[Elecraft] RX antenna & carrier-operated relay

[Fabio IZ4AFW / NZ1W]

Jim,
    thanks for the info about the VE3DO loop, I'll check OK1RR webpage out.
My short beverage runs away from the tower, starting about 5 meters from 
it and going towards USA (NW). Unfortunately I don't have much more 
space to relocate the beverage farther away.
My idea was to ask adding a menu option that automatically switches off 
the RX-ant input when the operator pushes the ptt, as usually the 
single-op doesn't need to keep it connected while transmitting. Of 
course it should also re-enable it at the end of the tx if needed.
I know that an external relay is easy to use, but this could come for 
free when a new firmware is released.

Ciao,
  Fabio
  IZ4AFW / IO4W / NZ1W


Il 05.03.2017 00:05, Jim Brown ha scritto:
> Fabio,
>
> You've seen my antenna farm -- Beverages run within 20-30 ft of my 
> 160M TX antenna facing NE. Beverages feed a DX Eng preamp before going 
> the sub-RX. I don't do anything special to protect the radio, but it 
> does occasionally protect itself. I also use the Beverages on 80, 40, 
> and 30M, but TX antennas are much farther away (more than 100 ft). 
> This is at 1.5 kW with a Ten Tec tube amp.
>
> BTW -- I just added a pair of VE3DO loops tuned for 160M and aimed to 
> EU.  Each loop is a rectangle 40 ft long and 10 ft vertical, with the 
> bottom wire 2 ft off the ground and fed at the center. Details on 
> OK1RR's website. The two loops are spaced 5/8 wavelength (350 ft). You 
> probably don't have room for two loops, but you might fit one of them.
>
> 73, Jim K9YC
>
> On Sat,3/4/2017 2:11 PM, Fabio IZ4AFW / NZ1W wrote:
>> Hi Dave,
>>     thanks for the suggestion.
>> I tried doing a quick measure using a cross-needle SWR meter today,
>> using the lowest setting.
>> On 40m the power appears to just deflect the needle, well below the 0.5W
>> mark. Probably I could say less than 250mW, maybe 100mW.
>> I usually have an external relay in a box to disconnect the RX antennas
>> while transmitting, but not today.
>> I was thinking why the RX antennas remain connected when transmitting if
>> there's not another use in a typical single-op station.
>>
>> Thanks,
>> Ciao
>> Fabio
>>   IZ4AFW / IO4W / NZ1W
>>
>>
>> Il 04.03.2017 13:12, David Olean ha scritto:
>>> Hello Fabio
>>>
>>>      I have two beverages  that are somewhat close to my TX antenna. 
>>> One
>>> had about 75 mw on it during TX while beverage #2 had about 1 watt! 
>>> This
>>> is enough power to cause damage to preamps, so I made two power 
>>> limiters
>>> and now the inputs are clipped at about 0 dBm. All it took was two
>>> transformers and two diodes in a box. Do you know what the power level
>>> is on your beverage during transmit periods?  Really high power levels
>>> could burn up the transformers.  Disconnecting the antenna is a good
>>> idea too.
>>>
>>> Dave K1WHS
>>>
>>>
>>> On 3/4/2017 9:53 AM, Fabio IZ4AFW / NZ1W wrote:
>>>> Hi guys,
>>>>      I was thinking of a possible firmware improvement related to the
>>>> carrier operated relay.
>>>> I use my radio on a small lot and recently I added a short beverage
>>>> antenna for low-bands receiving. My main activity is single-op
>>>> contesting.
>>>> Because of the interaction between the tx antennas and the 
>>>> beverage, on
>>>> some bands I have the COR (carrier operated relay) activating when 
>>>> I use
>>>> high power.
>>>> I know the good solutions, but my point is different.
>>>> As I have the COR activating only when the RX Ant input is 
>>>> selected, why
>>>> doesn't the K3 firmware disable it when pushing the ptt?
>>>>
>>>> In fact, when I push the ptt I don't need the RX-ant part to be 
>>>> active,
>>>> as I'm transmitting, and -at least in my setup- I have no other
>>>> rigs/devices that need that input (I mean, no in-band receivers and so
>>>> on).
>>>> Instead of using external relays (ptt-activated) that cut out the rx
>>>> input when I am transmitting, why the K3 firmware just doesn't disable
>>>> the RX ant input on its own (and re-enables it if needed when 
>>>> releasing
>>>> the ptt)?
>>>> Maybe I'm missing something here, or that could be a nice improvement
>>>> for a next firmware release.
>>>>
>>>> Thanks for any comment,
>>>> Ciao 73
>>>>    Fabio
>>>>    IZ4AFW / IO4W / NZ1W
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to iz4afw at iz4afw.org