[Heathkit] performance of SB-301

[KA4INM]

On 02/18/13 10:01, yash at aol.com wrote:

>     Just finished going thru the 301, all the usual stuff, replacing caps, out of tolerance resisters and doing a complete test equipment alignment, all came out just fine, as per the manual. Have worked on a lot of boat anchors over the years  and run a Drake 4 line, all the time. I was very disappointed with the 301, comparing it to the drake, several swans and a ken wood ts-599. Keeping in mind that these rigs are what they are, the Heath 301 doesn't even come close, to the performance of all the others. I am I overlooking something with the 301? Gone back and read the old reviews and writ ups in QST and the other out of print mags, all gave the 301 decent marks. I find few if any mod's for the 301 shown anywhere, please let me know of a source, about the rig. I guess I expected more from the old rig. I am seriously wonder if its worth the trouble to go ahead and rework the 401 transmitter and put them on the air as a working set of Heath twins.
>    I would sure like to hear from others concerning their results with the 300/301 receiver and as using as a twin setup.

   I noticed that also, I got around that by changing my SB-301's first 
mixer.
The first mixer is designed as a "plate mixer" unfortunately there is no 
such thing as a "plate mixer."

   I changed my SB-301 thus:  (as I recall)  (I have a SB-400 with it)
   I removed the capacitor mounted on the wafer of the switch that goes 
to the plate of the first mixer and comes from the crystal oscillator.
   Then I took the bypass capacitor off of the crystal oscillator's 
cathode resistor and ran a mini coax cable between the first mixer's 
cathode and the crystal oscillator's cathode, I think I had to 
ungrounded the mixer's cathode, so they now share the common cathode 
resistor.
   I kept the piece of coaxial cable (RG-174 I think) as short as possible.
   I created a cathode mixer which is a mixer.
It now works FB.  (10 X my 75A2)
-- 
   Ron  KA4INM - Youvan's corollary:
                 Every action results in unwanted side effects.