This episode of HamTalk Live is brought to you
by Tower Electronics. For connectors, cables,
and more, call 920 -435 -2973 or visit pl -259
.com. And by ICOM, heard it, worked it, logged
it. Visit www .icomamerica .com slash amateur
for more information about ICOM radios. Here
we go, welcome to Hamtop Live Call in, let's
talk, Neil's your guy Hamtop Live, here we go
on Hamtop Live Good evening, everyone. It's ham
talk live episode number 234 coming your way
right now. It's New radio performance from Rob
Sherwood nc0b recorded live on Thursday, October
29 2020 I'm your host Neil rap WB 9 VPG. Thanks
for tuning in to this episode of ham talk live
tonight. We're joined by Rob Sherwood nc0b and
we will take your calls live a little later in
the show. Last week, Rich Moseson W2VU was here
to talk about some recent moves at the FCC. If
you missed that show, you can listen anytime
at HamTalkLive .com or on your favorite podcast
app, or you can listen to it over on YouTube
and you can catch HamTalk Live. the rebroadcast
over on WTWW that's 5 0 8 5 a .m. Saturday afternoons
about 3 30 p .m. Eastern Time so get your performance
questions ready to go for Rob if you're listening
to us live on Thursday night You can give us
a call after the interview by Calling this phone
number and we'll give that out a few times here
tonight So you can have it ready to go. It's
eight five nine nine eight two seventy three
seventy three And we'll repeat that here in a
second so you can have it ready. It's not time
to call yet, but it will be, so have that number
ready to go. You can also send a question via
Twitter. The Twitter handle is at HamTalk Live,
and we actually have one there already. So we'll
take a look at that a little later on in the
show. But again, the phone number is 859 -982.
7373 and I'll be back with Rob right after this
word from Tower Electronics right here on HamTalk
Live. I'm sorry to bother you but I'm having
an antenna party and I ran out of PL 259s. Oh
come in. Thank you. Would silver -plated PL 259s
from Tower Electronics be too good for your guests?
Those will be fine. Thank you. You saved my life
the other night. Oh, the PL -259s from Tower
Electronics? Yes, they were very successful at
the antenna party. My antenna works like a charm.
Then how can you ever thank me? I'll try to think
of something. Don't be caught without PL -259s.
Visit Tower Electronics at a ham fest near you,
or visit them online anytime at PL -259 .com.
or call 920 -435 -2973. They have adapters, cables,
antennas, soldering supplies, and meters too.
A clean house is a sign of a broken radio. You're
listening to HamTalk Live with Neil Rapp. Welcome
back to HamTalk Live thanks to Scott and Jill
over at Tower Electronics for sponsoring the
show tonight. They help bring you HamTalk Live
each and every week and coming up next week they'll
be at Bedford, Indiana just down the road from
me. November the 7th and in Fort Walton Beach,
Florida November 13th and 14th. or you can visit
them anytime at PL -259 .com. Tonight's guest
is Rob Sherwood, NC0B. He was first licensed
in 1961 with a novice license WN8ADB at age 14
in Cincinnati, Ohio. He upgraded to general class
in about two months and his call sign changed
to WA8ADB. and he operated as Portable Zero in
the mid 70s out of Colorado and now lives there
just east of Fort Collins. He upgraded to Advanced
Nextra in the 80s and got his current call sign
NC0B. In 1974 Rob founded Sherwood Engineering
offering Drake radio upgrades and he started
testing transceivers. in 1976 which now total
well over 100 and that information is available
at his website nc0b .com or Sherwood engineering's
website sherweng .com and Rob you've been a very
popular guest on the show and earlier tonight
when I was actually talking to a friend of yours
I said that Rob Sherwood was the EF Hutton of
HamTalk Live. When Rob speaks, people listen.
So welcome back to the show. Well, thank you,
Neil. And good evening. By the way, Bedford in
Indiana is where my Sherwood family farm still
is over over a hundred years. Oh, wow. Yeah.
And you're just just down the road here and I'm
looking forward to Scott and Jill pulling in
here next week and get to hopefully visit with
them a little bit and hopefully the ham fest
goes well there. But yeah, it is just about 25
minutes down the road. All right. Small world.
Yeah. And all the Cincinnati connections. I got
a little bit of that tonight. We're talking with
next one of next week's guests actually Jay a
Drake Kate CJ Y and Was telling me you all went
to high schools that were like next to each other
and and And basically grew up together. Oh Yeah,
it certainly goes back to high school days and
actually one time before I could even drive I
was out with this whole gang and they were a
little bit older than I am by a few years and
My parents didn't know where I was once I got
home a little bit late, so it was kind of funny.
