Date
1 - 17 of 17
Locked Q65 in less favourable condx? #Q65
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johnsherry57 <Glecarron57@...>
Hi folks
Some advice please. At present I am working Q65a 30 seconds from Scotland GM into mainland Europe. Running a home brew 2 ele and 80 watts. Using the ON4KST chatroom I know guys are listening for me but not hearing me. I understand conditions play a part but has anyone had success in marginal conditions by changing mode or time? I am perhaps trying to work stations about 600 of more miles away early mid afternoon. Many thanks John GM0AZC |
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Derek Brown
Hi John What band are you TX ing on, I will beam north and take a look see. Derek G8ECI JO03ai.
On Friday, 16 April 2021, 14:32:24 BST, johnsherry57 <glecarron57@...> wrote:
Hi folks Some advice please. At present I am working Q65a 30 seconds from Scotland GM into mainland Europe. Running a home brew 2 ele and 80 watts. Using the ON4KST chatroom I know guys are listening for me but not hearing me. I understand conditions play a part but has anyone had success in marginal conditions by changing mode or time? I am perhaps trying to work stations about 600 of more miles away early mid afternoon. Many thanks John GM0AZC |
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johnsherry57 <Glecarron57@...>
Hi Derek six metres 50.305 Thanks
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Hasan Schiers N0AN
John, I can't speak for Europe, but after running well over 150 hours of testing on 6 meters, this it what we have concluded: 1. Q65 30B is better than 30A, by a significant margin. Our tests show 100w to 5 EL Yagis on each end will yield > 700 miles reliably. These would be called 'well equipped stations' 2. Low power 6m : use 120E, it is amazing. I am able to consistently work 670 miles with the distant station running less than 10w output, and I am running about 25w out because of his high noise. I also work two different stations who are running 75w at distances of 800+ miles quite easily. 3. Q65 30A is not as effective, but 100w to 5 EL yagis will work with some effort at 600 to 800 miles. Anything other than Q65-30A on the standard (whatever it might be) European 6m frequency, is likely to require a schedule. Also, we have found the best time of the day to be pre-dawn thru about 9 a.m. local time. Q65 is very effective for ANY mode of propagation. It makes use of and takes advantage of: 1. Ionoscatter 2. Meteor Scatter 3. Sporadic E 4. Ground Wave 5. Troposcatter 6. Tropo ducting. 7. Airplane Scatter This is why (our theory) Q65 30A, 30B and 120E work so well in the early morning hours...it takes advantage of 1,2, 4, 5 and 6 modes listed above, all at the same time, if they are available. While ionoscatter peaks at noon, mid-path, we have found that due to the eclectic rx capabilities of Q65, in the face of various propagation conditions, that the early morning hours have a significant advantage. KB7IJ, NM3G, K5GZR and WB4HIE and I have been testing on 6 meters for several months using Q65 30A/30B/120E for at least two hours every morning. The method of evaluation is to establish contact , then begin reducing power until decodes are missed and averaging begins. IA rough estimate: Power listed is their transmit power KB7IJ 7 EL @ 50' Hardline, 666 miles, Mode 30B: 15 watts, Mode 120E 5 watts or less Both cases I get > 80% decodes, mostly in the 90% range K5GZR 5 EL @ 50', 863 miles Mode 30B 100w, Mode 120E 25w WB4HIE 5 El ..., 800 miles Mode 30B, 100w, difficult at times, 30% decodes Mode 120E, 100w, > 90% decodes. (Mountain obstructions) This should give a feel for what to expect from Q65 on 6 meters. If you do not see these kinds of results: 1. You have high local noise, or your partner does. 2. Your rx system is inadequate, or your partner's is. As Joe has stated 'well equipped stations', should have no problem consistently working nearly 1000 miles. 100w to 3 EL yagis with low loss coax should permit 600 miles easily and 1000 with some patience on 6 meters. 73, N0AN Hasan
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Hi Hasan and John,
another factor is that here in the UK
we a a couple of grid fields higher in latiitude, that may have a
significant impact on ionospheric modes like iono-scatter. Long
term tests need to be done. There is anecdotal evidence that
iono-scatter on 2m is considerably better in the Summer months,
that may be due to longer periods per day of exposure to direct
Solar effects and possibly lower effective latitude with respect
to the Sun.
