Racal (V)LF converter RA37 i.c.m. Racal RA17L (Techniek Radio/TV)

door S.Leunissen , regio Zuid Limburg, 17.06.2014, 12:19 (3815 dagen geleden) @ S.Leunissen

Ik had mijn verhaal ook uitgezet op de racal RA17L group op yahoo. En heb daar technische uitleg gekregen van een engelse zendamateur hoe deze apparaten nu samen werken. Ook heb ik van andere behulpzame leden veel info mogen ontvangen. Dit gezegd hebbende geef ik hier de technische uitleg weer weliswaar in het engels:

On the RA37, there is a toggle switch labelled 12-980kHz and 980kHz-30MHz, and there is a rotary switch which has one position labelled Wideband.
The RA37 draws HT current from the RA17 through the HT1 AND HT2 connections. When the RA37 Is in use, the HT current is removed from the RF stages of the RA17 to keep the load on the RA17 power supply constant and to stop RA17 front end noise from degrading the signal from the RA37 - this is the function of the toggle switch labelled12-980kHz and 980kHz-30MHz. The RA17 will obviously not receive any signal from a connected antenna as long as there is no HT on the RF stages. (equally, when the RA17 is in use, no HT is supplied to the RA37 and so no noise from the RA37 will degrade the signals being received on the RA17)
The Wideband position of the rotary switch on the RA37 only removes all the tuned elements from the RA37 front end (perhaps it would have been better labelled Untuned). The RA17 will continue to respond only to signals received through the RA37 connected antenna, though probablky with degraded signal to noise ratio as the RA37 front end is now untuned.
So to receive signals in the range 980kHz-30MHz, the antenna needs to be connected to the RA17 and the toggle switch on the RA37 needs to be in the 980kHz-30MHz position to provide HT to the RA17 RF stages. To receive signals in the range12-980kHz the antenna needs to be connected to the RA37 and the toggle switch on the RA37 needs to be in the 12-980kHz position to provide HT to the RA37. The rotary switch on the RA37 may be in the Wideband position or in the appropriate tuned band position.
Hope this helps
cheers
Peter G8BBZ

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groet Sander