... but Kenyeacomco Model XYZ-123 claims it is "full-duplex" ...
Several of us have tried for years to properly educate the manufacturers and marketing departments of ham radio transceivers. What they term "full-duplex" is usually a radio with two, independent VFOs - but the "sub-band" can NOT be monitored while we key up on the other.
Clint, K6LCS http://www.work-sat.com
Clint,
Can you name a specific manufacturer that claims their equipment is "Full Duplex" when it isn't ?
I note Yaesu say the FTM-350 as well as being "Full Duplex" does:
"For emergency work, or to extend the range of a hand-held unit, the FTM-350R includes Cross-Band Repeat capability."
Now it seems to me the Cross-Band Repeat facility wouldn't work if it wasn't full duplex.
73 Trevor M5AKA
--- On Thu, 16/12/10, Clint Bradford clintbradford@mac.com wrote:
From: Clint Bradford clintbradford@mac.com Subject: [amsat-bb] Educate the Manufacturers To: "AMSAT BB" amsat-bb@amsat.org Date: Thursday, 16 December, 2010, 21:02
... but Kenyeacomco Model
XYZ-123 claims it is "full-duplex" ...
Several of us have tried for years to properly educate the manufacturers and marketing departments of ham radio transceivers. What they term "full-duplex" is usually a radio with two, independent VFOs - but the "sub-band" can NOT be monitored while we key up on the other.
Clint, K6LCS http://www.work-sat.com
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Full Duplex means that you can both receive and transmit simultaneously. Half Duplex means that you can both receive and transmit but only one at a time. Simplex means that you can either receice or transmit but not both. Frequency and bands are irrelevent to the definitions.
On 16-Dec-10 21:47, Trevor . wrote:
Clint,
Can you name a specific manufacturer that claims their equipment is "Full Duplex" when it isn't ?
I note Yaesu say the FTM-350 as well as being "Full Duplex" does:
"For emergency work, or to extend the range of a hand-held unit, the FTM-350R includes Cross-Band Repeat capability."
Now it seems to me the Cross-Band Repeat facility wouldn't work if it wasn't full duplex.
73 Trevor M5AKA
On 12/16/2010 4:47 PM, Trevor . wrote:
Now it seems to me the Cross-Band Repeat facility wouldn't work if it wasn't full duplex.
73 Trevor M5AKA
Spot on. It has to be full duplex for cross band repeat to work, whether the guys who write the manual, marketing literature, or QST review realize it.
I've never seen a radio advertised as full duplex, that wasn't. Even the G7 is, it just goes half-deaf. Non- full duplex rigs capable of reception of two bands at once are usually labeled as "dual receive".
Half-duplex is fine for getting your feet wet, but the increasing number of ops not moving up to full-duplex is having a real impact on the FM satellites over densely populated areas. Expense is no excuse. I've bought suitable uplink transmitters as cheap as $5 (IC-2AT), and the difference in an Arrow with and without diplexer is nearly the cost of a new simple 2m HT.
73, Drew KO4MA
At 12:11 PM 12/17/2010, Andrew Glasbrenner wrote:
On 12/16/2010 4:47 PM, Trevor . wrote:
Now it seems to me the Cross-Band Repeat facility wouldn't work
if it wasn't full duplex.
73 Trevor M5AKA
Spot on. It has to be full duplex for cross band repeat to work, whether the guys who write the manual, marketing literature, or QST review realize it.
That's correct, except that the radio doesn't need to be able to use the mic or speaker while in crossband receive mode, so it is theoretically possible to have a crossband repeat capable radio without being able to make use of the duplex capability otherwise.
I've never seen a radio advertised as full duplex, that wasn't. Even the G7 is, it just goes half-deaf. Non- full duplex rigs capable of reception of two bands at once are usually labeled as "dual receive".
Neither have I. The manufacturers have been honest in this regard.
Half-duplex is fine for getting your feet wet, but the increasing number of ops not moving up to full-duplex is having a real impact on the FM satellites over densely populated areas. Expense is no excuse. I've bought suitable uplink transmitters as cheap as $5 (IC-2AT), and the difference in an Arrow with and without diplexer is nearly the cost of a new simple 2m HT.
Agreed. Once you go full duplex, you won't want to go back. I've always done full duplex simply by using two separate radios. That also makes tuning easier in the event you need to tune the uplink for Doppler correction.
