Author Topic: Split frequency operation  (Read 2132 times)

k4lrx

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Split frequency operation
« on: October 13, 2013, 06:28:58 AM »
For those new comers to ham radio you may be a little dismayed over the idea of split frequency on the HF bands. It is nothing new and has been used for decades as a method to hear a dx station, yet call and be heard.

When I say it is nothing new for split frequency operation it is not, those of you that operate two-meter repeaters you are operating split frequency. You have about a six hundred KHz split and your rig does it for you.

However, on HF it is another scenario and you may ask why some fellows do this in order to work a DX station?   Consider the rarity of the dx station and the number of callers that would want to work the rare country, or major expedition. If everyone called on the same frequency it would be total bedlam, I have heard this type of operation on 20, 15 and ten, you have fellows yelling their calls over and over, yet the DX stations returns to one station in about a minute, or longer.

I personally avoid this type of “Zoo’ and it does turn in to one after a short time of all this calling. Splitting frequency of course is the answer and spreading out the callers.

On HF it does require for you to push a few buttons, turn a few knobs, but wait before you throw up your hands and run off to another place this can be quite simple.

Most modern rigs have a RX offset; this feature has three names depending upon whose rig you own. Some call it RX offset, others R.I.T. Receiver Incremental Tuning, or some call it RX Clarifier. They all do the same function, nothing mystical about these controls. So, you come across a dx station that states listening up 5, what do you do?

One, you can move your VFO up 5 kHz, then activate your RX offset and tune down to the DX frequency. Pretty simple. Keep in mind once you make the contact to deactivate the RX offset.

Second method most rigs have a TX offset, or labeled the same way, as the RX except it is TX for transmit. Same dx scenario as before, you hear a dx station stating I am listening up 5, so what is your move?  Activate TX offset up five KHz, your receiver tuned to the dx stations transmit frequency, nothing hard at this time.  Again, once you make the contact deactivate the TX offset.

Most TX, or RX controls will allow a 9.9Kz offset, but what about bigger splits, or is there another method for smaller splits?

Normally, I split in the following way, most modern rigs have two VFOs so I activate the A/B feature, then I hit A equals B, this puts both vfos on the same band, frequency.

I can use the swap feature A/B reverse and tune VFO B up five kHz, or ten, where the dx is listening, hit swap again to return to the main VFO then hit the split button. If you have done this correctly your main dial should show your transmit frequency. Be sure of course to deactivate split when you are finished.

Note some rigs do not indicate the split frequency on the main VFO readout, however they do have an Icon, or another means to indicate split. It depends on the rig you have at the time.

You do not want to be tagged as a lid by calling on a DX stations frequency or have some self appointed band cop making crude and rude remarks directed toward you. Make sure you have the method down and you can easily try this with a friend, once you get the procedure in your head, you are ready for some split operation and working some rare DX!

One more item of mention, if your rig has a sub receiver, use it, listen on the DX frequency, move your VFO to where ever and it could not be easier. Take your choice as to how you do it.