|
Hi all sorry I haven¡¯t posted much but been a fan of the RA17 since my school days but couldn¡¯t afford one
I have a nice clean RA 17 that was remanufactured for GCHQ
And I am in the market for a RA 63 side band adapter 100 KHz version
Regards Paul located south coast UK
|
One day, maybe I'll make a 100kHz to 1.6MHz convertor for my MA185.
Geoff
|
Also look for a 98 or a 121.
Brian g
|
|
|
Hi Paul,
Both are SSB/ ISB adapters
RA 98 : motor driven to lock also on a fading AM signal
RA 121 : has a scope build in; also a fine tune , nice for rtty use
Fits the RA 17 and RA 117 receivers
73¡¯²õ
Tjerk, PE1IOC
toggle quoted message
Show quoted text
Op 21 mrt. 2023 om 11:17 heeft Paul Bicknell G8KFW <admin@...> het volgende geschreven:
?OK Brian
What is a 98 or a 121.
Regards Paul
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of cougar_lou
Sent: 21 March 2023 08:28
To: [email protected]
Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version
Also look for a 98 or a 121.
Brian g
|
Independent sideband adaptors. Different types with slightly different facilities... but same job. Douglas Denny G3ZQE. On Tue, 21 Mar 2023, 10:17 Paul Bicknell G8KFW, <admin@...> wrote: OK Brian
What is a 98 or a 121.
Regards Paul
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of cougar_lou
Sent: 21 March 2023 08:28
To: [email protected]
Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz
version
Also look for a 98 or a 121.
Brian g
|
Hi thank you all for your return mail
Can I assume if I only want USB and LSB the RA63 is the best solution and the RA 98 and RA 121 are meant for RTTY
By the way why is there a deferens when using a 17 compared to a 117 it sounds like the RF mixing in the set is different resulting in a different IF
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Tj.A. Polee -PE1IOC- Sent: 21 March 2023 12:06 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version Hi Paul, Both are SSB/ ISB adapters RA 98 : motor driven to lock also on a fading AM signal RA 121 : has a scope build in; also a fine tune , nice for rtty use Fits the RA 17 and RA 117 receivers 73¡¯²õ Tjerk, PE1IOC Op 21 mrt. 2023 om 11:17 heeft Paul Bicknell G8KFW <admin@...> het volgende geschreven:
?OK Brian
What is a 98 or a 121.
Regards Paul
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of cougar_lou
Sent: 21 March 2023 08:28
To: [email protected]
Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz
version
Also look for a 98 or a 121.
Brian g
|
I obtained one of these a few years ago for a tidy sum thinking it would make the world of difference to SSB reception and while it does help with co-channel selectivity the actual audio quality is not as good as using a well aligned RA17 using just the BFO and the 3Khz filter. Most of the time I don't use it.
|
I obtained one of these a few years ago for a tidy sum thinking it would make the world of difference to SSB reception and while it does help with co-channel selectivity the actual audio quality is not as good as using a well aligned RA17 using just the BFO and the 3Khz filter. Most of the time I don't use it.
Did you do the usual? Replace all Hunts paper capacitors and any out of tolerance resistors. Regarding audio quality, were you using headphones for listening? And did you check the valves? On mine two or three needed to be replaced and were essentially dead. Craig
|
Stephen you make an interesting line as I have been told much the same in the past but that was a long time ago
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Stephen Hemsworth via groups.io Sent: 21 March 2023 22:37 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version I obtained one of these a few years ago for a tidy sum thinking it would make the world of difference to SSB reception and while it does help with co-channel selectivity the actual audio quality is not as good as using a well aligned RA17 using just the BFO and the 3Khz filter. Most of the time I don't use it.
|
Paul
I agree with Tjerk says, ie that the RA121 has a very fine tune of about 800Hz/rev. In my view it is essential when trying to tune in an SSB or FSK signal. The kHz tuning of the RA17s is 100kHz/rev and I think that is far too fast for easy tuning of SSB signals. More modern receivers, typically the RA1772, have a slow tune of about 2.5kHz/rev.
Some versions of the RA63 incorporate a fine tune too.
