Do tell!
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of ZR
Sent: Saturday, February 15, 2014 11:05 AM
To: jim@audiosystemsgroup.com; 'TopBand'
Subject: Re: Topband: Palomar R-X Noise Bridge
----- Original Message -----
From: "Jim Brown" <jim@audiosystemsgroup.com>
To: "'TopBand'" <topband@contesting.com>
Sent: Saturday, February 15, 2014 12:15 AM
Subject: Re: Topband: Palomar R-X Noise Bridge
> On 2/14/2014 7:00 PM, Charlie Cunningham wrote:
>> All generally true, I expect, but I also believe that dielectric constant
>> and dielectric losses also figure in and the lowest loss lines would be
>> filled with air, dry nitrogen or evacuated. I expect those would likely
>> be
>> the lowest loss AND highest velocity factor cases.
>
> If you run the equations, you find that below about 1 GHz, the losses are
> all copper losses. Dielectric loss is a few percent of the total loss in
> the 500 MHz range. The benefit of a foam dielectric at HF and VHF is that
> it allows the center conductor to be larger for a given shield diameter.
> But the improvement in loss of a foam dielectric coax below 1 GHz is
> entirely due to the center conductor being larger.
>
> BTW -- the relevant equation is on each Times data sheet.
>
> 73, Jim K9YC
Dielectric losses become evident at 2M with 1500W and at 432 400W of steady
carrier will heat up even the best N connectors and RG-213. For that reason
many are switching to the 7/16 DIN.
Carl
KM1H
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
|