"My main gripe with flex now is that their new projects are all dragging. The 1500 and the VHF/UHF module haven't been shipped. Of direct concern to me is their slowness in moving Pretty Betty out of beta."

Flex has always been slow.  Enthusiasm for new products doesn't necessarily get the product out the door.  The "new architecture" (which PB may or may not be) has been "real soon now" for more than 5 years, at least. (I have archived posts from the mailing list with 2005 dates talking about putting it into the 1.5 Beta.. <grin>)

Flex has good support for the existing products, and they get bug fixes turned around fairly quickly, and, back when they were getting ready to show at Dayton, they made a big push to get CW into a form that the brass pounders liked over about 6 months, but as far as "new stuff" goes, it takes a while.

The last big mod in software architecture (as opposed to new user features) was when the 5000 came out, replacing the SDR1K, which required changing the way in which the system interacted with the hardware (e.g. MIDI messages instead of parallel port pokes).  Before that, it was the change from SDRConsole (VB) to PowerSDR (VC#).  I think that was in the 2004-2005 time frame, around when Eric Wachtsmann was hired. I have a copy of SDRConsole with a 2003 date on the file, so it's at least that old.

Unless you really want to design and build your own power divider/hybrid/splitter, what about scrounging for a used commercial item from Narda or similar, although I confess the N connector ones from Narda I've seen start at 225 MHz. Likewise, the dummy load you need for the hybrid quadrature port or the dump load for the Wilkinson is something that surplus might do for.

Whether you think that RF exposure is a hazard or not is immaterial. The regs require you to make the assessment rather than just blindly going forward.  

Watch out for the "multiple transmitter" rule.. if you have more than one transmitter (not just amateur, that cellphone and/or wireless network count too), you have to assess them all (if only to show that the others are less than 5%).

The other thing to watch out for is "near field" vs "far field"... most of the online calculators assume a point radiator and being in the far field so they can do a simple inverse square calculation, not exactly the case with a vertical in your backyard, esp on low bands. WX7G's little calculation shows that at 70 ft (which would be the *far* side of my neighbor's lot) he's at 1/3 of the limit. Of course, I suspect he hasn't taken the duty factor and averaging into account, but still, it probably falls off as 1/r, so at 20 feet (the fence line), the level is right at the limit.

If you're thinking about it, get someone to run a NEC model, and if you're lower than a tenth of the limit (taking into account duty factor and averaging) as will almost certainly be the case, file the data in your notebook and be happy.

There was an FCC enforcement action (mentioned in QST as well) a few years ago where someone asked about an amateur's vertical antenna next door.  The FCC asked the ham for the data, but I never saw if it went anywhere after that.  Hopefully, the ham had done his assessment, eh?

I've had FiOS for 2 years now, and no RFI. That said, I wouldn't be surprised if there's an issue with the wired ethernet side.  Lots of routers/switches are pretty bad with noise radiated from the network cables (common mode) originating from the switching PS wallwart. Here, at least, Verizon supplies an Actiontec router/firewall/appliance that hangs off the ONT, powered by a small switcher wall-wart. (recently replaced by Verizon.. the new wall-wart showed up in the mail with instructions to replace it immediately for sort of vague reasons.. I didn't bother to inquire why).

There are LOTS of variations in installation of these things, by the way.  My ONT is in the telco cabinet on the side of the house, and the actiontec is is probably a meter away, as is the power supply for the ONT, all running off a dedicated branch circuit from the panel, which is right next to the the telco cabinet. All the wires are real short, both network and power. The installers told me that other folks in the tract, though, have had them put the ONT on the other side of the garage, and the router at the other end of the house, with many feet of power supply wiring, or network cables separating the boxes. That might account for some of the RFI issues.. Nothing like having the battery and charger 20 feet away from the ONT or routing a UTP network cable from the ONT to the router the length of the house.

I'd start with a stack of 2.4" toroids in 31 mix, and start choking all those cables.

A previous post mentioned
"real carbon Globar resistors."

Those aren't carbon, they're Carborundum (a trade name for silicon carbide), made in electric arc furnaces by, oddly enough, the Carborundum corporation, with electricity coming from Niagara Falls (one of the first industries to use hydro power).  It's really hard (Mohs 9) so it's used as a commercial abrasive.

