[ARC5] What is a "radio range filter"?
Richard Knoppow
1oldlens1 at ix.netcom.com
Tue Apr 26 19:28:34 EDT 2016
Eliminating the need for a modulator. I think this is also why most
range stations did not have voice capability, they used a separate
transmitter and antenna for that.
On 4/26/2016 3:39 PM, Michael Bittner wrote:
> Perhaps the more extensive use of 50 Hz power in Canada explains why
> the Canadian marine beacons use 400 Hz modulation?
> Another interesting factoid: Many USA beacons did not transmit MCW,
> but instead transmitted two carriers offset by 1020 Hz.
> Mike, W6MAB
> -
>
> ----- Original Message -----
> *From:* D C _Mac_ Macdonald <mailto:k2gkk at hotmail.com>
> *To:* Richard Knoppow <mailto:1oldlens1 at ix.netcom.com>
> *Cc:* ARC-5 Mail List <mailto:arc5 at mailman.qth.net>
> *Sent:* Tuesday, April 26, 2016 1:17 PM
> *Subject:* Re: [ARC5] What is a "radio range filter"?
>
> I never heard of any US area that used 60 Hz power but areas
> around Niagara Falls used 25 Hz as late as 1950s!
> Mac, K2GKK/5 in OKC, OK
>
> Sent from my iPhone
>
> On Apr 26, 2016, at 13:30, Richard Knoppow
> <1oldlens1 at ix.netcom.com <mailto:1oldlens1 at ix.netcom.com>> wrote:
>
> So what did they do in areas with 50Hz power, there were
> plenty of them in the U.S.
> There are detailed descriptions of the four course (sounds
> like a dinner special at the local chop house) radio ranges in
> several of the old engineering texts at www.tubebooks.org and
> elsewhere on the web.
> Not all range stations had voice communication, those that did
> had a separate transmitter and a center antenna for it. The
> method of feeding the antenna array was interesting because it was
> arranged to move the overall orientation electrically and also to
> "squeeze" the beams to line them up with particular air routes.
> There were many problems with the range stations; planes could get
> on reciprocal bearings, the beams could be distorted by nearby
> large objects, and skywave transmission could be confusing and
> unreliable. Most stations eventually had a VHF marker in the
> center pointing straight up to indicate when an aircraft was just
> over the station. The range pattern was null straight up, called
> the Zone of Silence.
> A lot of the transmitting equipment was made by Wilcox
> Electric, I don't know what happened to them.
>
> On 4/26/2016 10:06 AM, Michael Bittner wrote:
>> While we are on the subject of range/beam filters, I am still
>> looking for a schematic diagram and/or wiring diagram for my
>> F-90/AIC range/beam filter.
>> Scott W7SVJ confirmed that its input and output impedances are
>> 150 Ohms, and Mike Hanz provided information on its use in the
>> Intercommunication Set AN/AIC-8. However, its correct hookup and
>> internal circuitry remain an enigma.
>> BTW, 1020 Hz is the 17th harmonic of 60 Hz. Back in the day, the
>> power line was used as a readily available frequency standard.
>> Mike, W6MAB
>> --
>>
>> ----- Original Message -----
>> *From:* DSP3 <mailto:jeepp at comcast.net>
>> *To:* arc5 at mailman.qth.net
>> *Sent:* Tuesday, April 26, 2016 8:20 AM
>> *Subject:* Re: [ARC5] What is a "radio range filter"?
>>
>> Brian has is pretty much correct. The "range filter" was
>> designed to pass 1020 Hz audio through the phone audio system
>> of certain aircraft receivers when tuned to a "range
>> station". 1020Hz became the de facto standard for Morse
>> audio identifiers of NDBs, VORs, Marker Beacon, etc. as well
>> as the keyed tones for the now defunct Adcock system (the
>> true range stations). Both the AAF and the Navy had their
>> versions of the filter, some controlled at the filter, and
>> some remotely switched in and out. The FL-8 is one of the
>> more//prolific models. Most current audio panels and Nav or
>> NavCom sets will have a 1020 Hz filter circuit for the Marker
>> Beacon channel and to selectively filter the identification
>> audio from the other VOR/ILS modulations present.
>>
>> Jeep - K3HVG
>>
>>
>>
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> --
> Richard Knoppow
> 1oldlens1 at ix.netcom.com
> WB6KBL
>
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--
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL
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