DxPatrol frequency offset

PA3AXO · Nov 25th 2020

I purchased a mk3 up and down converter to work with a FT857 transceiver and home brew PA.

All set for 432 LO.

Reception is great and accurate.

Transmit works wel but is always 500 kHz above the RX frequency to my surprise.

Very inconvenient !

Dxpatrol responds that this normal and caused by the satellite transponder.

That is true but the 500 kHz can easily be corrected by a small change in LO frequency I would say. 1967.5 instead of 1968 MHz

I wonder how others work Q100 simplex with these devices

Jack

PA3AXO

PA3FYM · Nov 27th 2020

Yes, I had this from the beginning (12 Feb 2019) but nobody understood me

and I was 'crucified' for (suggesting) working 'simplex'. 😇

HB9SKA · Nov 27th 2020

If you select the DownConverter to 144.5 MHz and the Uplink Converter MK3 to 432 MHz then it should work Full Duplex. Where is the problem ?

Edit: The FT-857D is not full-duplex capable, you need a 2nd receiver. Is this the "problem" ?

PA3FYM · Nov 27th 2020

Quote from HB9SKA

Edit: The FT-857D is not full-duplex capable, you need a 2nd receiver. Is this the "problem" ?

My definition of a 'problem' is an 'un- or suboptimal solved issue'. Because I have no 'issue' with transceive mode, I have no 'problem'. 😇

ON4CJQ · Nov 29th 2020

Jack

If you check the bandplan, you see why there is a 500kc difference.

Using the FT857 is not a problem, just use it in SPLIT, band A for rx and band B for tx or vice versa. Ones you know your shift between up and dwn link, it's easy to use.

73's

Jerry

DxPatrol frequency offset

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