Multiport aerial amplifier, masthead or distributor?

[Kes]

I'm having a little trouble with our TV watching, or Humax Fox T2 DVR watching actually. We can see all the freeview programmes we want through the Humax but when we record one prog and watch another the signal drops and often one or the other fails. This is noticable on the COM7 channel 55, I think the others are better. BBC HD News drops as soon as we record anything. We are in north Worcs and the signal comes from Sutton Coldfield.

We have an old (20 years+) MaxView 6-port booster in the loft, and long and no doubt cheapo coax cabling to three tv's. At the TV set signal strength is around 66-70% on most channels and 57% on channel 55 (COM7). Bypassing the booster the signal strength falls to mid 60% on most channels, 44% on COM7. I don't know what db this is, the Humax just shows percentages. Signal quality is 100% on everything.

I'm thinking of getting a new signal amplifier, initially a four-output Labgear LDA204L. I'm worried that this will do no more than the old MaxView amplifier. I see that I can get a Labgear masthead amplifier, LMA415VR, which has lower noise and a greater gain than the LDA204L. This would also be fitted in the loft, not very near to the aerial. Would not the masthead amplifier, with it's low noise and high gain, be a better buy?

We don't and won't have Sky, and I'm certainly not going up on the roof, by the way.

 

[Lucid]

If you are picking up from Sutton Coldfield then Com7 is now running a lower power signal. This is due to the recent reshuffle required to free-up the 700MHz band for selling off to 4G telecoms. That echoes what your seeing with your signal levels.

The good news is you've got 100% quality.

I think you're on the right lines with something that's variable power. Sutton Coldfield is one of the higher-powered transmitters. The PSB national muxes are running at 200,000W as are Com4. Com5 and Com6. I'd be reluctant to get something fixed level that's substantially more powerful than whatever the MaxView is kicking out. The risk is that you fix Com7 but overcook on PSBs 1,2 & 3 and Coms 4, 5 & 6 in the process. There's also the question of what happens when everything gets shoved below c49 which is the long term game plan. At that point you should be looking for a new aerial; something that works better at the lower channel numbers, but you don't have to do that right now. But you may find you need less gain at that point, so keeping your options open is a good plan.

There's no problem with running a masthead amp in the loft. The only real change I guess from the Maxview is that a Masthead amp uses a remote power supply; it sends juice up one of the coax downleads. That Labgear could be okay if 4 outputs meets your needs. I'd also have a look at an Antiference Series 75 MHK6. It has a gain adjustment range of 1-20dB so you can bring the signal level up enough to get decent Com7 without blowing the higher powered muxes out of the water.

Both the above would be straight replacements for the MaxView. Being a 20 year old design it's unlikely that the specs are online. Looking at their current range PSB6 and PSB8 both have a noise figure of 4.5dB. The MHK6 is 2.5dB, and without looking it up I'd be surprised if the Labgear isn't in the same ballpark too.

 

[Kes]

Thanks for all that info. I'll have a look at the Antiference, seems like a decent bit of kit and good figues too.

 

[Kes]

And to muse a little on my original problem, it seems that one can have a signal strong enough on all channels to watch any program on FreeView through the Humax. When watching on one channel and recording on another (the Humax has two tuners), or recording on two channels, it appears to be the equivalent to splitting the signal, and the consequent loss of signal strength can cause one or both channels to fail. This might be obvious to the experts but isn't widely mentioned.