[mythtvnz] Freeview-T UHF Antenna in strong signal area

[Stephen Worthington]

On Fri, 4 May 2012 23:13:22 +1200, you wrote:

>>
>>
>>
>> 1: Get a medium/high gain antenna and mount and cable it properly. Get rid
>> of the soon to be useless VHF antenna.
>> 2: Put a mast head amp in. (I like the Kingray ones)
>> 3: Relocate the antenna to the other side of the house which has line of
>> sight and effectively divides the required cable length by 3 at least.
>
>
>Hi All,
>
>Sorry for the somewhat late reply to my original thread but things have got
>in the way with playing around. I have got back to it in the meantime
>though and got some interesting result. So I thought I'd share.
>
>I decided to get another antenna after the current one fell apart when I
>tried to move it after I removed the VHF antenna. Got a "antsig" 42 Element
>one. No mast head amp, no splitters, no diplexers. Directly from the aerial
>to my mythbox.
>
>1: HVR4000 still perfect signal
>2: Nova TD500 signal!!
>3: HVR2200 no lock what so-ever
>
>That's where I got to before I got sidetracked for a couple of weeks. I've
>been watching HD-TV occasionally to see how it performs and after some good
>results I decided to give the Nova-TD500 the highest input priority..   2
>days later.. unwatchable recordings. Artifacts all over the place. It was
>not even bad weather?
>
>So I've been experimenting. primarily using the HVR4000 as  "femon" seems
>to work quite well with it. I tried taking some elements off the antenna
>(making it a 21 element) as I thought it might have too much signal. I also
>tried a mast head amp and played with the gain just to see what the effect
>is.
>
>HVR4000 half ant (21 element, no mast head amp) (NovaTD500 & HVR2200 would
>not get a lock)
>status SCVYL | signal  21% | snr  99% | ber 69 | unc 0 | FE_HAS_LOCK
>status SCVYL | signal  21% | snr 100% | ber 0 | unc 0 | FE_HAS_LOCK
>status SCVYL | signal  21% | snr 100% | ber 0 | unc 0 | FE_HAS_LOCK
>status SCVYL | signal  21% | snr  99% | ber 5 | unc 0 | FE_HAS_LOCK
>
>HVR4000 half ant (21 element), mast head amp on 100%  (NovaTD500 & HVR2200
> would not get a lock)
>status SCVYL | signal  21% | snr  97% | ber 737 | unc 26 | FE_HAS_LOCK
>status SCVYL | signal  21% | snr  98% | ber 761 | unc 0 | FE_HAS_LOCK
>status SCVYL | signal  21% | snr  98% | ber 403 | unc 0 | FE_HAS_LOCK
>status SCVYL | signal  21% | snr  98% | ber 563 | unc 1 | FE_HAS_LOCK
>
>HVR4000 full ant (42 element), no amp  (NovaTD500 would get a lock, HVR2200
>would not)
>status SCVYL | signal  21% | snr 100% | ber 0 | unc 0 | FE_HAS_LOCK
>status SCVYL | signal  21% | snr 100% | ber 0 | unc 0 | FE_HAS_LOCK
>status SCVYL | signal  21% | snr 100% | ber 0 | unc 0 | FE_HAS_LOCK
>status SCVYL | signal  21% | snr 100% | ber 0 | unc 0 | FE_HAS_LOCK
>
>Interestingly (and a bit as expected), best reception seems to be with not
>using an amp and using 42 elements. I'm not sure if the signal level and
>snr actually correct, but the "BER" (Bit Error Rate) and "UNC" (number of
>uncorrected blocks?) seem to be actually work. I've left the antenna with
>42 elements and no mast head amp.
>
>I'm still at a bit of a loss here. I know I can improve things still more
>by moving the aerial to the other side of the house and replacing the cable
>with a new (so known good) one, but I'm not convinced. It should not be
>that hard? I have NEVER had reliable reception with DVBT on my mythbox.
>(well.. apart from the HVR4000). Maybe just get 2 of those :)
>
>Just to try, I have put the HVR2200 in a Win7 box. Installed the drivers
>and had clear TV. Sometimes some artifacts but only just after tuning. I
>would like to try the "firmware" that the win7 drivers use on my mythbox
>but have not found a way to extract them.  Has anyone done something
>similar? (currently using these
>http://www.steventoth.net/linux/hvr22xx/firmwares/4019072/NXP7164-2010-03-10.1.fw
>)
>
>Cheers
>Johan

If those signal level % values were from the TD-500, I would say they
were way too low.  But as far as I can tell, the numbers from each
card are only comparable to the same exact model of card.  For the
TD-500, if I am remembering correctly, you need > 65% signal level
before it will record reliably.

When you are getting lock on the HVR-4000 and TD-500, is that at the
same time, or are you moving the cable between them?  If so, then
adding the necessary splitter and its 6? db drop in the signal levels
is going to cause problems.