Hi gang, anyone have the specs for a coupling loop so I can get
started setting up some of my Roberts radios.

There are loads on the internet but vary wildly. Not a complicated
problem but nice to get right first time.

Many thanks, all the best...

On 4/23/2012 8:51 AM, bloke wrote:
Hi gang, anyone have the specs for a coupling loop so I can get
started setting up some of my Roberts radios.

There are loads on the internet but vary wildly. Not a complicated
problem but nice to get right first time.

Many thanks, all the best...

It's not clear to me what you are asking for.
Do you want a tuned loop for the AM band, like this?
http://www.mtmscientific.com/loop.html

If yes, then the standard is a 240uh coil and a 365pf variable
capacitor. But, you can use a smaller coil and a larger capacitor.

Mikek

On Apr 24, 12:56*pm, amdx wrote:
On 4/23/2012 8:51 AM, bloke wrote:

Hi gang, anyone have the specs for a coupling loop so I can get
started setting up some of my Roberts radios.

There are loads on the internet but vary wildly. Not a complicated
problem but nice to get right first time.

Many thanks, all the best...

* It's not clear to me what you are asking for.
Do you want a tuned loop for the AM band, like this?http://www.mtmscientific.com/loop.html

If yes, then the standard is a 240uh coil and a 365pf variable
capacitor. But, you can use a smaller coil and a larger capacitor.

* * * * * * * * * * * * * Mikek

Hi there, sorry for the confusion. Here is a quote from the RT8
service manual -

Equipment Required. An a.m. signal generator, an output meter of 20
ohm impedance, or an a.c. voltmeter; an r.f. coupling coil and a
narrow-bladed-type trimming tool.
During alignment the signal input should be kept as low as possible to
prevent a.g.c. action. All adjustments are made with the signal fed in
via the coupling coil.

Hope that makes a bit more sense, All the best..

bloke wrote:
On Apr 24, 12:56 pm, amdx wrote:
On 4/23/2012 8:51 AM, bloke wrote:

Hi gang, anyone have the specs for a coupling loop so I can get
started setting up some of my Roberts radios.

There are loads on the internet but vary wildly. Not a complicated
problem but nice to get right first time.

Many thanks, all the best...

It's not clear to me what you are asking for.
Do you want a tuned loop for the AM band, like
this?http://www.mtmscientific.com/loop.html

If yes, then the standard is a 240uh coil and a 365pf variable
capacitor. But, you can use a smaller coil and a larger capacitor.

Mikek

Hi there, sorry for the confusion. Here is a quote from the RT8
service manual -

Equipment Required. An a.m. signal generator, an output meter of 20
ohm impedance, or an a.c. voltmeter; an r.f. coupling coil and a
narrow-bladed-type trimming tool.
During alignment the signal input should be kept as low as possible to
prevent a.g.c. action. All adjustments are made with the signal fed in
via the coupling coil.

Hope that makes a bit more sense, All the best..

Jusst make a loop of about 10 turns of insulated hookup wire. Make the loop
about an inch diameter, Solder the ends of the loop to a piece of coax (any
type will do). If your signal source is cranky about being hooked into a
short circuit, solder a 51-ohm resistor between the center conductor of the
coax and one end of the loop. Position the loop to inject a signal into the
radio's antenna or internal circuitry.

--
Dave M
A woman has the last word in any argument. Anything a man says after
that is the beginning of a new argument.

On Apr 24, 10:20*pm, "Dave M" wrote:
bloke wrote:
On Apr 24, 12:56 pm, amdx wrote:
On 4/23/2012 8:51 AM, bloke wrote:

Hi gang, anyone have the specs for a coupling loop so I can get
started setting up some of my Roberts radios.

There are loads on the internet but vary wildly. Not a complicated
problem but nice to get right first time.

Many thanks, all the best...

It's not clear to me what you are asking for.
Do you want a tuned loop for the AM band, like
this?http://www.mtmscientific.com/loop.html

If yes, then the standard is a 240uh coil and a 365pf variable
capacitor. But, you can use a smaller coil and a larger capacitor.

Mikek

Hi there, sorry for the confusion. Here is a quote from the RT8
service manual -

Equipment Required. An a.m. signal generator, an output meter of 20
ohm impedance, or an a.c. voltmeter; an r.f. coupling coil and a
narrow-bladed-type trimming tool.
During alignment the signal input should be kept as low as possible to
prevent a.g.c. action. All adjustments are made with the signal fed in
via the coupling coil.

Hope that makes a bit more sense, All the best..

Jusst make a loop of about 10 turns of insulated hookup wire. *Make the loop
about an inch diameter, *Solder the ends of the loop to a piece of coax (any
type will do). *If your signal source is cranky about being hooked into a
short circuit, solder a 51-ohm resistor between the center conductor of the
coax and one end of the loop. *Position the loop to inject a signal into the
radio's antenna or internal circuitry.

--
Dave M
A woman has the last word in any argument. Anything a man says after
that is the beginning of a new argument.

Many thanks, I can get crackling with the radio tune ups now, Cheers...