But we had a great time visiting radio stations
in the middle of the night. Well, Jay is going
to be on next week along with Lee Hite, Kate
CLI talking about the Drake exhibit over at the
Voice of America Museum of Broadcasting in Westchester,
which is northern Cincinnati, Ohio. So we'll
be talking about that a little bit later. But
tonight we want to talk about some of the some
of the modern gear. You were here in January
of 2018. It's been way too long. The ICOM 7610
had just arrived on the scene. I believe you
had tested it but hadn't run a contest with it
yet, if I remember correctly. And there's all
kinds of new radios that have been released since
then. And I know you've got an update from last
time, too, on the ICOM 7300 to talk about. So
we'll get that in here in a little bit. But tell
us about the new radios that have been on the
scene since the release of the 7610. Well, actually,
because I did listen to our chat from two years
ago. The 7610 came up. My wife drove it up just
in time to hook it up for the first time in a
contest. So I just barely got it on the air.
But since then, I have two of them. And so, for
instance, CQ Worldwide was just last weekend.
And I had the two 7610s and the TS890S and had
a ball. Conditions are amazing after certainly
a dearth of sunspots. So the contest gods were
on our favor this time. I unfortunately was tied
up with family stuff and wasn't able to get on,
but I hear 15 and 10 was just a pleasant surprise.
Well, I had 77 contacts on 10 and I think 261
on 15, so it was a ball. Oh, that sounds great.
Well, tell us a little bit about the 76 -10 now
that you've got a second one. You've had a chance
to really put it through the... Oh, what's the
word I'm looking for? I've lost my word here.
You've put it through the paces. Right. Well,
the reason I have two and actually that plus
the Kenwood is I have three operating positions
here at the contest station. So I changed bands
by changing chairs. So like during the daytime,
I had 10, 15 and 20 set up on the three different
radios. The thing that I really like about this
7610 that I don't need to use very often myself,
but the noise reduction is very nice. That's
probably the first radio that I've ever, that
in the 7300, used the noise reduction. And then
of course the noise blanking is there too. Of
course it's got a big screen and very simple
to use and you don't have to go into a lot of
menus on a daily basis. So it's worked out very
well and I've had them, actually both of them
were produced or at least sold in December of
the first year they shipped here. So they both
been around, well, just coming up on two years.
And I know you mentioned that you had an update
on the 7300 from last time that you wanted to
make sure to get in. So let's talk a little bit
about it. Okay, and I think that's a fantastic
radio whether it's your first radio or you got
several radios. It's just a wonderful box Well
when it shipped the something called IP plus
which is a dithering method of linearizing the
ADC chip, the analog to digital chip, well, it
caused the noise floor to degrade, about between
11 and 13 dB. But ICOM fixed that. I don't know
the exact serial number when that happened. It
was a long time ago now. So my first one was
a serial number 1 ,400 range. But then I bought
a second one, maybe like a year later, it was
like 12 ,000 and something. And then a friend
of mine in Alaska has one at the 10 ,000 serial
number range and his is fine. So I don't know
when that happened, but of course now they've
sold over like 45 ,000 worldwide. So that issue
that really was not a deal killer at all, but
that's been fixed. Okay. Very good. Yeah. I remember
that was a big deal, especially if you were,
uh, Gonna do like field day or something with
it and I remember using Hours at school for that
and actually it worked just fine. So That sounds
like that's been taken care of well, what are
some of the other Some of the other rigs Actually,
I guess while we're on the icon bit here I know
you you have a 705 on the way, but you've been
able to get some numbers on it and Um, so let's
talk a little bit about it while we're on the
ICOM thread here. Okay. Well, I'd hope to get
one from hammered to outlet in Denver on Wednesday,
so I could throw it through the lab in a hurry.
And that actually didn't come in until today,
but I was already halfway to, uh, this QTH and,
uh, so I'll get it on Tuesday. I did get to talk
to a K zero MD, Scott Wright, who, uh, publishes.
national contest journal through QST. And of
course, if you subscribe to QST and are a league
member, you can now get that downloaded as a
PDF. So he's been using it a short time. He actually
ran some sort of a ready contest with it. Now,
Scott has, well, let's say a pretty good tower.
