[TowerTalk] Skinny QRO coax jumpers for station interconnection

Thu Mar 15 22:10:44 EDT 2018

Hello fellow DX travelers,

FWIW my experience with RG-8X has taught me not to use it much. I tried building jumpers as well as buying some like you find for sale at ham fest. But it seemed that half the time they developed shorts and opens, or at least center to shield shorts. I pretty much gave up on them and now buy the short jumpers I need from MPD Digital off ebay. They can build them much better than I ever had much success at and really put out a great variety. The RG-400 I'm not familiar with but think it is like the stuff I seen from one or two of the Waller Flag U-tube videos. Looked very much like stuff you would expect to see with VHF/UHF equipment and/or expensive test lab equipment. 

Terry
KI7M

> On March 15, 2018 at 7:35 AM "N2TK, Tony" <tony.kaz at verizon.net> wrote:
> 
> 
> Keith,
> Tnx for info. Only interested n 160-6M here. I need to make up some jumpers.
> I have RG8X low loss cable already. Trying to find out if any reason to buy
> some RG400 instead. Most of the jumpers will be only a couple feet. But I do
> need a 12' one too.
> 73,
> N2TK, Tony
> 
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Keith
> Dutson
> Sent: Thursday, March 15, 2018 9:57 AM
> To: Tower Talk <towertalk at contesting.com>
> Subject: Re: [TowerTalk] Skinny QRO coax jumpers for station interconnection
> 
> The key word here is QRO.  RG-8X can handle up to 1000 watts, but suffers
> some heat loss at 1500 watts, mostly for 100 percent duty-cycle digital
> modes like RTTY.
> 
> High dollar, double shielded skinny cables like RG-400 are used primarily
> for VHF/UHF repeater cabling to the duplexer, where signal bleeding between
> receiver and transmitter will cause de-sensing (range reduction).  Foil
> shielding does not seem to provide the same shielding as double, silver
> plated braid.
> 
> 73, Keith NM5G
> 
> -----Original Message-----
> From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of N2TK, Tony
> Sent: Thursday, March 15, 2018 7:40 AM
> To: 'Paul Christensen' <w9ac at arrl.net>; 'towertalk reflector'
> <towertalk at contesting.com>
> Subject: Re: [TowerTalk] Skinny QRO coax jumpers for station interconnection
> 
> For jumpers in the shack what about RG-8X low loss with foil and braid
> shield that Davis RF lists? How does it compare to RG-400? The most power
> these jumpers would see is 100W. I use Buryflex from the output of the amps
> which are in the basement. 
> N2TK, Tony
> 
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Paul
> Christensen
> Sent: Thursday, March 15, 2018 8:12 AM
> To: 'towertalk reflector' <towertalk at contesting.com>
> Subject: Re: [TowerTalk] Skinny QRO coax jumpers for station interconnection
> 
> For those wanting to crimp connectors on RG400, I've been using these two
> types from RF Industries:
> 
> PL-259:  RFU-505-C1
> Male N:  RFN-1005-3C1
> 
> For soldering RG400 with a male PL-259, a UG reducer is needed.  The RG400's
> silver shield easily bonds to a silver-plated reducer.  
> 
> Rarely do I recommend alternative installation practices beyond what
> connector manufacturers specify, but I recommend this method above all
> others.   Do just one and it will be addictive. 
> 
> http://www.n3sh.org/PL259.pdf
> 
> Paul, W9AC
> 
> 
> 
>   
> 
> -----Original Message-----
> From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Grant
> Saviers
> Sent: Thursday, March 15, 2018 1:23 AM
> To: Jim Smith <jimsmith at shaw.ca>; towertalk at contesting.com
> Subject: Re: [TowerTalk] Skinny QRO coax jumpers for station interconnection
> 
> RG142 will handle the power but the center conductor is silver plate on
> copper clad solid steel (SCCS).  RG400 is a more flexible choice as it has a
> stranded center, silver over copper, but given the double braid shield and
> TFE insulation it is still stiffer than RG8X.  I use soldered PL's since the
> TFE is very heat resistant.
> 
> Or get them made to order, not bad prices considering what the raw cable
> cost is per foot.
> 
> https://www.ebay.com/itm/6-10-RG400-M17-N-Male-Jumper-Silver-coated-RF-LAB-c
> able-USA/131261896246?hash=item1e8fd19636:m:mxHmFuMTID-ASNC8GHWzR7w
> 
> i think they will put whatever connectors you want on each end.
> 
> Grant KZ1W
> 
> On 3/14/2018 21:44 PM, Jim Smith wrote:
> > I have a number of filters and switches to wire up in my QRO station. 
> > I
> would like the necessary coax jumpers to be thinner (0.25" ?) and more
> flexible than, say, RG 213. They will be terminated by crimped PL 259s (or
> equivalent).
> >
> > Any suggestions as to what I should use?
> >
> > 73, Jim VE7FO
> > _______________________________________________
> >
> >
> >
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