fed with an average height above ground of 4-5m at most. Last night I was on 2W. I hate to think how low the ERP would have been on 40m!
Overnight 17 unique stations spotted me with best DX AE2EA (5654km). Even with a low and inefficient 40m antenna, WSPR still works well!
Overnight 17 unique stations spotted me with best DX AE2EA (5654km). Even with a low and inefficient 40m antenna, WSPR still works well!
 |
| 40m unique spots of my 2W WSPR last night |
6m - local, GDX and Es all in one transmission
The 0912 1W ERP 6m WSPR transmission today resulted in G4IKZ (18km), G0OQK (98km) and CN8LI (2113km) spotting me all in one transmission, A very good start on 6m after QSYing up from 40m overnight where the best report was from an AE2 on the east coast USA.
So far CN8LI has been seen twice and he has seen me three times. A promising start on 6m Es today,especially as it is very early still.
Sunspot count today is "only" 75 with 20-30MHz conditions described as "normal" so a reasonable chance of F2-layer DX on 10m.
UPDATE 0958z: G0LRD (25km) and G4FFC (45km) both spotting me too.
UPDATE 1025z: CN8LI seems to have a "pipe" to me: he is spotting me multiple times now remarkably strongly. Is this really Es? I know Es signals can be very strong and consistent but when propagation is there it is so good. It behaves almost more like a duct than a pure reflection.
So far CN8LI has been seen twice and he has seen me three times. A promising start on 6m Es today,especially as it is very early still.
Sunspot count today is "only" 75 with 20-30MHz conditions described as "normal" so a reasonable chance of F2-layer DX on 10m.
UPDATE 0958z: G0LRD (25km) and G4FFC (45km) both spotting me too.
UPDATE 1025z: CN8LI seems to have a "pipe" to me: he is spotting me multiple times now remarkably strongly. Is this really Es? I know Es signals can be very strong and consistent but when propagation is there it is so good. It behaves almost more like a duct than a pure reflection.
20 Jun 2014
WSPR non-reciprosity?
Sometimes my software give some stations on WSPR quite decent reports as the signal decodes well. In these situations I am surprised not to be decoded myself as, even allowing for power difference, I should still be well above -30dB S/N. The reasons could be many:
- The other station is just on TX only
- The other station has a very high noise floor
- The other station has a deaf RX.
6m GDX - there if stations are active
Today there have been a good number of G stations active on 6m WSPR allowing a really good opportunity to explore GDX paths out to 134km. It seems that if stations are active out to close to 200km (and probably further) then even a few watts of WSPR (polarisation probably unimportant?) will be decoded at the far end of the path eventually, depending on aircraft reflections and favorable Doppler.
This probably means JT65 or JT9 ranges on 6m probably extend to around 200km at least if the stations know the most favourable alignment of aircraft. The same probably applies on 10m, 4m and 2m ,as well as 70cms and microwave bands.
What I'm not (yet) clear about is the normal tropo range without aircraft reflections. For true tropo, polarisation is more likely to be important: one does not want to throw away valuable dBs with cross-polarisation losses. I don't think this matters where signals are randomly scattered off aircraft bodies.
This probably means JT65 or JT9 ranges on 6m probably extend to around 200km at least if the stations know the most favourable alignment of aircraft. The same probably applies on 10m, 4m and 2m ,as well as 70cms and microwave bands.
What I'm not (yet) clear about is the normal tropo range without aircraft reflections. For true tropo, polarisation is more likely to be important: one does not want to throw away valuable dBs with cross-polarisation losses. I don't think this matters where signals are randomly scattered off aircraft bodies.
Lightning damage risk
I am always nervous about lightning strikes.
The excellent Southgate News today told the (true) story of a local CBer who had his vertical and CB rig destroyed by lightning. See http://www.huntspost.co.uk/news/latest-news/
huntingdon_cb_radio_user_almost_electrocuted_after_lightning_
bolt_strikes_aerial_1_3648368http://www.huntspost.co.uk/news/latest-news/
huntingdon_cb_radio_user_almost_electrocuted_after_lightning_
bolt_strikes_aerial_1_3648368
I usually disconnect antennas when there is lightning about but I am still nervous. One of my friends (not a radio ham and with no big antennas in the air) who lived in a normal estate home had his home struck years ago and it took out lots of his household wiring. The chances of a direct hit are rare, but I am always bothered and never quite sure what the best advice is.
The excellent Southgate News today told the (true) story of a local CBer who had his vertical and CB rig destroyed by lightning. See http://www.huntspost.co.uk/news/latest-news/
huntingdon_cb_radio_user_almost_electrocuted_after_lightning_
bolt_strikes_aerial_1_3648368http://www.huntspost.co.uk/news/latest-news/
huntingdon_cb_radio_user_almost_electrocuted_after_lightning_
bolt_strikes_aerial_1_3648368
I usually disconnect antennas when there is lightning about but I am still nervous. One of my friends (not a radio ham and with no big antennas in the air) who lived in a normal estate home had his home struck years ago and it took out lots of his household wiring. The chances of a direct hit are rare, but I am always bothered and never quite sure what the best advice is.
