Decade CM-10 Field Test

timinbovey · 2015-09-11T18:50:11Z

My first question is: How do I know that I actually received a Decade CM-10 for the USA market? I bought it right from them, they shipped it to me in the USA, so I assume they sent me the right unit. However, today's tests do not lead me to that conclusion. Is there a way I can actually tell?I set up exactly as I did in the Whole House 3.0 test. Same field, same equipment, etc. So read that write up if you're concerned about the setup. I used the Potomac FIM-71 meter and corroborated my readings with the Z-Technology R-506. Not nearly as many tests as with the WH 3.0, as fewer options to experiment with (Have to have a power cable, and no power level switching).Note that the power supply with the CM-10 is required for use, no adapters, batteries, etc are provided. The WH 3.0 I tested with batteries. So any effect caused by having a power cord attached is a requirement with the CM-10. Adding any cord to the WH 3.0 greatly increased it's output, whether audio or power cord, even when not connected to an audio source or power. All tests taken with the receiving antennas in horizontal polarization.At three meters the CM-10 gave me 3375 uV/m with the transmit antenna in a vertical position. With the transmit antenna in a horizontal position the field strength at three meters was 6300 uV/m. Clearly both are well over the legal limit of 250 uV/m at three meters.The power cable for the CM-10 does have a ferrite choke on it an inch or so from the plug that goes into the transmitter. Also the power supply itself is not a wall wart as such, but a lightweight switching supply that has about 3 feet of cord on either side, one to the outlet, on side to the transmitter. There is no continuity from the plug for the transmitter to the power outlet plug. So any counterpoise effect would be with the three feet of cable I imagine. I did notice that the output varied quite a bit depending on the location of the power cable. By moving it out diagonally from the transmitter the field strength would vary. The readings above are taken with the power cable hanging straight down from the transmitter. Remember, transmitter and receiving antennas are at 7 feet above ground as specified in the meter manuals. I was clearly expecting this unit to give me much more close to legal limits. I couldn't remember the Canadian limits or I would have tested for them. These readings are not that far off from the WH 3.0 when it has an audio or power cable connected to it. Adding an audio cable to the CM-10 didn't make a noticeable difference, but then again it already had a power cable. And adding either cable to the WH 3.0 made a big difference but once one was added, adding the other cable didn't change things much. I took my first reading with the FIM-71 and was so surprised I doubled checked the batteries (they're new) and calibration three times, and took the readings three times, all the same, before setting up the R-506 to corroborate. Same readings. This is why I wondered if perhaps I received a Canadian unit. How do I determine this?TIB

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Anonymous

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Up on Post # 41 Rich responded to the talk about the Hobbytrashers website banning so many people: "I especially miss any new posts there from Ermi Roos."

That must mean that Mr. Roos was kicked off over there? What earthly reason did they have for doing that? I thought he was top echelon with them.

I also enjoyed following Ermi Roos's postings, both here and there.

So far as I know Ermi is a member here, nothing prevents him from signing in as he wishes.

Posted : 01/10/2015 6:05 am

Anonymous

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Below is the chart for the Antenna Factors of the antenna supplied with the Potomac Instruments FIM-71 (which system no longer is manufactured).

Posted : 01/10/2015 6:13 am

Anonymous

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My guess is that Ermi Roos has chosen not to post on Hobbybroadcaster lately -- not that he was prevented from doing so.

Posted : 01/10/2015 6:18 am

Anonymous

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But nothing's happen'in

Posted : 01/10/2015 7:08 am

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