In a message dated 97-01-15 09:59:58 EST, you write:
>I purchased a used MB-V-A from a sale of surplus equipment from
>a previous Greenpeace operation in the Antartic. The unit had
>burned sections of tinned copper braid between the terminals
>and the components. It had been in service with an Alpha 88, into
>a variety of non-resonant wire antennas.
>After replacing the braid, the unit has operated reliably
>at the 400w level for several years.
Braiding has much higher RF resistance that the same area smooth conductor.
Measurements I made several years ago at 30 MHz on a new chunk of 1/2 inch
wide copper braid indicated it had an RF resistance about equal to a number
12 wire.
The resistance varies with the depth of the weave, cleanliness of the braid,
and the mechanical pressure of the wire to wire connections in the braid.
NASA prohibits use of braiding for lightning protection and RF grounds unless
the connection absolutely has to be flexed.
73 Tom
>From n4bp@shadow.net (Bob Patten) Thu Jan 16 07:34:57 1997
From: n4bp@shadow.net (Bob Patten) (Bob Patten)
Subject: FSFD (50 States) Update for Jan 15 (fwd)
Message-ID: <Pine.SOL.3.91.970116023357.11766D-100000@hyper>
---------- Forwarded message ----------
From: Jim Hydzik <congress@magpage.com>
To: Low Power Amateur Radio Discussion <qrp-l@Lehigh.EDU>
Subject: FSFD (50 States) Update for Jan 15
Hello ALL, (QRP activity info at http://www.dancris.com/~ki7mn)
The 50 States In 50 Days (FSFD) activity started Jan 01 and runs through
Feb. 20. Below is a the schedule of States for the next few days. We will
attempt to provide digested schedules of states/times/bands/freqs. to help
reduce message traffic to the reflector. Typically, only 1 message per day.
ALL TIMES UTC
-------------------------------------------------------------------
Jan. 15 Wednesday IOWA KD0CA, Jerry 1230-1345 UTC 3.559
0100-0300 Thur-UTC 7.042
0300-0330 " UTC 7.039
-------------------------------------------------------------------
Jan. 16 Thursday WISCONSIN (substituted in place of Kansas-later)
WA9PWP, Paul 2300-0000 UTC 10.115
0100-0300 FRI>UTC 7.037
0300-0400 FRI>UTC 3.700
-------------------------------------------------------------------
Jan. 17 Friday KENTUCKY KC4O, Roy 1400-1420 FRI-UTC 7.042
1430-1445 7.118
E-mail Roy for any spcl. 1500-1520 14.059
times or freqs. 1700-1720 10.115
1800-1815 18.078
1830-1900 10.115
2100-2120 7.042
2130-2200 7.118
0000-0100 SAT-UTC 7.042
0100-0120 " " 7.118
0130-0200 " " 3.710
0215-0400 " " 7.042
-------------------------------------------------------------------
Jan. 18 Saturday LOUISIANA #2, K5RV, Brian TBA (ends at 6 PM)
| Look at MI-QRP Contest this weekend; Info-Jan QST |
| Start 0700 UTC 1/18/97 End 2359 1/19 |
-------------------------------------------------------------------
Jan. 19 Sunday MAINE, WA5CVM, Joel, after MI-QRP Contest TBA
-------------------------------------------------------------------
Most every sign-up came with a note saying they would go longer if busy.
Frequencies are +/- QRM & typ. may reach as far as 3-4 KHz from posted freq.
CALLING CQ: A suggestion. If we call CQ WAS or WAS QRP de K6.... etc,
we give those not on QRP-L an indication of what we're doing. FSFD type
calling might be too cryptic for all but ourselves. However 'FS' is fine
when busy. Exchange RST, State/Province/Country, and Name. Power level is
nice to know.
ALASKA & HAWAII: Jim-AL7FS is back from Hawaii and will activate ALASKA as
soon as KL7Y's 40M beam repairs are complete. Watch for Jim's postings.
Thanks to him for the HI effort.
KB0ROL will also be in HAWAII between Jan. 17-25 and will post his time/freq
info to the group when ready. Don't miss this double QRP HI shot.
If you want to sign-up for an upcoming State, e-mail band/freq/time directly to:
congress@magpage.com
Thanks for all the responses/encouragement and suggestions. Lets have a blast!
Jim K3QIO Wilmington, Delaware
>From morel.grunberg@telrad.co.il (Morel Grunberg) Thu Jan 16 12:36:50 1997
From: morel.grunberg@telrad.co.il (Morel Grunberg) (Morel Grunberg)
Subject: Hy-Gain TH-11DX beam : opinions summary
Message-ID:
<c=US%a=_%p=TELRAD%l=MISMAIL-970116123650Z-102@mismail.MIS.ELEX.CO.IL>
Two weeks ago I sent a request on few relevant reflectors asking for
opinions on Hy-Gain TH-11DX beam. Till now I received 84 answers from
United States
( 74 ), Europe ( 4 ) Asia ( 4 ) and Africa (2).
I was quite surprised about the very favorable opinions from the
people who taked the time to answer. Actually, 82 were very satisfied
with the antenna and
warmly recommended to buy one.
This is a brief summary of the answers:
This beam was described like a real winner and a very good and
effective solution for those who need a 5-bands beam with reasonable
gain, F/B and
good SWR. Here are the opinions:
* 72 declared their satisfaction on general radiation performance and
traffic
results while only four are not so happy with the front to back ratio.
* 55 were very satisfied by the good SWR over the 5 bands and only four
reported SWR problems as result of bad assembly work, improper
guywires
and insufficient tower height.
* 60 declared their satisfaction over the ruggedness and mechanical
construction quality.
* 19 favorably compare the TH-11DX electrical, radiation and mechanical
performance to previous owned antennas from other manufacturers with
similar or better figures claimed in the technical specifications.
* 12 were delighted to see the new powerful balun and hi-power antenna
capability. 5 of them beleive that the general lower noise and statics
is due to
direct grounding of the balun and to the DC coil connected to the
BN-4000.
* 68 were satisfied with the antenna but experienced difficulties in the
assembly process ( with understanding that such large and complicated
antenna needs extensive assembly and installation works ).
Low points:
It was interesting to see that almost all the criticism was
concentrated on
the assembly concept and instruction manual.
* 56 would clearly prefer colour, numbering or any other markings for
easier
and faster identification of the large number of components.
* 48 were quite exhausted trying to ensure that the elements are
installed on
the boom perfectly parallel and they are feeling that some kind of
pre-drilling
of the element to boom brackets and of the boom, will greatly reduce
the
time and the efforts to messure the inter element spacing and
exhaustive
alignement and paralleling procedure. 20 of them do not understand how
an
antenna of this class doesn't have such facility.
* 36 would prefer an improved graphic presentation and assembly manual
while
23 clearly stated that simplified drawings of the components,
component
check-list and assembly steps check-list, will greatly improve the
human
enginering. 14 would prefere some simple drawings on installation tips
issues. Also, 10 people are feeling that recommendations for use of
some
materials should be more specific ( like the RTV and protective paints
) while
8 expressed their prefference for an optional kit for coastal
installations with
improved hardware quality.
* 9 peoples feel they want stronger and heavier pigtail wires.
* 5 are willing to see the antenna radiation lobes for the installation
recommendations from the manual.
73,
Morel, 4X1AD
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