Designated Operational Coverage

[Mooncrest]

EGNM. Delivery is normally on 121.805 with a DOC of 5 miles. Recently, the position has been temporarily moved to the standby Radar frequency of 125.380, which has a much greater DOC of 40 miles. Would it have been a requirement to reduce the power output of this frequency's transmitter in order to comply with the 5 mile DOC ? 121.805 is unused at the moment.

It might seem a daft question but these technical matters intrigue me! Thankyou.

[mike current]

Leeds have a delivery position????

[Gonzo]

No, I wouldn't have thought they'd have to reduce the power. Provided the 'new' freq is operating within its own promulgated DOC that will be fine.

If they moved 121.805 on to a new Tx set then that would be the time to check the power is appropriate.

[chevvron]

Leeds have a delivery position????
Presumably operated by an assistant so the ADV/ADI position can do both air and GMC.

[Mooncrest]

Thanks all. I wasn't sure if the DOC came with the position or the assigned frequency.

Leeds Tower ATC is something of an anomaly. There is enough RTF traffic to justify two positions but the lack of taxiways (no parallel after all these years) means GMC is largely pointless. So the Tower controller isn't overloaded, the assistant provides clearance delivery, except at night or at quiet periods during the day. They've been doing this for about fourteen years. The existence of SIDs must simplify matters.

[Jim59]

When a channel is licensed the fee payable depends on several factors, including the DOC. If you use the channel for a different purpose temporarily you don't get any money back from Ofcom so why would you reduce the power?

[Mooncrest]

Dunno Jim. My knowledge of DOCs and associated matters is limited, hence my original question.

[Equivocal]

When a channel is licensed the fee payable depends on several factors, including the DOC. If you use the channel for a different purpose temporarily you don't get any money back from Ofcom so why would you reduce the power?Interesting point. In the old days when I had some involvement in such things, the channel assignment also included the service to be provided and station callsign...and I don't recall any means for the licencee to vary those elements, whether temporarily or otherwise.

[Mooncrest]

One curious exception to the foregoing is if an aircrew requests departure from the runway not in use. In such an instance, the Assistant/CDO is either unable or not permitted to issue the clearance and the aircraft has to be transferred to the Tower controller to obtain the clearance. In practice, that would often mean a NELSA 3W from RW32 would become a Pole Hill 2X from RW14. I do not know why the CDO cannot make such a distinction and issue the appropriate clearance. This is the case with all IFR departures. I confess it's not likely to apply to VFR as the aircraft involved generally take the runway in use anyway.

I digress. None of this has anything to do with DOC!

[Buster the Bear]

At Lasham, our DOC was 25nm up to FL100 for the air/ground frequency. Mind you, sharing a similar frequency with Bristol Radar, I would often have chats with pilots having 'finger problems'. In theory I should have not transmitted in response, but being air/ground, I had no idea where Bristol was :) During Lockdown 1, I had a lengthy conversation with a BBJ over mid S Ireland at FL410. The American crew had never heard of Lasham! Outrageous I thought! I even tried to convince them to get the Boeing maintained in Hampshire!

The TX power was limited to whatever wattage is prescribed by OFCOM, but being sat on top on a hill and with a decent Jotron RX/TX system installed, operational coverage was excellent.

[Mooncrest]

Radio can be equally fascinating and frustrating. Just occasionally, (usually with autumn and winter anticyclones), I can hear the Tower controllers at Manchester from my home near LBA. That's with a distance of about forty statute miles and some Pennines in between. I never get Radar or Director though. On the moors above Otley, the Teesside UHF Tower uplink comes through quite well on a handheld and rubber helical antenna. It's quite possibly line of sight and a distance of about 35 miles.

Leeds Delivery is now back on 121.805. I don't know why it went there in the first place.

Leeds Radar on 134.580 continues to be afflicted by background interference, resulting in hissy white noise behind the controller's transmissions.