The CRT gives a Lissajous display on AM signals to show the correct tuning point. Additionally, both the RA121 and RA98 have AFC. This will lock onto either a full carrier or a pilot carrier and hold the system to within a few Hz. I personally find that the more sophisticated AFC of the RA98 is tricky to set up and much prefer the simplicity of the RA121.
I replaced all the small audio components in my RA121 with new ones and that improved the recovered audio quality. For me poor audio quality is unacceptable.
As you are discovering, the SSB/ISB adaptors are far rarer and often a lot more expensive than RA17s!
73s
Michael
G8MOB
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Tj.A. Polee -PE1IOC- Sent: 21 March 2023 12:06 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version Hi Paul, Both are SSB/ ISB adapters RA 98 : motor driven to lock also on a fading AM signal RA 121 : has a scope build in; also a fine tune , nice for rtty use Fits the RA 17 and RA 117 receivers 73¡¯²õ Tjerk, PE1IOC Op 21 mrt. 2023 om 11:17 heeft Paul Bicknell G8KFW <admin@...> het volgende geschreven:
?OK Brian
What is a 98 or a 121.
Regards Paul
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of cougar_lou
Sent: 21 March 2023 08:28
To: [email protected]
Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz
version
Also look for a 98 or a 121.
Brian g
|
Hi Paul and group,
The RA 121 was used with the RA 37 LF converter in a separate cabinet by the dutch army, the ¡® Koninklijke Landmacht ¡® in the 1960¡¯s and - 70¡¯s
Most in combination with a RA 17-c16 , a special version made by Racal for the dutch army.
A 17-c16 could calibrate every 10 kc ( normal : every 100 kc ) for a better QRG readout.
The ¡® normal ¡® calibrator had 2 tubes on top, the 10 kc version had 4 .
Also included a poster out of the 70¡¯s. Goal was to interest more young people for the army.
It¡¯s an ¡® artist impression ¡® ; very detailed but please note the ROUND filmscale in both receivers ..?
These RTTY stations were most mounted in a ( NATO) shelter on the back of a 5-tons DAF truck YA 4440 ( all wheel drive )
73¡¯²õ from the Netherlands,
Tjerk, PE1IOC
(Photo: my RA 121; very happy with it ; the fine tuning is a pleasure ! )
[image0.png][image2.png][image3.png]
toggle quoted message
Show quoted text
Op 22 mrt. 2023 om 12:55 heeft Michael O'Beirne via groups.io <michaelob666@...> het volgende geschreven: ?Paul I agree with Tjerk says, ie that the RA121 has a very fine tune of about 800Hz/rev. In my view it is essential when trying to tune in an SSB or FSK signal. The kHz tuning of the RA17s is 100kHz/rev and I think that is far too fast for easy tuning of SSB signals. More modern receivers, typically the RA1772, have a slow tune of about 2.5kHz/rev. Some versions of the RA63 incorporate a fine tune too. The CRT gives a Lissajous display on AM signals to show the correct tuning point. Additionally, both the RA121 and RA98 have AFC. This will lock onto either a full carrier or a pilot carrier and hold the system to within a few Hz. I personally find that the more sophisticated AFC of the RA98 is tricky to set up and much prefer the simplicity of the RA121. I replaced all the small audio components in my RA121 with new ones and that improved the recovered audio quality. For me poor audio quality is unacceptable. As you are discovering, the SSB/ISB adaptors are far rarer and often a lot more expensive than RA17s! 73s Michael G8MOB -----Original Message----- From: [email protected] < [email protected]> On Behalf Of Tj.A. Polee -PE1IOC- Sent: 21 March 2023 12:06 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version Hi Paul, Both are SSB/ ISB adapters RA 98 : motor driven to lock also on a fading AM signal RA 121 : has a scope build in; also a fine tune , nice for rtty use Fits the RA 17 and RA 117 receivers 73¡¯²õ Tjerk, PE1IOC Op 21 mrt. 2023 om 11:17 heeft Paul Bicknell G8KFW <admin@...> het volgende geschreven: ?OK Brian What is a 98 or a 121. Regards Paul -----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of cougar_lou Sent: 21 March 2023 08:28 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version Also look for a 98 or a 121. Brian g
|
I'd say the audio quality from the RA63 is pretty good.
