I had this happen to me also a while back.....tried to delete a post and change it but wouldn't delete and just posted it again. Seems you can edit and change something or make a correction but not cancel post entirely. You get an error and the post duplicates. I mentioned this to Admin. and this is a done intentionally for a reason I can't remember now.
Mark
I had this happen to me also a while back.....tried to delete a post and change it but wouldn't delete and just posted it again. Seems you can edit and change something or make a correction but not cancel post entirely. You get an error and the post duplicates. I mentioned this to Admin. and this is a done intentionally for a reason I can't remember now.
Mark
Maybe some SOB is hacking the site.
Bruce.
Wondering if I should resurrect this topic or start a new one regarding this transmitter?
Point is I'd like to continue a discussion about experimentation with regards to getting this transmiiter to reach more than 10 feet. I see there were some posting issues in this thread and a few other things, so I am curious if starting a new thread in regards to mods to improve the range of this transmitter to legal allowed range is better than continuing it here?
This kit was designed for very short personal range, and needs an RF power stage improvement for any type of part 15 AM broadcasting.
Bruce.
Whether to continue here or start a new thread is your choice. When posts are added to a thread it gets bumped up the recent posts listing so it won't go unnoticed.
One possible problem with getting help for this is that it appears that the schematic was never published. If you can find one and post it that would help.
Neil
MrBruc4e, in your opening Post # 1 you said...
"The output on a 100 foot wire is limited to maybe 20 or so feet."
Do you really mean "100-feet?"
If so, that might be part of the problem.
Answering posts #36 and 37
To Neil, there is a scematic diagram and I do have it, it is hand drawn in stages and there is questions about whether I can publish it or not. I personally, have tried to make personal contact with Chris Cuff, even as friends on Facebook, but have failed to get a response from him. He seems to be vary active in media related to old record players. I have sent him several friend requests on Facebook, which have gone unanswered thus far.
Now, Jeff, Radio8 has been in slow and limited contact with Chris, he has been trying to redesign the C-Quam AM stereo schematic diagram so it can be drawn out in a better layout on paper and save it as an .pdf file, then he is supposed to send the enhanced copy back to chris so he has a copy of it.
I am not sure what stage Jeff is at at this point with this project, he is also supposed to be making an owner's manual complete with pictures of the completed transmitter from various angles inside and out.
Again, Jeff has been slow on these projects for some unknown reason, but then again, he owes no one anything, so that is his choice to go at his own pace for whatever reasons he so chooses.
To answer Carl, I originally had a 10 foot wire hooked up to the antenna output and a short wire hooked up to water faucet for ground. I had it in my kitchen to use the plumbing as the ground. The transmitter could not reach into the next room through the wall. It was powered by a good radio shack wall wart, no hum at 12 volts DC, this wall wart has a switch that selects 3 volts up to 6 volts, 9 and 12, plus I can select the working current on a separate switch.
So as you can see, my wall wart can select various power outputs and amperage and it has a very clean output, I've used it on video stablyzing equipment as well as radio shacks mixing boards with no hums or buzz isssues, but the transmitter's output range was very limited to the same room pretty much, no matter what voltage or amperage was choosen.
Now Carl, to answer your question about 100 foot wire length. I have various television antennas on top of my roof, I use coax as my signal lead in into my house and television related equipment, one cable, was designed as a cable television drop line, it has a copper wire running the full length used to tie the cable to the trunk line and the other to a hook embedded into the subscriber's home, it supports the cable in mid air without strain on the cable's shield or nucleus. I have one cable where this wire is not attached to the antenna structure above, infact, this coaxial cable isn't being used at all, it's strung up to the roof as a back up cable in case I wish to add another antenna to the structure. The length of this coax cable is 100 feet and so is the supporting wire, the one attached to the outside of the coax cable.
I brought the transmitter over to my entertainment center area and attached that single 100 foot copper wire to the transmitter's out put stage, the ground wire from the cable television ground was attached to the transmitter's ground lug. Since the cable television coax is grounded outside my home along with the power utility drop line service to an 8 foot ground rod in the ground.