Email from space?
Just had an email with this at the end:
"Sent from the ISS ...-.-"
I am assuming this came from the International Space Station (ISS).
If correct, this is a first for me.
"Sent from the ISS ...-.-"
I am assuming this came from the International Space Station (ISS).
If correct, this is a first for me.
6m Es today here on WSPR
This is being written at 1740z and so far today just one 6m Es opening, which was to IW1PAK (1092km) around 1100z today. Spots were exchanged in both directions. No other 6m Es see today at all, but things could change later.
Sunspot count is 108 but 20-30MHz propagation is only "fair". I have not been checking 10m for F2 DX but there would have been a reasonable chance today.
UPDATE 1940z: No further Es seen today, as yet. At this time there are 40 stations active on 6m WSPR including some in the eastern USA. I am always hopeful! This is the highest number so far this DX season.
Sunspot count is 108 but 20-30MHz propagation is only "fair". I have not been checking 10m for F2 DX but there would have been a reasonable chance today.
UPDATE 1940z: No further Es seen today, as yet. At this time there are 40 stations active on 6m WSPR including some in the eastern USA. I am always hopeful! This is the highest number so far this DX season.
6m Doppler
On 6m it is amazing how much Doppler there is on longer distance GDX stations. The screenshot shows just how much Doppler there is on G4BRK's signal today. There were something like 6 aircraft involved at times with WSPR managing to decode when the Doppler is low. On more local signals (e.g. G4FGJ) there is much less (or nil) Doppler. Clearly aircraft reflection plays an important part in long GDX paths. I have no idea where these planes are located.
19 Jun 2014
6m - yet more GDX this evening
Even if Es is not around for me on 6m WSPR, then GDX certainly is.
Just a few moments ago G4BRK (134km) was spotting me at -18dB S/N with low Doppler (1Hz). I seem to regularly get GDX stations in the log, most usually as a result ( I think) of favorable aircraft alignment. If the planes are moving along the path between me and the other station then Doppler is normally too bad and no decodes occur. If the plane crosses the path then Doppler is usually low and there is a better chance of WSPR decoding. Clearly, modes that are sensitive and more Doppler tolerant would mean such long GDX paths would be workable - JT65 or JT9-1 maybe?
There are software packages used by microwave guys that show aircraft movements in relation to paths between stations, allowing one to work out when planes en route would be most favorably aligned to allow a path to be worked. My memory fails me on the package name, but it was mentioned in a blog post earlier this year by G3WKW. UPDATE 1925z Friday: Bob has kindly reminded me of the software (see comment below too) http://www.airscout.eu Airscout.
134km (83.5 miles) is a very decent distance on 6m inter-G with QRP. I wonder if a horizontal halo would be better or worse? If signals are being scattered off aircraft, then polarisation is less important. A halo would probably have less gain than my V2000 vertical 2dbD omni for halo(?) and 0dBD omni for V2000(?). I guess it will also depend on the other station's polarisation. For pure tropo, I suspect a halo would be better to other stations equipped with horizontal beams, but few GDX paths seem to be pure tropo on 6m.
Just now G8DOR (103km) and G8JNJ/A (184km) were spotting me on 6m WSPR.
Just a few moments ago G4BRK (134km) was spotting me at -18dB S/N with low Doppler (1Hz). I seem to regularly get GDX stations in the log, most usually as a result ( I think) of favorable aircraft alignment. If the planes are moving along the path between me and the other station then Doppler is normally too bad and no decodes occur. If the plane crosses the path then Doppler is usually low and there is a better chance of WSPR decoding. Clearly, modes that are sensitive and more Doppler tolerant would mean such long GDX paths would be workable - JT65 or JT9-1 maybe?
There are software packages used by microwave guys that show aircraft movements in relation to paths between stations, allowing one to work out when planes en route would be most favorably aligned to allow a path to be worked. My memory fails me on the package name, but it was mentioned in a blog post earlier this year by G3WKW. UPDATE 1925z Friday: Bob has kindly reminded me of the software (see comment below too) http://www.airscout.eu Airscout.
134km (83.5 miles) is a very decent distance on 6m inter-G with QRP. I wonder if a horizontal halo would be better or worse? If signals are being scattered off aircraft, then polarisation is less important. A halo would probably have less gain than my V2000 vertical 2dbD omni for halo(?) and 0dBD omni for V2000(?). I guess it will also depend on the other station's polarisation. For pure tropo, I suspect a halo would be better to other stations equipped with horizontal beams, but few GDX paths seem to be pure tropo on 6m.
Just now G8DOR (103km) and G8JNJ/A (184km) were spotting me on 6m WSPR.
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