Thanks Walt. I'll give that a try and see what happens. I still have that small batch of crystals on my bench.

73

Mike M.? KU4QO

On Sun, Mar 16, 2025 at 2:05?AM Walter Thomas/K3ASW via <wt3i14297=[email protected]> wrote:

G3URR crystal measurement method

Mike,

In one of his more recent postings to his website (~last two or three years), W7ZOI changed the oscillator's emitter resistor from 1K to 3k3 to reduce drive to the crystal under test and noted more stable readings when doing the measurements.

Regards,

Walt ? K3ASW

On Thu, Mar 13, 2025 at 1:03?PM chuck adams via <chuck.adams.phd=[email protected]> wrote:

What is SSB?? :-)

Yes, you're right.? Yes. Please post.? We need more data.
There are always tradeoffs between the two crystals.
One operates in the shear mode and the other in the
flex mode.? One of the reasons I want a internal photo.
Some machinist is going to have to do that as I no longer
have my mill and lathe.

I didn't think (do I ever?) to do a search of youtube and
now I find several videos on measuring different ways.
I did not compare with G3UUR fixture, but we can add that
to the list of 'to do' things or better known and 'bucket
list'.

chow,

chuck, look at the leader of 'send in the clowns'

On 3/13/25 09:48, Michael Maiorana via wrote:
> Hi Chuck,
> Yes, the HC-49S crystals can have excellent Q, but their Lm to Lc
> ratio is very high which makes them impractical for use in wider
> filters (SSB, etc).
> I have some measurements somewhere. If you'd like, I can dig them up
> and post them.
> 73
> Mike M.? KU4QO
>
> On Thu, Mar 13, 2025 at 11:44?AM chuck adams via
> <> <chuck.adams.phd=[email protected]> wrote:
>
>? ? ?One more thingy.
>
>? ? ?I forgot to mention.? If you will note, the K7QO paper had one HC-49S
>? ? ?(the short
>? ? ?crystal).? In a current shopping spree I find that the HC-49U has
>? ? ?practically
>? ? ?disappeared from the face of the earth.
>
>? ? ?But that may be a good thing.? Note:? the HC-49S crystal in the paper
>? ? ?had the
>? ? ?highest Q rating!!
>
>? ? ?Figure 1 in Chucks paper shows a HC-49U carefully taken apart. Try
>? ? ?to find
>? ? ?a photograph of a HC-49S.? I dare you.? Some take one apart and do
>? ? ?a high
>? ? ?resolution photo.? Please.
>
>? ? ?chuck
>
>
>
>
>
>