I powered up the transmitter, took a portable AM radio with internal AM antenna out into the yard and tuned to the frequency of 1250KHz, which the transmitter's crystal is tuned for and walked away from the house. With the wire in plain view, I walked a total of 25 feet from my home, the antenna probably 30 feet away from me max! Since it is in the middle of my roof and 10 feet from the edge of the house which I was testing from, so I'll say 30 feet total with an unobstructed view of the wire the signal was coming from.
Now, the reason I tried this wire, is because, it is often said if the TOTAL length is more than 3 meters, the installation is illegal. If I am not mistaken, that rule implies that a 100 foot wire would result in a grossly over the limit signal output, so the signal should have carried outside my property line, but this was not the case. The signal at 30 feet was COMPLETELY gone, no traces of any signs that it was there.
Now I do have an RF sniffer that I made from a Popular Electronics magazine project they published in the 1980's, a coupling capacitor and diode circuit that reads RF AC on a VOM meter. When I touch that devices probe to the output stage of the transmitter, the AC scale on my VOM pegs out big time, so there is a significant amount of AC output from the transmitter.
Now corrrect me if I am wrong, but even an AM part 15 transmitter puts out an AC signal on the final output stage correct? I mean, it's not DC correct?
Now back to that 100 foot wire, if 10 feet is legal and 100 feet is illegal, shouldn't that transmitted signal have traveled further than the 10 foot antenna?
I mean we're talking LOS here, not obstructed signal like when I tested inside my home and through the walls.
Just woke up about an hour ago, mind is not quite awake yet, time to edit my typos, to which I am sure there are 100's.
Bruce.
MrBruce the questions about the Chris Cuff transmitters are very fascinating.
You are not the only person I have heard say confusing things about the transmitters.
According to reports I've heard, the stereo capability of the transmitters is excellent, but there are reports of poor output strength.
After awhile you'd expect Mr. Cuff or someone to make an explanation of what's going on, but it remains a mystery.
Something doesn't make sense, but I think the problem is with the transmitter and not something you are doing wrong.
This will sure be interesting to follow as you and Station8 and maybe other people report on what they learn.
LOL! Told you I was half asleep, I called him radio8 , I thought that looked strange. I meant to type Station8.
If Chris Cuff would communicate with me, I would ask him about what I can and can not publish, then I would try publishing his roughly drawn schematic diagram, it may not have the final developments included in it, that may also be why Station8 wants to redraw it.
In the meantime, I have an AM stereo transmitter I can't use besides a "personal" mp3 player to AM radio device.
The output stage is built to reach ONLY a few feet.
Can it power an external linear amplifier? I guess that depends on the requirements of the amplifier, but then again, can that device be added and the whole set up still be a legal part 15 device?
I'm not talking 100 watts here, just enough RF output to equal other legal part 15 AM transmitters.
By the way, if you look at post #1 of this topic, I have photos posted of the final output stage section of this transmitter, it also shows the tuning capacitor and coil.
Bruce.
Hey Neil, if you could, look back and please delete the posts from this topic that were multi-repeats, you'll see some posts were posted 4 times in a row, I guess the boards were acting strange back then, cleaning those out, will make this thread a lot easier to follow.
To the membership out there, if you own this Chris Cuff AM C-Quam Stereo transmitter, this is the topic to discuss improvements to the final output stage.
Although, many have said the audio input stage needs some type of AGC or compression/limiting, we could also discuss 'in' circuit additions to the left/right audio input stages of this kit that helps control over-modulation peaks that often happens with these devices.
Bruce.
OMG! Just seen a post on "I take pictures of electronic parts" on Facebook by Chris Cuff and I asked for him to add me as a friend, finally got a response from him and we are now friends on facebook.
Once I calm down, perhaps I can talk to him about his transmitter. Perhaps, maybe I can also convince him to participate here in this discussion as well?
Bruce.
I looked at the duplicated posts and took out the repeated text. There was some mention that some of you tried to delete your posts. The site doesn't allow this and because of the way the software is designed even admins cannot delete a post (only edit out the text) because doing so deletes all the posts which follow in the thread. The posts in a thread are linked together to form the thread by tags attached to each post which point to the next post so deleting a post destroys the links and the rest of the thread is lost. This also makes it nearly impossible to move a post to another thread. It is a weakness in the design of the database, at least as I understand it.
Neil