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AB3FN

Joined: Tue, Jun 5th 2007, 14:11 Roles: N/A Moderates: N/A

Latest Topics

Topic Created Posts Views Last Activity
CW for stroke victim ? Jun 17th, 13:45 1 68 1 week, 4 days ago
power loss in tuner ? Jul 17th 2016, 00:37 3 351 on 18/7/16
questions about AM broadcast band images Aug 24th 2015, 13:20 2 584 on 24/8/15
Use of old laptop power packs ? Dec 28th 2014, 15:30 1 928 on 28/12/14
Strange RFI on 10 meters and 6 meters Jun 19th 2014, 17:12 2 1,146 on 19/6/14
Two important functions missing in new radios ? Feb 4th 2013, 15:16 5 1,848 on 28/2/13

Latest Posts

Topic Author Posted On
CW for stroke victim ? AB3FN 1 week, 4 days ago
Is anybody aware of a stroke victim who cannot speak communicating with his/her caretakers via code? For example, the person who had the stroke, but who still has mental acuity and use of one hand, might tap out a Morse message on a caretaker's hand. The communication might be facilitated by posting a Morse code chart on the wall, and instructing the stroke victim to tap slowly.

If you have any knowledge or experience in this area, I would like to hear from you. Please respond in this forum or to my email AB3FN at ARRL dot NET.

Thanks very much.

QST mobile reader which does not suck? piranha32 on 20/12/16
I had no problems in the past viewing QST on my iMac, but the new PageSuite implementation is impossible to read. The resolution is bad - everything is fuzzy regardless of the magnification / zoom. When zooming, for just a second or so everything seems to be in focus, but then the image deteriorates again. I emailed the circulation group, but wonder if I'm doing something wrong. Any suggestions from others who use an iMac ? Thanks.
power loss in tuner ? AB3FN on 17/7/16
It seems obvious that some power loss will occur in an antenna tuner, and it also seems that many factors determine the loss, e.g. SWR, resistance in the inductor(s) and wiring, frequency, Q of components, etc. Although we could, hypothetically, use high quality instruments to measure the loss in any specific situation, how would the loss be calculated?

For example, assume that we know the frequency, component values, purely resistive losses of wiring, etc., how would we calculate the theoretical loss.

Given today's modern equipment, I doubt losses are high enough to worry about in most circumstances. But perhaps this matters more when running QRP, or when building miniature tuners or matching networks from scratch.

Thanks in advance for your comments, thoughts, guidance.
Lightweight, small HF rig - used Lfox368806 on 1/11/15
Suggest you look at the Yaesu FT-450. Its very compact and lightweight, but is a solid performer and has many features. Used ones are well under $600. The menu system is not too complex, although all radios have their idiosyncrasies.
questions about AM broadcast band images AB3FN on 24/8/15
I want to explore the spectrum below the AM broadcast band. The second IF in my late-model triple-conversion radio is 455 kHz, and I'm getting swamped with broadcast band images. E.g., an AM station broadcasting on x kHz has a powerful image at x-910 kHz. My radio is a modern one, but I live near a large metropolitan area with a lot of AM broadcasters.

Is this a common problem with modern radios? Any comments about specific brands / models? I've had marginal results with a home-brew filter - any suggestions about filters? Of course, I'm only interested in receiving, not transmitting.

Thanks in advance for your comments and suggestions.

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