Affichage digital pour IC402 par Thierry F6HLD [Hyper Bulletin No 266 mars 2020 page 8]

Cet affichage digital a été réalisé pour un IC402 utilisé dans une station SHF.
Après avoir vendu mon IC402 à Christian F1AFZ, plusiers OM lui ont demandé comment était
réalise l'affichage digital. Etant l'integrateur, la question má finalement été posée.

Après examen du schéma, l'appraieil utilise deux de fréquence:
-Un OL fixe piloté, au choix, par un de ses quatre quartz permettant ainsi de choisir le segment
de bande utilisé. Après multiplication la sortie est +/- 385,14 MHz en function de quartz selectionné.
-Un OL variable (le VFO) sur 48,86 à 47,06 MHz (VXO sur 15,... MHz multiplié par trois).
Donc la seule fréquence variable est celle du VFO.
La solution consiste à mesurer la fréquency du tripleur suivant le VXO et en y ajoutant, à l'aide
du prépositionnement, une valeur fixe permettant d'afficher la fréquence de 432,... MHz. Le
modèle PLJ-0802f (pour 8,5 € sur Ebay) permet de faire cela.
Fréquence du VXO 46,86 + 385,14 MHz (valeur du prépositionnement à rentrer dans le
fréquencemétre) = 432,000 MHz.
47,06+385,14=432,200 MHz pour le 1 er tronçon de bande.

Seul default de système, lors du changement de segment de bande, il faut rajouter mentalement
200 kHz à l'indication. Mais le traffic se limitant à 400 kHz c'est faisable! Vous pouvez au choix
changer la valeur de prépositionment pour obtenire 432,200 à 432,400 MHz.
On pourrait envisager un système plus complexe avec un melangeur qui tiendrait compte a de la
fréquence fixe et de la fréquence du VCXO pour obtenir la fréquence exacte... mais quel
gain réel?
Un seul endroit pour mesurer: le point CP1 (sortie VCXO), prelever le signal del'IC402 avec un
petit coaxial et l'alimentation du module. Le boitier a été réalisé avec de l'époxy et vient se
greffer sur l'IC402; les liaisons passent par le trou de l'antenne qui a été supprimée car inutile.
Si possible calibrer l'IC402 sur les différentes fréquences internes et vous serez sûrde votre
affichage.


Google translate:

Digital display for IC402 by Thierry F6HLD [Hyper Bulletin No 266 March 2020 page 8]

This digital display was created for an IC402 used in a SHF station.
After selling my IC402 to Christian F1AFZ, several OM asked him how it was
produces digital display. Being the integrator, the question was finally asked to me.

After examining the diagram, the device uses two frequencies:
-A fixed LO controlled, of your choice, by one of its four quartz thus allowing you to choose the band segment
used. After multiplication the output is +/- 385.14 MHz depending on the crystal selected.
-A variable LO (the VFO) on 48.86 to 47.06 MHz (VXO on 15,... MHz multiplied by three).
So the only variable frequency is that of the VFO.
The solution consists of measuring the frequency of the tripler following the VXO and adding, using
of offset, a fixed value allowing the frequency of 432,... MHz to be displayed. THE
model PLJ-0802f (for €8.5 on Ebay) allows you to do this.
VXO frequency 46.86 + 385.14 MHz (value of the prepositioning to enter into the
frequency meter) = 432.000 MHz.
47.06+385.14=432.200 MHz for the first band section.

The only system fault is that when changing the band segment, you must mentally add
200 kHz at indication. But traffic being limited to 400 kHz it is doable! You can choose
change the preset value to obtain 432.200 to 432.400 MHz.
We could consider a more complex system with a mixer which would take into account the
fixed frequency and the frequency of the VCXO to obtain the exact frequency... but what
real gain?
Only one place to measure: the CP1 point (VCXO output), take the signal from the IC402 with a
small coaxial and power supply module. The case was made with epoxy and comes
graft on IC402; the connections pass through the hole in the antenna which was removed because it was useless.
If possible calibrate the IC402 on the different internal frequencies and you will be sure of your
display.


Yandex translate

Digital display for IC402 by Thierry F6HLD [Hyper Bulletin No. 266 March 2020 page 8]

This digital display was made for an IC402 used in an SHF station.
After selling my IC402 to Christian F1AFZ, several OM asked him how was
realizes digital display. Being the integrator, the question was finally asked.

After examining the scheme, the device uses two frequencies:
-A fixed LO controlled, optionally, by one of its four quartz thus making it possible to choose the band segment
used. After multiplication the output is +/- 385.14 MHz in selected quartz function.
-A variable LO (the VFO) on 48.86 to 47.06 MHz (VXO on 15,... MHz multiplied by three).
So the only variable frequency is that of the VFO.
The solution consists in measuring the frequency of the tripler according to the VXO and adding to it, using
of the offset, a fixed value making it possible to display the frequency of 432,... MHz. The
model PLJ-0802f (for €8.5 on Ebay) allows you to do this.
Frequency of the VXO 46.86 + 385.14 MHz (value of the prepositioning to be entered in the
frequency meter) = 432,000 MHz.
47.06+385.14=432.200 MHz for the first band segment.

The only system fault, when changing the band segment, it is necessary to mentally add
200 kHz at the indication. But the traffic being limited to 400 kHz is feasible! You can choose from
change the preposition value to get 432,200 to 432,400 MHz.
We could consider a more complex system with a mixer that would take into account the
fixed frequency and the frequency of the VCXO to obtain the exact frequency... but what
real gain?
Only one place to measure: the CP1 point (VCXO output), pick up the IC402 signal with a
small coaxial and module power supply. The case has been made with epoxy and comes to
graft on the IC402; the links go through the hole of the antenna which has been removed because unnecessary.
If possible calibrate the IC402 on the different internal frequencies and you will be sure of your
display.