SiC has a very high temperature limit, so it's used for thermal elements.  It's also used for dummy loads and absorber (as for anechoic chambers) in vacuum chambers, because it doesn't outgas.

They also make ceramic non-inductive resistors with a thin film of SiC.  The core is a ceramic tube, with a thin layer of the resistive material, often with silver plated ends.  These are used as dummy loads for RF, in pulse discharge apparatus, etc.

The names have changed over the years, Carborundum became Cesewid, then Sandvik, now a division of Saint Gobain abrasives.

Capacitor input filters (to generate the raw bus for a PWM supply, typically) are why the code was changed 10 or so years ago to require a larger neutral in 3 phase Wye connected (e.g. the 208/120 scheme) systems supplying offices/light industrial. In the "good old days" with resistive loads, they'd just make sure that all phases had about the same load, so the neutral current was small.

But with the very peaky current waveform for a lightly loaded capacitor input filter, the neutral would be overloaded, with the pulses at 6*line frequency (3 each positive, 3 negative).  There are some modular office (cube farm) power distribution systems (with too small neutrals) that had real problems.

Modern switching supplies (especially if they're CE marked) have harmonic content requirements (essentially, you can't have the peaky current waveform).  You can look through things like the Vicor catalog and see the prefilters or active compensators. In the late 90s, the harmonic content requirement was often met with lumped LC filters, which are big, heavy, and expensive.  These days, active circuits are more popular (essentially a PWM switcher on the input that makes the current drawn from the line look sinusoidal).  Either way, it means you've got to have some energy storage to smooth things out.

I haven't looked at the CF lightbulb waveform, but I'll bet that either a)they're not covered by the harmonic content rules or b)they're crummy designs that don't meet specs, but as long as nobody complains before the company goes out of business...

About the 220 or 230 vs 240 thing...
The voltages in use haven't changed in a long long time, but how they're described has.


These days, the higher is the "supply voltage" (e.g. 120V, 240V, 480V).. the lower is the "utilization" or "load" voltage.. for instance, if you look at the nameplate on a motor, it will almost always be 230V, not 240V.  

That's because they are allowing for the voltage drop in the wiring from feeder (at 240) to load.. 230 is 10V or about 5% lower.

For some strange reason, though, light bulbs have the supply voltage (120V) on them.  It's probably all just tradition.

Wes Attaway did some tests with decent equipment and calibration some years ago:
http://users.triconet.org/wesandlinda/ladder.htm

shows "many dB/100ft" difference wet vs dry in loss at 50MHz with several commercial "window lines"

lots of analysis and modeling of the results to understand why the measurements are what they are.

Interesting experiment.
As pointed out:"How does UL determine the 'hot spot' temperature of a magnetic component? The usual method is the 'change of resistance' method where the temperature of the copper wire is measured indirectly via the change in resistance. The tempco of the resistance is 3920 PPM/deg C."  

This is how we used to measure thermal properties of things like motors and transformers. We'd short one winding of the transformer or lock the rotor of a motor (same thing, really) and apply power with a variac, periodically checking the resistance.  You put it in a suitable insulated box and bring it up slow so that it reaches internal equilibrium.  

Then, you'd take it out of the box (or, more accurately, take the box off of it sitting on the bench fixture) and run it (to see how fast it cools down). Likewise, you do this to evaluate motor running temperature in the installed case.

Why do the test hot, as opposed to room temp? The idea is to get an idea of how much effect you get from thermally driven convection.  Of course, just about any external air flow changes the picture dramatically..it seems the slowest fans in the world move air faster than thermally driven convection.

Interesting experiment.
As pointed out:"How does UL determine the 'hot spot' temperature of a magnetic component? The usual method is the 'change of resistance' method where the temperature of the copper wire is measured indirectly via the change in resistance. The tempco of the resistance is 3920 PPM/deg C."  

This is how we used to measure thermal properties of things like motors and transformers. We'd short one winding of the transformer or lock the rotor of a motor (same thing, really) and apply power with a variac, periodically checking the resistance.  You put it in a suitable insulated box and bring it up slow so that it reaches internal equilibrium.  

Then, you'd take it out of the box (or, more accurately, take the box off of it sitting on the bench fixture) and run it (to see how fast it cools down). Likewise, you do this to evaluate motor running temperature in the installed case.

