Confused of Cambridge!

The place for discussion about the 4-channel WinterHill DATV Receiver
Post Reply
G0DDX
Posts: 14
Joined: Tue Oct 10, 2017 8:38 am

Confused of Cambridge!

Post by G0DDX » Sat May 22, 2021 2:53 pm

Ok, I have got a 1.2m Offset dish correctly pointing at the sat. I have a (new) Bullseye lnb on it, and its rock solid working perfectly on NB.

There are some things I cannot get my head around. I have read the documentation several times and find it hard going. I mean some things are obvious to the writer, but not to others like me!

There are 4 receivers, and 4 sockets. Logically that's one socket per receiver.
When I have a cable (to the lnb) in Nim A, Top socket, I get the beacon, with the garbled video and good audio, AND I then have got a P5 picture on VLC window 2 from a Amateur DATV transmission as well, despite NO other lnbs being connected.

What I cant seem to figure out is which Nim socket is associated with which receiver. Sounds daft, but I cant see anything in the docs to tell me.
Logically I would expect Nim A Top to be rx1 and, the bottom to be rx2, and Nim B to be Top for rx3 and bottom for rx4.
OR Nim A to be rx 1and 3, and Nim B to be rx 2 and 4.

When I first fired up my Winterhill, I got P5 with good audio from the beacon.
Now I cannot get the beacon video as its garbled with vertical striping, although the audio is still good.
I don't understand why I get garbled video on Vlc Window 1, and P5 picture on Window2 (This is the G8HKN transmission in the picture)despite only one lnb cable being connected.

Can someone tell me which socket Nim a/b, top / bottom etc is associated with which receiver (1-4).

Also how the hell do you change a frequency on the Winterhill in Local mode with a keyboard and mouse. Basically I cant see or understand how to drive it. Maybe this is the answer to the above issues! Is there an "Idiots Guide" ??

I think I am getting a good Signal from the Sat, as the Beacon Mer is always around 8, is this good?
Furthermore the Launch window is scrolling (in Red) like crazy, they look like error messages (see picture below).

In desperation, I have completely rebuilt the Rpi software from scratch, and its still the same.
I have checked the PCB for solder bridges, and poor joints and cannot find any. I have been soldering for more years than I can remember, (ex BT Engineer) and am not a novice. I have several SMD other projects which worked! (including 2 x Minitiouners)

I need some pointers please.

Regards
Geoff
G0DDX
20210522_145845sm.jpg
20210522_145845sm.jpg (641 KiB) Viewed 2558 times
20210522_144853sm.jpg
20210522_144853sm.jpg (1.2 MiB) Viewed 2558 times
De Geoff
G0DDX

G4EWJ
Posts: 1358
Joined: Wed Feb 17, 2010 10:11 am

Re: Confused of Cambridge!

Post by G4EWJ » Sat May 22, 2021 3:32 pm

Hi Geoff,

The A71A beacon on 10491.500MHz regularly goes bonkers and you get the messy video that you see. It gets reset overnight, so it may be OK tomorrow.

>>There are 4 receivers, and 4 sockets. Logically that's one socket per receiver.

No. The NIM effectively has an RF router on each F socket. The default configuration for WinterHill is to feed the LNB signal into the TOP F socket on each NIM and route the signal coming in on the TOP socket to both receivers in that NIM.

The WH system has 4 receivers: RX1 and RX2 are in NIM_A and RX3 and RX4 are in NIM_B. Each of the 2 receivers for a NIM can be independently fed from the TOP or BOT F socket on that NIM. This is selected in the receive command sent to WH.

If you are using QuickTune, each receiver in the settings can be set to FPlugA, which is the TOP F socket, or FPlugB, which is the BOT F socket. The default for WH is to always use FPlugA (TOP).

The MER wil vary depending on how many other TV stations are using the transponder. On a clear transponder, I get MER 10.9 on the beacon on a 1.2m, but there will be some variation depending on your LNB.

You can often get VLC errors in the launch window, even though video is being displayed OK. It may be complaining about the faulty beacon data, although mine isn't doing that.

There isn't a way to change a frequency directly on the Raspberry Pi. The options are to use QuickTune on a PC for QO-100, or the Receive Commander software (whpcrxcom) on a PC, which can set any frequency. Setting up both is described in the Operations manual.

Brian

Edit: corrected 'Remote Commander' to 'Receive Commander'
Last edited by G4EWJ on Mon May 24, 2021 11:34 am, edited 1 time in total.

G8HKN
Posts: 52
Joined: Mon Jan 21, 2019 4:04 pm

Re: Confused of Cambridge!

Post by G8HKN » Sat May 22, 2021 7:20 pm

Hi Geoff
Thanks for the P5 report
The Beacon has good and bad days!
My receive dish is 1M with Octagon pll lnb and with an empty
transponder gives a mer of just over 9.
73 Roger G8HKN

G0DDX
Posts: 14
Joined: Tue Oct 10, 2017 8:38 am

Re: Confused of Cambridge!

Post by G0DDX » Mon May 24, 2021 2:37 pm

Thanks guys,

I'm still a bit of a beginner at these frequencies despite being licenced for 40 years!

I suppose I'm trying to do too many things at once.
I've always had trouble learning from a book. I need to actually do things, or hit it with a hammer etc to get an understanding of things. Which makes it hard for me when I'm on my own.

But I'll keep plodding on. I'm nearly there.

Thanks for the help and support.

Geoff
G0DDX
De Geoff
G0DDX

Post Reply

Return to “The WinterHill DATV Receiver”