At the weekend my wife was asking "what does the RA63 do?", so I demonstrated SSB reception. On a good signal, with a bit of judicious knob twiddling on the RA17, results were pretty similar.
On a poorer signal the RA17 was essentially unlistenable and RA63 was streets ahead.
More of my adventures here:
|
Hi Paul,
It is perhaps worth remembering that the RA98 and RA121 both have 6kHz audio bandwidths intended for the reception of 4 channel ISB. The RA63 and RA218 are more suited to SSB working, having audio bandwidths of 3 kHz.
Thus the RA98 and RA121 will probably sound better, providing that there is no interfering signal in the adjacent channel, while the RA63 and RA218 will do better in a crowded band given the more tightly controlled audio passband.
hope this helps
Peter G8BBZ
|
Hi peter
Thank you for your posting ok about the 3 kHz and 6 KHz bandwidth 3 KHz is generally the best for Audio
But you have bought a new side band adapter to the party as in the RA 218 I must read up on this new comer to the party
Regards Paul
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of PeterG8BBZ Sent: 22 March 2023 16:00 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version Hi Paul, It is perhaps worth remembering that the RA98 and RA121 both have 6kHz audio bandwidths intended for the reception of 4 channel ISB. The RA63 and RA218 are more suited to SSB working, having audio bandwidths of 3 kHz. Thus the RA98 and RA121 will probably sound better, providing that there is no interfering signal in the adjacent channel, while the RA63 and RA218 will do better in a crowded band given the more tightly controlled audio passband. hope this helps Peter G8BBZ
|
Hi WD40Addict
I am sorry but I can't find your name!
I have tried the RA63 here (the one with a crystal-controlled LO) and it's good. I have seen the fine-tune version used with RAF's RA17Ls at a bunker "somewhere in England".
It is primarily for SSB /voice and does a good job. The audio has a higher LF cut-off than the RA121. I personally preferred my RA121! I like a deeper LF response and I retuned the 18kHz filters with a borrowed spectrum analyser to give a -6dB response of around 300Hz. The owner of the analyser printed out the respective IF responses. It was interesting that the opposite sideband response was about 60dB down at 1kHz into the opposite sideband. That compares well with a good asymmetric crystal filter.
The RA17 will demodulate SSB with its BFO and a 3kHz IF filter but the traditional CW detector is not ideal and for me the RA121 sounds better.
Peter makes the valid point that the RA63 and RA218 are designed for 3kHz SSB whereas the RA98 and RA121 have a 6kHz audio bandwidth and therefore sound a bit more natural but with less ability to reject adjacent signals. For me the fine tune on the RA121 and the AFC trump any disadvantage.
An interesting adaptor is the transistorised RA298 using 100kHz offset LSB and USB Kokusai mechanical filters. These are the professional ones in a light grey case about the size of a packet of cigarettes and have an excellent response (-3dB points at 250 and 3400Hz). Do not confuse these with the cheapo (and usually faulty) cylindrical ones found in the KW2000 transceiver and elsewhere. It has a separate carrier filter made by Plessey, about 85Hz wide, and provides both AFC and carrier-derived AGC. These are excellent but very rare. The AGC is only useful with the RA217 and RA1217 series. I bought mine in pristine condition and still with its original inspection labels from that slightly eccentric Racal dealer living in Sussex (I think). He inevitably sold kit in fine condition.
73s
Michael
G8MOB
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] < [email protected]> On Behalf Of wd40addict via groups.io Sent: 22 March 2023 14:13 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version I'd say the audio quality from the RA63 is pretty good. At the weekend my wife was asking "what does the RA63 do?", so I demonstrated SSB reception. On a good signal, with a bit of judicious knob twiddling on the RA17, results were pretty similar. On a poorer signal the RA17 was essentially unlistenable and RA63 was streets ahead. More of my adventures here:
|
?
?
Hi Michael,
I agree with you the RA 298 is a very nice solid state adapter !
Mine has the ¡® good ¡® small filters installed with the exellent specs
Bought in the 1980¡¯s , brandnew out of the crate !
A ham brought it with him for me from a trip to the UK and found it at a dealer called John Finch Radio (?)
