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💬General Category => General Discussion => Topic started by: dhouston on November 02, 2011, 03:51:19 PM

Title: Any interest in a CM15A Antenna Kit?
Post by: dhouston on November 02, 2011, 03:51:19 PM
I have an existing preamplified eggbeater antenna design (plus an inventory of preamps and other components) which I'll be using with my RR5x5 project.

It would be a simple matter to design a 50-ohm BNC connector with a small attached PCB to supply power from a CM15A to the preamp over the coax.

I have someone lined up to build/distribute kits that would include a preassembled antenna base w/preamp, 6'3" of coiled, precut copper-clad wire with two pieces of 36" heat-shrink already on it and the two ends preformed. Users would need to cut the antenna wire at the mid-point, form the resulting ends and attach the loops to the base. They would also need to modify the CM15A case to mount the BNC connector and solder three leads (5V, Vss, RCVR). I will provide photos of the CM15A modifications. The individual providing the kits will also have pre-made 50-ohm coax in 1' to 50' lengths. My preliminary guesstimate is that it will cost about $35 plus any coax plus Priority Mail. It will probably take 6 weeks or so to get things rolling should there be enough interest to justify buying PCBs, etc.

You can see the eggbeater antenna details at http://davehouston.org/eggbeater.pdf
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: Knightrider on November 02, 2011, 04:59:47 PM
I think I might be game to try one.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: bvrwally on November 04, 2011, 10:34:31 AM
I too may be interested Dave! Sounds like a good plan!! :)
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: Andytec on November 06, 2011, 04:47:27 PM
Just wanted to let you know I made one yesterday and it works great - cost me about $6 tops
Thanks for the idea

Andy
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on November 06, 2011, 04:54:59 PM
... cost me about $6 tops
The $35 guesstimate includes copper-clad steel wire pre-cut and with ends pre-formed, heat-shrink tubing to insulate it, the enclosure w/preamp, phasing line and all the nuts & bolts pre-installed as well as the BNC connector with PCB to pass 5V up the coax from the CM15A.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: m82a1pa on November 22, 2011, 02:42:28 PM
I'd really be interested in getting a kit.  Thanks.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: Marcio Ylasova on December 02, 2011, 05:19:58 AM
Just wanted to let you know I made one yesterday and it works great - cost me about $6 tops
Thanks for the idea

Andy

WOW! $6? maybe you found a good store that sells ingredient for the egg beater antenna @ very affordable price. And I found also a site that sells heat shrink tubes at low cost and high quality. Maybe you should check this http://www.cabletiesandmore.com/heatshrink.php to compare the prices and quality.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: luke03 on December 02, 2011, 05:04:54 PM
Great idea, Dave!
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: mike on December 20, 2011, 06:45:30 PM
... cost me about $6 tops
The $35 guesstimate includes copper-clad steel wire pre-cut and with ends pre-formed, heat-shrink tubing to insulate it, the enclosure w/preamp, phasing line and all the nuts & bolts pre-installed as well as the BNC connector with PCB to pass 5V up the coax from the CM15A.


Dave, r u plowing ahead with this?  Now that Mercury stopped being renigade, my SC1200 is again working (coincidence) ha!  but it is still marginal on receive strength of ds10s.  If u r going to do this please let us know asap.  Or i will be buying a tv antenna preamp like this and trying it:

http://www.google.com/products/catalog?q=rf+preamp+kit&um=1&ie=UTF-8&tbm=shop&cid=7703557689243124224&sa=X&ei=xOrvTrWAKcy1twew2-zgAw&ved=0CIoBEPMCMAI

or ramsey kit:

http://www.ebay.com/itm/Ramsey-SA7-Broadband-RF-Preamp-Kit-/360283781260?pt=LH_DefaultDomain_0&hash=item53e296388c#ht_1624wt_667

thanks.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on December 20, 2011, 06:59:36 PM
Yes, but it will be mid to late January before I have the printed circuit boards for providing power over the coax and before the person who will sell them ca get setup to take orders. Right now, I'm dealing with 15 different prototypes for my ZarduinoTM project.

If you don't want to wait, the Ramsey kit will work fine, especially if you build an eggbeater. I built and tested one a few years back. You will need a separate power supply for it.

The TenTec 1001 kit will also do a good job and also needs a separate power supply.
I don't recommend UHF/VHF preamps as they will have 75 ohm impedance while the eggbeater and the RF receiver are 50 ohms. The mismatches will cause losses. This is not a fatal flaw but I believe you should do it right.


Title: Re: Any interest in a CM15A Antenna Kit?
Post by: mike on December 20, 2011, 07:35:22 PM
I'm really really good at procrastinating so mid jan is no prob  :...)

I'm lazy too so would prefer ur stuff to doing myself too.  :)

If I did my own I would prob not use the ramsey kit tho - its 4db noise is pretty hi and most tv cheap preamps are about 1/2 that I think.  also, I would have to modify the 9-12v supply input bias resistors and all to run off the lower sc12 voltage rather than needing a sep one...

