NEW AMPLIFIER - WHICH TO CHOSE ?
JKAHRS at delphi.com
JKAHRS at delphi.com
Sun Oct 1 22:42:53 EDT 1995
On 1-OCT-1995 16:52:22.4 ron said to JKAHRS
> --
> ----------------------------------------------------------------------
> -----
> | Ron Stone, GW3YDX - EMail ron at gw3ydx.demon.co.uk
> ----------------------------------------------------------------------
> -----
> Chaps
> At last I have decided to part with the faithful Drake L7.
> This station is about to enter the era of ceramic tube technology.
> As I can't track down an Alpha 78 the choice is boiling down to
> either the Command Technology HF2500 with the Svetlana option,
> or the ETO 91 B, also with the 4CX800 tubes.
Ron, As of Aug, I am the owner of an ETO 91 Beta. Normally I could look at a
schematic and answer ur question ... but the amp was delivered with a VERY
temporary Operating manual. The word from Ray was that Dick himself was
writing the manual and that the final copy WOULD have a schematic.
As to the amp ... my last "amp" was a GLA-1000 that Radio Shack kept in free
tubes (remember the Gold Seal warranty). I stopped using that when I moved
from CA in 1981.... this one worked great right out of the box and will
surely finish 5BDXCC for me on 80!
My only addition is a 8 inch piece of mylar recording tape that is taped
between the top tube vents in the shape of a "U". The fan is quiet and with
cans on, I just look at the tape flying in the breeze to insure that the fan
is working.
As to the wait...mine was 15 months ARO... and when I got it I STILL had not
run the 220V line into the shack! Plan, plan and then plan to wait! The
first contest will be CQP next weekend. My rotor is stuck on EU, so if the
new cable doesn't come soon, it will be up the tower with the control box to
put the beams on CA!
73, Hank/K2UVG ...I don't have problems sending it but some do!
internet: jkahrs at delphi.com
>From jbmitch at vt.edu (JOHN MITCHELL) Sun Oct 1 02:41:12 1995
From: jbmitch at vt.edu (JOHN MITCHELL) (JOHN MITCHELL)
Date: Sat, 30 Sep 1995 21:41:12 -0400
Subject: TS-870 - First Impressions
After 48 hrs with new TS-870, herewith some initial operating impressions.
Past experience: TS-850, FT-1000
This receiver is the cleanest I have ever heard... I now listen thru
hi-quality stereo headphones to enjoy the improved audio over the 850. It's
hard to define the difference, but vastly superior audio reproduction of
received signals.
Transmit audio reports (Heil HC-5, moderate processing, +6db emphasis on hi
frequencies selected on processor) consistently get top notch audio reports
from knowledgable receivers)
DSP NR: disappointing on ssb. Not earth-shakingly better than the 850 with
Timewave. Expected better from IF digital filtering.
Other DSP features: pretty good in auto notch, beat frequency auto filter
works well in some cases, with less degradation of received audio. Not
evaluated in CW mode yet.
Filter selectivity: excellent, much better than the factory filters in 850.
Wish there were more intermediate setting to choose from (provide a dozen or
so per mode)
Ultimate receiver sensitivity: believe the 850 beats it by a smidgen, but
the combination of features in the 870 seems to make up for the slight
difference.
Anomalies: echo in monitored transmit audio when using vox. Not totally
disgusting, but annoying. (anyone know why this occurs - only when operating
vox??)
Favorite features: continuously adjustable agc; real time accessibility to
special option menus; two menus allow tailoring of options to preferences of
two ops; layout of controls.
Just a quick note for those who may be contemplating purchase. I think the
receiver audio almost justifies the upgrade, alone. Comments encouraged
from other users.
John, WD4MUR
>From broz at csn.net (John Brosnahan) Mon Oct 2 05:32:59 1995
From: broz at csn.net (John Brosnahan) (John Brosnahan)
Date: Sun, 1 Oct 1995 22:32:59 -0600
Subject: 91B info in response to NEW AMP - WHICH TO CHOSE ?