Connected to a 117 trough a homebuild interconnection box it worked fine
The 298 is very hard to find , never see a second one .
Unique for mevtrough the build in LF amplifier ?
Cheers,
Tjerk, PE1IOC
[image0.png][image2.png]
<image2.png>
[X][image5.png]
toggle quoted message
Show quoted text
Op 22 mrt. 2023 om 19:42 heeft Michael O'Beirne via groups.io <michaelob666@...> het volgende geschreven: ?Hi WD40Addict I am sorry but I can't find your name! I have tried the RA63 here (the one with a crystal-controlled LO) and it's good. I have seen the fine-tune version used with RAF's RA17Ls at a bunker "somewhere in England". It is primarily for SSB /voice and does a good job. The audio has a higher LF cut-off than the RA121. I personally preferred my RA121! I like a deeper LF response and I retuned the 18kHz filters with a borrowed spectrum analyser to give a -6dB response of around 300Hz. The owner of the analyser printed out the respective IF responses. It was interesting that the opposite sideband response was about 60dB down at 1kHz into the opposite sideband. That compares well with a good asymmetric crystal filter. The RA17 will demodulate SSB with its BFO and a 3kHz IF filter but the traditional CW detector is not ideal and for me the RA121 sounds better. Peter makes the valid point that the RA63 and RA218 are designed for 3kHz SSB whereas the RA98 and RA121 have a 6kHz audio bandwidth and therefore sound a bit more natural but with less ability to reject adjacent signals. For me the fine tune on the RA121 and the AFC trump any disadvantage. An interesting adaptor is the transistorised RA298 using 100kHz offset LSB and USB Kokusai mechanical filters. These are the professional ones in a light grey case about the size of a packet of cigarettes and have an excellent response (-3dB points at 250 and 3400Hz). Do not confuse these with the cheapo (and usually faulty) cylindrical ones found in the KW2000 transceiver and elsewhere. It has a separate carrier filter made by Plessey, about 85Hz wide, and provides both AFC and carrier-derived AGC. These are excellent but very rare. The AGC is only useful with the RA217 and RA1217 series. I bought mine in pristine condition and still with its original inspection labels from that slightly eccentric Racal dealer living in Sussex (I think). He inevitably sold kit in fine condition. 73s Michael G8MOB -----Original Message----- From: [email protected] < [email protected]> On Behalf Of wd40addict via groups.io Sent: 22 March 2023 14:13 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version I'd say the audio quality from the RA63 is pretty good. At the weekend my wife was asking "what does the RA63 do?", so I demonstrated SSB reception. On a good signal, with a bit of judicious knob twiddling on the RA17, results were pretty similar. On a poorer signal the RA17 was essentially unlistenable and RA63 was streets ahead. More of my adventures here:
|
Hi Michael
I think I will be looking out for a side band adapter with 3KHz band width as commercial voice channels are 300 to 3300 Hz
Regarding the trader in Sussex England I think you must be talking about Bob Finch he has retired but visiting him this Summer is on the top of my list
Regards Paul located Sussex
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Michael O'Beirne via groups.io Sent: 22 March 2023 18:42 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version Hi WD40Addict I am sorry but I can't find your name! I have tried the RA63 here (the one with a crystal-controlled LO) and it's good. I have seen the fine-tune version used with RAF's RA17Ls at a bunker "somewhere in England". It is primarily for SSB /voice and does a good job. The audio has a higher LF cut-off than the RA121. I personally preferred my RA121! I like a deeper LF response and I retuned the 18kHz filters with a borrowed spectrum analyser to give a -6dB response of around 300Hz. The owner of the analyser printed out the respective IF responses. It was interesting that the opposite sideband response was about 60dB down at 1kHz into the opposite sideband. That compares well with a good asymmetric crystal filter. The RA17 will demodulate SSB with its BFO and a 3kHz IF filter but the traditional CW detector is not ideal and for me the RA121 sounds better. Peter makes the valid point that the RA63 and RA218 are designed for 3kHz SSB whereas the RA98 and RA121 have a 6kHz audio bandwidth and therefore sound a bit more natural but with less ability to reject