Any one made up the Jaycar Mini FM Transmiter.. (KC5341)

Seems to be full of Faults, the RF BP filter is shown the wrong way around,
can't use the 107mhz bands, wrong Vericap diode used as per the ROHM Data
sheet.


The one chosen is a 28v one with a limited Cap swing when use in the
Transmitter.

KV-1471E as per ROHM.


ZMV833ATA is no were near a equivalent as it has a larger voltage swing, so
ends up with a lower capacitor range.



If I spread the RF coil windings and with the slug nearly out I can tune to
the 107Mhz band.


But then you can't tune the 88Mhz band..



Some thing is drastically wrong with this design.

 

[wozzr]

Yes, its not a easy kit to build,
make sure the tuning coil is wound exactly as
specified, keep the turns close together
although the former jaycar supplies for this is not
very useful, try and obtain one from DSE.
I had lots of problems tuning in , and eventually
replaced the coil former and drilled out the hole to
suit the replacement one.
eventually got it going, better still , buy a Dick Smith
one if they are available there, they are much easier to get going
Cheers,
Wozz.

roger.s@para.net.nz wrote:

Seems to be full of Faults, the RF BP filter is shown the wrong way around,
can't use the 107mhz bands, wrong Vericap diode used as per the ROHM Data
sheet.

The one chosen is a 28v one with a limited Cap swing when use in the
Transmitter.

KV-1471E as per ROHM.

ZMV833ATA is no were near a equivalent as it has a larger voltage swing, so
ends up with a lower capacitor range.

If I spread the RF coil windings and with the slug nearly out I can tune to
the 107Mhz band.

But then you can't tune the 88Mhz band..

Some thing is drastically wrong with this design.

 

On Tue, 28 Dec 2004 18:03:07 +1000, wozzr <wozzr@coldmail.com> wrote:

Yes, its not a easy kit to build,
make sure the tuning coil is wound exactly as
specified, keep the turns close together
although the former jaycar supplies for this is not
very useful, try and obtain one from DSE.
I had lots of problems tuning in , and eventually
replaced the coil former and drilled out the hole to
suit the replacement one.
eventually got it going, better still , buy a Dick Smith
one if they are available there, they are much easier to get going
Cheers,
Wozz.

DSE dropped most of there kits here.

Yes Coil is pre specs, but even what tuning the 88 meg band I have to
stretch the windings a little just to get the slug into the coil former.

But to get it to tune to the 107 meg band that is almost impossible, have to
stretch the coil even more and the coil slug is way out..

roger.s@para.net.nz wrote:

Seems to be full of Faults, the RF BP filter is shown the wrong way around,
can't use the 107mhz bands, wrong Vericap diode used as per the ROHM Data
sheet.

The one chosen is a 28v one with a limited Cap swing when use in the
Transmitter.

KV-1471E as per ROHM.

ZMV833ATA is no were near a equivalent as it has a larger voltage swing, so
ends up with a lower capacitor range.

If I spread the RF coil windings and with the slug nearly out I can tune to
the 107Mhz band.

But then you can't tune the 88Mhz band..

Some thing is drastically wrong with this design.