It's 130 feet tall. And the whole tower rotates
and he's got stacks on that tower. And he had
the little 705 hooked up to his fancy antenna.
He was quite happy with it. I got some numbers
out of a friend in Europe. And it looks like
the numbers are going to be pretty much in the
ballpark of the 7300 as far as noise floor and
dynamic range and things like that. So it looks
like it's going to be a great little QRP rig.
And actually, I'm going to run it, not QRP. I'll
let it drive my off amplifier in the ARRL contest
in December. 160 meter CW, the 10 meter CW and
single sideband and probably the W1BB 160 meter
contest. So I'm going to have fun with it, uh,
driving in a linear. Oh, okay. Very good. Yeah.
Uh, Scott has, uh, has raved about it and said
that, uh, he can't tell the difference in the
receiver between that and a 76 10 and that that's,
that's pretty impressive. We did a little video
back and forth for about 45 minutes a couple
of days ago with Scott and that was finally seeing
his shack and Him tune in the radio. So that
was that's as close to I've got my hand on a
knob, but by Tuesday I'll have my hand on a knob
All right. Well, we look forward to To hearing
about that and and I guess is like I said as
long as we're on the icon thread here The IC
9700 is one that's been out since then too. So
we'll talk a little bit about it Sure, well,
I have one of those. And I retired my ICOM 275H.
That was a 100 watt multi -mode, two meters only.
Great front end, nice little radio. Had pass
band tuning, which they later unfortunately went
away due to some dispute with patents. But I
did replace the 275H with the 9700, and I love
it. Now and it works pretty much like all all
the rest so you figure out all the functions
why you're in pretty good shape and Full disclosure
ICOM is a sponsor of the show so we'll get that
in there But then you've got some some other
rigs that are on here. One of the newer ones
is the Yezu FTDX 101D And I'm looking at your
table right now and it's sitting at the top.
And I was lucky in time before, you know, Dayton
Zoom, we'll call it, or Hamm Contest University
Zoom method. Hamm in New York loaned me the rig
in time for that. I ran it through the lab. Of
course, there was a recall early on and all the
rigs had to go back to California. So it got
the overshoot update. ALC overshoot update and
it came back and tested it again and that was
corrected. And then it went back to its owner.
I got to listen to it a bit in Denver, but I
didn't get to use a lot on the air, but it certainly,
Yezu had made a major strides in the cleanliness
of the synthesizer, which is outstanding. The
Dymec range obviously is really outstanding.
It happened to be the top of the list by a few
DB over a few other very fine rigs. So it was
great to see really get to the top of their game.
So I'm sure it's been a good seller. And I kind
of watched the Groups .io group and a lot of
chatter on that. And then we've got the Flex,
which has been there for a while, and the ICOM
receiver, which we kind of expect to be pretty
similar. And just cruising down here, we've got
the Kenwood TS. 890 correct and actually I was
an owner of the TS 990 for three years and unfortunately
a really close lightning strike that took out
several things it took out the 990 so then after
There was the 890 didn't exist then at that point.
And then I think the 890 has been out about two
years. So I got one of those and that's over
here to my right right now. The thing I like
about the 890 versus any other standalone radio
with a direct sampling band scope is the way
it tunes. As I tune the radio, the waterfall
doesn't slew off at an angle. The band scope
doesn't sort of fade out if I've got averaging
on. And so it makes it really easy. I call it
like shooting fish in a barrel that works particularly
CW contact tax in a contest, maybe the station
every three or 400 Hertz. And so I use the 890
with a 10 kilohertz span on 160, for instance.
And I think on 10 meters, probably a 10 kilohertz
span. And I'll just see the signal on the waterfall.
I centered in the passband. The passband width
highlights itself while you're tuning. So you
just drop that signal right in the middle of
your passband, whatever bandwidth you've chosen,
and you're dead on frequency, and you work the
guy. And then the sooner you're done with that,
I'm doing S &P. I'm not running search and pounce.
So I just tune the next station. So it's just
a fantastic the way the waterfall and the band
scope work. So that's. From my standpoint of
contesting, that's my favorite way to do CW contesting
with the way the waterfall works. Uh, the next
one on the list is the Apache 7 ,000 DLE. That's
been interesting because Apache is, of course
it's open source software, which is different
than everybody else's software. That's a proprietary.
And so a lot of really smart hams, right? the
software for the radio, the DSP software, and
what's called Pure Signal, that's the pre -distortion
that makes it the cleanest rig on the air, period.
