[AK-VHF] LMR 400 loss at 70cm

[Brandon Clark]

I would be very surprised if it was bad coax. That might have been common
post WWII, but not these days. Crushed or damaged coax is another issue
though . . . .
As a check of the meters themselves, have you tried swapping the positions
of the wattmeters? It could be a wattmeter that has gone bad or has an
issue. If both are good and there is actually a loss issue then they
shouldn't give the same reading when at the
Brandon


On Aug 3, 2018 19:23, "Paul Kiesel" <k7cw at yahoo.com> wrote:

You might have some corrosion on one or more connectors. Try taking all
connections apart and re-connecting them tightly. You might also have coax
that is not up to snuff (even though it may be new). At the 400 watt power
level on 432, you might consider using LMR-600.
--------------------------------------------
On Fri, 8/3/18, Tom Elmore <tom at telmore.com> wrote:

 Subject: RE: [AK-VHF] LMR 400 loss at 70cm
 To: "'Paul Kiesel'" <k7cw at yahoo.com>, "'Brandon Clark'" <kl7bsc at gmail.com>
 Date: Friday, August 3, 2018, 8:03 PM


 I took the switch out of line
 thinking the same thing but it didn't reduce the loss
 much. I have standardized on N connectors for everything
 these days.

 -----Original
 Message-----
 From: ak-vhf-bounces at mailman.qth.net
 [mailto:ak-vhf-bounces at mailman.qth.net]
 On Behalf Of Paul Kiesel via ak-vhf
 Sent:
 Friday, August 03, 2018 7:01 PM
 To: ak-vhf at mailman.qth.net;
 Brandon Clark
 Subject: Re: [AK-VHF] LMR 400
 loss at 70cm

 Yes, the
 connectors are almost certainly adding to the loss. N-type
 connectors are called for on 432. Also, the switch isn't
 helping, either. Is the switch necessary? If not, it might
 be possible to use less coax, too.

 73, Paul K7CW
 --------------------------------------------
 On Fri, 8/3/18, Brandon Clark <kl7bsc at gmail.com>
 wrote:

  Subject: Re:
 [AK-VHF] LMR 400 loss at 70cm
  To: ak-vhf at mailman.qth.net
  Date: Friday, August 3, 2018, 7:37 PM

  Hi Tom,

 Yep,
  something is wrong with your setup.
 The lost for a 25-foot
  run should
  be just under 1 decibel. I use
  that same coax extensively in my mobile
  contesting setup. What kind of connectors
 are
  you using, and what shape are
  they in? I
  would check that
 as the first thing that is likely to go

 wrong.

  Times microwave
 has
  a online calculator tool that is really
 useful. I keep
  it bookmarked for my various
 VHF projects:

  http://www.timesmicrowave.com/calculator/?productId=56#form

  Brandon

  On Fri, Aug 3, 2018, 18:07 Tom Elmore <tom at telmore.com>
  wrote:

  >
 Does anyone use
  LMR 400 ultra flex on 432?
 I am surprised what I am
  seeing
  > for loss on short cable runs.
  My 432 transverter sits across the room
 from
  > the amplifier and is fed with
 about 13
  feet of LMR 400 then the amp
 feeds
  > and
  antenna
 switch probably another 10 feet away or so and with
  400 watts
  > out of the amp
 I am loosing
  almost 100 watts by the time
 it gets to the
  > alpha delta 2 port
 switch. The antenna
  analyzer isn't
 showing much loss but
  > the wattmeter
 sure is. I thought maybe I
  would loose a
 couple of watts
  > between
  the two different cable runs but not nearly
 100.
  >
  >
  >
  > Thank You
  >
  >

 >
  > Tom Elmore

 >
  > Anchorage, Alaska
  >
  >

 >
  >

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