Topband: VK3ZL
Hi all..I have been completely overwhelmed with all the best wishes emails and just want to humbly thank you all.. I am in a very critical situation at present..The tumor was discovered last November and I had surgery prior to Christmas to stabilise it and give me time to pick up a bit of strength for major surgery.. Unfortunately the tumor decided to move up to my right kidney effectively blocking it..I had more surgery a week ago to save the kidney and they have put a stent between the kidney and bladder as a temporary fix.. I am extremely unwell and naturally apprehensive about the future but I will do my best..I have to face removal of my bladder, prostate and lymph nodes and I will have an artificial bladder made from a section of small bowel and a stoma for drainage. I am home again for a while and have my radio always listening on 1.824.5 and I will try and get back on air...I can always be found on the ON4 topband chat also.. Once more I thank you all, more than 250 pm's, and Dave WoFLS one of my numerous Topband contacts.. Bob..VK3ZL.. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Anyone purchased the ARRL book on Short Antennas for 160???
I will have to put that book on my wish list..I have been using a short 43 foot high vertical antenna for quite a few years now...It is based on the Minooka design, A spoked Top Hat with a Loading coil just below the Hat..I use another inductor series to ground to resonate the antenna and match into 50 ohms...Bottom coil is 10 turns of 5/8 dia copper tube 1TPI...The Heliax LDF 4/50 is tapped in about 2 turns up from ground and the mast tapped down a couple of turns to resonate the antenna around 1.825mhz..There are around 40 150 foot and random length radials pinned to the ground.. I have used this antenna for many years now very successfully..As I only operate CW the narrow 2-1 vswr points give me about 25khz of operating bandwidth..I have an inverted V on an 85 foot mast and the short vertical is 3-8db better on long haul DX average..I only use the V for receive.. Short verticals work surprisingly well if one puts some thought into it's construction... Bob..VK3ZL.. _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Vacuum variable capacitors.
Steve, you can purchase excellent quality vac variable caps from Dr Alex Gavva UR4LL for a very reasonable price Bob..VK3ZL.. _ Topband Reflector
Topband: 160
Thanks John for the post re 160 meters being open to VK...This year there has been a real lack of activity on the band..I am always in the shack qrv around 1824.5...It is unusual not to have few contacts into the Pacific, US/VE, JA and UA2 during the week..I have noticed an absence of what was the regular operators over the years..Similar in VK where you can count the regulars on one hand... There is no real Season for the band to be Open , more, that summer qrn etc keeps many from operating..This of course is reversed as the North and South seasons change...Sunrise and Sunset times also play a big factor on what paths are likely to be open.. For us diehards the band produces unexpected dx rewards quite often and that is what keeps us there...Others appear on the band briefly only if there is a rare dx entity operating from some remote location..They rarely contribute to the band as regular operators do, rather, they just want that bit of wallpaper.. Anyhow I guess horses for courses.. 73..Bob..VK3ZL.. _ Topband Reflector
Topband: Mile, VK6HD.
I am very sad at the passing of Mike..He was an excellent Topband operator, and an inspiration to all.. Bob..VK3ZL.. All good topband ops know fine whiskey is a daylight beverage. _ Topband Reflector
Topband: GI-46B Revisited..
Thanks for the reply Tom..This subject was supposed to be in the amps@contesting thread...Sorry all..HNY..Bob..VK3ZL.. _ Topband Reflector
Topband: GI-46B Revisited..
Gidday all..I have built around 25 aVHF amplifiers over the past three years using the Russian triodes, GS-35 and 31B tubes as well as GI-6 and 7B tubes..All of these amplifiers are in daily service on 6 and 2 meters and trouble free.. I have looked through all the information on the GI-46B tube and a few things don't add up..A company in Europe uses these tubes in their amplifier product's...I see many retro fits in UTube clips for TL922 and Heathkit amplifiers replacing the 3-500Z and supposed power outputs of 1600 watts.. Just taking the TL922 conversion to GI-46B tubes as an example the tubes are openly mounted with GI-7B coolers in place of the original 46B cooler...The film clip shows the TL922 cooling fan retained blowing against the tubes...I question how are they getting rid of all the heat produced with such a pissy setup..I would have thought the tube should be mounted in a box construction with a good blower and chimneys etc... According to the Russian GI-46B specs the tube is only rated at 350 watts anode dissipation...Most of these conversions will be running at close to 3kv and to produce 1600 watts output even at 50% efficiency a pair of tubes will have to be dissipating a lot more than the tube anode rating.. Obviously the sketchy information for the GI-46B supplied on the Russian spec sheet must be very conservative... I am wondering if there are any members on this reflector have used the GI-46B triode and what the real results are and also the cooling used..I am about to do a 46B 6 and a 2 meter amplifier for a client using these tubes..I am confident that with proper attention to the cooling etc that the amplifiers will turn out ok..It has been suggested that the GI-46B is a substitute for a 3CX800 tube.. Bob..VK3ZL.. _ Topband Reflector
Topband: one- way propagation
Interesting theories and observations regarding one way propagation..My take is that most of the seemingly one way prop is more dependent on operator skill and the local qrn at one end of the circuit..With the current conditions this past 12 months most usually strong signals on the band are often attenuated due to less than a reliable path..I hear many signals that may be only S1-3and few hear a station calling them..These conditions may give the impression of one way prop but it is more likely due to qrn conditions at the listening end...I am looking at this from the VK cross the Equator Summer/Winter differences which have a big influence on making a contact..My observations over 35 years show that there is propagation most of the time all year if stations take the time and patience to listen for DX.. Bob..VK3ZL.. ___ Topband reflector - topband@contesting.com
Topband: Spark Gaps..
