= HF8V = / = SP8WJT = / = SP0106RZ =
HF-2836
PROJECT: HF-2836
DESCRIPTION: HF Preselector
STATUS: u
PROJECT START DATE: 2024 (datecode 2438)
LOCALISATION: PM (Panel-1)
DOCUMENTATION: TM, 6 pages
CASE: HF-91153
DIMENSIONS: 50 x 150 x 120 mm (HWD)
HF-2836
| PROJECT | DESCRIPTION | STATUS | PCB | REMARKS |
|---|
| HF-2836 M-1 | Main board | u | TPD10101 | |
| HF-91153 | Case | u | -------- | |
This is very simple and well known construction on J310, I just copied original circuit diagram because it is simple and good. Thanks to J310 and T68 toroid cores (T68-2 red for low band and T68-6 yellow for high HF band) this preselector works quite well.
For tuning I used Aliexpress tuning knob with 0-100 markings, and Calibration Table was created. Works accurate, I tested setting from Calibration Table for choosen band and usually no corrections were needed. With 1SV149 varactor diode and 12V supply I obtained following freqs for LOW/HIGH BAND:
LOW BAND: 1.8 - 8.2 MHz
HIGH BAND: 6 - 30 MHz
with very narrow tuning around 1.8 MHz.
This preselector works as better as worse receiver is! So you could not see big difference on ICOM or KENWOOD TRX but for bad receivers like HF-17135 it can really help.
HF-2836 CKT diagram
There is no need to use RF connectors like UC-1 or BNC for such equipment. For HF receiving equipment audio CINCH connectors are sufficient, but cable must be good quality and short. Some cheap audio-video CINCH cables can have small attenuation.
Sources:
[1] J310 datasheet
[2] 1SV149 datasheet
Prefix 28
HF Register
Microcontrollers in my constructions
UC Database - my CPU collection
Electronics
Main Page
Generated by HF Projects Page Creator ver. 2.03