[Hallicrafters] Fw: SX100

[Harry Vaught, KT4AE]

John,

This is from a 1997 post on "Boatanchors at the Porch" by  John Sehring 
who made many informative posts on this series of Hallicrafters:

"HF oscillator is pulled by signal strength on 10m.  SSB up there is
almost impossible.  1st mixer current runs thru the HF osc. ct. (mixer
is cathode driven) & that may be the problem, although the mixer is not
AGC controlled & so runs Class A, constant current, or?  Don't know of a
fix--maybe a buffer between HF osc & mixer."

This is true on my SX-100 Mk.1A on 20m & up.  Too bad.  I like 15m.

While I didn't have an SX-117 to go with my HT-44, I tried using the 
SX-100.  The HT-44 cal. signal would cause the pulling and it was 
impossible to have the two in sync with an incoming signal.

It appears to be a feature of the series.

Harry, KT4AE
Maryville, Tennessee


John King wrote:
> I have just finished recapping my SX 100 and it is receiving GREAT.
  The problem is that there is frequency pulling when the RF sensitivity 
pot is turned wide open. Movement of the pot from about 8 to 10 makes 
the oscillator pull to the extent that the frequency change  is 
extremely noticeable.
>