Thank you to all the email's received re my use of trailer balls for a spark gap..It is a simple answer to a big problem and it works.. It pays to think outside the box at times when presented with a problem and be a bit innovative.. I also use a trailer ball at the bottom of the 90 foot mast and on my 160 meter vertical antenna...Using triangular mast section I have tapered the three bottom sides of a triangular section and welded a trailer ball on the bottom ...I used a 66kv three skirted Electric supply insulator which has a galvanised metal plate on the top with four 1/2 inch studs about 4 inches longI cut out a 1/2 inch metal plate to fit on top of the insulator mounting plate..I then used a piece of heavy 2 inch tube 3 inches long and welded it to my mounting plate..I reinforced the tubing on four sides with some 1/2 inch plateThis mounting socket is strongI drilled a couple of holes at the bottom of the tube as a water drain and also added a grease nippleI then bolted this assembly on to the insulator top plate...The insulator is in a 2 cubic meter concrete block in the ground with four copper clad earth rodsThe mast with the trailer ball sits into my home made socket and is well insulated from the ground.. So there you areAll you need to do is use the old noggin and many mechanical problems are easily solved... 73Bob..VK3ZL.. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: Spark Gaps..
Has anyone thought about using two trailer towing balls set up for a spark gap? I use this on a 90 foot insulated mast in a very lightning prone environmentTo date (25) years, with many direct hits, I have sustained no damage...Mast is located 20 feet from my lounge room.. 73..Bob..VK3ZL.. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: Monopole Radiation Patterns, Takeoff Angles etc,
Hi all.. This thread has been very interesting and educational...I guess we all strive to make our installation as efficient as we possibly can...Much of the radial theory has to go out the window for those who don't have the room, (acres) to install a good radial field and have to compromise with whatever can be fitted into a given small space...That being the case probably for the larger majority of Topband operators, doesn't always mean that their station will be insignificant compared to those whom have the room and money to put in a large installation, 4sq and big radial fields.. I hear too many Topband operators complaining that they can't compete with the so called Big Guns and many probably don't give it a serious go for that reason... Well, I have news for you...I have been a consistent operator from VK for 35 years being a keen CW dxer...My observations over the years working thousands of dx stations world wide have showed a few definite observations...Given an average evening dxing and the band conducting shall we say signals are generally averaging S5 to S7...Many of these signals are those whom only have a wire antenna and whatever radials they can fit in their qth with no real to the book installations...In amongst these signals there will be a few of the better installations, most whom will be no better than the average 5-7 signal...Occasionally one or two signals will pop up 1-2 S units above the crowd..This may be a bigger antenna installation but more likely hit the propagation on a peak...You have to remember that the band is very dynamic and changing by the minute... We always hear about the so called big contest stationsLet me tell you that on an average their signals are not always any better than the average signals...I have heard of and seen written many tines about these so called super stations and can assure you that most don't rate any better in the long haul to VK than the average JoeI can name about five dxers from the US who have signals consistently above the average and most of these are fairly ordinary installations.. I think that much of it is the luck of the draw, location, and a bit of thought put into your antenna installation..Operating methods are also a big part of being successful...No point in having the biggest and best installation if your operating habits aren't up to scratch...The best Topband operators spend more time listening than banging away making lots of qrm... So I take my hat off to all those who have to really struggle to get a reasonable antenna system runningNever give up or feel intimidated by the Big Guns..I can assure you that if I hear you in the qrm and qrn I will always try to give you VK... 73 allBob..VK3ZL.. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
