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Old April 24th 07, 12:31 AM posted to sci.electronics.design,rec.radio.amateur.equipment
John Siegel John Siegel is offline
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First recorded activity by RadioBanter: Oct 2006
Posts: 15
Default A Kenwood HF rig's "real" frequency in CW



Dee Flint wrote:
Did you read my answer??? You have an older Kenwood radio. It displays the
transmit frequency only when you transmit. It displays the receive
frequency the rest of the time. So set your receive at 7.0392 in receive
mode. When you transmit it will then be transmitting at 7.040 as shown by
the readout.

NEW radios (including new Kenwoods) display the transmit freq. at all times
whether receiving or transmitting.

Dee, N8UZE


"billcalley" wrote in message
ups.com...

On Apr 22, 2:13 pm, Wimpie wrote:

On 22 abr, 20:24, billcalley wrote:


Hi All,

This may sound like a very silly question, but what is the "true"
frequency of, lets say, a Kenwood TS-530S? What I mean is, when it is
said that a particular CW calling frequency is exactly "7.040MHz",
then should I set the TS-530S' frequency display to 7.040MHz (in
receive mode), or to 7.0392MHz (for a display of 7.040MHz during
transmit) to be spot-on a designated Calling Frequency? I obviously
would like to make 100% sure that I'm exactly on frequency, and not
off by 800Hz, when monitoring for any CQs!

Thanks for any clarification,

-Bill

Hi Bill,

It sounds silly, but it isn't.

I don't know the answer with high confidence, but maybe I can help you
to get it.

I "believe" that when you tune in to a station with 800 Hz beat, you
will transmit on exactly the same frequency as the station that you
are listening to. Make sure the RIT is in the middle or off.

You can check it yourself.
Do you have a separate frequency counter (or other receiver)? If so,
try to tune to a source with a known frequency (with the TS530S, for
example a broadcast station or). Now you can compare the actual
frequency with the reading on the TS530S and you know the difference
in reading and actual transmitting frequency of other station.

Now the transmitting case
Press the key (check frequency in use or use dummy load) and read the
frequency from the counter, or tune with the other receiver to find
out the difference in the transmitting frequency of the other station
and your frequency.

I hope this will help you a bit.

I had several problems with adjusting old equipment to make sure that
SSB receive and transmit (carrier) frequencies are the same.

Best Regards,

Wim
PA3DJS



Thanks for the info Wim. The TS-530S's actually show you only the
RX frequency on the digital display dial while you tune around or sit
on a frequency waiting for a CQ, and then -- but only when you
transmit -- they shift the dial display (and I assume the TX frequency
too) 800Hz higher. Frankly, I had thought most other radios did
*exactly* the opposite (I.E.: Their BFO's shifted the RX frequency by
800Hz or so, while their TX frequencies where as displayed on the dial
-- but I must be incorrect about that!). But I'm still hoping to
understand if it is correct to set a Kenwood to "7.040MHz" on the
digital display when listening to the 7.040 MHz Calling Frequency (but
it then shifts 800Hz higher on TX...), or set it to 7.0392MHz (for a
display of 7.040MHz during transmit with its 800Hz TX offset)? With
all the Kenwood rig's out there, you'd think that someone would have
the answer -- but maybe no-one has really thought about this? (Hard
to believe!!).

-Bill







Another consideration, particularly for VHF operators, is what happens
when you switch from SSB to CW. For example, the TS2000 says that it
always displays the carrier frequency regardless of mode. If you are on
SSB and need to switch to CW becaue you have a weak signal look at what
happens. If the displayed frequency is the carrier and does not change
when you change mode you are now transmitting zero beat with the
receiving station and he won't hear you. You actually have to tune off
a bit (by the sidetone amount) so the receiving station can hear you.
The TS2000 actually has a menu choice to allow the frequency to
automatically make this correction if you wish.
John