Thanks For this information Bob. I don't have a metal tower or guy lines,
as I'm using wooden masts to support the antenna, but certainly several
places along the way that might detect and mix strong AM broadcast stations,
especially at night. The most likely place for this signal detection and
hetrodyne mixing is probably in the SG 230 tuner or the MFJ Deluxe Versa
Tuner, which is only used for a switch to a dummy load anyway. So when the
sun shines, off I go with soldering iron in hand to recook all coax and wire
connections along the way and take out and test each item of equipment
involved along the transmission line.
Ron KA7U
-----Original Message-----
From: Robert & Linda McGraw K4TAX [mailto:RMcGraw@Blomand.Net]
Sent: Tuesday, January 03, 2006 5:49 AM
To: Ron
Subject: Re: [TenTec] LW receiver
Based on what you've observed, I'd expect to find a corroded coax connector,
or a bad connection between two different metals and etc. Typical is guy
wire looped around a tower leg which under certain conditions makes for a
good diode. In the presence of strong RF signals this will cause harmonics
to be generated and to some extent radiated. FYI - guy wires should be
bonded to the tower with a grounding strap at each attachment point. Sounds
like time to do a "clean up" of the site. Every connection much be touched,
inspected and cleaned. Even those that are ground connections and other
metallic support structures.
As to the SG-230 tuner, while not specifically familiar with it, take it out
of the line and see if anything changes. If it does, then you can suspect
something in the box is causing the problem. Mighty likely in my opinion.
Bottom line, I don't think it is in or caused by the Orion II. As to the
Orion filtering, if the signal is a harmonic or heterodyne signal that falls
in the passband, no amount of filtering will remove or reject it.
73
Bob, K4TAX
----- Original Message -----
From: "Ron" <ron@morell.us>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Cc: <RMcGraw@Blomand.Net>
Sent: Tuesday, January 03, 2006 12:48 AM
Subject: RE: [TenTec] LW receiver
>I heard another today at 3580 KHz on the Main receiver. Found one of the
> stations at 1460. This time I could detect another station faintly
> overlaid
> with the main station from 1460 KHz. This signal was still there after
> filtering down to 600 Hz with the roofing filters. Curious to me that
> these
> broadcast stations can hetrodyne up into the amateur bands on this ORION
> II
> even with roofing filters and all that to prevent it. I find AM broadcast
> stations on 160 and 80 quite regularly... Maybe something is up with my
> SG-230 antenna tuner or other anomalies in my antenna system that is
> producing these signals and hence the detection of them by the ORION II.
> No
> way the ORION II is going produce these hetrodynes and detect them in the
> amateur bands on the main receiever, right?
>
> Ron KA7U
>
> -----Original Message-----
> From: tentec-bounces@contesting.com
> [mailto:tentec-bounces@contesting.com]On Behalf Of Robert & Linda McGraw
> K4TAX
> Sent: Monday, January 02, 2006 6:21 PM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] LW receiver
>
>
> Mixing products of 1160 minus 900 = 260
>
> or
>
> 1160 mixed with 1420 = 260 kHz
>
> in these cases, I'd expect to hear audio of both stations at 260.
>
>
> Another combination is the 2nd harmonic of the local oscillator minus the
> 455 kHz IF = 250 kHz.
>
> Just do a bit of math, consider any BC station in the area and you'll find
> the combination.
>
> 73
> Bob, K4TAX
>
>
> ----- Original Message -----
> From: "Ron" <ron@morell.us>
> To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
> Cc: <CATFISHTWO@aol.com>
> Sent: Sunday, January 01, 2006 7:44 PM
> Subject: Re: [TenTec] LW receiver
>
>
>> Tom,
>> Ineresting idea of two AM broadcast stations producing the signal at 260
>> KHz, but as I did not hear any signal but the 1160 KHz station there, I
>> think it is probably a product of the IF mixer. I was using the Sub
>> Receiver. It was a 10 over S-9 signal at 260 KHz and a 40 over S-9
>> signal
>> at 1160 KHz. When I get time, and conditions are similiar and I can tune
>> it
>> in, I'll hook up my old Tuned Receiver Front End Regenerative (RAK-8)
>> receiver and see what I hear at 260 KHz. No IF in that old boat anchor.
>>
>> Thanks for you reply.
>> Ron KA7U
>>
>> -----Original Message-----
>> From: tentec-bounces@contesting.com
>> [mailto:tentec-bounces@contesting.com]On Behalf Of CATFISHTWO@aol.com
>> Sent: Saturday, December 31, 2005 1:56 PM
>> To: tentec@contesting.com
>> Subject: Re: [TenTec] LW receiver
>>
>>
>>
>> In a message dated 12/31/2005 10:31:52 A.M. Pacific Standard Time,
>> ron@morell.us writes:
>>
>> Listening on 260 KHz with my ORION II tonight and heard KSL5 radio in
>> Utah
>> which broadcasts on 1160 KHz. That would be 900 KHz below their
>> broadcast
>> frequency. I'm curious about this and wonder what exactly I'm listening
>> to.
>>
>> Besides, it is time to talk about something besides headphones... :)
>> Ron KA7U
>>
>>
>>
>>
>>
>>
>> I had similar a few weeks ago, and it is possibly "your station" and a
>> second broadcast station near by proudcing a ifference frequency between
>> the
>> 2
>> stations and the rig is picking up the combined signal and detecting it
>> at
>> .260
>>
>> it is not a harmonic, but could be a difference freq if two strong am
>> stations are close by.
>>
>> tom N6AJR
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>
>
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