Message-ID: <199510020432.WAA11806 at uucp-1.csn.net>
> Ron Stone, GW3YDX - EMail ron at gw3ydx.demon.co.uk
>As I can't track down an Alpha 78 the choice is boiling down to
>either the Command Technology HF2500 with the Svetlana option,
>or the ETO 91 B, also with the 4CX800 tubes.
>On this reflector we must have somebody who has these amps and who can
>comment. I would be particularly interested in the technical details
>of the screen supply arrangements for both amplifiers, and how the
>91B has behaved in production models. The Conway Reef one blew up but
>that has been attributed to a dodgy mains supply.
Ron, here are a few thoughts about my ETO 91B amplifier experiences.
I was asked at the last minute to take Dick Ehrhorn's place on the XR0Y
expedition when his chief engineer needed surgery and Dick didn't feel that
he could leave during a critical period on one of his commercial contracts.
(The amateur amplifier line is only a relatively smaller part of ETO's business.
They also build a lot of RF equipment for Magnetic Resonance Imaging for the
medical field, as well as other products.)
BTW-- I build high power RF amplifiers at HF and VHF for atmospheric
research so I have a strong background in transmitting tube technology and I
also own two 87As and an 86.
Dick was planning on going on the Easter Island trip since a total of five
91Bs were to be used--four on EI and one on Salas y Gomez--and because there
had been reports of problems on the Conway Reef trip that ETO was not able
to duplicate in the lab and that Dick wanted to see first hand. I believe
that the amps we used, which were pre-production ones, were the same ones
used on Conway Reef. And these amps are on their way to Heard Island as we
speak (err, as I write).
I spent a day at ETO before the trip, going over in great detail the design
of the amps and all of the protection circuits (and how to defeat them if
necessary) and the bottom line is that I never opened a cover on the four
amps on EI (can't speak for what happened to the fifth one on SyG since I
wasn't there) except to install the plate transformers. BTW There is no
microprocessor in the 91B. All control and protection circuits are done
with 4000 series CMOS and LM324 op amps, making it relatively eaasy to
trouble shoot the equipment.
There are two issues of interest that relate to the perception of problems
with the amplifiers. 1) The pre-production units had a pc board in the HV
rectifier section that had the two HV transformer wires running half way
around the board with marginal spacing. One (possibly more, but I only
heard about one) developed an arc across the pc board. The pc board has
been redesigned for the production units and no longer has HV from the
transformer running around the board. Although the EI units were
pre-production units with the original pcb design, we had no problems
associated with the close spacing, even though we were right on the beach
with plenty of salt air. 2) There have been reports of relay dropout
during operation that were reported to be due to running from poorly
regulated generators. I believe that this is a mis-diagnosis of what
happened on Conway Reef and what was also an issue on Easter Island. All
VSWR sensing circuits are right at the antenna (of course) but none are
smart enough to be able to determine if that big signal coming back from the
antenna is really reflected energy due to high VSWR on the antenna or pickup
of energy from another nearby transmitter. Something that is common in
multi-tx operations--especially on expeditions where the antennas are low
and close to each other. After watching the amplifiers shut themselves off
and then back on again after a few seconds it was obvious that it was due to
RF from a nearby rig that was causing the problems.
For example the EI operation had two sites about 500 ft apart. The CW site
had two rigs and amps as did the SSB site. The SSB site had a number of
antennas that were all pretty close together and when one rig was running
15M on the tribander and a second rig was running 20M on the 20M monobander,
the 20M signal would get into the VSWR sensor on the 15M rig since its
tribander provided no inherent rejection of the 20M sig. The sensor would
shut the rig down for three seconds, reacting to the perceived VSWR fault
and then reset itself, but this sequence only occurred if the other rig was
transmitting at the moment. This resulted in intermittent operation at the
100 W level and at the KW level that was noticed by many of the stations
being worked. I made some coaxial stub filters that greatly reduced the
problem but it was difficult to get the ops to put the correct filters on
the rigs--which depended not only on the rig in question's frequency but
also the frequency of the interfering rig.
