[CQ-Contest] Station Re-Build - Coax
Mark n2qt
n2qt.va at gmail.com
Thu Mar 14 22:38:00 EDT 2019
I’ve always liked Andrew 1/4 inch super flex for in the shack cabling. Corrugated solid
copper shield and handles 1.7 KW on 6m.
Wouldn’t wind it on a toroid but is good to connect things. It tends to stay where you
put it as it will take set and is not springy. Also you don’t use it as a rotor loop with
many repeated endings. If you use the reducer meant for rg59 it will go on a pl259.
I had convinced myself I needed more in shack isolation and while I’m sure it helps I’m
not sure it was needed as my inter aerial isolation over rides that. I’ve also stuck with
100w so2r so not pushing things but do much.
Mark. N2QT
> On Mar 14, 2019, at 2:28 PM, donovanf at starpower.net wrote:
>
> Hi Pete,
>
>
> I can easily wrap my Times Microwave RG-400 around my finger.
>
>
> But the improved shielding effectiveness of double shielded
> coaxial cables such as RG-400 and RG-214 doesn't provide a
> useful performance improvement except for multi-operator
> and SO2R stations.
>
>
> Just because RG-400 has greater than 90 dB shield effectiveness,
> 1500 watt power handling capability ( at HF only), and one inch
> minimum bending radius, that doesn't mean that you need or will
> benefit from those capabilities.
>
>
> Small diameter coaxial cables such as RG-58 have relatively poor
> shielding effectiveness, roughly 40 dB or much worse for RG-58
> with less than 95% shield coverage. RG-213 with 95% shield
> coverage has roughly 55 dB shielding effectiveness.
>
>
> But there are only a few situations where greater shielding
> effectiveness of double shielded coax will improve the
> effectiveness of contest stations, for example:
>
>
> - when coaxial cables for receiving antennas must be bundled
> with coaxial cables connected to a transmitter in a multi-operator
> or SO2R station (an undesirable practice unless it cannot be
> avoided for some reason).
>
>
> - when coaxial cables must be run alongside a tower leg
> in a multi-operator or SO2R station. In this case, solid shield coax
> such as Heliax is more cost effective and significantly more
> resistant to physical damage and moisture intrusion than
> braided shield coaxial cables.
>
>
> RG-223 is much less expensive and has the same shielding
> effectiveness as RG-400 but its power rating is 100 watts at HF.
>
>
> 73
> Frank
> W3LPL
>
>
>
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>
> ----- Original Message -----
>
> From: "N4ZR" <n4zr at comcast.net>
> To: "Wayne Kline" <w3ea at hotmail.com>, "charlie carroll" <k1xx at k1xx.com>, cq-contest at contesting.com
> Sent: Thursday, March 14, 2019 12:48:38 PM
> Subject: Re: [CQ-Contest] Station Re-Build - Coax
>
> Oops. I did some more dissecting on the cable, and I'm wrong about the
> shielding. That leaves only the absence of printing - this is advertised
> as Harbour Industries RG-400 - and its stiffness. This stuff is quite
> hard to bend in even an 8" coil. Can anyone who has used real RG-400
> confirm whether it feels supple and flexible to the touch? I have one
> jumper in my station that looks like the same stuff, but which is very
> supple. I bought it at Dayton a few years aho, already connectorized. I
> can believe a 1" minimum bend radius with it, but not with the stuff
> from China.
>
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at <http://reversebeacon.net>, now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
>> On 3/13/2019 9:51 AM, N4ZR wrote:
>>
>> I just bought 10 feet of RG-400U (supposedly Harbour Industries)
>> through E-bay for $13. Belatedly, I learned it was coming from
>> China. It's now here, but I don't think it is for real - it only has
>> one shield, and is somewhat stiff. At least the inner conductor isn't
>> magnetic.There's no printing on the cable.
>>
>> Buyer beware.
>>
>>
>> 73, Pete N4ZR
>> Check out the Reverse Beacon Network
>> at<http://reversebeacon.net>, now
>> spotting RTTY activity worldwide.
>> For spots, please use your favorite
>> "retail" DX cluster.
>>> On 3/12/2019 11:35 PM, Wayne Kline wrote:
>>> I third the sugjestion of the RG400 small enough for all the switching in a more then one radio setup.
>>>
>>> The tight bend radius the small diameter make for a clean instlation that coupled with the double shielding it’s a WIN WIN
>>>
>>> Watch Ebay or other surplus suppliers
>>>
>>>
>>>
>>> Wayne W3EA
>>>
>>>
>>>
>>> Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10
>>>
>>>
>>>
>>> ________________________________
>>> From: CQ-Contest<cq-contest-bounces at contesting.com> on behalf of charlie carroll<k1xx at k1xx.com>
>>> Sent: Tuesday, March 12, 2019 10:23:06 PM
>>> To:cq-contest at contesting.com
>>> Subject: Re: [CQ-Contest] Station Re-Build - Coax
>>>
>>> Keith:
>>> A couple very similar candidate cables are RG-400 and RG-303. RG-400 is
>>> double shielded while 303 is single. They're good as interconnects
>>> because they have a small bend radius (about 1"). RG-400 uses
>>> multi-strands of copper for the center conductor; RG-300 uses copper
>>> clad steel. Either will handle 1500 watts at HF.
>>>
>>> 73 charlie, k1xx
>>>
>>>> On 3/12/2019 7:51 PM, Keith Dutson wrote:
>>>> My multi-two station, with third spotting station, is being rebuilt into new
>>>> digs. I have a lot of 3-4 foot RG213 cables running between the amp, power
>>>> meter, tuner and switch. I have heard there may be a smaller cable that has
>>>> very little loss, but handles 1500 watts. I would appreciate any comments
>>>> on what is being used today. Thanks.
>>>>
>>>> 73, Keith NM5G
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