73 de VK3JED / VK3IRL http://vkradio.com
Spot on. It has to be full duplex for cross band repeat to work, whether the guys who write the manual, marketing literature, or QST review realize it.
That's correct, except that the radio doesn't need to be able to use the mic or speaker while in crossband receive mode, so it is theoretically possible to have a crossband repeat capable radio without being able to make use of the duplex capability otherwise.
I believe this is the operative statement. I haven't tried it in a while (years), but I recall that my Alinco DR-610T mobile rig was not able to receive on 70cm while I was keyed up on 2m for a satellite contact. I remember this because it's frustrating when you can't hear what's going on. Haven't tried V/U satellite mobile since (and that was while parked in my driveway).
The DR-610T is definitely capable of Cross-band Repeat, however.
Greg KO6TH
On 12/17/2010 12:09 AM, Greg D. wrote:
I believe this is the operative statement. I haven't tried it in a while (years), but I recall that my Alinco DR-610T mobile rig was not able to receive on 70cm while I was keyed up on 2m for a satellite contact. I remember this because it's frustrating when you can't hear what's going on. Haven't tried V/U satellite mobile since (and that was while parked in my driveway).
The DR-610T is definitely capable of Cross-band Repeat, however.
Greg KO6TH
The 610 was definitely full duplex; see the second bullet at http://www.alinco.com/Products/DR-610T.shtml. I used a 605 extensively on satellite, and a friend has a 610 still.
Just think about how a cross band repeater works, and you'll realize that any radio that does that must by design be capable of full duplex.
73, Drew KO4MA
Date: Fri, 17 Dec 2010 00:40:56 -0500 From: glasbrenner@mindspring.com To: ko6th_greg@hotmail.com CC: vk3jed@gmail.com; m5aka@yahoo.co.uk; amsat-bb@amsat.org Subject: Re: [amsat-bb] Re: Educate the Manufacturers
On 12/17/2010 12:09 AM, Greg D. wrote:
I believe this is the operative statement. I haven't tried it in a while (years), but I recall that my Alinco DR-610T mobile rig was not able to receive on 70cm while I was keyed up on 2m for a satellite contact. I remember this because it's frustrating when you can't hear what's going on. Haven't tried V/U satellite mobile since (and that was while parked in my driveway).
The DR-610T is definitely capable of Cross-band Repeat, however.
Greg KO6TH
The 610 was definitely full duplex; see the second bullet at http://www.alinco.com/Products/DR-610T.shtml. I used a 605 extensively on satellite, and a friend has a 610 still.
Just think about how a cross band repeater works, and you'll realize that any radio that does that must by design be capable of full duplex.
73, Drew KO4MA
Hi Drew,
Well, I need to try it again, then, because I definitely recall that the operation was difficult. Have you or anyone had problems with desense? Maybe that was it. I was using the mobile setup, with the radio and a Larsen 2/70 glass-mount antenna. I think I was trying AO-27 at the time.
Greg KO6TH
At 08:40 PM 12/16/2010, Andrew Glasbrenner wrote:
On 12/17/2010 12:09 AM, Greg D. wrote:
I believe this is the operative statement. I haven't tried it in a while (years), but I recall that my Alinco DR-610T mobile rig was not able to receive on 70cm while I was keyed up on 2m for a satellite contact. I remember this because it's frustrating when you can't hear what's going on. Haven't tried V/U satellite mobile since (and that was while parked in my driveway).
The DR-610T is definitely capable of Cross-band Repeat, however.
Greg KO6TH
The 610 was definitely full duplex; see the second bullet at http://www.alinco.com/Products/DR-610T.shtml. I used a 605 extensively on satellite, and a friend has a 610 still.
Just think about how a cross band repeater works, and you'll realize that any radio that does that must by design be capable of full duplex.
73, Drew KO4MA
To repeat it has to receive while transmitting (that is duplex), but the DR-610T probably does not provide receive audio to the speaker when in cross-band mode. That means it is less useful for satellite work. It gets tricky to avoid audio feedback in that situation. Most repeaters do not have either mics or speakers, but certainly operate duplex. They often have connection for both for testing, however.
73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw, 432-100w*, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubususa@hotmail.com ====================================== *temp not in service
participants (7)
-
Andrew Glasbrenner -
Clint Bradford -
Edward R. Cole -
Greg D. -
Nigel Gunn G8IFF/W8IFF -
Tony Langdon -
Trevor .