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SAQ Grimeton Alexanderson Day Broadcasts Sunday 4 July




 
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Author Topic: SAQ Grimeton Alexanderson Day Broadcasts Sunday 4 July  (Read 858 times)
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AJ1G
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« on: July 01, 2021, 01:32:39 PM »

SAQ will be back on the air this Sunday with its Alexanderson Day CW broadcasts on 17.2 kHz, here is a link to their website:

https://grimeton.org/alexandersondagen-4-juli-2021/

Schedule for the broadcasts July 4, 2021
Start-up and reconciliation 10:30 CET (08:30 UTC) Message transmission 11:00 CET (09:00 UTC)   Reconciliation = tune up VVVs de SAQ
Start-up and reconciliation 13:30 CET (11:30 UTC) Message transmission 14:00 CET (12:00 UTC)

The early broadcast tuneups start at 0430 EDT over here, around first light.

The second broadcast tuneups start at 0730 EDT 0ver here, well into daylight.

You don't need a very fancy antenna to copy SAQ 0n 17.2 kHz, but you must have location with a very quiet EMI free noise floor.  I have been successful over the last several years copying the transmissions using just the 75 meter Hamstick whip on the Tacoma 4x4 with a Wandell and Goltermann AT-611 Selective Level Meter.  Long wires laid directly on the ground, even if only 65 feet or so also should work, or ferromagnetic loopsticks. When a long wire was deployed behind the Tacoma and connected to the mobile antenna feed point on the left rear corner of the truck in lieu of the Hamstick ,there was significant directivity on VLF, with the highest signal levels with the truck on the head of the axis of the trailing wire.

I successfully copied both of last years July broadcasts, the early one while parked at a small cliff above the ocean at Weekapaug Point RI, and the second one from near the Watch Hill Point RI lighthouse.  Only used the 75 meter Hamstick at those locations.  The limiting factor this time of year will be thunderstorm static of course, which did prevent what otherwise would have been 100 percent solid copy last year.  I copied almost all of their UN Day transmissions this past October from a location about a mile from the home QTH at Barn Island State Boat Launch, which is very quiet EMI wise.  That transmission  occurred well after local noon time here.

A good litmus test on the probability of being able to copy SAQ is if you can copy NPM on Oahu HI on 21.4 kHz with at least a 10 dB SNR, you should be able to hear SAQ, which will likely be somewhat weaker here at least on the US East Coast.
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Chris, AJ1G
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« Reply #1 on: July 01, 2021, 10:03:50 PM »

My biggest challenge was finding a receiver that could tune 17.2 kc, after that, it was antenna matching. Incredibly, an audio transformer worked the best (17.2kc *is* within its design range) and any receiver desensitizing caused by higher frequency RF was eliminated.
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AJ1G
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« Reply #2 on: July 02, 2021, 03:44:26 AM »

Yes Clark, I remember you mentioning it a while back, and tired your approach with an audio transformer a while back, it was quite effective, alomg with some low pass filtering to improve performance of an SDR running on the station iMac desktop at the home station in cleaning up crossmodulation from the local broadcast station on 1230 kHz.  However, the SDR was quite numb at VLF, it was obvious I was hitting its electrical noise floor at that extreme of its frequency coverage.  I was able to improve things quite a bit using     a fixed 20 dB gain wide frequency response preamp in a Ballantine 300G AC voltmeter, which has an upper frequency range of 250 kHz.  I would imagine a good quality audiophile magnetic phonograph cartridge preamp or a stereo system preamp such as the Dynaco PAT-4 would also work.  There must be SDR receivers    that do have good performance at VLF, many of the on-line Kiwi SDRs appear to have very good performance at VLF, and of course can be used if one wants to hear SAQís near 100 year old alternator in operation.  The signal is obviously very strong in European on-line SDRs.

Here is a link to the SAQ on-line video stream from Grimeton, which will go active shortly before the startup for the first transmission on July 4th:

https://youtu.be/ybGdKzwIMss
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Chris, AJ1G
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« Reply #3 on: July 04, 2021, 01:15:05 PM »

Well, no joy copying SAQ here locally at Barn Island CT this time on either broadcast today...very heavy thunderstorm static at -110 to -120 dBm, SAQ was just not cutting through that mustard.  Used a nominal 65 foot wire connected to the mobile antenna base in lieu of a mobile whip, has worked well in past and did give higher level signals relative to the whip this morning on the signals commonly detected at VLF (NPM Oahu 21.4, NAA Cutler Maine 24.0, WWVB Colorado 60.0 kHz).  Did not see any other North American listeners commenting in the SAQ livestream chat. Next SAQ VLF transmissions likely in October.

Hereís a pix of the setup in the Tacoma:
QIX please take note of the Bose Soundlink III used for the audio output from the W &G AT-611.


* E8CD00F8-EEEB-4303-921F-C7903877EDF9.jpeg (3303.83 KB, 4032x3024 - viewed 102 times.)
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Chris, AJ1G
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« Reply #4 on: July 04, 2021, 04:02:32 PM »

Well, no joy copying SAQ here locally at Barn Island CT

By way of comparison do you hear any Euro longwave broadcast stations on that setup?   153kc? 198kc ? etc
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« Reply #5 on: July 04, 2021, 04:06:35 PM »

Hi!

Receiving SAQ at my QTH is not difficult, I have approx 80 miles to the TX site.
So, 15 ft of wire on the floor (in the basement) connected to a RFT EKD500 receiver was more than adequate.

The SAQ station is truly an amazing piece of equipment, to see it in action is something to write home about...

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« Reply #6 on: July 04, 2021, 07:46:04 PM »

Quote from: AJ1G

By way of comparison do you hear any Euro longwave broadcast stations on that setup?   153kc? 198kc ? etc
[/quote

Canít say Iíve heard programming in that part of the spectrum, have heard weak carriers.  The AT-611 does not have a normal AM envelope detector, just a product detector with selectable side bands and two relatively narrow filter bandwidths, 400 Hz and 1.74 kHz.  Not very good for AM reception.
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Chris, AJ1G
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« Reply #7 on: July 04, 2021, 10:00:13 PM »


Canít say Iíve heard programming in that part of the spectrum, have heard weak carriers.  The AT-611 does not have a normal AM envelope detector, just a product detector with selectable side bands and two relatively narrow filter bandwidths, 400 Hz and 1.7 kHz.  
Extra lev


Would have been interesting to know. The 198 kc transmitter is BBC in Droitwich England at 500kw.

A few years back I did manage to catch Radio France Inter on 162 kc on a car radio while parked at the Jersey Shore so these things are possible under the right conditions.
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