Comments for Tech Notes from the Field

Comment on Week of Fun by Bill Bartmann

Bill Bartmann — Fri, 09 Oct 2009 18:42:45 +0000

Hey, I found your blog in a new directory of blogs. I dont know how your blog came up, must have been a typo, anyway cool blog, I bookmarked you.

Comment on Week of Fun by JimmyBean

JimmyBean — Thu, 01 Oct 2009 12:00:24 +0000

I don’t know If I said it already but …Great site…keep up the good work. I read a lot of blogs on a daily basis and for the most part, people lack substance but, I just wanted to make a quick comment to say I’m glad I found your blog. Thanks,

A definite great read..Jim Bean

Comment on Bored or Not Bored. That is the question. by Bill Eisenhamer

Bill Eisenhamer — Sun, 09 Aug 2009 03:24:18 +0000

Eric,

I admit I have not kept up as I have had some busy weeks. The answer to the question: There is no resolve at this time! Last week I sent more data for DaySequerra last week. Still no answer. Suspect a front end overload of the tuner, but I’m skeptical at this time. It does not matter what input I use I do not get good RF readings on the unit, yet I can pick up everything under the sun. Off site using the antenna input it appears to work normally.

The last I hear is they want me to attenuate the RF sample to a level I can use the low/antenna input and see what happens. Still nothing yet. I plan on purchasing more attenuators to go down further, but I do not think that will work.
Crazy, eh?

Thanks for you interest!

Comment on Bored or Not Bored. That is the question. by Eric

Eric — Sat, 08 Aug 2009 19:07:36 +0000

What issue did you find in your M2.2R?

Comment on Harris Visit by Bill Eisenhamer

Bill Eisenhamer — Mon, 15 Jun 2009 22:25:45 +0000

Well, I’ve been ratted out. Actually, no, I was brain dead on a little description. Geoff caught it and I am now posting his description of the filament aging process. Thanks Geoff for catching my neuron misfire!

“Just a clarification on the filament depletion process called “de-carburization” where the carbon is slowly cooked out of the thoriated tungsten filament.
As the de-carburization process continues, the hot resistance of the filament goes down causing the filament current to increase for a given filament voltage. For example, a new 4CX20,000 filament would draw about 140A @10VAC while the same filament nearing end of life would perhaps draw as much as 160A @10VAC. This is why the filament voltage had to be lowered when the new tube was installed, to compensate for dynamic impedance of the filament transformer designed in to limit the cold start in-rush current.”

And there you have it!

Regards!

Comment on About by knowledgetoday

knowledgetoday — Mon, 30 Mar 2009 09:43:13 +0000

I love your site. Keep it up !

Comment on 92kHz subcarriers and HD by Thomas Shanks

Thomas Shanks — Mon, 09 Feb 2009 16:43:53 +0000

Sounds like you need to talk to John Kean at NPR Labs, who has tested and quantified this issue. It is indeed the receiver, but SCA receivers are not designed for such a close adjacent digital signal.

I’m researching further on main-channel effects of the adjacent digital channel interference myself, though NPR Labs seems to have covered most of the bases already. Car radios can handle it better than home radios because they filter better, in general. See the DRCIA paper and his NAB BEC Proceedings papers for more info.

Thomas Shanks
Chief Engineer
WREK Atlanta, Georgia Tech Student Radio

Comment on About by beisenhamer

beisenhamer — Fri, 23 Jan 2009 05:02:18 +0000

Paul,

Either of two addresses are good: bill (at) eisenhamerengineering (dot) com or at the full-time gig: bill.eisenhamer (at) lincolnfinancialmedia (dot) com.

Regards,
Bill

Comment on About by Paul McLane

Paul McLane — Thu, 22 Jan 2009 20:55:32 +0000

Hi Bill, thanks for the link to RW on your page. What’s a good email address to contact you?

Paul McLane
Editor in Chief/U.S.
Radio World