This identical problem can occur without the amplifiers in the circuit and
was noted on occasion with only the Kenwood exciters when the 100W bandpass
filters weren't being used. Rig A would have its power reduced by its VSWR
protection circuitry when rig B dumped enough power into Rig A, no matter
what the frequencies chosen for either rig. The fact that receivers were
not blown is a tribute to how much abuse the rigs can handle.
BTW the actual signal level picked up by the amplifier's VSWR sensor is a
function of the frequency of operation of the two amps and the coaxial cable
length on amp A, since amp A is tuned to freq A and amp B is putting RF into
amp A at freq B--a freq where the pi-L network of amp A is not resonant and
the feedline is anything but matched to 50 ohms.
Now that I have explained the issues that have been questioned about the
reliability of the ETO Alpha 91Bs let me summarize it by saying that I was
very impressed by the general quality of the design and the construction.
They seemed to be relatively easy to tune and virtually idiot proof. They
will protect themselves from most forms of abuse, but if you keep the drive
below a level of about 15 watts you are below the threshhold of the
protection circuits and you can tune to your hearts content without worry of
damage and without the protection circuits shutting you down. Presetting
the tune and load to the values in the manual resulted in a "good enough"
tuning for most circumstances--needed only a little tweaking when
used with some of the low antennas.
It is too late on a Sunday evening to pour over all of the preliminary
schematics that I have in order to determine all of the ways that the screen
may be protected but as a last resort the screen voltage is regulated with a
series FET regulator with a 15 ohm 1/2 watt resistor from the input (+430
volts) side and a 10 ohm 1/2 watt resistor on the output side(+360 volts) of
the regulator. These appear to make good fuses as a last resort -- should
the plate voltage disappear. It is not obvious at this late hour which
other protection circuits would fire first but the Arc Fault would certainly
operate before any damage could occur. (This protection circuit samples the
input and output signals and protects things when the amplifier is not
showing a minimum amount of gain--something that can occur when the amp is
mistuned and this circuit eliminates any chance for tuning/loading capacitor
arcing.
With close to 20 operators of different technical capabilities, and the
normal screw-ups associated with operating day and night on an expedition,
and with generator power and its relatively poor regulation, somewhere in
the neighborhood of 40,000 qso's were made without any component failures of
the amplifiers. If you are a single operator in a contest then you will
have no problems using a 91B. If you are using any amplifier with a VSWR
protection circuit in a multi TX operation then you may experience false
operation of the VSWR circuit due to RF from the other TX(s) getting into
the amplifier and this is not limited to the ETO amps.
Would I buy one? YES, but I already own two 87As. Disclaimer: Although I
am not an employee of ETO I did fly on Dick's ticket with the understanding
that I would look after the amps as my primary responsibility. Since they
were so trouble free I got to spend most of my time putting on
PL-259s--doesn't anyone else know how to do it right and have them come out
looking pretty?
Hope this info helps all contesters who are interested in the 91B.
73 John W0UN
John Brosnahan W0UN
La Salle Research Corp 24115 WCR 40 La Salle, CO 80645 USA
voice 970-284-6602 fax 970-284-0979 email broz at csn.net
>From M Glenn Vinson Jr <mgvinson at crl.com> Mon Oct 2 07:06:29 1995
From: M Glenn Vinson Jr <mgvinson at crl.com> (M Glenn Vinson Jr)
Date: Sun, 1 Oct 1995 23:06:29 -0700 (PDT)
Subject: 91B info in response to NEW AMP - WHICH TO CHOSE ?
