We are experiencing major network shows that do not record on the Recast because of an insufficient signal. However, we also have a HDHomeRun Quatro feeding Plex, and the Plex DVR is properly recording those same shows (with apparently excellent quality, at least to a non-expert viewer). OTA signals are subject to strength variations based on certain weather patterns, but if the HDHomeRun can receive the signal, why can't the Recast. This doesn't make sense. [We have both tuners because my wife uses the Recast to record her shows and I use Plex to record movies which I subsequently edit to remove commercials and save so that my father-in-law has plenty to watch when he visits. Now I have to record her shows using Plex, too, because she's missed several shows in the a couple of the series she follows.] Is something wrong with this specific Recast device? Is it just a less sensitive tuner? Sure would appreciate some advice...
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Are you two DVRs utilizing the same antenna signal via a splitter (powered or unpowered) or are you using two different antenna sources. If you are using two antenna's switch devices to see if the Recast DVR follows the DVR or stays with the antenna.? Before the early February release (3 or 4 February), I had issues with some of the Recast channels that I did not when I switched my television input to the antenna. Since that release, I have not had the pixilation issues I had before February and the replay has been flawless and comparable to the image I receive directly from the antenna (going through a channel master powered 4 way and a powered 2 way splitter to provide signals to 4 TVs as well as the Recast box.)
In DTV, signal quality is a greater problem than signal strength. Even a strong signal can be degraded by multipath (formerly "ghosting") or by interference. I had problems with a 2-tuner Recast on WFYI/Indianapolis on physical CH21 in spite of a clean, strong strong signal as viewed simultaneously on a spectrum analyzer. Recast's "weak signal" popups can represent recoverable errors as well as a weak signal, but if frequent enough, such errors can cause pixellizations and freeze-ups. In my setup, the same split signal applied to a flat screen instead of the spectrum analyzer was received perfectly while the Recast pixellated or froze, suggesting some weakness in the Recast itself.
As the Recast regrettably has no signal quality (SNR or error rate) indication, aiming an antenna is nearly impossible without a spectrum analyzer, although splitting the signal into a flat screen or other receiver that does have a signal quality indication may help. Judging "better" or "poorer" is a matter of judging the frequency of errors. I traced my problem to having a strong, nearly co-located station on CH20 because I could reduce the rate of errors from several per minute at times to an hour between them by weakening that adjacent signal with a homemade coaxial trap.
I was also having to make tradeoffs between programs for the lack of an available tuner, so when a price promotion appeared on amazon.com, I purchased a 4-tuner Recast. It worked substantially better, maybe an error every few hours on WFYI CH21 without the CH20 trap, and has shown no errors for multiple hours of viewing WFYI with the trap. There thus appears to be adjacent channel rejection variations from unit to unit and possibly tuner to tuner. This suggests another diagnostic that I didn't try: while having frequent errors on a particular channel, "tie up" the default tuner by starting a recording of a long program on a more reliable channel then resume watching the problematic channel with the next available tuner. If the errors cease, then the first tuner is probably not meeting standards, which problem you can take up with Amazon.
You can query the FCC’s TV database for the call sign of a problematic channel to find its current physical channel, then query for your city to identify any adjacent channels. These appear to still be rare at the moment, but some stations will move later this year under the FCCs “repacking” initiative. Those will show both a license for the current channel and a “construction permit” for the new one. The FCC is no longer following its adjacent channel distance rules based on lab measurements that showed early DTV tuners would tolerate packed channels and the assumption that they would only improve over time, but that assumption may not hold for newer, cost-reduced tuners.
Adjacent channel traps are not difficult to build, but are impossible to tune finely enough without specialized lab equipment. If you have two UHFs and they aren’t co-located, a horizontally directional antenna properly aimed to throw a null at the stronger one may help; otherwise you can hope that the repack will move the interfering channel.
In DTV, signal quality is a greater problem than signal strength. Signal quality can be also degraded by multipath (formerly ghosting) or by interference. I had problems with a 2-tuner Recast on WFYI/Indianapolis on physical CH21 in spite of a clean, strong strong signal as viewed simultaneously on a spectrum analyzer.
My brother-in-law also has problems with WFYI on his Recast. So you used some sort of notch filtering on channel 20 (WHMB-FOX)? I see that station is supposed to move to channel 7 this year. Rabbitears.info says the power will go from 530 kW to 29 kW yet serve a GREATER population. (assuming everyone buys a new antenna).
I'm not sure I'd want to sacrifice FOX for PBS.
(someone on Facebook was just asking about notch filters and I pointed him to Holland Electronics for some cheap ones. Others suggested more expensive versions.)
My solution is a handmade trap consisting of 1" copper pipe, a 5.45" 18-gauge copper center conductor, and paralleled, hence 25 ohm, 1/4 wave transformers of RG316 coax in and out. I found it to be most effective when tuned to the upper part of CH20 (511.6 MHz) where it provides 40 dB attenuation in the notch with 1.1 MHz between the -30dB points. Its return loss is around 15dB so I put a second preamp behind it, though I'm not sure that's necessary. The construction details of the trap are simple, but building it to dimensions would never hit the desired channel closely enough. Tuning by means of a loading screw impinging on the open end of the center line requires a spectrum analyzer with tracking generator, a network analyzer, or the like to do, but mine has been stable once tuned.
The CH19/CH20/CH21 triplet in Indy appears to be rare. Other posters having problems with a single channel, e.g. Raleigh-Durham, don't show adjacents to their desired channel in the FCC TV query, but some FCC observers predict the Repack will eventually compress the entire UHF broadcast allocation down to 15 channels, in which case, receiver performance to the ATSC's A/74 recommendations will become critical - and some products mght not make it. In the WFYI case, the CH20 signal appears as an extension of the vestigial sideband of CH21. It's uncorrelated to CH21 (so it acts as noise) and must be rejected in the rolloff rate of the tuner's RRC filter.
The panel of DTV receivers available to the FCC when the Repack was proposed appear to have been double conversion designs using SAW filters. Those are considered too costly now, so the popular technique appears to single conversion with Root Raised Cosine (RRC) filtering by a DSP in the low IF. I have no information about the Recast's hardware architecture, so I'm guessing that is what is used. A DSP algorithm is what it is, but its performance still depends on the quadrature accuracy between the I and Q injections and the linearity of the I and Q A/Ds, all of which might vary from chip to chip. A triplet also presents intermod potential that has been identified as a potential problem with the Repack, but I saw no evidence of that.
My second, 4-tuner Recast would error once every few hours on WFYI without the trap. It has viewed or recorded WFYI for dozens of hours so far without a single glitch with the trap. That might have all been on just one of its four tuners, but I haven't had time to try pushing WFYI onto the other three tuners without the trap to see if they all perform the same. I'm happy with the solution, at least. The trap has no effect on WXIN/FOX/CH45, though we seldom watch it. There is nothing of interest to us on WHMB.
I was unaware of Holland, but after looking at their web site, they surely could provide something better as a custom.
Thanks for all your help and advice to other posters on this forum.