Repeater for weak DTT signal area

[Apsattv]

Suppose their was a situation where a small community was wanting DTT service but were in a dead hole signal wise.

Let's assume its a remote rural area with a suitable hill top reception site from a main DTT transmission site.

What would be the simplest design for a "hilltop booster"?

Back to back yagi's?

any thoughts on a theoretical construction?

[musikdj]

From what I've seen the line of work I do, the infill sites are linked with a fibre ring and are line fed, from the same encoders/servers as the main sites, but I have heard in remote areas of the use of a satellite feed for the muxes.

[Apsattv]

In the early days of NZ television, many locals setup their own repeater or booster sites to officially/unoficially bring signals into regions that had no reception.

I'm talkng about D.I.Y boosters/gapfillers / passive antennas on Hilltops, maybe a little amp in between (ooops just theory no license= illegal :rolleyes:)

Is there anyone reading that has built or designed such a thing?

[Rose]

It can be done... Not sAying you should however... As long as the isolation between rx and tx Antennas is less than the amplifier gain you insert between them then you can build a gap filler for cofdm signals. The other trick is to ensure that all signals seen by the dtt rxs in the coverage area (both direct and via the repeaters) fall inside the gaurd interval. It is done overseas as low cost infill.

[shadownz]

I do remember a small town called Whangamomona setting up a repeater from Mt Egmont (pre digital days) and them getting into trouble due to not having a license to do so.

Anyway, can the DTT infill sites be microwave fed? I noticed where the Hamilton infill is there is a microwave dish pointed at mt te aroha, I just assumed the signal is piped in that way. Can the signal just be "rebroadcast" ? (receive the UHF signal and retransmit it on a different freq)

[Rose]

I do remember a small town called Whangamomona setting up a repeater from Mt Egmont (pre digital days) and them getting into trouble due to not having a license to do so.

Anyway, can the DTT infill sites be microwave fed? I noticed where the Hamilton infill is there is a microwave dish pointed at mt te aroha, I just assumed the signal is piped in that way. Can the signal just be "rebroadcast" ? (receive the UHF signal and retransmit it on a different freq)

Yes sure could. A simple frequency shift would re transmit any errors on the input though and if the margins were low the final wtb could struggle to rx the Signal the reapeater I described above would do the same. Seperating the rx and tx paths would allow for error correction and ensure radiated signals were clean,

[wiilliiss]

repeaters are easily done with channelised amplifiers and a respectable input signal. now the question is not if it can be done but the crucial bit is will the broadcasters pay the liscencing costs demanded by the ministery? who charge $100+ to issue each licence & $45 per year per frequency.
programme content is copyright & broadcasters wont generally allow private licensing of private apparatus carrying their programming.

[Apsattv]

I was hinting at a simplified not so legal approach.

Example

A small rural location with a couple of farms. A reception dead spot with no UHF reception either now or futurewise. A good DTT signal available when tested on local hill top from a Transmission site located 150K away.

Only choice for HD is Sky..:rolleyes:

But for a few $ and some DIY ;) FREEVIEW HD might be within reach.

[wiilliiss]

there is a certain beach where the campground is out of reach of satellite signals so an informal dtt relay will pop up there soon. the men from the ministry will find it eventually though.

[shadownz]

it must be next to a very high hill or have high trees if it can't get satellite ;)

[wiilliiss]

at the base of a very large,steep forested hill

[kiwisteve]

The MED / RSM will issue there normal $ 1200 Infringment notice
for any unlicenced or transmission not conforming to a licence

this includes TV under management rights :D:D:D

[Apsattv]

I thought a passive device such as a signal deflector? might work well for DTT. A 3M high metal water tank on the hilltop should do it

[Apsattv]

This design looks simple to follow..

[Rose]

This design looks simple to follow..

Simple in concept, but unless constructed carefully, could turn into an ocsillator ...

If the input signal is reasonable and the RX location nearby, then what might work is a passive repeater - interconnect two high gain antennas with low loss feeder - point one at the Kordia DDT transmitter site to collect the input, the other at where you desire coverage as the output. Obviously, what actually gets to the RX location will be small, but if you are lucky useable. Havent looked at the legal side of things, but you may not even need a license....

[kiwisteve]

Quite Common on Low and High Band

Coupling loss may reduce the effective system advantage
unless the input signal is very strong !!! You have to look very carefully at Spectrum licence condition re legality

I think the cellular operators have the same issue with ON SITE extenders !!:D

[kiwisteve]

Broadcasting 007.doc Page 1 of 1 Issue 1

Document Section Number Issue

POLDOC Broadcasting 007 1

File Reference: RSM 1/4/1 Date of Issue: 29 May 1996

RADIO SPECTRUM POLICY

BOOSTER SYSTEMS FOR REMOTE AREA TV

1. Policy.

Licences are to be granted for a maximum of five years only to avoid preventing the creation
of more permanent coverages.

2. Specific Criteria.

A single licence would be provided with frequencies suitable to re-transmit the UHF TV or VHF TV
services nominated by the applicant, although separate licences would be required where the
frequencies are under separate management rights.
Licence applicants must agree in writing to cease transmissions immediately if interference occurs on
frequencies other than those specified on the licence. Transmissions may recommence once an
appropriate action to avoid the interference has been taken. The applicant must also agree that any
interference to existing reception from the main signal would be remedied. The applicant is responsible
for the costs incurred in remedying the interference where the interference is caused by the booster
system
Licences will be granted for a maximum of five years and will specify a maximum population
coverage.
Licences will not be granted for commercial use.
Licences will specify a maximum effective isotropic radiated power (eirp) of 0.5 watts per frequency.
The eirp may be increased at the discretion of the Ministry where the signal is weak. A Receive
Coverage Location (RCL) will be specified close to the site and the Maximum Permitted Interfering
Signal (MPIS) will be specified at a very high level.
No resource rental will be payable, though normal engineering and regulation fees will apply.

3. Background.

"On channel booster" systems involve amplifying and re-transmitting incoming signals to a pocket area
on the same frequency. There are limitations as to the coverage possible (say up to 1-2 kilometres),
and such systems are often temporary until a more permanent solution is found. For this reason, and to
avoid restricting the potential for the creation of more permanent coverages in the future, licences are
granted for a maximum of five years only.
Given the fact that only a very low coverage is achieved, often with a less than good quality picture,
and that very little interference protection is afforded, the low value licence fee of $500 is waived for
these licences.

Approved By:
Manager
Radio Spectrum Policy

[wiilliiss]

Simple in concept, but unless constructed carefully, could turn into an ocsillator ...

If the input signal is reasonable and the RX location nearby, then what might work is a passive repeater - interconnect two high gain antennas with low loss feeder - point one at the Kordia DDT transmitter site to collect the input, the other at where you desire coverage as the output. Obviously, what actually gets to the RX location will be small, but if you are lucky useable. Havent looked at the legal side of things, but you may not even need a license....

unless the signal level is about 110uv, waste of time.

as for the ministrys guidelines,generally common sense ,no different to previous .
still,give it a try see what happens, then see what freeview say when asked to approve a repeater license.

[Apsattv]

[QUOTE=wiilliiss;6076]unless the signal level is about 110uv, waste of time.
QUOTE]


Why a waste of time? considering Digital will load and play at far lower levels than watchable analogue reception?

Also it would seem MED need to update their booster system policy.