HF Diversity reception ?
 

I know that Hallicrafters made a dual diversity set up and RCA used
three AR-88s in a trioka, selecting the best signal with a tone decoder
that switched in the best and let the other/s idle or squelched. I've
heard that Collins used the R 390 (51J or 51S?) , and Hammarlund the
Super Pros ( only 600s or others?). It seems like three antennas spaced
about 1000 feet apart on an equilateral triangle was a 100% solution.
Did the Brits use it a Bletchley? But I don't see anything these days
and have to wonder if diversity reception was made obsolete by SSB or
the news & financial services using wire for TTY. I also know that
Telstar was the final nail. Was the primary use for RTTY or was it used
to voice well as CW? Anyone have some real personal experience to
offer?
Thanks
Hank WD5JFR

HF Diversity reception ?
 

"Henry Kolesnik" wrote in message
...
I know that Hallicrafters made a dual diversity set up and RCA used three
AR-88s in a trioka, selecting the best signal with a tone decoder that
switched in the best and let the other/s idle or squelched. I've heard that
Collins used the R 390 (51J or 51S?) , and Hammarlund the Super Pros ( only
600s or others?). It seems like three antennas spaced about 1000 feet apart
on an equilateral triangle was a 100% solution. Did the Brits use it a
Bletchley? But I don't see anything these days and have to wonder if
diversity reception was made obsolete by SSB or the news & financial
services using wire for TTY. I also know that Telstar was the final nail.
Was the primary use for RTTY or was it used to voice well as CW? Anyone
have some real personal experience to offer?
Thanks
Hank WD5JFR
I don't own one- but believe the Elecraft K3 can do diversity but woud
require the 2nd RX option.
There's space diversity (which you allude to) but also polarity diversity.
Dale W4OP

HF Diversity reception ?
 

Dale Parfitt wrote:

Hank WD5JFR
I don't own one- but believe the Elecraft K3 can do diversity but woud
require the 2nd RX option.
There's space diversity (which you allude to) but also polarity diversity.
Dale W4OP


And frequency diversity and time diversity.

HF Diversity reception ?
 

Space diversity is what they call it for microwave systems and they also
use frequency diversity. I've not heard of polarity diversity used on
commercial HF systems but I have used it quite a bit myself with a
horizontal dipole and a 18AVT. The military and FEMA use a computer
control systems to automagically establish links on various bands for a
round tables, and switching to the best link whenever required. I can't
recall the acronym but I hams have a PC based system. I've seen it in
use at a swapmeet using Sunair transceivers.
Does the Elecraft have a built in tone decoder?

Hank wd5jfr
"Dale Parfitt" wrote in message
...

"Henry Kolesnik" wrote in message
...
I know that Hallicrafters made a dual diversity set up and RCA used
three AR-88s in a trioka, selecting the best signal with a tone
decoder that switched in the best and let the other/s idle or
squelched. I've heard that Collins used the R 390 (51J or 51S?) , and
Hammarlund the Super Pros ( only 600s or others?). It seems like three
antennas spaced about 1000 feet apart on an equilateral triangle was a
100% solution. Did the Brits use it a Bletchley? But I don't see
anything these days and have to wonder if diversity reception was made
obsolete by SSB or the news & financial services using wire for TTY. I
also know that Telstar was the final nail. Was the primary use for
RTTY or was it used to voice well as CW? Anyone have some real
personal experience to offer?
Thanks
Hank WD5JFR
I don't own one- but believe the Elecraft K3 can do diversity but woud
require the 2nd RX option.
There's space diversity (which you allude to) but also polarity
diversity.
Dale W4OP

HF Diversity reception ?
 

Henry Kolesnik wrote:
Space diversity is what they call it for microwave systems and they also
use frequency diversity. I've not heard of polarity diversity used on
commercial HF systems but I have used it quite a bit myself with a
horizontal dipole and a 18AVT. The military and FEMA use a computer
control systems to automagically establish links on various bands for a
round tables, and switching to the best link whenever required. I can't
recall the acronym but I hams have a PC based system. I've seen it in
use at a swapmeet using Sunair transceivers.
Does the Elecraft have a built in tone decoder?

