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All posts by KC

Below are all of KC's postings, with the most recent are at the bottom of the page.

I live in Cheltenham and have a high-gain wideband ariel directed NW at Ridge Hill. Unfortunately (as well as receiving DVB transmissions from Ridge Hill on C21, C22, C24, C25, C27, C28, C29, C30 and C32) transmissions from the much further away Wrekin transmitter on C23 and C26 can be decoded which throws the channel allocation in my TV - i.e. weaker Wrekin-sourced versions of channels are given preference over stronger Ridge Hill multiplexer-transmissions of the same channels.

So I no longer retune the TV using automatic mode and have resorted to nominating individual channels (not including C23 and C26) when retuning the set.

Are there plans to overcome this undesirable transmission competition from weaker further-away transmitters?

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Dave Lindsay, responding to your question about overcoming the undesirable transmission competition. I would expect a standard solution to be incorporated in to the DVB standard for use during automatic re-tuning of a DVB receiver.

In my case, my PVR reports this table of tuned in frequencies:

Channel Frequency Strength Quality Network Mux Type Channels
21 474.0 MHz 60% 100% Gloucestershire COM4/SDN DVB-T(SD) 32
22 482.0 MHz 61% 100% Gloucestershire PSB3/BBC B DVB-T2(HD) 6
23 490.0 MHz 31% 100% West Midlands PSB2/D3&4 DVB-T(SD) 9
24 498.0 MHz 57% 100% Gloucestershire COM5/ARQ A DVB-T(SD) 32
25 506.0 MHz 61% 100% Gloucestershire PSB2/D3&4 DVB-T(SD) 9
26 514.0 MHz 33% 100% West Midlands PSB1/BBC A DVB-T(SD) 22
27 522.0 MHz 55% 100% Gloucestershire COM6/ARQ B DVB-T(SD) 29
28 530.0 MHz 61% 100% Gloucestershire PSB1/BBC A DVB-T(SD) 22
29 538.0 MHz 60% 100% Gloucestershire PSB2/D3&4 DVB-T(SD) 1
30 546.0 MHz 30% 100% West Midlands PSB3/BBC B DVB-T2(HD) 6
32 562.0 MHz 51% 100% Gloucestershire COM7/ARQ C DVB-T2(HD) 10

The undesirable ones received from the Wrekin have the "West Midlands" network id. Only the C23 and C26 instances cause me an issue because the automatic re-tuning (on both TV and PVR) see them before their (more preferred because of less noise) Ridge Hill brothers: i.e. PSB2/D3&4 on C25 and PSB1/BBC A on C28.

So arbitration logic based upon scanning for multiplexors and comparing their network and muliplexor id info, along with signal strength and quality (to me) does not seem beyond the processing capability of a DVB receiver's CPU.

The question should probably be: how big is this problem across the DVB user community? Including the bulk of users that never go passed automatically retuning their sets. Will changing the automatic re-tuning algorithm be cost effective?

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For the last week or so the channel 21multiplexor's output has been flakey on my TV. Looking at the channel 21 signal shows circa 65% strength and most of the time signal quality is 100%. But quality sporadically drops to below 80% - whatever that means.

All the other tuned in channel multiplexors are also circa 65% strength, but their quality stays consistently at 100% - I see no sporadic drops.

I suspect the channel 21 issue is not in my TV or aerial.

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