Kahn PowerSide

[DanStrassberg]

In the absence of a spectrum analyzer, is there any way to detect with reasonable certainty, that an AM is using the Kahn PowerSide? I do have a CC Radio+ with a digital frequency display and a tuning knob that is calibrated in 1-kHz steps. I've tried to eliminate human error from my observations by listening carefully and closely watching the radio's (questionably reliable) signal-strength indicator as I tuned across several stations in addition to the one in question. My observations of the station in question are enough different from the others I have tried that I think I have detected a difference, but I could easily be imagining the difference.

 

[frankberry]

If you will tune towards the lower sideband and then towards the upper sideband, the difference should be pretty obvious.
Of course, the difference in the sidebands could also be due to the characteristics of the transmitting antenna.
I don't know of too many stations which are using the Powerside Exciter. I know of a few stations that tested the Powerside and took it offline because it didn't perform well into their antenna systems.
Have you called the station and asked whether they're using the Kahn Powerside?

 

[DanStrassberg]

Have you called the station and asked whether they're using the Kahn Powerside?

I doubt whether the station has an engineer on its payroll. Most likely, they are using a contract person and I strongly doubt whether they would identify him and even more strongly doubt whether they would put a caller in touch with him.

 

[satech]

If you can get your hands on an old multi-system AM Stereo radio, you can switch it into Kahn mode and listen if one channel becomes louder than the other (left channel = lower sideband, right channel = upper sideband).

Some PowerSide stations even still transmit the 15 Hz Kahn AM Stereo pilot tone, which switches automatic multi-system receivers (very rare in the USA) into Kahn mode, but serves no useful purpose. 1280 WADO in New York City did this until they gave up on PowerSide a few years ago and switched to IBOC.

 

[stacker]

Any radio with an asynchronous detector will tell you. When you push the sync button to change from one sideband to another, you'll a difference in amplitude and frequency response.

 

[fm-engineer]

Oh no, here we go again.......The Wrath of Kahn is coming back to the AM dial

 

[BobOnTheJob]

Only benefit I saw to the system is if you wanted to be a good neighbor & not splatter in one direction, this was your toy. As far as improving coverage, I fail to see how cutting your sideband power in half could do anything but reduce your coverage.

 

[RadeoEngineer]

I think this system was first developed when we still had analog tuned radios, so you could put more power in the sideband least affected by interferance.

 

[RadioMan203]

Back when I engineered an Kahn AM Stereo daytimer back in the late 1980's I ran an overnight test for the National Radio Club. I simulated PowerSide as I had separate left and right 4-band compressors with variable drive and eq. I had several NRC members comment that noticed improved tuning, but as a previous post pointed out that this was when analog tuned radio were still the popular choice.

 

[Tom Wells]

It's not "analog" tuning. It's infinite tuning resolution...it really is a big difference.

I cannot ever be satisfied with fixed, preset steps for tuning. Not for an AM signal.
Much like I don't think I can be satisfied with square wave detection or ceramic 455 IF filters.

Preset step tuning on AM is like trying to eat soup with a fork.

I'd love to see someone try to do a violin what has happened to radio, and then try to pass off
the poor results by talking up the digital features, pitch correction, etc..
Which one is really a violin?

What happens when no one can afford to make real violins any longer and they all have to be some kind digital thing?
There are a few "passive", real-time, continuous tuned AM radios being made somewhere, I'll bet.

As far as powerside, it should be really easy to tell with a continuously tuned radio,

I always wanted to try a dual-455 khz AM stereo which I'd L/R slice-tune with Hi-Q at 455khz and then multiply up the
intended AM BC frequency. Maybe someday. There are lots of ways to play with the coupling and tuning of 455 khz IF
xformers, and I have some ideas on building one specifically for such a generator.

If one ever was used in the Chicago area, I never noticed a stronger sideband tuning around.
If I heard one while on the road, it would have likely been on a rental car radio, so no way of telling.

 

[speakerman]

Check this out Tom. A few friends and I use the TMC SBE-2 or SBE-3 exciter for our ham stations. The exciter is independent sideband with a variable carrier insertion for AM mode. This was the favorite of the Navy for many years and was used at many short wave relay and broadcast stations. It is an oldie but goody. You can feed either sideband separately. It has pretty decent sound quality and gives the nice warm glow and sound of tubes.

It uses 250kc balanced ring modulators with high quality crystal filters after each channel for upper and lower sideband. The 250kc is mixed to get it to the carrier frequency. I use a Wavetek bench generator as my VMO.

It is paired up at my station with the TMC PAL-1K 1kw amplifier which produces 1kw for 60mw of drive.

Here is a fun link http://www.navy-radio.com/xmtrs.htm . TMC made some great equipment that still works well today.

The schematics are easy find with a Google search.