gw0nvn
| Joined: | Sat, Apr 4th 1998, 00:00 | Roles: | N/A | Moderates: | N/A |
Latest Topics
| Topic | Created | Posts | Views | Last Activity |
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| Logged Time for SSB SS Contacts | Jun 22nd 2012, 23:29 | 3 | 8,385 | on 26/6/12 |
Latest Posts
| Topic | Author | Posted On |
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| Appraisal of Setup esp. Grounding! | G5UK | on 1/6/20 |
| Hi A quick one. Just had a look on your QRZ page. Have a look through the OFCOM technical documents. They have specifications for grounding of masts and transmitter buildings. ( sorry can't find my copy ) There are the IEE Wiring Regs. Grounding and Bonding for the Radio Amateur ( ArrL ) is useful. The Article " The Killing Fields " by the RSGB explains PME ( Protective Multiple Earthing ) and how not to mix it with RF earthing. Polyphaser have some good documentation. Confederation of Aerial Industries has information Other observations I would not use RG213 for your long antenna run. Due to the high losses and dilectric breakdown especially under high VSWR. eg 28MHz 696 W assuming no mis-matches with 1KW in from your Accom 700S. Looking at the photo of your surge arrester. Your coax connections are not well made or weather proofed. Dampness will ingress into your cables and will ruin them very quickly. Poor connections will introduce mismatches and galvanic noise issues. Check the RF Connectors that you use. Best quality with ptfe dielectric. I've had ( PL259 ) arc with static caused by wind through a dipole. One glowed purple in a car in a lightning storm. I thought it was a cigarette lighter!! Try to make a surge arrester for your Ladder line before it is connected to your outside ATU. The GB2 Marconi Station on the Lizard had an article in PW discribing what they did. Basically a spack gap on each leg to a ground spike. It is worth thinking about the other services coming into your shack. Phone line/internet, data cables, audio feeds. Proper earthing and filtering will minimise noise issues. Also the new OFCOM rf safety audits we now have to do. Same as in the USA. If you are going to be on VHF and UHF using ssb FT8 etc, I would suggest that you also install some Horizontal polarised antennas for those bands. Even omni-directional ones. As I have measured losses of over 20 dB ( 100x ) when measuring field strengths, when using the wrong polarity. I'm renewing my feeder cables. My pipes were full of snails! Best regards 73's Simon GW0NVN N1XIH |
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| Vertical Antenna 160M-10M | donavangaffney | on 21/5/20 |
| Hi, The ARRL website has a number of antenna articals from QST which may be suitable. Also design articals for HF verticals. Have a look at:- http://www.arrl.org/hf-vertical Build this Novice Four Band Vertical https://www.arrl.org/files/file/Technology/tis/info/pdf/7806016.pdf If you wanted to 'remote' the band change switch. I would suggest you use some relays and a multi-core cable back to a multi-way switch in the Shack. If you wan't hi tech, a micro controller and a wifi link. Or better and simpler is 'A Multiband Groundplane Vertical Antenna with tuned Feeders by K4TP from QST. This is a simple vertical with radials fed with 450 Ohm Ladder Line balanced feeder to the shack. The balanced feeder is connected to a Balun and then to the Auto ATU of the transceiver. The length of the vertical isn't critical. They used 16ft 5ins (5m) for operation from 40m -10m. I use this arrangement for doing IOTA portable. I use 33ft (10m ) for operation on 80m - 10m. Make the radials the same length. My vertical is on the shore edge, with the radials over the sea. By mounting it on a post, a few feet off the ground, it is easy to connect the radials, the ladderline and make measurements. It has low loss with high VSWR on the feeder. The materials are easily and cheaply obtainable from Hardware Stores. The inductors and capacitors you can make or purchase off the Internet. The good thing is that you can use materials to suit your local conditions. Extra guying as you see fit. You could even make you own ladderline. Bring the ladderline from the antenna back to the shack. It should not be lying on the ground and no right angle bends. You will need a balanced to un-balanced transformer ( Balun ) to connect to the unbalanced antenna connector on your transceiver. Again the ARRL website has articles on building ladderline and Baluns. If you want a commercial antenna, a Butternut HF9V at 25ft is a good multiband antenna. I would ask the suppliers about the guying arrangements and survivability at you location. The choice of antenna and feeder will depend on what you want to do. Is it for local working, DX or to a specific target area? I would suggest you do some reseach on the properties of hf antennas and Hf propagation. So that you choice the best antenna for your use. All the articles I have suggested appear in the ARRL Antenna Anthology by WB1FSB. A collection of articles from QST. It is an old book and will be available secondhand on the internet. The articles are separately on the website. Whatever antenna you build, record any measurements and observations. So that you can diagnose any future issues, or compare with another antenna. If you can, Use a Field Strength Meter close to the antenna to show how well it is radiating. Also use an online SDR to both give you a signal report and a recording of your modulation. A poorly performing transceiver with a good efficient feeder and antenna system will perform much better than a 'State or the Art' working transceiver with a poor in-efficient feeder and antenna system. best regards 73's Simon GW0NVN N1XIH |
