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3 - 30 MHz Choke
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2m amplifier using BLF 27...
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visualising my logbook da...
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FTDX101D or IC7610 ?
Forum: Transceivers, Transmitters & Receivers
Last Post: VK4SMJ
10-07-2024, 12:02 AM
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Wire Antennas and Foliage
Forum: Towers, Masts & Transmission Lines, Antennas
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09-07-2024, 05:42 PM
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LOTW back on air official...
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Release Candidate WSJT-X ...
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Multiple instances of WSJ...
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30-06-2024, 10:03 AM
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has anyone had any luck u...
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Shocking news from Tom KC0W/T30COW |
Posted by: VK4WDM - 05-10-2016, 01:44 PM - Forum: General Discussion
- Replies (1)
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![](https://www.ahrdf.net/forum/images/default_avatar.png) |
Tom's dxpedition has come to a halt. He has sent this shocking message from Kiribati:
“Everything I own was stolen on 28 September from here in Kiribati. They took all the radios, computers, amplifiers, antennas, coax, EVERYTHING. They even took my clothing & shoes. I have literally NOTHING left…..I type this with tears in my eyes.” Tom KC0W
I worked all over the Pacific Islands for 25 years and only had minor problems with theft, nothing like this.
One wonders how these crims are going to dispose of the electronic and computer equipment from such an isolated spot with very poor transport links. Hopefully local police and customs can retrieve it.
Wayne VK4WDM
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Ceramic filter failures in multimode rigs. |
Posted by: ZL3OZ - 30-09-2016, 03:16 PM - Forum: Transceivers, Transmitters & Receivers
- Replies (9)
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![](https://www.ahrdf.net/forum/images/default_avatar.png) |
Had a Yaesu FT857 come in for repair with very sick receive sensitivity on FM mode mainly VHF was reported.
I found it actually still worked but RX sens was about -62dBm and the squelch could not be opened from the squelch control.
Also on SSB HF seemed at a first listen to be still ok but both sidebands hearable at the same tune by. i.e. like a double sideband receiver. (Never checked TX)
Did a search on Google and found many hits. It seems this is caused by breakdown of one or more of the ceramic 455 filters.
Usual configuration is an AM, a wideband FM and a narrow FM. (i.e three filters)(main SSB filters and CW filters not affected) and the FM one is the most likely culprit because it is most often selected (i.e. for the longest periods) and the manufacturers did not isolate the filter with caps so that the diode switching selection voltage is applied to the filter input and output as a byproduct after passing through the switching diode. This causes electron migration and a crystal buildup occurs across the tiny ceramic slices inside, shorting them out. Theres a heap on Google about dismantling and cleaning then out. I tried it and it was about 90% successful but very fiddly and still lost about 3dB more than it should.
Do a google search on ft857 filter problem or ft897 filter problems, and the iceberg starts to take shape, and this only the tip.
Also affected that I know about is the FT897, Ft817, Kenwood TS2000 and there will be others, not sure about Icom but someone said one of their marine radios is affected.
The radios all built between late 90s and 2009. Now reaching the crucial age.
I contacted Coms Centre in ZL and requested replacements. Well that was a waste of time and an argument into the bargain, seems they may not have them, might not want to supply them to anyone anyway because they are so hard to get.
I saw on line someone had found them available on ebay so thought "wonder what Aliexpress has to offer". There they were at very reasonable prices.
So if you have that trouble either go to Ali or contact me as I bought lots of 20 of all three types. So far two types have arrived and running the sig gen over them they are indeed filters and not what i feared, tiny bits of cleverly painted
wood.
Thought I would post it here as there will be quite a few of these rigs among us.
Ken
ZL3OZ
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ARRL Sponsors VHF-UHF 222 MHz & Up Distance Contest |
Posted by: VK2ZRH - 30-09-2016, 06:49 AM - Forum: Contests, Field Days, Portable Operation, JOTA, SOTA
- Replies (1)
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![](https://www.ahrdf.net/forum/uploads/avatars/avatar_85.jpg?dateline=1496719722) |
Quote:Rules Released for New ARRL 222 MHz and Up Distance Contest
09/27/2016
The official rules for the new ARRL 222 MHz and Up Contest have been released. The contest will debut in August 2017. Participants will attempt to work as many stations as possible on the 222 MHz through 241 GHz bands, “using any allowable mode.” Competing stations will exchange six-character grid locators (“sub-grid”). Rovers report their grid locator at the time of each contact.
Contact point values will be computed on the basis of both the center-to-center distance in kilometers between the sub-grid square of each station and an arbitrary “band factor,” a multiplier ranging from 1 to 20. For example, contacts made on 222 MHz will have a band factor of 2, contacts on 432 MHz will have a band factor of 1, and QSOs made on 24 GHz and higher will have a band factor of 20.
To encourage participation, the new contest encourages the formation of operator teams. These may be made up of Single-Operator, Fixed; Multi-Operator, Fixed and / or Rover category participants operating within a single Contest Region as defined in the contest rules. Participants may only be on one team, and the scores of all team members are combined.
Get the skinny here: http://www.arrl.org/news/rules-released-...ce-contest
Posted in the interests of sharing the news.
73, Roger Harrison VK2ZRH
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Power outage in VK5 |
Posted by: VK3ALB - 29-09-2016, 05:31 PM - Forum: General Discussion
- Replies (6)
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![](https://www.ahrdf.net/forum/uploads/avatars/avatar_10.jpg?dateline=1530142470) |
A statewide power outage is a pretty unusual occurrence and given the circumstances I think most people would be thinking about things other than radio. I wonder if noise levels changed significantly when almost every electrical gadget in the state was offline. Did any VK5's have time to jump on the radio during the outage? Was there a noticeable difference in your local noise level?
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