Topband: Receive ant - binocular cores

[Tim Shoppa]

Tony, I have abused BN-73-202 cores at the 100W level when I accidentally
transmit into the receive antenna through the transformer. I have smoked
the termination resistor but never damaged the transformer by transmitting
into them.

I have used single BN-73-202 cores at the several watt level continuously,
in step-up/step-down voltage inverter applications.

None of the above means that the core would survive a lightning strike.

The ferrite material is mechanically fragile. When (for example) PCB
mounting in outdoor conditions you have to take into account the lead
stress from temperature changes etc. I think the two-hole BN form is way
more mechanically robust than the skinny rings but I have broken both kinds
due to mounting them "too tightly down" to a PCB.

Tim N3QE

On Mon, Oct 5, 2020 at 7:19 AM tony.kaz--- via Topband <
topband at contesting.com> wrote:

> I use BN-73-202 cores for my receive antennas - Pennants, BOGs.
>
> Finally getting time to check out my receive antennas. One BOG was very
> low.
> The BOG transformer was broken. I mean it was totally destroyed. The
> largest
> piece was 1/8" long. The primary and secondary wires, #30 were intact and
> neither open or shorted. The wire looked pristine. Any ideas what could do
> that to a ferrite core? Any reason I should change anything other than just
> wire another transformer?
>
> N2TK, Tony
>
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