[ARC5] 4th Receiver Drift Test from KE6F Hallicrafters S38B

[millerke6f at aol.com]

Hi to all and thanks to those who have been responding to the postings


Here comes a few notes on the much maligned Hallicrafters S38B  AC/DC shock hazard and probably one of the most produced SW radios ever,


Generally the radio that was tested is in good condition and worked on all bands although I only ran drift tests on 80 40 and a quick test on 20 meters.  The test environment was nearly the same as previous runs, but due to what I assumed was going to be less than stellar performance the following processes were put into play


1. Excitation voltage was held to 50 microvolts
2. A 30 minute warm up was allowed before any drift measurement were made
3. A fully isolated AC power source was used (Non Regulated) as the leakage AC on the antenna ground connections was around 70 vac and I did not want to fry my new Agilent Sig Gen.  Ambient temperature through out the tests was 62 degrees F.


80 Meters


2:00 pm	3,750000 MHz (Start test)
2:30 pm   3.748740	MHz (-1260 Hz change)
2:40 pm   3,500000 MHz (restart at 3.5 MHz)
3:30 pm   3.498970 MHz (-1030 Hz change)


40 Meters


3:55 pm	7.000000 MHz (Start Test)
4:15 pm   6.999931 MHz (69 HZ change--but there was a lot of wandering around)


20 Meters


The base frequency set up on 20 meters was somewhat problematic but I was able determine that the S38B would be a bit of a challenge for SSB use as unit wandered around about a KHz or so in the first few minutes of the test so I stopped at that point.


Not having used the S38B as an on the air receiver I found that on 80 and 40 meters that it was quite usable on CW and that it was fairly HOT as they used to classify these old radios. AM reception on 75 meters  was quite nice and even some SSB and had the unit an RF gain control SSB would have been less of a challenge.  I did listen to some SW AM broadcasts along with WWV on 5 and 10 MHz. 


I got the HQ129 out of storage today and will try to get that test done tomorrow if the creek don't rise.


73


Bob, KE6F