Why do the test hot, as opposed to room temp? The idea is to get an idea of how much effect you get from thermally driven convection.  Of course, just about any external air flow changes the picture dramatically..it seems the slowest fans in the world move air faster than thermally driven convection.

If by "the industry" you mean the RF components industry, they DO have a standard way of rating things (typically given as dB loss and a maximum power handling), and the test processes to back it up. You'll get a certificate of conformance along with the packing slip, etc.  Look at MiniCircuits datasheets for examples.  And, I'm sure that when DoD buys 4:1 balun from Harris for their green radios, it has copious testing and data.

If by "the industry" you mean ham radio suppliers, I don't see it happening.  A lot of ham products are basically "productized" versions of something that someone originally put together in their garage or derived from a historical design in a handbook.  The mfr of the product has neither the budget nor the facilities to do the testing, and hams, as a group, tend not to pay anything extra for products which have actual test data.

w8ji said:
If your splatter or a spur causes a problem off frequency, it is up to you to correct it. This doesn't mean if a problem 44 dB down causes a problem it is OK. It is only OK to sell that gear, not to operate it where or when it causes a problem.


I think that captures the essential distinction.. you can sell at -X dBc, but that, in and of itself, doesn't make it OK to do.

Hmm. And you think the phase shift through these amplifiers and combiners will be reasonably stable?

You can do a 8 way divider and an 8 way combiner (heck, you can BUY them from MiniCircuits, although they probably can't handle all the power on the output side, and you'll wind up spending a fair amount in SMA connectors and cabling)

You might look at quadrature hybrids (either lumped or Lange coupler style), or at a distributed amplifier scheme.

But.. to return to your original question.. you've got plenty of power.. An inexpensive mini-circuits double balanced mixer and some pads and a volt meter will do just fine.  Get yourself some transmission line sections to introduce known phase shifts to resolve the ambiguities.

I confess the rules are somewhat vague (say, compared to an actual spectral mask.) on the other hand, that's what's nice about amateur radio.. nobody is going to bring the hammer down on you as you tinker on something homebrew.  Commercial products are probably a different matter...
but

(a) No amateur station transmission shall ... in accordance with good amateur practice.

>>excellent..all we have to do is define "good amateur practice" <grin>  I certainly wouldn't want to impose a strict limit based on theory (After all, the"information content" of many QSOs is pretty limited)

(b) Emissions resulting from modulation must be confined to the band or segment available to the control operator. Emissions outside the necessary bandwidth must not cause splatter or keyclick interference to operations on adjacent frequencies.


>> but where do "emissions" stop.. is it "detectable", is it "43 dB down from the peak", etc... This is tough to evaluate objectively, except for the "interference to ops" aspect, but even there, that's subjective.  If I'm radiating a kilowatt, and my phase noise is -90dBc at 10 kHz away, that's still going to cause problems if my neighbor is 10kHz away and looking for signals at the noise floor.  Is that intefering?  How would I know who's out there.  In the commercial world you do compatibility analyses, ring-arounds, self interference testing, etc.  And, you know the transmitter/receiver/antenna configuration.

Back to "good amateur practice" I suppose, and folks who can gently educate other folks on what is reasonable and practical.

(c) All spurious emissions from a station transmitter must be reduced to the greatest extent practicable.... in accordance with good engineering practice.

Another subjective "good engineering practice" (different than "good amateur practice" from (a)??)



(d) For transmitters installed after January 1, 2003, the mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency below 30 MHz must be at least 43 dB below the mean power of the fundamental emission.
 
The only spectral mask kind of requirement in there, and as you've pointed out, one can meet this particular requirement, and still be might annoying to others on the band.

averaged over the state, the number could be close..
'WIK has a much higher "non-TV" load than the average Californian (e.g. electric dryers are getting less common)

And those TVs stay on lots and lots of hours. My cable box used to burn 120W, day and night. A big TV might be several hundred watts, and run for 8 hours a day. A quick check of
http://reviews.cnet.com/green-tech/tv-consumption-chart/
shows the big LCDs coming in at a 100-200W, and the big plasmas at 400-500W.

500W for 8 hr a day is 4kWh/day.. that's about 10-15% of my daily consumption in southern california in a 2300 sf house (30-50 kWh/day, depending on temperature and whether the kids leave the windows open so we A/C the great outdoors), and we're kind of a big power consumer.