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| 160 meters | SIZE358 | on 7/2/16 |
| Hi, I'm assuming by 'skywire' you mean a horizontal loop. The thing to think about is the height of the horizontal Loop above the ground. At 1/4 wavelength (20m 67ft ), or less above the ground much of the radiation will NVIS. Good for local contacts ( few 100 Km/miles ) It will need to be at least 1/2 wavelength (40m 132 Ft ) for DX contacts. At such a low height there will be losses both due to the wire resistance and ground losses. Just to check, I Googled 2 wavelength Loops and was directed to eham.net. where some amateurs who have built 2 or more wavelength loops for 160m told of their own experiences. I use a 40m loop at 12m ( more than a 1/4wavelength) and get good reports for local signals on 40m. When I used an inverted L of 33m (103ft) I get much better DX reports but not so good local. If you can, try computer modelling the antenna. It should give you some ideas. Also have a look at www.n1su.com best 73's GW0NVN/N1XIH |
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| SS Contest Stratgy | W9FY | on 9/11/13 |
| Dear Olaf, I'm just sorting out my planing for the SSB Sweepstakes and came across your question on the forum. Try the Austrialian Government Website. http://www.ips.gov.au/ This has tools for making real time predictions for HF comunication. I have just used the Combined HF Prediction Tool for the HF Amateur bands in your area for throughout today. Even for me the site is fairly straight forward to use and has much information on it. But here is how I used it. 1) from the home page click on 'HF Systems' 2)Then under 'Online Tools' click on 'Prediction Tools' 3) Click on ' Combined HF Prediction' A Java aplet will start to run. Make sure that it is allowed to run. Also any 'pop ups' 4) Click on the 'HAP' button and the World map will appear. 5)Put in the Map location by one of three ways. Move your mouse to the location and 'Left Click'. Fill in the Lat and Long boxes. Or click on the 'Base Location' tab and type in/sellect the City from the list. Chicago and Boston are in it. 6) Click on the 'Frequencies' tab. 7) Click on the 'Amateur' tab 8) Click on the 'Date and T-Index' tab and select 'Northern Hemisphere' in the 'Current real-time T- Index section' button. 9) Click on the 'Predict' button. You will then be instructed to 'define the area' This is done using the Left Click of the mouse to form a box. 10) Click on the Predict' button and then a new web page will appear with four sets of prediction maps. Make sure 'pop ups' are allowed. As far as suitable antennas are concerned. There is much infomation on the ARRL website. Including an article for Sweepstakes in 'The Doctors In' I myself use an inverted V antenna at about 45ft. It is quite long ( 500ft) and so has many lobes on the 15m/10m bands. With propagation moving throughout the day. It can act like a 'search light' for my QRP signal to various areas of the USA. Helping me a little more, when there are large signals all around. The ARRL website also has an article on the design of a 10m/15m/20m two element wire beam antenna for the Sweepstakes. Hopefully I will have mine completed before next weekend. A few days ago I had a very low, at10ft, inverted V dipole as an antenna here in Europe and managed to work VE3, VE5, 9X, ZS, GI on 10m with 5 W. So there will always some close in signals getting through. The contest is great for learning about local propagation. I know for my location during the short time the Greyline moves accoss my location I will get very good propagation on 20m,15m,10m up to WA, NT and AK. Before they disappear and I get great coverage to Australia and New Zealand. Last year 40m went long much earlier than I thought so I couldn't work stations which I would normally 300 mls away. Look forward to working you in the contest Simon GW0NVN |
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| Overseas Membership Fees, no longer such a bargain. | G0KZZ | on 28/7/12 |
| A bit 'tongue in cheek' But many years ago I paid for life membership at Dayton which is very easy for the ARRL. At the same time I paid the same for the RSGB. Which was very difficult. One of the best things I did. The only annoying thing was that I did not realise (Its not published by RSGB or ARRL ) is that the the fees are tax deductable in the United Kingdom. However the inability to download QST to a phone due to its new digital format is a real pain. I use the pdf versions up to 2012 all the time now. Please don't use a proprietry DRM. Logging into your website and downloading QST is easy and can be used on most devices. Is there a lifetime subscription to QEX? Maybe send out the anual CD with the Christmas edition of QST. there's one in each handbook and many other books All the very best GW0NVN N1XIH |
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