That's written by Warren Pratt, NR0V, and he
lives in Loveland, Colorado. It's about 30 miles
from me right now. So I use that in a contest,
160 contest, about a year and a half ago, approaching
two years, and the He's got something called
a spectral noise blanker. Now, normally when
we're in a contest, you know, a zillion stations
on the band, if we do have a noise issue, you
turn on the blanker and usually they false trigger
and they just cause more trouble than they're
worth. But he has this amazing spectral noise
blanker that it only looks at the bandwidth that
you've set on your transceiver, whether it's
sideband or CW, 500 hertz or 2 .4 or whatever
the bandwidth is you've chosen. And it makes
an approximation of the amount of signal that's
there in between the noise pulses and fills in
the blanks. And it's just amazing. So the software
is great. And I really want to commend them on
their transmit signal. I actually am on a 75
meter chit chat, 8 o 'clock each day of the week,
on a 3 ,652 that's around this area. and some
neighboring states. And the stations that are
all running Apache, when you look at them on
the band scope, they're just straight up and
down. Absolutely, there isn't any fuzz on it.
So you can tell who's on an Apache and who's
not. It's just amazing. And this is good for
everyone because anytime we can narrow our bandwidth
from a splatter standpoint, and of course, every
transceiver has a less than perfect because perfect
doesn't exist in the radio world. And Class A
is pretty much gone. They used to offer Class
A on two or three rigs, but not any longer. So
anyway, this pure signal, pre -distortion. And
of course, you can also sample the output of
your linear amplifier when you're running full
power or 500 watts or whatever your amplifier
is and feed that back into the rig. And it corrects
any distortion by 20 or 30 dB. It's just amazing.
Well, let's see what else we have here we have
the flex 6400 Well the 64 and the 66 pretty much
are right next to each other on my table There's
no I think they're 1db different which is insignificant.
Obviously. It's just uh, you know that so you
could put that down to a sample variation or
even the experimental error, but of course they
do operate with a computer just like the Apache
and so that's the difference between like the
Kenwood and the Icom and the Yezu which are standalone
so you do need the computer. Some of the people
run their Flex with an iPad so that's flexible
and of course they put a lot of emphasis on remote.
And actually, I was during Siki Worldwide, I
think I was on 15 meters and talking to a station
that I think was zone 33. But the operator was
really in Finland and he said, Hi, Rob, you should
put my rig on your test bench. He was making
a joke, of course. And he said, I'm in Finland,
but the transmitter transceiver is a flex and
it's I think it was zone 33. But anyway, it was
hundreds of miles away. So that was kind of fun.
Let's see I'm looking through the list here and
I think we've got one More that we have not hit
on And that would be where did it go Looking
here all the lab the lab 599 the TX 500. Oh,
yes And that's a QRP rig, 10 watts. Of course,
you can run five watts. And I borrowed it from
a very nice amateur that loaned it to me for
several days. I ran it through the lab. It's
on my website. It's the most recent update. And
it's very sturdily made. It's like machined aluminum
clamshell, half and half. It has a band scope
built in and very easy to use. The numbers are
quite fine. I think it came up at 79. And really,
for years, I used to say NWAJI, time route. So
you know, 80 dB radios are adequate almost all
the time. And I've kind of moved that number
up to 85 because now we probably have two or
three dozen radios that are 85 to the 110 range.
So it looks like a cute little radio. I just
did use it in the lab. I didn't climb a soda
mountain or something like that. But it looks
very rugged and if you got some sprinkles on
it, it's not going to die in a little bit of
rain. All right. Very good. Well, we're looking
at the tables here at nc0b .com and there's a
yellow bar down at the bottom. You click on that
and it puts all of these transceivers and receivers
that you have analyzed. In order and I know you
always want to talk about the order and we should
do that. The more extensive. uh, interview about
all the numbers and what all the numbers mean
and, and all that, um, is on the previous episode.
So you go back and, and, and check that out if
you're interested in digging into the numbers
and what these ratings are, but give everybody
just kind of the quick, uh, the quick spiel about
how you've arranged these in order and, and what
that really means. Sure great and by the way,
just if you go to the home page There's a banner
that crawls across the top of the screen you
click on that banner it goes to the the table
as in addition to the one at the bottom and also
I think there's a broken link at the bottom on
an explanation but on the on the Table page is
not broken. Am I webmasters gonna fix that but
but anyway, so you have to rank the radios by
some parameter and the reason it's sorted by
close in dynamic range is the reason I started
testing radios back there in the mid -70s. I
had a radio that, with the older standard test
that came out in 1975, which meant the two -tone
test for the dynamic range was 20 kilohertz.
