OK at least your getting that. Like I said on Low Power I'd only get 20 feet at best. 200 Ft would be about from my house to the house next door maybe the one after that. So at least your doing pretty good. Actually better than other reports I've read about the C. Crane. So looks like the coupler was the issue between the antenna to the circuit board. They just need to make sure all their transmitters are soldered or whatever way they make that connection is a solid one.
I love it!
Brooce, WLP
From an FCC Report and Order dated August 5, 2015, in review of accomodations for wireless microphone users in the core VHF & UHF TV bands under Part 74 and Part 15, this section directly addresses the FM band and 15.239:
Well this sounds like we may be looking at an oppertunity for extended part 15 now that they are revisiting part 15:239.
It says that the FCC looked at 15.239 in regard to wireless microphones and it says they decided not to change anything because the FM band is not suitable for wireless microphones.
In his duplicity our good buddy Carmine5 is giving advice for us but posting it at hobbycaster, referring to us as "the good folks on the other site."
He thinks we should forget FM and petition the FCC to open up other bands.
But since, according to his earlier posts, we are magical thinkers living in a fantasy world, I suggest we stick with our fantasy and let him can keep his.
Based on observations by me and others, the certified transmitters we've inspected have very carefully isolated RF ground well out of reach of the user.
It seems obvious that the reason for concealing the RF ground is to discourage implementation of full dipole antennas, which could result in range well in excess of 15.239.
Do you agree/disagree with this opinion?
Based on what I've observed on the Decade CM-10 and wholehouse 3.0 that I have received in the past few days. There is no access to RF ground, and in fact the "Reverse SMA" connector on the WH 3.0 is listerally just a 1/4 x 36 bolt with no center conductor at all and the use of this bolt is certainly no way to prevent ssomeone from connecting whatever the heck they want to this output terminal.
After I do my field strength reading and range work I'll be taking these buggers apart to see what's up. I really want to put them on an RF watt meter and see what they're really generating as far as output, and how much loss they're counting on in the antenna.
Tim in Bovey
... There is no access to RF ground, and in fact the "Reverse SMA" connector on the WH 3.0 is listerally just a 1/4 x 36 bolt with no center conductor at all and the use of this bolt is certainly no way to prevent ssomeone from connecting whatever the heck they want to this output terminal....
No matter how simple/cheap the transmitter or how complex/expensive, the antenna system it uses is subject to the laws of physics in order to produce e-m radiation.
Those laws show that useful power cannot be delivered across an open circuit.
For a simple proof of this, disconnect one terminal of your car battery, and see if you can start your car.
For a test needing less effort, turn off a ceiling light in your house or apartment using its wall switch or dimmer, and note what happens.
In the case of these transmitters used for Part 15 FM, the return path needed for e-m radiation is provided by some combination of the d-c circuit "common" return trace on the transmitter board, and the radiating cable(s) used as the progam source connected to that transmitter.
On the Decade CM-10 the ground can be located by removing the top of the case and you will see how the telescoping antenna is connected to the board. You'll see the centre connection to the swivel for the antenna and right beside is the ground where the BNC board mount used to be...also the two posts that the antenna assembly is mounted is also ground. The aluminium case is ground if you scrape a tiny bit of black anodised coating off. Also anywhere you see the silver tracing on circuit board along left side is circuit board ground.
With the Wholehouse the threaded reversed SMA is only + not ground....you have to open and find on circuit board or the negative battery connection should be circuit board ground.
Mark
... With the Wholehouse the threaded reversed SMA is only + not ground ...
Just to note that a-c (r-f) signals are not conveyed using two terminals/conductors where one of them always has a positive voltage.
That characteristic applies only to d-c circuits.
Regarding the RF ground of certified RF transmitters, Rich said: "In the case of these transmitters used for Part 15 FM, the return path needed for e-m radiation is provided by some combination of the d-c circuit "common" return trace on the transmitter board, and the radiating cable(s) used as the progam source connected to that transmitter."
Having the circuit diagram for the C.Crane FM1 Transmitter I see that the audio shield and the power lines have inductors in-line which I suspect inhibits RF flow and avoids radiation from power or audio cables, and also discourages attachment of a negative antenna element.
I would expect to find similar filtering in all part 15 transmitters, unless physically found otherwise.
I've thought about it, and here is what I believe is true about the RF ground path of the certified part 15 FM transmitters.
Half of what Rich said is true: "the return path needed for e-m radiation is provided by the d-c circuit "common" return trace on the transmitter board."
The few inches of the circuit card carrying the negative trace of the circuit is the RF counterpoise.
In his duplicity our good buddy Carmine5 is giving advice for us but posting it at hobbycaster, referring to us as "the good folks on the other site."
He thinks we should forget FM and petition the FCC to open up other bands.
Really? Just what other bands shall we open? And who would listen? Now I'm all for getting rid of the ground rule for AM even if they keep it to 100mW. But really I'd like to see 1 Watt. AM needs to have a breath of freshness and part 15 hobby Radio could save it. At least part 15 operators won't be afraid to experiment with music on AM Stereo. Maybe awareness will get more AM Stereo receivers available to the public. Along with more power we need to get the FCC to have higher standards for phone chargers and the power supply that powers laptops and other things. Once this has been fixed we can expect more possibilities for AM Radio and part 15.
I saw that post too and just shook my head. His logic about the scarcity of FM radios *40 years ago* was silly.
No, we're going to march on and get something accomplished.