73
Bill G4WJS. On 16/04/2021 23:57, Hasan Schiers N0AN
wrote:
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Jim Brown
On 4/16/2021 3:57 PM, Hasan Schiers N0AN wrote:
This should give a feel for what to expect from Q65 on 6 meters. If you do not see these kinds of results:This is VERY common. Most of us are surrounded by noise sources that boost our noise level 10-15 dB above atmospheric noise. If you're lucky, and if you've made a serious effort chase down and kill those sources in your own home (the typical home has at least a couple dozen of them) those numbers are 3-6 dB. 2. Your rx system is inadequate, or your partner's is.There is tendency among hams to think only about making their signal louder, with little attention to hearing better. The principle virtue of antenna directivity, pattern control, and putting a great choke at the feedpoint is NOT making us louder, but rather letting us HEAR better! http://k9yc.com/KillingReceiveNoise.pdf 73, Jim K9YC |
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johnsherry57 <Glecarron57@...>
Many thanks to all for feedback and information. John GM0AZC On Sat, 17 Apr 2021, 05:44 Jim Brown, <k9yc@...> wrote: On 4/16/2021 3:57 PM, Hasan Schiers N0AN wrote: |
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M0PWX
On 4/16/2021 3:57 PM, Hasan Schiers N0AN wrote: 100% agree When I talk to some local amateurs they say I am wasting money on low loss coax for HF operation, My answer is losses in coax work both ways, TX AND RX, and with a 25m coax run I can lose half or more of my recieved signals if I use RG58 like them They will spend hundreds of pounds on antenna’s then lose all the gains of the antenna by penny pinching to save less than 10 pounds on the coax run I started HF as a M7 / foundation license holder only able to use 10 watts max, so every watt I can get to the antenna helped, the benefit of the low loss for QRP is then transferred to low loss for received signals, something those with higher power licenses seem to forget The other benefit of low loss coax is poor swr is not masked by the coax losses, so you likely have a better tuned and more efficient antenna as well Peter M0PWX
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Buddy Morgan
All these guys that want to install a mast mounted preamp. I ask them, "Is there a reason you can't run larger cable?" Most of the time the answer is no. Then I ask,"Have you considered the cost of larger cable vs a preamp?" The answer is always no. Mast mounted preamps are more troublesome than Heliax. With Heliax, you gain, on receive and transmit. I have been a ham, for over 50 years and have not used a mast mounted preamp, yet.
Buddy WB4OMG
-----Original Message-----
From: M0PWX <M0PWX@...> To: main@WSJTX.groups.io <main@WSJTX.groups.io> Sent: Sat, Apr 17, 2021 10:00 am Subject: Re: [WSJTX] Q65 in less favourable condx? #Q65 My answer is losses in coax work both ways, TX
AND RX,
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Jim Brown
On 4/17/2021 7:23 AM, Buddy Morgan via groups.io wrote:
All these guys that want to install a mast mounted preamp. I ask them, "Is there a reason you can't run larger cable?" Most of the time the answer is no. Then I ask,"Have you considered the cost of larger cable vs a preamp?"Certainly big coax (or hard line) is a great ideal. But at VHF/UHF, the loss even in that big coax can be a dB or two in a long feedline. THAT'S why serious weak-signal ops use mast-mounted preamps. 73, Jim K9YC |
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Alan G4ZFQ
the benefit of the low loss for QRP is then transferred to low loss for received signalsPeter This depends on the band and sensitivity of the receiver. With transmit antennas on HF many receivers are more sensitive than required and an attenuator may be used. As others have said for VHF a preamp gives best results. With QRP TX it depends whether you want to transmit a particular low power or whether you want to transmit the maximum a TX will provide. The best low loss is an ideal, practically several runs of cheaper coax may be more versatile. 73 Alan G4ZFQ |
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The best of all would be a SHORT run of low loss coax and a mast mounted preamp. But that costs $$$ and we are hams! At VHF and UHF a low noise figure preamp is the way to go. At HF, more of a waste of time due to ambient noise.