And that was OK for radios designed in the 50s
and 60s and maybe most of them in the early 70s,
but it really didn't work once we had roofing
filters. Because once the roofing filter came
along, you had a lot of gain within the bandwidth
of the roofing filter, and selectivity was way
downstream. And if you tested it at 20 kilohertz,
that means those two signals are 20 kilohertz
down the band and 40, or 20 kilohertz and 40
kilohertz up the band. Well, you're not testing
anything but the first mixer and it may be passive
intermod in the roofing filter or something like
that. But once the signals get inside the roofing
filter and really for 25 years, all the roofing
filters, like 99 % of the roofing filters were
15 kilohertz wide, you can have a lot of CW signals
in that bandwidth. It's really mostly a CW issue
and RTTY for sideband most of the time. our adjacent
channel splatter, the intermods, even if we have
a relatively clean signal, we still have a width
that's approaching 10 kilohertz if we're going
in like 60 dB down. So most of the time on sideband,
if a station is three or four kilohertz away,
the limit isn't going to be the dynamic range
of the radio, but it'll be to whatever. unintended
splatter comes from the transceiver. But on CW,
of course, we don't have that. We do have key
clicks, which can be an issue. And maybe in a
field day environment, transmitted composite
noise. But for the most part, the signals are
pretty narrow. So if we have 15 kilohertz worth
of signals, which could be 50 signals, it can
really cause havoc. I started testing at 2 kHz
spacing instead of 20, and I did that ever since
about 1976. And eventually the league got there.
It took a long time, but they test the 2 kHz
now just like I do. So if you're a CW op into
contest, de -expedition, pile -up band type of
conditions, or RIDI, That's really the number
you need to look at. Now, sometimes I get asked,
well, why don't you sort it by sensitivity or
noise floor? But I just gave a presentation in
the last few weeks and showed some data on, well,
the R390A has a sensitivity of 0 .2 microvolts.
The R4C has a sensitivity of. 0 .2 microvolts.
The K3S with preamp number one turned on, sensitivity
of 0 .2 microvolts. Now sensitivity is a sideband
measurement. And then if you look at the noise
floor, which is the way we look at for the CW
measurements, they're all within 1 dB of each
other. So the radios today are phenomenal from
that standpoint. You can hardly buy a radio that's
not sensitive enough. For that matter, we really
have too much on the lower bands. Radios today
are designed for 10 meters and now 6 meters.
Everybody's radio covers 6 meters today. And
so you've got amazing sensitivity for 12, 10,
and 6. But once we're down on 160 or 80, the
band noise at night is like 30 dB higher than
band noise at the daytime it is on 10 meters.
So we've got all sorts of sensitivity that goes
to waste. You should be running attenuation at
night for multiple reasons that I do go to in
my talk. So that's the reason it's sorted that
way. Of course, there's other information. How
clean is the synthesizer? That's important for
like 20 or 25 years that synthesizers were really
the limit. But now the synthesizer in the new
Yezu, in the new Kenwood, the direct sampling
radios, if you put a decent. clock oscillator
in a direct sampling radio. You're not going
to have a phase noise problem or a reciprocal
mixing dynamic range problem. So we're really
amazing condition from that standpoint that we
didn't have years ago. All right. Well, uh, before
we go to break here, I do want to, uh, to mention
that, that you've retired since last time. So
congratulations on that. And, uh, Are you still
doing any business? Do you still have any of
your upgrades available? What's going on with
the business side of things? Well, we pretty
much shut it down. I'm 73 and my technician has
worked with me for 28 years. He's 83. So we just
decided it's time to call it a day. I happen
to have two or three mix fours left for the R4C,
but otherwise everything's gone. The cooling
kits for the 781 are gone and the little upgrade
for the NRD535. So, you know, I started all this
in 1974 and was really kind of surprised. If
you'd said in 1980 or 1985 that I would be still
updating Drake R4Cs in 1999 and early 2000, I
would have said, really? But There was still
a lot of interest, but at some point I had to
call it a day, but I've gotten some emails that
said you cannot quit, you cannot retire. So what
can you say? Yeah. And we're going to talk about
those are fours and, uh, and the upgrade a little
bit next week as well. So we'll save that for
then, but, uh, but congratulations on the retirement
and, and we're glad you're still, uh, testing
and. providing all the data and that gives you
a little more time to play radio, hopefully,
anyway. Well, I'm definitely not retiring from
testing radios. That'll go on as long as I can.
