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ALPB Member Jeff Station8 has called for a SPECIAL MEETING Saturday 7:30 PM EDT at TeamSpeak.
Jeff wants to report on observations he has made regarding certain FM transmitters.
If you are available, join us.
Total posts : 45366Sorry but I have a previous committment to take my wife out.
Total posts : 45366Everything will be fine, Jim.
Based on Jeff Station8’s Alert, the matter pertains to FM transmitters, and your station Jim is strictly AM, so perhaps this should be mentioned.
Here is the main text posted by Jeff at ALPB:
I know it short notice but I just found about it recent in more detail!
TO ALL ALPB MEMBERS BOB, CARL,NEIL,JOHNNY C, THELEGACY,BARRY,RADIODUGGER,JIM HENERY
ARTISAN AND ANY OTHER PERSONALLY I FORGOT!
NOTE: Can someone get a hold of Neil for me!( thank you )“This is very important I did some testing on various FM transmitters and found a serious issues
That need to be address IMMEDIATELY!“This has to do with a interference frequency I found in the testing I will disclose
More at the meeting in great detail ( Carl or johnny please record if possible ).“I would like other member to look into this and see if it’s happing to them as well.”
As an ALPB Meeting the conversation will be limited to certified transmitters compliant with 15.239.
Total posts : 45366The ALPB can talk about any transmitter that is legal SOMEWHERE in our membership countries and regions, such as Canada and New Zealand.
Off-frequency emissions must be at least 20 dB below the main carrier when the main carrier is producing a legal field strength.
Total posts : 45366Quick question. Do the transmitters used in the low power New Zealand service have to be type accepted and/or approved by the appropriate regulatory body? That is certainly the case with all transmitters used in Canada, whether it be BETS, RSS210, RSS123 or the big boys.
Total posts : 45366As far as I know there is no list of type approved transmiters for LPFM here in NZ. They just have to comply with the regulations. I have found a list of a few that dont meet them http://www.low-power-fm-radio.spacejunk.co.nz/forum/forum_posts.asp?TID=482&PN=1 . These said transmiters are not allowed to be sold as well. Here are our regs https://www.rsm.govt.nz/about-rsm/pdf-and-documents-library/spectrum-policy/official-information-notices-gazette/gurl-notices/low-power-fm-broadcasting/radiocommunications-regulations-general-user-radio-licence-for-low-power-fm-broadcasting-notice-2010.pdf
Total posts : 45366Last night a SPECIAL IMPORTANT URGENT MEETING OF THE ALPB was convened at the summons of member Jeff Station8 for the purpose of informing and alerting the membership to certain discoveries regarding FM transmitters.
Total posts : 45366Thanks for recording and posting Carl.
Total posts : 45366Thanks DHR.
The 10-minute Blare OnAir captured the main message being delivered by Jeff Station8 and the meeting continued on after that with what I think was a good trouble-shooting discussion with Neil Radio8Z, Johny Cole Rag FM, Troy TheLegacy and yours truly trying to figure out what was going on.
I would be willing to post the fuller version of the meeting if anyone requests.
Total posts : 45366At the request of Druid Hills Radio a test has been rum on the Ramsey FM30b to compare it to Jeff Station8’s interference issue.
This afternoon we set the Ramsey FM30b to 90.3 MHz, the same frequency used in Jeff’s reports.
Power output is set at the legal Part 15 level, which was compared to 3 certified transmitters, all of which luckily agree with each other and are thus a fair guideline.
The spectrum analyzer is 15-feet away in a permanent position on a desk.
90.3 MHz showed 39 dB.
Next I looked at 105.5 Mhz, the frequency where Jeff reported receiving a strong spur. We do not have a local station on 105.5. There was no spur at all in our test.
Looked at 7.6 MHz in the shortwave band, the fundamental frequency of a crystal inside the transmitter. No signal observed.
Looked at 15.2 MHz on the shortwave band. No signal observed.
Looked at the 2nd harmonic of 90.3, 180.6 MHz, saw a bump measuring 15 dB, which is 24 dB below the main carrier, well within guidelines of 15.209.
No testing was done outside of Part 15 levels because I do not have verbal permission from the FCC to exceed the rules during testing.
Re-Printed with permission from myself
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