Lastly, I give:  what is a zuichini(tm) all I can find on line is Arduino minus the trademark (open source)....
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on December 20, 2011, 07:48:25 PM
ZarduinoTM
although zucchini, sauteed in olive oil and dusted with freshly ground white pepper is excellent, too.  >!
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on December 21, 2011, 09:47:29 AM
It apears that Mini-Circuits has discontinued the small preamp IC that I use for this so once my inventory plus that of the only other supplier I can find is gone (mine+his<100), we'll have to find another solution. 
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on December 24, 2011, 05:14:34 PM
Dave, r u plowing ahead with this?  Now that Mercury stopped being renigade, my SC1200 is again working (coincidence) ha!  but it is still marginal on receive strength of ds10s.  If u r going to do this please let us know asap.  Or i will be buying a tv antenna preamp like this and trying it:
Mike,

I hadn't noticed that you want to use this with the SC1200. I've never seen the SC1200 and have no idea whether it's internal OEM antenna is isolated from the powerline. Any X10 device that can send PLC codes is suspect and one with an internal antenna is doubly suspect.  I cannot recommend adding an external antenna, whether with or without a preamp, without seeing a schematic of the SC1200.

Is there an FCC ID on the case? If so, I might find a schematic in the FCC filing. However, if they are using a superheterodyne receiver like in the CM15A, there is no longer a requirement for testing in an FCC-approved lab and, thus, there may be no FCC ID. (The CM15A also has an RF transmitter so it still requires testing and an FCC ID.)
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: mike on December 24, 2011, 05:32:36 PM
Little rcvr is very similar if not same as cm15 in looks;  I didnt copy chip no down and check it...  sc12 uses wall wart with like 9vdc output so I am pretty sure it is isolated but they may feed line thru a cap anyway; i will verify tomorrow when i go back out to shop.  i had sent u a pm today since I will have a couple tentec 1001 amps in a couple days so right now just would like to try eggbeater rather than my normal coaxial 14 wave.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: Brian H on December 24, 2011, 05:47:12 PM
The small receiver in the SC1200A is the same one as in the updated TM751.
As Mike has pointed out. It has a wall wart. The power line transmitter and zero crossing detector are in the wall wart and four wires connect to a 4P4C connector in the SC1200A.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on December 24, 2011, 05:48:44 PM
There's no way to send PLC through a wall wart transformer - you just cannot push enough current through one and that's especially so with switching supplies. So, since the SC1200 sends PLC codes, it must have a path to the powerline and my concern is that they used the same idiotically dangerous methods they used with earlier transceivers. The CM15A antenna is not isolated (although it is insulated). The fact that they did not use a similar, external antenna here is a concern.

Mike - I got and responded to your PM but I really want no part of the SC1200 unless I see a schematic. I don't want to feel responsible for anyone electrofrying themself.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: Brian H on December 24, 2011, 05:57:49 PM
Dave, It is not a standard wall wart. It may look like one but it is not.  It is a total interface that provides DC power to the SC1200, sends the zero crossing data to it and has transmitter keying signal from the SC1200 to key the X10 power line transmitter in the interface.

There is a real power line transmitter board built into the interface. I have seen it and tuned it to 120KHz as mine was a few KHz off.
The transmitter coupled to the power line through capacitors and a isolation transformer.
The SC1200A chassis is not hot.
The power supply part is a linear one and not a switcher.
The receiver chip is the same one as in the CM15A. Hymark RX3310

I have not seen any schematics and kind of doubt there are any publicly available.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on December 24, 2011, 08:21:08 PM
You're probably right about the lack of a schematic since there was no need for an FCC filing. It may be isolated but, without a schematic that makes that clear, I won't touch it and will add a disclaimer to cover it, as I have for the TM751 and RR501, when we start selling CM11A antenna kits.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on December 25, 2011, 11:30:56 AM
For the CM15A antenna kit, I have designed a small PCB that will solder to a bulkhead 50-ohm BNC connector. The PCB has an RF choke, bias resistor and two capacitors plus thru-hole solderpads for +5V, GND & SIGNAL. The board is small enough to pass through the lock-washer and nut for mounting the connector. It passes 3.5V over the 50-ohm coax to power the preamp mounted in the base of the eggbeater antenna. Since my health prevents me from doing the assembly and handling packing and shipping, I designed it to be as simple as possible as I expect a nephew to take it over once everything is ready and he has no electronics/radio background. Most of the soldering is done with solder paste, a stencil and small toaster oven so he can carry on with it should I leave suddenly for med school.

I'm looking at a couple of small RF isolation transformers that appear small enough to mount along with two capacitors on a similarly sized PCB that will solder to a similar bulkhead 50-ohm BNC connector. If we can get them in small quantities and if the assembly can pass through the lock-washer/nut, I'll design an unamplified antenna that can be used with the isolation transformer/capacitor assembly and the TM751, RR501, SC1200 and perhaps other X10 RF devices where there is no isolation from the mains or where the isolation cannot be verified by a schematic. In most cases, adding an unamplified eggbeater will provide adequate range. Where it does not, users can add the TenTec 1001 or Ramsey SA-7 preamp kit (in the antenna base) and an external power supply. An external supply is required as powering it from the TM751 or RR501 would defeat the purpose of isolating the antenna circuit from the mains.