Well, we appreciate all of that and we really
like all this information that you provide all
together in one nice neat little package. It
makes it very easy to come in and do the receiver
comparisons. Although, like you said, most of
them are really, really good these days. Well,
we're going to take a break. When we come back,
we'll talk some more with Rob and we'll start
taking your questions on Twitter and on Spreaker
and on the phones at 859 -982 -7373. And we'll
come back and do that right after this word from
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Join the conversation. Give us a call at 859
-982 -7373. Again, the number to call is 859
-982 -7373. Or, if you'd rather type than talk,
tweet us at HamTalk Live. Now, here's Neil Rapp
with more HamTalk Live. Here's the snap, Rapp
takes the rig, he breaks through the pile up,
he's on 80, now 40, now 20, 15, 10, 2 meters,
touchdown Hamtok Live! Welcome back to HamTalk
Live. Check out the IC 705 and all the gear from
ICOM at icomamerica .com slash amateur. HamTalk
Live is on the air every Thursday night at 9pm
Eastern time right here at hamtalklive .com and
be sure to check us out on Facebook, Twitter
and Instagram and apologize for the dead air
there. Windows is messing with me on switching
windows back and forth and apparently the phone
so we'll try to get that uh resolved here uh
but uh now it is time actually before we go back
to rob for the HamTalk Live Ham Radio Joke of
the Week with N9GSU. Now it's time for the HamTalk
Live Ham Radio Joke of the Week, the part of
the show where Rick tells us a ham radio joke.
The HamTalk Live Ham Radio Joke of the Week is
brought to you by QRM Labs. Now, here's Rick
Garrett, N9GSU with today's HamTalk Live Joke
of the Week. Was listening to the local repeater
the other night and somebody started playing
don't stop believing I'll tell you what that
was an unexpected journey This has been the ham
talk live ham radio joke of the week with Rick
Garrett in nine GSU Tune in again next week for
another joke from Rick Well, there you go a little
journey Thank you, Rick. And it's time for your
call. So give us call eight, five, nine, nine,
eight, two, 73 73. If I can get this thing to
answer the phone, uh, or you can tweet us it's
at ham talk live. And if you're listening to
us on WTW. or on the podcast edition, you won't
be able to reach us live since we're doing this
on Thursday night. And while I try to get the
phone to answer, we do have a tweet here from
Dan. He says, hi Rob, Dan Robinson in Maryland
as someone who benefited from your deep experience
in the radio field so long. Congratulations on
your retirement and all the best luck to you.
A tough question, but if you could line up in
your head, a ranking of the most sensitive and
quiet HF receivers, what would that be? OK, well,
I'm going to answer the question sort of. But
we have to realize that our receivers are completely
adequate for sensitivity. But that's the left
hand column. Well, noise floor, which is in that
500 Hertz bandwidth, just like you see in QST.
And then in sort of the middle column, this listed
as sensitivity. And I put it in microvolts instead
of dBm, because if you have a radio that goes
back before 1975, no one heard of dBm in the
amateur world. So I keep sensitivity in microvolts.
And you can look at either of those columns.
And they're not sorted that way. But it's kind
of a non -issue. Let's look at the first few.
I've got. Like 10 of them up here on the screen.
We've got the new Yezu Of course, they've got
preamp 1 and preamp 2 in some cases They all
have preamp 1 at least but look at the noise
floor minus 141 for several 145 139 and on 6
meters that might be useful on 10 meters probably
138 is plenty good in a quiet location Now, that's
the key. Most of us live in an urban environment.
I would say that band noise, meaning RFI noise
from all these electronic things we have today,
line noise, switching power supplies, microprocessors
in our refrigerator, our washing machine, our
dishwasher, they all put out racket, your charger
for your iPhone or whatever. They put out noise.
Matter of fact, My four towers that are further
from the house pick up way less noise from my
own house as the two that are close to my house,
because I got lucky I have 10 acres and six towers.
So but if you're in an urban environment like
I am in Denver, it almost doesn't matter because
local noise is terrible. I'm a mobile fan and
when I drive through a town, I might as well
turn the mobile off. So really don't focus on
sensitivity or band noise by trying to decide
on a radio because really all the good radios
are just fine. All right. Well, let's see here.
