SB-102 Output Inquiry

[Bob Groh WA2CKY]

I would guess (note operative verb 'guess') that the observed effects are due to the closeness of the transmitter(s) to the receiver and, secondarily, to the use of a portable SWL receiver. Suspect the close proximity is giving multiple signals from the transmitter yielding all kinds of odd effects. THe facts that two transmitters give somewhat similiar effects is verification. I might suggest you try to separate the receiver by couple of hundred yards - you transmit and someone else listens or, since you will be transmitting a very low level signal (i.e. leakage from the dummy load), have someone else use the rig and you go out with the SWL receiver and start walking until the signal drops to mid-range and listen to the signal there. 

Let us know how it turns out!

73
Bob Groh, WA2CKY

----- Original Message ----
From: Martin Minnicino <mminnicino at PHENV.COM>
To: HEATH at LISTSERV.TEMPE.GOV
Sent: Wednesday, October 10, 2007 8:11:18 AM
Subject: [HEATH-TEMPE] SB-102 Output Inquiry

I noticed something interesting on the output of the SB-102, and needed
some advice on whether this was normal...  I will try to keep this as
short and clear as possible.

 

After connecting my new Heil high-impedance microphone to my SB-102, I
wanted to monitor the signal to verify that the new microphone was
working properly (without bothering other hams).  So I sent the properly
tuned SSB output into a resistive dummy load and listened to the signal
with a portable shortwave receiver and headphones.  I made sure that the
shortwave receiver did not experience any front-end overload (as best I
could).

 

The sound that I heard in the headphones seemed alright with the
exception that there was a definite "beat" on top of my voice that
varied according to the pitch of my voice and/or deviation in tuning.
To check if this phenomena was common, I did the same experiment with my
Kenwood rig and noticed the same effect.  I this normal?  And did I just
notice it because of the close proximity of the receiver to the
transmitter?  No one has ever mentioned it to me on a signal report...

 

Also, on a side note, I noticed what appears to be a slight
heterodyne-like sound accompanying the SB-102 SSB signal, almost like I
am transmitting on AM (?)  Is this a null carrier problem?

 

Thanks in advance.

 

Martin Minnicino

PHEnv

 


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