adjacent signals. For me the fine tune on the RA121 and the AFC trump any disadvantage. An interesting adaptor is the transistorised RA298 using 100kHz offset LSB and USB Kokusai mechanical filters. These are the professional ones in a light grey case about the size of a packet of cigarettes and have an excellent response (-3dB points at 250 and 3400Hz). Do not confuse these with the cheapo (and usually faulty) cylindrical ones found in the KW2000 transceiver and elsewhere. It has a separate carrier filter made by Plessey, about 85Hz wide, and provides both AFC and carrier-derived AGC. These are excellent but very rare. The AGC is only useful with the RA217 and RA1217 series. I bought mine in pristine condition and still with its original inspection labels from that slightly eccentric Racal dealer living in Sussex (I think). He inevitably sold kit in fine condition. 73s Michael G8MOB -----Original Message----- From: [email protected] < [email protected]> On Behalf Of wd40addict via groups.io Sent: 22 March 2023 14:13 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version I'd say the audio quality from the RA63 is pretty good. At the weekend my wife was asking "what does the RA63 do?", so I demonstrated SSB reception. On a good signal, with a bit of judicious knob twiddling on the RA17, results were pretty similar. On a poorer signal the RA17 was essentially unlistenable and RA63 was streets ahead. More of my adventures here:
|
[image0.png]
toggle quoted message
Show quoted text
Op 22 mrt. 2023 om 20:38 heeft Tj.A. Polee -PE1IOC- <dekotex@...> het volgende geschreven: ? ? Hi Michael, I agree with you the RA 298 is a very nice solid state adapter ! Mine has the ¡® good ¡® small filters installed with the exellent specs Bought in the 1980¡¯s , brandnew out of the crate ! A ham brought it with him for me from a trip to the UK and found it at a dealer called John Finch Radio (?) Connected to a 117 trough a homebuild interconnection box it worked fine The 298 is very hard to find , never see a second one . Unique for mevtrough the build in LF amplifier ? Cheers, Tjerk, PE1IOC [image0.png][image2.png] <image2.png> [X][image5.png] Op 22 mrt. 2023 om 19:42 heeft Michael O'Beirne via groups.io <michaelob666@...> het volgende geschreven: ?Hi WD40Addict I am sorry but I can't find your name! I have tried the RA63 here (the one with a crystal-controlled LO) and it's good. I have seen the fine-tune version used with RAF's RA17Ls at a bunker "somewhere in England". It is primarily for SSB /voice and does a good job. The audio has a higher LF cut-off than the RA121. I personally preferred my RA121! I like a deeper LF response and I retuned the 18kHz filters with a borrowed spectrum analyser to give a -6dB response of around 300Hz. The owner of the analyser printed out the respective IF responses. It was interesting that the opposite sideband response was about 60dB down at 1kHz into the opposite sideband. That compares well with a good asymmetric crystal filter. The RA17 will demodulate SSB with its BFO and a 3kHz IF filter but the traditional CW detector is not ideal and for me the RA121 sounds better. Peter makes the valid point that the RA63 and RA218 are designed for 3kHz SSB whereas the RA98 and RA121 have a 6kHz audio bandwidth and therefore sound a bit more natural but with less ability to reject adjacent signals. For me the fine tune on the RA121 and the AFC trump any disadvantage. An interesting adaptor is the transistorised RA298 using 100kHz offset LSB and USB Kokusai mechanical filters. These are the professional ones in a light grey case about the size of a packet of cigarettes and have an excellent response (-3dB points at 250 and 3400Hz). Do not confuse these with the cheapo (and usually faulty) cylindrical ones found in the KW2000 transceiver and elsewhere. It has a separate carrier filter made by Plessey, about 85Hz wide, and provides both AFC and carrier-derived AGC. These are excellent but very rare. The AGC is only useful with the RA217 and RA1217 series. I bought mine in pristine condition and still with its original inspection labels from that slightly eccentric Racal dealer living in Sussex (I think). He inevitably sold kit in fine condition. 73s Michael G8MOB -----Original Message----- From: [email protected] < [email protected]> On Behalf Of wd40addict via groups.io Sent: 22 March 2023 14:13 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version I'd say the audio quality from the RA63 is pretty good. At the weekend my wife was asking "what does the RA63 do?", so I demonstrated SSB reception. On a good signal, with a bit of judicious knob twiddling on the RA17, results were pretty similar. On a poorer signal the RA17 was essentially unlistenable and RA63 was streets ahead. More of my adventures here: <image0.png> <image2.png> <image5.png>