Assuming we can get transformers that fit, the second, unamplified antenna kit will be a couple of months down the road - I have an overwhelming amount of prototyping and testing to do on the ZarduinoTM project and that takes priority as a distributor is helping finance that.

In both cases, users will merely need to mount the BNC/PCB assembly and connect 2-3 leads inside the X10 device, mount the antenna elements on its base (Polycase LP-11F, which will have all associated hardware premounted) and connect a 50-ohm coax between them.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: luke03 on December 26, 2011, 12:13:28 PM

Assuming we can get transformers that fit, the second, unamplified antenna kit will be a couple of months down the road - I have an overwhelming amount of prototyping and testing to do on the ZarduinoTM project and that takes priority as a distributor is helping finance that.

Dave,

Sorry for changing the topic slightly. Where is your distributor for the Zarduino board? Is that available in US today?  I looked your web site about that project, it has so many different varieties of them. Look pretty interesting.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on December 26, 2011, 01:02:20 PM
Sorry for changing the topic slightly. Where is your distributor for the Zarduino board? Is that available in US today?  I looked your web site about that project, it has so many different varieties of them. Look pretty interesting.
The distributor (YourDuino.com (http://YourDuino.com)) is in China. There may be a US outlet also. The ZarduinoTM boards will not be available until I finish all the testing which will likely be 4-6 weeks if all goes well or a bit longer if hardware tweaks are needed. At the moment I have about 100 PCBs (10 of each device) with another 50 or so coming. I need to assemble and test a few of each device before finalizing the designs. The plan is to offer them as kits but with all SMD components installed.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: luke03 on December 29, 2011, 05:31:05 PM
Dave,  thanks! Interesting web site, it sells relay boards and other stuff.  Look forward to see your boards listed there, too.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: mike on December 29, 2011, 06:12:21 PM
For the CM15A antenna kit, .........users can add the TenTec 1001 or Ramsey SA-7 preamp kit........

Hi Dave,  I had sent tentec emails asking for noise figure on their amp, but got no replies, so ordered a couple anyway.  they just came in -- 5.5db noise added.  whew....  wondering if this will do any good at all or just cover up the small sigs....  sa7 said <4, which i thought was too hi....  i will experiment and report back results anyway since I have them.    sure hope u keep good source for those integrated amps with 1-2db noise figures!
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on December 29, 2011, 08:09:03 PM
...sure hope u keep good source for those integrated amps with 1-2db noise figures!
It turns out that they're still available. I was just confused by Mini-Circuits revamped web page.

I expect to have everything on order by early next week and should have amplified antenna kits for the CM15A and unamplified kits for the TM751/RR501 available by late January.

I think you'll find the TenTec will be more than adequate although my own testing was with RF receiver modules like those on my web site rather than with X10 receivers. The HiMark is a superhet receiver so it should do OK. The biggest problem is that it's fairly narrow bandwidth may not match X10's poorly tuned transmitters. There was a thread where someone replaced it (in the CM15A) with an RM1SG which is a very wideband superregenerative receiver and got significant increases in range from various X10 transmitters.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: mike on December 31, 2011, 09:44:05 AM
Hey Dave,

I added the tentec preamp to input off an sc12a using small 2" piece of coax to feed it to the ant input of the rcvr and then reused the same 8" piece of wire antenna;  it appears the 5.5db noise figure makes the previoiusly working sc12 deaf now.  Guess with a better tuned antenna it may not just wipe out the receiver, but as standalone unit with crappy 1/4 wave vertical w/o a ground plane, it can't hear ds10's anymore.

BTW, ohm meter check and ac voltage checks to wall socket seems to indicate sc12 chassis (ground) and antenna are isolated from the power line.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on December 31, 2011, 11:13:11 AM
BTW, ohm meter check and ac voltage checks to wall socket seems to indicate sc12 chassis (ground) and antenna are isolated from the power line.
You are probably right but, without an X10 published schematic, the potential liability is too great.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: mike on December 31, 2011, 02:25:16 PM
understood my friend!
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: m82a1pa on February 15, 2012, 12:51:32 PM
Hi Dave,

Any luck with the kit yet?
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on February 15, 2012, 02:24:41 PM
Any luck with the kit yet?

I have 120 bare PCBs and all the needed components but haven't had time to build any just yet. Hopefully, they'll be available in a few weeks.
Title: Re: Any interest in a CM15A Antenna Kit?
Post by: dhouston on April 29, 2012, 02:49:52 PM
I have 120 bare PCBs and all the needed components but haven't had time to build any just yet. Hopefully, they'll be available in a few weeks.
This is going to be delayed. I've spent 4 and 7 out of the past 16 days in the hospital (2 episodes). The second was to deal with a nasty infection I probably picked up during the first. They poured vancomycin, penicillin & one other antibiotic into me for a week and I'm not going to be up to doing anything remotely physical for a long, long time.

The distributor who is going to handle the Arduino-compatible system I've designed says they may be able to provide the kits later (Q3) this year.