[TenTec] Hercules 444 with Corsair II, Paragon, or Omni-VI+.

[Douglas]

>Date: Mon, 18 Jul 2005 20:24:52 EDT
>From: CATFISHTWO at aol.com
>Subject: [TenTec] Hercules 444 with Corsair II,
>Paragon,	or Omni-VI+.
	Is it  possible? QSK?
>To: tentec at contesting.com
>Cc: kg6tt at tomorrowsweb.com

>Well on an impulse I bought a working Hercules 444
>over the weekend  
>with the intent of using it with either my Corsair
>II station, my Paragon,  or 
>should I be immensely fortunate, my Omni-VI+. This
>morning I received an  
>email from Paul Clinton at Ten-Tec informing me that
>the Hercules Model  
>444 could only be used with the earlier Omni series
>transceivers (Omni-C or before). Of course I traded
>off my Omni-C >station some months back 
>in  order to get my Corsair II station (had the
Omni->C for many, many years).

>Paul says that the newer Ten-Tec radios don't have
>the necessary  'T' voltage for keying the Hercules
>444.... although he did take a look at  
>the accessory jack on the Corsair II and saw that
>the 'T'voltage is on  
>pin 1 (with pin 8 as ground). He has no direct
>knowledge as to whether  
>the Hercules 444 will work ok on the Corsair II or
>not but is concerned  
>that the timing may be incorrect.

>So my question to the list is to  anyone who has
>attempted to use the Hercules 444 with the Corsair
>II,  Paragon, or Omni-VI+ and if so what 
>was the result? Any success at  all?

>Thanks in advance.  

>Jerry,  KG6TT
>kg6tt at arrl.net
>Albany,  CA


Hi Jerry,

As others have said, its quite possible to use the
Hercules 444 with the Corsair II.
I've got the combo right in front of me.

However, although the "t" line switching basically
worked ok, I did find that timing was critical.

On higher CW speeds, the Over Drive protection
circuitry of the 444 would kick in. This may well vary
from being no problem to being a constant hassle
depending on the exact "T" line T/R timing of the
Corsair II and the sensitivity of the overdrive
protection circuitry within your 444. The trip out was
due to the fact that the rise time of the signal input
from the Corsair II was faster than the rise time of
the output signal from the 444. The O/D circuitry
compares the two and shuts the amp down when the
timing is not almost identical.

In my 444 I finally had to add around a 10 uf
capacitor across the shutdown circuit output line.
As I remember it after briefly checking the schematic,
this 10 uf cap went from the anode of diode D14 on the
display PCB, to ground. All of the protection circuits
have an output that affects that "trip" line at the
anode of D14. Adding that capacitance causes a very
small delay before the protection circuitry kicks in.

Of course, I worried about what affect this added
delay would have on the final transistors. I discussed
it with Garland Jenkins, the tech at Ten-Tec for the
"old time" equipment. He felt that it wouldn't hurt,
but of course, offered no guarantees.
Again this was my mod, not one suggested by Ten-Tec.

Well, so far, one year after doing the mod, despite
numerous protection circuitry trip outs for various
factors, there has been no damage and things work
fine. When I occasionally goof and don't have the
444's bandswitch set to the right band, the O/D
circuit still trips the amp out, it's main purpose.

73,
Doug/WA1TUT

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