Message-ID: <Pine.SUN.3.91.951001222338.23656A-100000 at crl5.crl.com>
The 91B problems surfaced first on the YK0A operation in November, 1994
and I believe this was all thrashed out on this or the DX Reflector in the
Spring. The Conway operation merely mirrored what had already happened.
The 91B in Syria failed while running about 1300-1400 watts on rtty into a
Force 12 C3. I was there. Upon examination in the field, it appeared
that a filter capacitor in the power supply had failed and that the swr
sensing circuit had been blown (consequently or subsequently, we did not
know). All filter capacitors were replaced but the swr circuit could not
be repaired in the field. There was no "dodgy mains supply" in Conway,
only generators--maybe they are "dodgy" by definition. The "dodgy mains
supply" explanation originated as an hypothesis of the Syrian failure by
one of the YK0A ops and has been repeated from time to time. I doubt its
validity. In any event, that is all history. Where are the reports from
normal, at-home users of this amp? I expect they would be more useful
than reports from the inherently abusive treatment of DXpeditions. I use
an Icom 4KL and a 2KL so I don't have any experience with Alphas other
than at YK. 73, Glenn, W6OTC (mgvinson at crl.com)
On Sun, 1 Oct 1995, John Brosnahan wrote:
> > Ron Stone, GW3YDX - EMail ron at gw3ydx.demon.co.uk
>
> >As I can't track down an Alpha 78 the choice is boiling down to
> >either the Command Technology HF2500 with the Svetlana option,
> >or the ETO 91 B, also with the 4CX800 tubes.
>
> >On this reflector we must have somebody who has these amps and who can
> >comment. I would be particularly interested in the technical details
> >of the screen supply arrangements for both amplifiers, and how the
> >91B has behaved in production models. The Conway Reef one blew up but
> >that has been attributed to a dodgy mains supply.
>
> Ron, here are a few thoughts about my ETO 91B amplifier experiences.
>
> I was asked at the last minute to take Dick Ehrhorn's place on the XR0Y
> expedition when his chief engineer needed surgery and Dick didn't feel that
> he could leave during a critical period on one of his commercial contracts.
> (The amateur amplifier line is only a relatively smaller part of ETO's business.
> They also build a lot of RF equipment for Magnetic Resonance Imaging for the
> medical field, as well as other products.)
>
> BTW-- I build high power RF amplifiers at HF and VHF for atmospheric
> research so I have a strong background in transmitting tube technology and I
> also own two 87As and an 86.
>
> Dick was planning on going on the Easter Island trip since a total of five
> 91Bs were to be used--four on EI and one on Salas y Gomez--and because there
> had been reports of problems on the Conway Reef trip that ETO was not able
> to duplicate in the lab and that Dick wanted to see first hand. I believe
> that the amps we used, which were pre-production ones, were the same ones
> used on Conway Reef. And these amps are on their way to Heard Island as we
> speak (err, as I write).
>
> I spent a day at ETO before the trip, going over in great detail the design
> of the amps and all of the protection circuits (and how to defeat them if
> necessary) and the bottom line is that I never opened a cover on the four
> amps on EI (can't speak for what happened to the fifth one on SyG since I
> wasn't there) except to install the plate transformers. BTW There is no
> microprocessor in the 91B. All control and protection circuits are done
> with 4000 series CMOS and LM324 op amps, making it relatively eaasy to
> trouble shoot the equipment.