|
Hi all
I am interested in reading up on the RA 298 so does anyone have the operators / service manual for it
Ok I was only looking for a RA 63 side band adapter for my sylph and I believe that has been sorted early on in this thread
but as there is a lot of interest and Bob Finch has been talked about
I will make a few phone calls over the next few days but the phone numbers I have might be too old
so I will do my best to see what is available in Sussex UK
Can someone in the uk come back To me off line with the Value of each of the side band adapters
As in what is a reasonable price people would pay if I find any
as I will probably only have one chance to set up any deal and so I must be armed with the information
Paul G8KFW
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Tj.A. Polee -PE1IOC- Sent: 22 March 2023 19:38 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version ? ? Hi Michael, I agree with you the RA 298 is a very nice solid state adapter ! Mine has the ¡® good ¡® small filters installed with the exellent specs Bought in the 1980¡¯s , brandnew out of the crate ! A ham brought it with him for me from a trip to the UK and found it at a dealer called John Finch Radio (?) Connected to a 117 trough a homebuild interconnection box it worked fine The 298 is very hard to find , never see a second one . Unique for mevtrough the build in LF amplifier ? Cheers, Tjerk, PE1IOC [image0.png][image2.png] <image2.png> [X][image5.png] Op 22 mrt. 2023 om 19:42 heeft Michael O'Beirne via groups.io <michaelob666@...> het volgende geschreven: ?Hi WD40Addict I am sorry but I can't find your name! I have tried the RA63 here (the one with a crystal-controlled LO) and it's good. I have seen the fine-tune version used with RAF's RA17Ls at a bunker "somewhere in England". It is primarily for SSB /voice and does a good job. The audio has a higher LF cut-off than the RA121. I personally preferred my RA121! I like a deeper LF response and I retuned the 18kHz filters with a borrowed spectrum analyser to give a -6dB response of around 300Hz. The owner of the analyser printed out the respective IF responses. It was interesting that the opposite sideband response was about 60dB down at 1kHz into the opposite sideband. That compares well with a good asymmetric crystal filter. The RA17 will demodulate SSB with its BFO and a 3kHz IF filter but the traditional CW detector is not ideal and for me the RA121 sounds better. Peter makes the valid point that the RA63 and RA218 are designed for 3kHz SSB whereas the RA98 and RA121 have a 6kHz audio bandwidth and therefore sound a bit more natural but with less ability to reject adjacent signals. For me the fine tune on the RA121 and the AFC trump any disadvantage. An interesting adaptor is the transistorised RA298 using 100kHz offset LSB and USB Kokusai mechanical filters. These are the professional ones in a light grey case about the size of a packet of cigarettes and have an excellent response (-3dB points at 250 and 3400Hz). Do not confuse these with the cheapo (and usually faulty) cylindrical ones found in the KW2000 transceiver and elsewhere. It has a separate carrier filter made by Plessey, about 85Hz wide, and provides both AFC and carrier-derived AGC. These are excellent but very rare. The AGC is only useful with the RA217 and RA1217 series. I bought mine in pristine condition and still with its original inspection labels from that slightly eccentric Racal dealer living in Sussex (I think). He inevitably sold kit in fine condition. 73s Michael G8MOB -----Original Message----- From: [email protected] < [email protected]> On Behalf Of wd40addict via groups.io Sent: 22 March 2023 14:13 To: [email protected]Subject: Re: [RacalRA17forum] wanted RA 63 side band adapter 100 KHz version I'd say the audio quality from the RA63 is pretty good. At the weekend my wife was asking "what does the RA63 do?", so I demonstrated SSB reception. On a good signal, with a bit of judicious knob twiddling on the RA17, results were pretty similar. On a poorer signal the RA17 was essentially unlistenable and RA63 was streets ahead. More of my adventures here:
|
Douglas Denny
PeterG8BBZ
