Re: [IRCA] Re: Radio Marti 1710

["Robert Foxworth" <rfoxwor1@xxxxxxxxxxxxxxx>]

I think it is fair to say that this is NOT a harmonic. A harmonic is
radiated from the xmtr. It appears to be a mixing artifact in the
receiver. This is the significance of my having heard three of
them at once, all on adjacent frequencies, with mathematically
consistently related  "source" frequencies.

A harmonic would appear somewhat consistently, since one
would expect the xmtr characteristics which cause the harmonic
would not vary from night to night. Especially in such a range
as either on or off.

If this is mixing/crossmod/whatever in the receiver, then some
unknown factor appears to be switching this effect on and off.
But then the idea that different DXers hear it at different times
stops making sense, unless the different DXers are listening
at very random times.

Perhaps the first thing to do is establish whether or not each
receiver that experiences this is (1) synthesized tuning and
(2) uses a 450 kHz IF and not 455 kHz. You can test this by
tuning the subject receiver to 1000 and holding another one
next to it tuned to 1450 and listening for the interference from
the local oscillator. (Or use any other similar pair).

If someone hears this artifact signal on an analog tuned set
such as a HQ-180 them this whole idea gets shot out of the
water and another explanation has to be sought.

Bob

----- Original Message ----- 
From: <richtoebe@xxxxxxx>
To: "Mailing list for the International Radio Club of America"
<irca@xxxxxxxxxxxxxxxx>
Sent: Friday, July 09, 2004 17:18
Subject: Re: [IRCA] Re: Radio Marti 1710


> That was at the back of my mind also--since we already established
through previous posts that this is a harmonic--why is this the only
time it's been heard (it wasn't there last night), and why it peaks at
what should be a null to the transmitting area?  Besides, I would think
1710 is a pointless frequency to reach Cuba.
>
> I cannot confirm 1700 anymore thanks to XEPE which is quite strong at
night.  The slop from 1690 KFSB doesn't help either.
>
> Rich Toebe
> Vacaville CA
>
> -----Original Message-----
> From: Robert Foxworth <rfoxwor1@xxxxxxxxxxxxxxx>
>
> The real mystery is why it is only noticed occasionally and not
nightly.
> What needs to be done is to identify the triggering factor that makes
> this happen.
>
> I must have posted about this a half dozen times by now, but generally
> on another list.
>
> I would suggest, when this appears again, also looking for a RHC
Habana
> "signal"
> on 1700 but this is probably quite hard to separate from the other SS
> now.
>
>
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