>
> There are two issues of interest that relate to the perception of problems
> with the amplifiers. 1) The pre-production units had a pc board in the HV
> rectifier section that had the two HV transformer wires running half way
> around the board with marginal spacing. One (possibly more, but I only
> heard about one) developed an arc across the pc board. The pc board has
> been redesigned for the production units and no longer has HV from the
> transformer running around the board. Although the EI units were
> pre-production units with the original pcb design, we had no problems
> associated with the close spacing, even though we were right on the beach
> with plenty of salt air. 2) There have been reports of relay dropout
> during operation that were reported to be due to running from poorly
> regulated generators. I believe that this is a mis-diagnosis of what
> happened on Conway Reef and what was also an issue on Easter Island. All
> VSWR sensing circuits are right at the antenna (of course) but none are
> smart enough to be able to determine if that big signal coming back from the
> antenna is really reflected energy due to high VSWR on the antenna or pickup
> of energy from another nearby transmitter. Something that is common in
> multi-tx operations--especially on expeditions where the antennas are low
> and close to each other. After watching the amplifiers shut themselves off
> and then back on again after a few seconds it was obvious that it was due to
> RF from a nearby rig that was causing the problems.
>
> For example the EI operation had two sites about 500 ft apart. The CW site
> had two rigs and amps as did the SSB site. The SSB site had a number of
> antennas that were all pretty close together and when one rig was running
> 15M on the tribander and a second rig was running 20M on the 20M monobander,
> the 20M signal would get into the VSWR sensor on the 15M rig since its
> tribander provided no inherent rejection of the 20M sig. The sensor would
> shut the rig down for three seconds, reacting to the perceived VSWR fault
> and then reset itself, but this sequence only occurred if the other rig was
> transmitting at the moment. This resulted in intermittent operation at the
> 100 W level and at the KW level that was noticed by many of the stations
> being worked. I made some coaxial stub filters that greatly reduced the
> problem but it was difficult to get the ops to put the correct filters on
> the rigs--which depended not only on the rig in question's frequency but
> also the frequency of the interfering rig.
>
> This identical problem can occur without the amplifiers in the circuit and
> was noted on occasion with only the Kenwood exciters when the 100W bandpass
> filters weren't being used. Rig A would have its power reduced by its VSWR
> protection circuitry when rig B dumped enough power into Rig A, no matter
> what the frequencies chosen for either rig. The fact that receivers were
> not blown is a tribute to how much abuse the rigs can handle.
>
> BTW the actual signal level picked up by the amplifier's VSWR sensor is a
> function of the frequency of operation of the two amps and the coaxial cable
> length on amp A, since amp A is tuned to freq A and amp B is putting RF into
> amp A at freq B--a freq where the pi-L network of amp A is not resonant and
> the feedline is anything but matched to 50 ohms.
>
> Now that I have explained the issues that have been questioned about the
> reliability of the ETO Alpha 91Bs let me summarize it by saying that I was
> very impressed by the general quality of the design and the construction.
> They seemed to be relatively easy to tune and virtually idiot proof. They
> will protect themselves from most forms of abuse, but if you keep the drive
> below a level of about 15 watts you are below the threshhold of the
> protection circuits and you can tune to your hearts content without worry of
> damage and without the protection circuits shutting you down. Presetting
> the tune and load to the values in the manual resulted in a "good enough"
> tuning for most circumstances--needed only a little tweaking when
> used with some of the low antennas.
>
> It is too late on a Sunday evening to pour over all of the preliminary
> schematics that I have in order to determine all of the ways that the screen
> may be protected but as a last resort the screen voltage is regulated with a
> series FET regulator with a 15 ohm 1/2 watt resistor from the input (+430
> volts) side and a 10 ohm 1/2 watt resistor on the output side(+360 volts) of
> the regulator. These appear to make good fuses as a last resort -- should
> the plate voltage disappear. It is not obvious at this late hour which
> other protection circuits would fire first but the Arc Fault would certainly
> operate before any damage could occur. (This protection circuit samples the
> input and output signals and protects things when the amplifier is not
> showing a minimum amount of gain--something that can occur when the amp is
> mistuned and this circuit eliminates any chance for tuning/loading capacitor
> arcing.
