[600MRG] Emergency Traffic on 630m

[Ed Cole]

John,

This experience repeats what Laurence-KL7L and I did the summer of 2012 
as experimental licensees on 495-KHz

I would transmit 100w at the transmitter with est 4w EIRP and Laurence 
would receive it about 70 miles north showing 35 dB above noise solid 
signals every time.  We sked at noon every Saturday for most of the summer.

I was using a 43-foot high by 130-foot inverted-L with two parallel 
wires separated 2-foot.  I had three radial of 2-foot chicken wire laid 
on the ground 50 to 70-foot long.  Fourth radial was my 120-foot run of 
1-5/8 inch hardline from support tower to the house (shield grounded at 
both ends).

That 50-foot support tower came down in high winds a year ago so I 
decided to run my 80m dipole with ladder line strung at 40-foot in a T 
configuration with ladder line shorted and fed by a large base coil 
(essentially the same antenna as you used).  Things didn't get done this 
year.

I plan to run a 40m dipole at right angles to the 80m dipole feed point 
so both will act as top loading the T configuration.  I plan to "plant" 
up to 8 radial wires in the lawn by splitting the sod with an axe and 
pushing the wire into the slot that results.  Hope to have that working 
by end of next summer.

I think most of the HF emergency comms are using a digital mode.  That 
would work on 630m but how much spectrum would it occupy on 630m?

Biggest challenge for 630m is the antenna.  A 40-foot high T would be no 
more challenge than setting a HF antenna during FD.  Ground radials 
would probably take the most effort/time.

100% reliable range should extend to maybe 200-miles (or more?).  CW 
would be simple but running a digital mode more useful as text could be 
printed at either end.  I was involved in professional emcomm at my 
workplace 1994-2009 (Head of Comm dept.).

73, Ed - KL7UW (ex WD2XSH-45)
http://www.kl7uw.com/630m.htm

On 11/30/2021 9:54 AM, John Langridge wrote:
> Hi Warren,
> 
> 
> About 3 years ago KE7A and I exchanged radiogram traffic on CW between
> one another at field day.  At the time we were about 100 miles apart
> and we were both using a Monitor Sensors transverter (50w), bucket
> coil (that went to WM3M after the event) and a ladder line fed dipole
> that this particular club's field day site was using on their CW
> station.  I temporarily configured it as a Martconi T, about 40 foot
> tall with just a very minimal number of radials.  I would have to look
> at my notes for estimated EIRP but it was very low but there were no
> problems in passing the traffic, even with summer noise and storms
> that were in the area, as I recall.
> 
> We exchanged three pieces of traffic and I used it as a topic for a CQ
> article on tactical comms on 630m.  UTC notification had been
> submitted for the site of the exercise about 6 months prior.
> 
> I can tell you that it has been a hard sell to the traffic folks since
> it requires a little more effort than the typical plug and play ham
> radio and we really aren't doing anything on the mechanical side in
> software...  It's just good old-fashion radio.
> 
> I can't say that this exercise  had any influence but I was encouraged
> to see the RRI folks talking about prospects of doing the same
> scenario on 160m  using the same type of setup just a few months after
> my article went to press.  SO perhaps there are some "baby steps" at
> play.  I should have followed up at the time and asked a few more
> questions to them but I did not.
> 
> Traffic handling is changing a lot and has been for quite some time.
> I tried to offer this exercise from the perspective  of just another
> tool in the bag for a traffic handler that wanted to be really
> prepared.  Whether it hit home or "stuck", I can't say.  As a
> semi-regular op on a state level CW traffic net, I can tell you that
> no one has ever asked me to QSY to 630m to pass a piece of traffic but
> I would be happy to if they ask.
> 
> So in summary, we did it on 630m to show it could be done with minimal
> hardware and that value could be realized from doing it (in this case
> the recipient received their traffic).  Had there been a real
> emergency, we could have done it.  Ground wave was stable and strong
> enough and we didn't have to compete with QRO stations during the
> field day period on HF to send the same traffic.  Obviously no
> emergency in this case, but like most traffic nets, they are training
> opportunities.
> 
> Just my perspective.
> 
> 73,
> 
> John KB5NJD..
> 
> 
> 
> 
> 
> 
> 
> 
> 
> On 11/30/21, Warren Ziegler <wd2xgj at gmail.com> wrote:
>> It's been some years now since U.S. Amateurs have been allowed to use the
>> 472-479 KHz band. The justification was that it would be useful for
>> emergency traffic. Just wondering how many of you have handled emergency
>> comms on 630m? If so, can you provide details on the nature of the
>> emergency and why you chose 630m to pass the traffic?
>>
>> Tnx & 73 Warren K2ORS
>>
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