Hank wd5jfr
"Dale Parfitt" wrote in message
...

"Henry Kolesnik" wrote in message
...
I know that Hallicrafters made a dual diversity set up and RCA used
three AR-88s in a trioka, selecting the best signal with a tone
decoder that switched in the best and let the other/s idle or
squelched. I've heard that Collins used the R 390 (51J or 51S?) , and
Hammarlund the Super Pros ( only 600s or others?). It seems like
three antennas spaced about 1000 feet apart on an equilateral
triangle was a 100% solution. Did the Brits use it a Bletchley? But I
don't see anything these days and have to wonder if diversity
reception was made obsolete by SSB or the news & financial services
using wire for TTY. I also know that Telstar was the final nail. Was
the primary use for RTTY or was it used to voice well as CW? Anyone
have some real personal experience to offer?
Thanks
Hank WD5JFR
I don't own one- but believe the Elecraft K3 can do diversity but woud
require the 2nd RX option.
There's space diversity (which you allude to) but also polarity
diversity.
Dale W4OP


http://www.elecraft.com/

HF Diversity reception ?
 

"Henry Kolesnik" wrote in message
...
I know that Hallicrafters made a dual diversity set up and RCA used three
AR-88s in a trioka, selecting the best signal with a tone decoder that
switched in the best and let the other/s idle or squelched. I've heard that
Collins used the R 390 (51J or 51S?) , and Hammarlund the Super Pros ( only
600s or others?). It seems like three antennas spaced about 1000 feet apart
on an equilateral triangle was a 100% solution. Did the Brits use it a
Bletchley? But I don't see anything these days and have to wonder if
diversity reception was made obsolete by SSB or the news & financial
services using wire for TTY. I also know that Telstar was the final nail.
Was the primary use for RTTY or was it used to voice well as CW? Anyone
have some real personal experience to offer?
Thanks
Hank WD5JFR
Years ago at Collins we used a frequency diversity system that sent the same
signal on upper and lower sideband. Additional improvement was achieved by
delaying one sideband a few milliseconds, then doing the inverse delay at
the receiving end. The time delay approach worked well, but never caught on
commercially.

Additionally, separate antennas were deployed for space diversity. I have
forgotten the siting guidelines.

The frequency diversity system was used for RTTY, and antenna space
diversity for voice/data.

HF Diversity reception ?
 

Henry Kolesnik. WD5JFR wrote:
"It seems that three antennas spaced about 1000 feet apart on an
equilateral triangle was a 100% solution."

Radio Free Europe relayed broadcasts from Munich to Lisbon by HF.
Satellites now make HF obsolete.

The point to point relay used one or more rhombics in Munich and three
in Lisbon for triple diversity reception. The three rhombics in Lisbon
may not have had optimum spacing. We had to clear cork and olive trees
to make room, but the recieved signals in them faded separately, in
spite of their side by side placements. We had apace diversity. All
rhombics were horizontal.

Frequency diversity was also used by transmitting on more than one
frequency in Munich. More than one horizontal rhombic was sometimes used
in Munich. Due to ionospheric polarization scrambling, no attempt was
made at polarization diversity.

Each receiving rhombic fed three or more receivers. The outputs of three
receivers were fed to an election box which selected the strongest and
least noisy signal while squelching all others in its group.

Henry mentioned, among others, the 51-J and SP-600 receivers. The 51-j
was incompatible with this mission. It had too many spurious responses.
We once tried to use one as a bridge detector at a transmitter site and
it was useless. The SP-600 has the front end selectivity required.

We used double sideband (AM) transmissions, but the SP-600`s had
selectable sideband responses which allowed us to supress interference
on one side of the carrier frequency.

These TDR systems worked like gangbusters.

Best regards, Richard Harrison, KB5WZI

HF Diversity reception ?
 