>
> With close to 20 operators of different technical capabilities, and the
> normal screw-ups associated with operating day and night on an expedition,
> and with generator power and its relatively poor regulation, somewhere in
> the neighborhood of 40,000 qso's were made without any component failures of
> the amplifiers. If you are a single operator in a contest then you will
> have no problems using a 91B. If you are using any amplifier with a VSWR
> protection circuit in a multi TX operation then you may experience false
> operation of the VSWR circuit due to RF from the other TX(s) getting into
> the amplifier and this is not limited to the ETO amps.
>
> Would I buy one? YES, but I already own two 87As. Disclaimer: Although I
> am not an employee of ETO I did fly on Dick's ticket with the understanding
> that I would look after the amps as my primary responsibility. Since they
> were so trouble free I got to spend most of my time putting on
> PL-259s--doesn't anyone else know how to do it right and have them come out
> looking pretty?
>
> Hope this info helps all contesters who are interested in the 91B.
>
> 73 John W0UN
>
>
>
>
> John Brosnahan W0UN
> La Salle Research Corp 24115 WCR 40 La Salle, CO 80645 USA
> voice 970-284-6602 fax 970-284-0979 email broz at csn.net
>
>
>From Larry Schimelpfenig <lschim at mailstorm.dot.gov> Mon Oct 2 11:46:06 1995
From: Larry Schimelpfenig <lschim at mailstorm.dot.gov> (Larry Schimelpfenig)
Date: Mon, 2 Oct 1995 06:46:06 -0400 (EDT)
Subject: more on guywires and insulators
Message-ID: <Pine.SUN.3.91.951002064340.4671A-100000 at mailstorm.dot.gov>
Hi Stan. Make the bottom ten or twelve feet EHS so they can't reach the
Philly stuff.
de K7SV Larry - lschim at mailstorm.dot.gov
On Sat, 30 Sep 1995, Stan Griffiths wrote:
> >By the time you add up the cost of insulators and clamps, and if your time
> >is worth _anything_ , and if you consider the odds of a component failing
> >increases by the multiple of every part you add to the guy system, then
> >Phillystran is the only game in town....
> >
> >Denny
> I certainly hope they have changed the composition of Phillystan since the
> last time I played with a piece of it. As an experiment, I strung it up in
> my garage at a 45 degree angle from the floor to the ceiling. Then I took
> an ordinary book match and proceded to light it on fire at the floor. It
> burned with a lot of black smoke and dripping flaming black goo, still
> burning as it hit the floor. The flames crept right up the Phillystan and I
> finally put it out. I am sure it would have burned to the top and set my
> garage on fire!
>
> I had visions of the neighborhood kids lighting my guy system on fire and
> the black flaming goo landing on my roof and burning my house down. If they
> didn't think of that, they might be able to bring my tower down with a
> pocket knife and a little patience. How do you Phillystran users protect
> against this kind of vandalism?
>
> Stan W7NI at teleport.com
>
>
>From Takao KUMAGAI <je1cka at dumpty.nal.go.jp> Mon Oct 2 12:59:16 1995
From: Takao KUMAGAI <je1cka at dumpty.nal.go.jp> (Takao KUMAGAI)
Date: Mon, 2 Oct 1995 20:59:16 +0900
Subject: RUFZ at Telegraphy World Championships
Message-ID: <199510021159.UAA28377 at dumpty.nal.go.jp>
Hi Chas
Sorry for the inconvenience with the email status. I have no idea
why your emails were bounced back. My email to you was bounced
back also. So I asked the postmaster at aol.com to check the problem.
Why did I introduce RUFZ program? I had a notice of the 1st International
Telegraphy Championship and the panphlet stated that RUFZ would be the
official program for the championship. So I wrote to the Author to have
the current version of RUFZ.
: The RUFZ program is my first attempt at really high
: speed CW reception since then, and it has been a blast. It would really be
: interesting to see how the competitors score on RUFZ; I suspect that the
: Eastern Eu ops might break 50K.