Uh, John W four U S F says, love Rob's antenna
farm. I am one jealous ham radio operator this
evening. And there, there was the, you mentioned
the, the six towers and 10 acres. That that's,
uh, that's definitely, um, Worthy of being jealous
Well, I've been here for 13 years my wife said
you've wanted to do this it was kind of at the
When the housing market kind of crashed and so
that was the time and my wife was very supportive
and off we went Well, that's great Fabulous that
you can do that. I am in the middle of trying
to get property to put up one. And maybe today
was the first step of that. We'll see. But I'm
fighting that battle. All right. Well, the phone
is ringing, but I can't answer it. So we'll keep
trying the tweets here. Go ahead. Let me make
a comment on the antennas. I consider antennas
extremely important. If you want to say in order,
what's most important? Well, location. And maybe
you can't do anything about that. But I moved
out in the country. And then antennas and operator
skill. And you could argue, well, operator skill
antennas, maybe you'll flip them around. And
then the radio. So really, put up the best antenna
you can. On the upper bands, when we can have
a tri -band or a mono -band or whatever, there's
nothing more important than the directivity of
a yagi or a quad or whatever it is. I happen
to have two yagis per band, like on 20 and 15
and 10, so they'll be pointed in different directions
during a contest. It's like two different bands.
You can't believe the amount of attenuation.
Maybe you rotate your beam around and you say,
well, I guess it helps. But when you can flick
a switch and go between antenna one and antenna
two in two different directions, it's like two
different bands. So if you can put a Yagi up
at 35 feet, that should be your number one priority.
And of course, higher is better. And you mentioned
too, while I'm still trying to reboot the phone
system here, you mentioned too the footnotes.
There's always footnotes on the table, so let's
talk a little bit about the footnotes. Good reminder.
Okay, well, like on that first column with the
noise floor, the footnote just describes the
preamp, whether it's on or off and which preamp.
That's pretty straightforward. The big thing
is over in the right -hand column, since it is
sorted by close in a dynamic range, two kilohertz,
or there's also the 20 kilohertz numbers too.
If there's a footnote... Read it carefully because
it may have a big significance. Let's just look
at the K 3 for instance and It had different
bandwidths and that different numbers or let
me find the see if I can find the K X 3 because
that's an interesting one It has I think three
footnotes dealing with here it is dealing with
whether you were in the zero IF version, whether
you had the quote roofing filter or whether you
were concerned about the opposite sideband rejection
because the KX3 is kind of a phasing rig. If
you guys are as old as I am, you know what a
20A was. That was a phasing transmitter, but
you have it's kind of a phasing receiver. So
the opposite sideband rejection is around 65
dB. So if you did happen to have a signal just
on the opposite side band of your beat note on
CW, let's say you like the 700 hertz beat note
and you were on the opposite side band at 700
hertz with a big signal and it was that the rejection
is 65 dB, that would be a limit in that case.
So read the footnotes carefully and there's details
there and if you have a question about the footnote
and don't... Totally understand what I'm trying
to say. Send me an email, robettnc0b .com, robettnc0b
.com. All right. Very good. Well, I know the
phone lines are lit up and I I can't get the
software to answer. So we're going to have to
resort to Twitter here. So if you have something
to ask, give us a tweet at ham talk live. And
we are actually about out of time, but we'll
see if we can get a couple of them in. But my
apologies for for windows updates, slowing everything
down here. Once again, the new computer is on
the way, by the way. Rob, what were your thoughts
from CQ Worldwide this weekend? Well, the conditions
were an amazing surprise. I spent as much time
on 15 as possible and then went to 20 when I
had to and then went to 40 later, but 40 in the
middle of the country here in Colorado with even
a two element beam at 70 feet. trying to plow
through to Europe with all the guys in the East
Coast, a lot closer, kind of difficult, not so
bad towards the Caribbean or South America. But
I did keep running over to the 7610 set up on
10 meters with an ACOM 1000. And actually, Sunday,
the opening in the afternoon was amazing. Not
that it was an amazing period. Two weeks before
CQ Worldwide was a 10 -10 sprint QSO party. And
I worked one station. in about 30 miles away.