Wayne wrote:
"The time deay approach werked well, but never caught on commercially."

Our receiver selection boxes were made by Crosby or Pioneer if I
remember, but it`s been a half century.

Best regards, Richard Harrison, KB5WZI

HF Diversity reception ?
 

"Henry Kolesnik" wrote in message
...
I know that Hallicrafters made a dual diversity set up and RCA used three
AR-88s in a trioka, selecting the best signal with a tone decoder that
switched in the best and let the other/s idle or squelched. I've heard that
Collins used the R 390 (51J or 51S?) , and Hammarlund the Super Pros ( only
600s or others?). It seems like three antennas spaced about 1000 feet apart
on an equilateral triangle was a 100% solution. Did the Brits use it a
Bletchley? But I don't see anything these days and have to wonder if
diversity reception was made obsolete by SSB or the news & financial
services using wire for TTY. I also know that Telstar was the final nail.
Was the primary use for RTTY or was it used to voice well as CW? Anyone
have some real personal experience to offer?
Thanks
Hank WD5JFR

The Flex 5000 will also do diverstity RX with the 2nd RX option installed.
W4OP

HF Diversity reception ?
 

"Richard Harrison" wrote in message
...
Wayne wrote:
"The time deay approach werked well, but never caught on commercially."

Our receiver selection boxes were made by Crosby or Pioneer if I
remember, but it`s been a half century.

Best regards, Richard Harrison, KB5WZI

Heh heh. Yeah, long time.
We made our own time delay box under Navy funding. In a prototype, we
provided the time delay by recording the RTTY signal on tape and playing it
back soon afterwards on a different tape head. The original and delayed
were then sent on different sidebands. Noise was simulated with recorded
static, and the noise audio was injected at the receiving end before
deconstructing the delay with another tape deck.

IIRC, we found combinations that gave about a 3-5 db improvement. Fun
project that would be even more fun with modern circuitry.

HF Diversity reception ?
 

Wayne wrote:
"In a prototype, we provided the time delay by recording the RTTY signal
on a tape and playing it back soon afterwards on a different tape head."

That is a technique used to add echo to a recording without a long audio
chamber or worse yet springs stretched between transducers.

Best regards, Richard Harrison, KB5WZI

HF Diversity reception ?
 

In article ,
"Henry Kolesnik" wrote:

I know that Hallicrafters made a dual diversity set up and RCA used
three AR-88s in a trioka, selecting the best signal with a tone decoder
that switched in the best and let the other/s idle or squelched. I've
heard that Collins used the R 390 (51J or 51S?) , and Hammarlund the
Super Pros ( only 600s or others?). It seems like three antennas spaced
about 1000 feet apart on an equilateral triangle was a 100% solution.
Did the Brits use it a Bletchley? But I don't see anything these days
and have to wonder if diversity reception was made obsolete by SSB or
the news & financial services using wire for TTY. I also know that
Telstar was the final nail. Was the primary use for RTTY or was it used
to voice well as CW? Anyone have some real personal experience to
offer?
Thanks
Hank WD5JFR



my icom 2820h does diversity, thou i really understand that in
a 'fm' uhf/vhf rig

I was sorta surprized that the flex radio has diversity, i mean
why not , but what i really wonder is if you had two nicely
spaced antennas aside from obvious a/b switching of the
antennas which you could do w/a coax switch i wonder how it would
or if it would be able to reduce noise both a) local and b) not
local




very interesting



as far as commercial, I work at a phone company we have a
cellular division and most all of our sites have very
complicated diversity systems built in , as most of the problems
we have are typically caused by multipath

on the same front data modems such as for example the (sierra)
airlink raven X evdo modem has a 2nd antenna port for rx
diversity ant the GSM models typically don't have it least not
that i ever saw

so diversity isn't dead but it's a best kept secreate sorta

HF Diversity reception ?
 

ML wrote:
"So diversity isn`t dead----."

Either diversity or alternate routing is essential for high reliability
when using terrestrial microwave.

Best regards, Richard Harrison, KB5WZI