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Art, N2KA.. On Apr 17, 2021, at 3:01 PM, Alan G4ZFQ <alan4alan@...> wrote: |
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Lance Collister, W7GJ <w7gj@...>
On 6m EME, almost everyone uses a low noise external preamplfier in the shack and low loss feedline to the antenna. As long as the feedline loss is under 1 dB, it seems to make no difference where you have the preamp on 6m. And at 50 MHz, it is not that difficult to find good coax so that the feedline loss is under 1 dB. Many of us use use Heliax up the tower with an LMR600 Ultra Flex jumper around the rotor. Most of the activity on 6m EME now is on the new Q65 mode in WSJT-X 2.4.0.
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GL and VY 73, Lance On 4/18/2021 00:38:02, Arthur Bernstein via groups.io wrote:
The best of all would be a SHORT run of low loss coax and a mast mounted preamp. But that costs $$$ and we are hams! At VHF and UHF a low noise figure preamp is the way to go. At HF, more of a waste of time due to ambient noise. --
Lance Collister, W7GJ(ex WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX, 3D2LR, 5W0GJ, E6M, TX5K, KH8/W7GJ, V6M, T8GJ, VK9CGJ, VK9XGJ, C21GJ, CP1GJ, S79GJ, TX7MB) P.O. Box 73 Frenchtown, MT 59834-0073 USA TEL: (406) 626-5728 QTH: DN27ub URL: http://www.bigskyspaces.com/w7gj Skype: lanceW7GJ 2m DXCC #11 - 6m DXCC #815 - FFMA #7 Interested in 6m EME? Ask me about subscribing to the new Magic Band EME email group, or just fill in the request box at the bottom of my web page (above)! |
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In November of last year, as part of our earliest tests of the new mode Q65, K9AN (Steve Franke) and I made extensive tests of submodes Q65-15A, Q65-30A and B, and Q65-60A and B. These tests led us to recommend Q65-30A for making scatter QSOs on 6 meters.
Recently several have raised questions on which Q65 submodes are most effective for scatter on 50 MHz. For general interest, then, I offer the following explanation and summary of our early test results. Scatter signals are so highly variable that the only way to make statistically reliable quantitative comparisons of different sumodes is to transmit and receive them simultaneously. Of course, you can't do this with standard WSJT-X. So I wrote a special version that transmitted an audio waveform equal to the sum of those for the A submode at TxFreq=1000 Hz and the B submode at 1500 Hz. The summed waveforms do not have a constant envelope, so we made sure to keep the audio drive levels low enough that our amplifiers maintained good linearity. The path from K1JT to K9AN is 1148 km, essentially East-West. We did a 4-hour test on November 12, 2020, as follows. Local noon at mid-path is around 1730 UTC. UTC Submodes -------------------- 1600-1700 30A+30B 1700-1800 60A+60B 1800-1900 30A+30B 1900-2000 60A+60B Both stations use a single Yagi (5 el at K9AN, 7 el at K1JT), and we ran at 400 W average power output (800 W PEP). This means equivalent 200 W signals in the A submode and 200 W in the B submode. We ran with "Save all" enabled, so after the fact we could decode the two modes separately and count their successful decodes. When decoding we could intentionally degrade the recordings by specified numbers of dB, to see how similar stations using less Tx power would have fared in the same conditions. We ran the decoding tests with Enable averaging and Auto Clear Avg after decode enabled. Here are the test results as summary tables showing the Number of decodes per hour for each submode and each sequence length. The column labeled "Pwr" shows the equivalent transmitted power levels after the specified SNR degradation is applied. K9AN Received at K1JT
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dB Pwr 30A 30B 60A 60B
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0 200 57 58 28 29
-5 63 41 48 19 23
-10 20 22 24 12 15
-15 6 12 12 5 6
-20 2 5 7 1 1
-------------------------------
K1JT Received at K9AN
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dB Pwr 30A 30B 60A 60B
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0 200 57 59 29 30
-5 63 43 51 19 26
