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View Full Version : UHF Masthead Amp replacement - help needed finding product

MorrisR
21-04-2005, 4:49 PM
Please bear with me - first post. Have searched FAQs and think that this is right forum, but not sure.

I want to replace an old masthead amp ( and even older 12V PSU) with an in loft head amp. I want variable gain, low noise, 240V supply instead of 12V. Min is UHF in and one output, but would prefer UHF and FM in, and two outputs, each with multiplexed UHF/FM. (FM is a future project)

Any bright ideas?

SLx4L nearly does it, but no variable gain.
Televes 5392 nearly there, but only one output, and am not sure that it actually replaces masthead, as has option for pre-amp input and LV supply to preamp.
Not convinced that Labgear MRX352 or MSR340 fit either.

Yes, I know that I could put a masthead in the loft (approx 2m from external aerial), but don't want the 12V supply, and anyway can't find an appropriate masthead which fits the bill either.

Richard ( dazed and confused)
gbmitie
21-04-2005, 5:54 PM
have a look here but u will have to purchase from a dealer.

http://www.johansson.be/htmen/searchprod.php

hope I can post a live link!
gbmitey
MorrisR
22-04-2005, 8:11 AM
What a star !! The Johansson 7490 does exactly what I want, except for power supply which is no real problem. It also has "F" connectors, which was a desire but had to be optional given that I couldn't find anything.

many thanks,

Richard
vex
22-04-2005, 10:10 AM
Why do you need variable gain on the network?
MorrisR
25-04-2005, 10:05 AM
Other manufacturers' advice is to beware overloading device inputs. I thought that variable gain was likely to be better than fixed gain and additional variable attenuator(s) . I don't have access to signal strength meters and the like. However, given that Johansson's British distributor hasn't got back to me yet, I may need to rethink.
vex
25-04-2005, 11:16 AM
The simple solution to overloading of either input stages of the amplifer or the viewing devices is to knock the antenna off-line slightly, thus reducing the received signal level.

Used to be common on analogue satellite receivers, but AFAIK less so now with Digi Sat and UHF signals. Receive devices are much more tollerant.

Let me know if you have problems with the importer - Martin Turner Direct IIRC.