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
----- Original Message -----
From: "N4ZR" <n4zr@comcast.net>
To: "Wayne Kline" <w3ea@hotmail.com>, "charlie carroll" <k1xx@k1xx.com>,
cq-contest@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@contesting.com> on behalf of charlie
>> carroll<k1xx@k1xx.com>
>> Sent: Tuesday, March 12, 2019 10:23:06 PM
>> To:cq-contest@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
>>> _______________________________________________
>>> CQ-Contest mailing list
>>> CQ-Contest@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/cq-contest
>>>
>> _______________________________________________
>> CQ-Contest mailing list
>> CQ-Contest@contesting.com
>> http://lists.contesting.com/mailman/listinfo/cq-contest
>> _______________________________________________
>> CQ-Contest mailing list
>> CQ-Contest@contesting.com
>> http://lists.contesting.com/mailman/listinfo/cq-contest
>>
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
|