-10 20 25 33 12 19
-15 6 14 16 6 9
-20 2 4 5 2 2
-------------------------------
We draw the following summary conclusions: 1. Even at the lowest usable SNRs, 30-second submodes produce twice as many decodes per hour as 60-second submodes, 2. Q65-30B (bandwidth B=433 Hz) produces 12% more decodes per hour than 30A (B=217 Hz). 3. Considering bandwidth requirements and the advantage of permitting many non-overlapping signals in a 3 kHz spectral slice, we conclude that Q65-30A should be the preferred submode for general use in a channel designated as the 50 MHz scatter meeting-place. 4. Other tests have shown us that longer and wider submodes such as Q65-60C or even Q65-120E are also usable for 6m scatter work, and can possibly be attractive alternatives for completion of QSOs in QRP or compromise-antenna situations. However, the large bandwidths and long times to complete a QSO in these submodes will probably limit their use to scheduled or specially-arranged QSOs. -- 73, Joe, K1JT |
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Jim Brown
On 4/18/2021 9:08 AM, Joe wrote:
Scatter signals are so highly variable that the only way to make statistically reliable quantitative comparisons of different sumodes is to transmit and receive them simultaneously.Very interesting. Given the highly variable nature of propagation and the different modes of which we try to take advantage, it would be interesting to see this sort of work repeated on multiple days and at different times of day. 73, Jim K9YC |
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Joe Dz
Thank you Joe for the data and Jim also makes a very good comment. When I
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was looking at how weather storm systems affect transatlantic 6m communications, and also during the winter months when we have the second Es season, Es formed over storm systems and fast moving jet stream fronts. However, a geomagnetic storm (G1 or K5 or better) would negate the effect. It would be very interesting to see as people collect data, that they also record what the geomagnetic field was doing at the time. The question being: does an unsettled or stormy geomagnetic field also negate the ionosphere scatter like it negates the weather effects that would normally cause Es over storm systems or fronts? If folks also record the K value as well on multiple day tests, that data would be very interesting. Joe, K1YOW -----Original Message-----
From: main@WSJTX.groups.io [mailto:main@WSJTX.groups.io] On Behalf Of Jim Brown Sent: Sunday, April 18, 2021 3:24 PM To: main@WSJTX.groups.io Subject: Re: [WSJTX] Q65 in less favourable condx? #Q65 On 4/18/2021 9:08 AM, Joe wrote: Scatter signals are so highly variable that the only way to makeVery interesting. Given the highly variable nature of propagation and the different modes of which we try to take advantage, it would be interesting to see this sort of work repeated on multiple days and at different times of day. 73, Jim K9YC |
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Hi Jim and all, Probably it will not surprise you that we've done some of this, especially with respect to time of day. It's very easy to show that ionoscatter conditions are best around mid-day and worst around 7 or 8 PM local time.Scatter signals are so highly variable that the only way to makeVery interesting. Given the highly variable nature of propagation and But we decided not to spend time on more extensive tests with respect to time of year, but rather to spend some time in a good research library. Steve and I have access to excellent ones at the University of Illinois and Princeton University, respectively. D-Region ionospheric scattering at VHF was studied exhaustively in the late 1950s. An excellent summary of such studies carried out by the Central Radio Propagation Laboratory of the US National Bureau of Standards was published in 1961, and I've posted a copy here: https://physics.princeton.edu/pulsar/k1jt/NBS_D-region_scatter.pdf. For a summary of diurnal, seasonal, and frequency dependence of signal strengths see their Figure 6. -- 73, Joe, K1JT |
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