Re: Dual band feed query


Hello John,

As per DL3IAE, I do it the same way, by putting all relais in TX when operating a band in tx. Using 3 seperate stations(transvertr ampli preamp sequencer relay) in a box per station, using 1 IF radio. Switching all sequencers when transmitting to put all relais in TX. No problems yet(100w 23cm, 75w 13cm, 10w 3cm)

Looking for stations using RF-Hamdesign mesh dishes on 3cm. Plse contact off list.


----- Oorspronkelijk bericht -----
Van: "john" <john@...>
Aan: "UKMicrowaves" <>
Verzonden: Donderdag 15 augustus 2019 14:35:23
Onderwerp: [UKMicrowaves] Dual band feed query

Hello all

I have a dish with a dual band loop feed for 23 and 13cms. Coupling between
the two loops is high; between 15 and 20dB, so I need to take action to
protect equipment on whichever band is not in use. This is particularly the
case when I transmit on 23cms, with around 300w.

Protection could be achieved with an additional relay, although making this
totally idiot proof may not be as simple as I first thought.

It's also become evident that I need a bandpass filter in front of the 13cms
transverter, due to problems from a nearby mobile phone mast. I have a
suitable filter - it just isn't fitted yet.

But, my question is, can the filter also perform the function of protecting
the 13cms equipment when I transmit on 23cms? It's attenuation at 1296MHz is
some 75dB. I favour this option if possible because I feel it is more

Thoughts please ?

John G4ZTR

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