Baron wrote:

ian field Inscribed thus:


"Baron" wrote in message
...
ian field Inscribed thus:

Does anyone have schematic/plans for a Band III (175 - 240MHz)
antenna booster?

Thanks.

65Mhz ! Thats a pretty big bandwidth to cover.


Is Band III still used for TV in the US?

I don't know ! The guy that will know is Michael in SED.


That would be 'high band' VHF in the US which runs from 174 to 216
MHz

I've used this style of amplifier for at least 25 years:

http://www.mcmelectronics.com/product/33-917&cid=prodCrossSell

Which works from 5 MHz to 950 MHz


They sell the power supply separately, or you can build your own:

http://www.mcmelectronics.com/product/DISTRIBUTED-BY-MCM-PS-10-/33-915

This is a typical one piece amp:

http://www.mcmelectronics.com/product/33-290&cid=prodCrossSell


A simple, DIY amp can be built on a piece of single sided PC board
with one of the monolithic amps from Minicircuits

http://www.minicircuits.com/pages/app_notes.html They sell individual
amp hybrids, hybrid assortment kits and development kits.

Most are designed for 50 ohm, but a six hole ferrite bead (Like those
used in baluns) are easy to make a 5 turn to six turn RF transformer
which will convert the impedance to about 72 ohms.

You should have little or no problem finding a local source, since
they are used in a lot of commercial radio equipment.


By the way, do do know that I'm not in the USA. I'm just up the road
from you. :-)

A google search turned up a few results, but mostly bipolar - most of
the bipolars I have with adequate fT are in scrap TV tuners, they're a
bit fragile!

I do have a small stash of SMD medium power bipolars, but they weren't
cheap.

BFR91's are good up there.

What I had in mind was something simple with a BF991, the plan is to
re-radiate from the communal aerial who's socket is diametrically
opposite the radio and no easy way to route a cable.

You might find that phase differences in the direct and re-radiated
signals cause problems.

The walls are plastered on steel mesh, so the room is pretty much a
faraday cage - no chance of feedback to the master aerial.

Mmm I've never seen that done in a domestic property. Its usually only
the corners that have a steel edging strip. The only other time that
I've seen steel used, is as re-enforcing in prefabricated concrete
construction or the old style window and door frames.

--
Best Regards:
Baron.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.