Re: 100W Automatic Antenna Tuner...


Ashhar Farhan
 

At 28 dollars, this looks like a steal. It would be best to rewrite the code for arduino for this group. It should be a simple task. I have used a similar setup earlier.
There were a few challenges:
1. The relays have 300 ohms coils. Together, all of them can consume over 12/30 = 350ma of current at all times. To save on this, you need latching relays. With them, the current can drop to less than a milliamp.
2. The relays must be of top quality as they will chatter quite a bit.
The way out is a little more elaborate:
A. Use a variable cap with a servo. Servos are cheap, capacitors are not.
B. Use high voltage FETs to short the inductors. 

On Tue 22 Sep, 2020, 9:06 AM Shirley Dulcey KE1L, <mark@...> wrote:
I don't know what kind of automatic ATU you got. If it's one of the kits from China it's probably based on the N7DDC design, which is documented at https://github.com/Dfinitski/N7DDC-ATU-100-mini-and-extended-boards

On Mon, Sep 21, 2020 at 10:33 PM Aaron K5ATG via groups.io <k5atg=yahoo.com@groups.io> wrote:
Mine came in the mail today, I have yet to find any instructions for it but the search will continue. 
--
'72
Aaron Scott
QRPARCI# 16443
GQRP# 16389
4SQRP # 1080

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