Well, there is a 50k Breaker now who is not a Eastern Eu op but
DF4PA did it. (got a permittion to forward the following to
the contest reflector)
------- je1cka at nal.go.jp forwards -------
Date: Mon, 25 Sep 1995 15:08:31 +0100
From: pke22 <pke22 at rz.uni-kiel.d400.de>
To: JE1CKA at nal.go.jp
Subject: "50K WITH RUFZ
Hi Tack,
I think, the scores depend more on the level of difficulty of the calls in
a run of 50 calls than on different computer speeds. 5k plus/minus is the
statistical error of a rufz-run. Anyway, my profit is the improvement in
reading calls, not the score. Started some 8 weeks ago at 25k. It became a
nice habit to have two or three rufz-runs with a cup of coffee after lunch.
73&gl, Mark, DF4PA, pke22 at rz.uni-kiel.d400.de
RUFZ HIGH SCORE:
1 50153 DF4PA5 7 480 9.664600
------- End of forwarded message -------
>From sfraasch at ATK.COM (Steve Fraasch) Mon Oct 2 16:36:08 1995
From: sfraasch at ATK.COM (Steve Fraasch) (Steve Fraasch)
Date: Mon, 02 Oct 1995 08:36:08 -0700
Subject: Shooting Tower Guy Points
Message-ID: <1995Oct02.084000.1180.106900 at msm.atk.com>
Regarding Rohn tower tolerances and where to find them:
It's on a print called "dimensions and tolerances," and was in the back of
my 1988 and 1994 sales catalogs.
I seriously doubt these tolerances need to be that tight;
but that's what Rohn says "in the book." Who am I to know otherwise ?
BTW +/- .1 degree amounted to +/- 3 inches az for my 120' guy anchor radius.
I believe I was +/- 2 inches or .08 degrees when using power-installed A.B.
Chance screw-anchors.
I believe the azimuthal tolerance is derived for tower stability,
not because of a concern for degraded anchor capacity.
Nevertheless, each of my screw anchors can hold back 20,000 lbs,
which is twice what the "Block 4B" concrete
anchor was rated for in the catalog; therefore, a little misalignment of the
anchor only
eats some of this redundant safety factor (4 x).
The shaft of the A.B. Chance "SS - Square Shaft" anchors is 1.5" x 1.5"
as opposed to 5/8" or so for the GAC-34 Rohn anchors.
The total cost to install 3 (which includes one in the swamp) was $1250,
which I considered reasonable given I had no solution for the swamp anchor
point.
A surveying transit will allow your to meet the +/- .1 degree
(assuming this instrument is PERFECT (don't know accuracy of this tool),
but you've also got to get them INSTALLED in tolerance, which I contend
is more difficult, especially if you're using screw-in anchors.
Concrete anchors are probably easier to get in the right place, assuming you
place the
anchor rod properly (in line with two site stakes) and you wire-in the
anchor
to the rebar in the hole so that the anchor rod does not move when
pouring the concrete.
In my case, these technical problems pale in comparison to the
electro-political problems
I have. But, it's a lot more fun to think about.
73,
Steve Fraasch, K0SF
sfraasch at atk.com
>From Tim S. Ellam <TELLAM at mccarthy.ca> Mon Oct 2 15:01:23 1995
From: Tim S. Ellam <TELLAM at mccarthy.ca> (Tim S. Ellam <TELLAM at mccarthy.ca>)
Date: Mon, 02 Oct 1995 10:01:23 -0400
Subject: 870
Message-ID: <s06fb7ed.083 at mccarthy.ca>
Like Fred, I also had a chance to try the new 870 at CY3IARU. I would echo
Fred's comments about the RX being very quite, but I also noted the front end
collapsed when the second radio fired up.
I did see both radios in operation on the same band(the 870 into an A4 and a
450 to a R7 only a few feet apart) without the benefit of band pass filters on a
couple of occassions so that may have effected the 870!!
Tim VE6SH
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