Welcome to new 160m band blog
This blog is the replacement of the my preview Topband blog here http://topband.blog.cz/ because of an aggressive advertising and flash banners inserted by the blog provider. For older posts access You can visit the old blog link which will exist still... but it will not be updated anymore.
Effective from 1st Jan 2017 please paper QSL via OM-bureau only.
Tuesday, October 18, 2016
I noticed that the terminating resistor value and material/type for good working Beverage receiving antenna for low bands DX-ing is never ending story and object of many discussions and internet threads so I decided to post over here few useful information in order to help those guys who do not want to spend annoying time to browse and investigate about this topic.
Why Composition Types?
The important is to look for carbon composition / ceramic composition resistors at 2W power rating at least. The Ohmite has their OY series / 2W for example.
Mouser 10 pack for $16.20
Farnell / Newark:
The resistors datasheet:
It is highly recommended to put a 75V 10 kA GDT in parrallel with the resistor at the end of the beverage antenna. The 10 pack at $1.41 and it will last a long time in the field.
More info links:
Hope it helps,
73 - Petr, OK1RP
Friday, February 26, 2016
as I received several emails with questions about the preamplifier which I am using for my LB external RX antennas like W2PM MiniDiamond loop, EWE loop, K9FD loop etc. I decided to post over here some informations about this unit.
The basic design is inspired with his permission by Larry, W7IUV. The complete article about his preamplifier was published on his web here:
The size, shape and terminals has been choosen according to my alu-case available...
The most important part of this design in my opinion is the transformer and working state of the transistor 2N5109. You must follow the winding rules as same as core material for transformer and finally you must use prescribed current of the transistor in order to reach expected performances.
If you are interested in the suppliers for Amidon, Fair-Rite cores or even you have problem with finding the 2N5109 there are some links which I used...
The heatsink on the transistor is a must. Do not change the resistors in order to decreasing the collector current of the transistor! These conditions are key parameters for high IMD immunity / OIP3 performance...
Testing the assembled preamplifier is straight forward. Before applying power double check your work. The most common problems are solder shorts and resistors inserted in the wrong place. Once you are satisfied you have correctly assembled the circuit place 50 Ohms terminations on the input and output.
Hope it helps.
73 - Petr, OK1RP
Monday, February 1, 2016
We really tried to catch our kangaroos friends in this event too. I am really sorry but no way to work VKs in this CQ160...
I was both evenings on time around 1820-1825kHz. Our VK Beverage sounded also quite well with no usual high noise level.
I really looked for famous Ron, VK3IO and both Steves, VK6VZ and VK6IR. Unfortunately the band was extremely crowded and I am pretty sure that even although we used narrow filters (only IC7600...) our receiver/AGC has been knocked down from so strong nearby signals so I was very deaf even with 330m long Bev to VK.
Well the only single spot I realized on cluster with VK6IR on 1833 on Sat evening but I did not hear Steve unfortunately on this frequency. No VKs readable at our QTH even with Bev to 90deg at all.
As Ron, VK3IO already mentioned on Topband Reflector - http://www.contesting.com/_topband "This year's contest was almost a total wipe out as far as VK was concerned, due to summer storms on the east coast and the usual topical storms up north and a cyclone off the west coast made it impossible."
Never mind, it is just hobby. I was really happy to work XE2X, YV1KK, HK1X, BA1CW, B1Z. Many thanks for your time and effort and hope to work you soon outside the contest on quiet band.
73 - Petr, OK1RP
Thursday, January 7, 2016
thanks to Jeff, VY2ZM(K1ZM) we are able to go back into the TB history and read the Stew's (W1BB) 160m BULLETINS!
As Jeff posted on the TB reflector...
"Most of STEW's 160m BULLETINS from 1930 to 1965 are on my website in the W1BB section - these chronicle the history of the early TRANSATLANTIC TESTS and were sent to me courtesy of PY1RO. Stew used to send these out to anyone who wanted to be on his distribution list - GRATIS too - just another measure of the man....
They are from his mimeo machine and some of them are a bit hard to read - but well worth a looksee.
The site is K1ZM.com/w1bb
73 JEFF VY2ZM"
I would like to thank Jeff, VY2ZM for his job and sharing these documents. It is great chance to study the history of the band, operation and other details from 1930 up to now!
73 - Petr, OK1RP