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Re: Harmonics and Relay Replacement

 

I agree with you Raj. Also, I believe it's because the Axicom relays were designed from the beginning to be used in RF applications where the ones originally used in the uBITX were and are not. The originals are power relays and no thought was given to RF isolation when they were manufactured. It's unfortunate but not all relays of this type are created equal and it is difficult to design RF carrying circuits using power relays when the internal capacitance and/or inductances are not known and not provided in the respective data sheets.

As to being "possessed", I know the 40 meter band on at least one of my uBITX boards IS possessed because the Axicom relays only marginally helped on 40. On all the other bands the 3rd harmonic was reduced significantly (at least 15 dBC) over the original relays.

Jim Sheldon - W0EB

------ Original Message ------
From: "Raj vu2zap" <rajendrakumargg@...>
To: [email protected]
Sent: 10/11/2018 6:01:37 AM
Subject: Re: [BITX20] Harmonics and Relay Replacement

Kees,

My guess is that the contacts being underside are close to the ground plane of the board and that must be
helping decreasing the "coupling" of both sets of contacts.

Imagine a loop on one side of the relay and another on the other side.. perfect inductive coupling. The
Axicom has smaller loops compared to Virtual and others.

My Panasonic relays made the harmonics worse.. BUT the power out increased !!! about 20%.

It's possessed I tell you!

Raj

Panasonic relay DS2Y-S-DC12V



At 11/10/2018, you wrote:
Those inductances all look right. Sure would like to know WHY the Axicom relays have better readings.
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