|
Title: DX-60 parasitic resistor Post by: N1OHN on March 27, 2016, 02:08:29 PM Was wondering if anyone new what the value of the parasitic resistor is in the DX-60 at the 6146 tube? Mine is burnt.
Thanks all!!!! Title: Re: DX-60 parasitic resistor Post by: N9axl on March 27, 2016, 04:17:57 PM I just emailed you the schematic.
Title: Re: DX-60 parasitic resistor Post by: K9DXL on March 27, 2016, 04:28:16 PM In my DX-60B manual the choke is shown as a pre-assembled part. I searched with Google, and came up with a mod to add a second, parallel, 6146. The resistor specified was 47 Ohm, 1 watt, composition type. http://www.arizona-am.net/TUCSON/K3YAZ/DX-60_parallel.pdf
Title: Re: DX-60 parasitic resistor Post by: N1OHN on March 27, 2016, 07:12:32 PM N9AXL
Unfortunately the parsitic resistor is not in the schematics as is normal for they apparently consider it as a module or just choke. Title: Re: DX-60 parasitic resistor Post by: N1OHN on March 27, 2016, 07:14:43 PM K9DKL
Yeah I found that also thanks ... 47ohm 1w is a 50/50 guess alot of times it is a 47. Title: Re: DX-60 parasitic resistor Post by: N1OHN on March 27, 2016, 07:16:18 PM Still looking for a that value of the parasitic resistor in the dx-60
Thanks all!!!! Title: Re: DX-60 parasitic resistor Post by: K5IIA on March 27, 2016, 11:16:02 PM I do not belive it is really a critical value. Most use 47 to 50 ohm, or even a pair of 100 ohm parallel non inductive resistors. I do belive you want to use non inductive resistors. You can look up sb220 parasitic suppressors if you want to get really anal about it and go overboard on it, but they are really not very critical.
Title: Re: DX-60 parasitic resistor Post by: DMOD on March 28, 2016, 12:18:19 AM A 47 ohm resistor in parallel with a 0.047 uH coil (3.5-4 turns of #16) and its distributed capacitance constitutes a wide band (100 mHz to 400 Mhz) VHF/UHF bandstop filter.
As others have stated, a 47-51 ohm 1W resistor is sufficient for a low power DX-60 and it is not that critical. Phil - AC0OB Title: Re: DX-60 parasitic resistor Post by: N1OHN on March 28, 2016, 06:48:55 AM Thanks all for your help :)
Title: Re: DX-60 parasitic resistor Post by: kb2vxa on March 30, 2016, 07:57:54 AM Sorry for the late reply, but have you forgotten KISS? No not the band, Keep It Simple Stupid. Take a look at the suppressor and count the turns, then use a piece of bus wire and wind the same number of turns on an old 47 ohm 2W resistor from your junk box. You may consider an improvement, use a short bit of solder wick between it and the plate cap for strain relief, the cap will thank you.
Title: Re: DX-60 parasitic resistor Post by: N1OHN on March 30, 2016, 08:03:46 AM Hi Warren AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Yeah thanks ... that is exactly what I did. Also I use the solder wick trick all the time :) I did find that in the DX-60 it calls for a 1w 47 ohm resistor if anyone was wondering. |