I normally work K8 DEL in Cincinnati. If I can't
work Dell on 10 meters, the band's dead. And
I did hear him a few times for a second or two
here and there, maybe five seconds or 10 seconds
at a time, but he didn't hear me. So I don't
know what happened. Obviously we had some sunspots
and 15 meters was just wall to wall and a lot
of fun. So I'm sure the This the CQ worldwide
CW coming up in November. They're going to hope
for equally good propagation. Who knows what
will happen Very good. Well, we're going to to
finish up here, but Again, my apologies on the
phones here, but it was out of our control. So
a lot of great information and you know, there's
just so many good radios out there and I look
forward to hearing what you have to say about
the 705 after you get a chance to play with it
yourself a little bit. Obviously, there's been
this big shift into direct sampling and I'm just
amazed at how quiet they are. And from the ICOM
standpoint, if you can run one of them, they
all work the same way, whether it's the 7300,
the 7610, the 9700, or I'm sure the 705. So that
user interface is very consistent. If anyone
would like to have a PDF copy of my most recent
Zoom presentation, I believe it was to the Ham
Radio Club in Austin, Texas, it includes a list
of the top 18 transceivers, not the 18 counting
down from my table because let me explain something
here. There are more than one data point for
like a K3 came out in 2008 and the K3 was updated
with a new synthesizer and then the K3S came
out. So it's there at least three times. The
direct sampling radios have a little more variation
in the way they test in the lab. Probably don't
notice it on the air. But there's second samples
on several of the direct sampling radios of all
the brands. So I have this list that is the top
110 down to 90. And believe me, a 90 dB radio
is just fine. Clear up to 110. There's 18 different
transceivers there that anyone should be happy
using. Of course, the used market is now a bargain
since the $7 ,300 is so inexpensive at $1 ,000.
You can buy like a TS590S at maybe $600. So if
you have a budget that doesn't go to the stratosphere,
it's a buyer's market in the used market. And
then even some of the new ones here at amazing
prices. So if you would like to see a PDF, just
send me a... Email at rob at nc0b .com and I'll
send you a pdf of presentation. I just made a
few weeks ago Very good rob. Well, thank you
so much for being back on the show and I look
forward to hearing more from you in the future
and And we'll see what radios are out next. I
know One you're you're really excited to see
is the new k4 Right, do we have two minutes to
talk about that? We got a couple of minutes.
Go ahead. Okay. Well, we know the architecture.
So a straight K4, we'll call it like half of
a 7610. It's going to have one ADC and one set
of bandpass filters, and you can get two receivers.
But if you were actually wanted two receivers
on two different bands, it would have to go broadband.
The K4D would be like a 7610 as far as the architecture.
two ADC chips, two sets of front -end LC filters,
and of course then you could work 20 meters and
15 if you're an SO2R guy, which I'm not, you
could be listening on two bands and have full
front -end filtering. Then of course we have
the HD, which we have no idea what the price
of that's going to be, and that would have like
a K3S built into it, a SuperHat module with four
roofing filters. That would be a sideband roofing
filter, and a CW roofing filter for the main
receiver, and one sideband roofing filter and
one CW roofing filter for the second receiver,
call it the sub receiver. So we know the architecture.
I think we can kind of guess the numbers. I mean,
all the direct sampling radios are more or less
100 dB plus or minus a few. And then the K3S,
for instance, is about 106 or 107. So I guess
you'd have to assume the K4HD would be around
that, maybe a couple DB higher, who knows. So
we kind of have an idea on raw numbers. Of course,
features, one thing that Ellicraft is saying
that they will have someday is pre -distortion
like Apache. And Flex has talked about pre -distortion
for years. So it would be really good if two
major OEMs in the US could offer the same thing
for a super clean sideband signal that we currently
only have from Apache. So of course, I'm anxious
to get one through the lab. But at the moment,
we're still all waiting for the K four. But I
think we know it's it's approximate performance
level. All right, well, we'll have to talk about
that. at a later date when that's out as well
as others out there on the market. So Rob, thank
you so much for being here again and chatting
with us tonight and appreciate all of your efforts
and enjoy the retirement and we'll talk to you
soon. 73, Neil, thank you. All right, well that's
a wrap for this week's edition of HamTalk Live.
Thanks to my guest, Rob Sherwood, NC0B and everybody
out there in cyberspace for listening and typing
in tonight and invite you back next Thursday
night at 9 p .m. Eastern time when Jay Adrick,
K8CJY and Lee Hite, K8CLI will be here to talk
about the new Drake radio exhibit at the Voice
of America Museum of Broadcasting. For a list
of all of our upcoming guests, visit HamTalk
Live. And if you like the show, please leave
us a review. That'll help others find us faster.
So for now, this is Neil Rapp, WB9VPG saying
7 3 7 5 and may the good DX be yours.