[BC] sports audio feed

[Mike McCarthy]

  For field to station use, the base station RX antenna with any gain 
will be HUGE!!!  A 4 bay cardioid leg mounted loop antenna will be 
around 130ft.  How many stations are going to spend upwards of $8K to 
buy and install a gain HF RPU antenna (before even factoring pattern, 
line and loading issues).

Heck, even an Avanti Sigma 5/8 is a whale of an antenna to be mounted on 
a tower...and it's by no means durable.  Plus that pattern will be 
rather cardioid even with a 9 ft. sidearm.

Conversely, a field receive antenna is SO inefficient at that range 
UNLESS you can somehow get it to around 45 deg. At 12 meters, that's 
something around 5ft.

Now for a vehicle which has a roof or even trunk to put an antenna, 
that's one thing.  But I certainly would not want a 60" whip on top of 
my van to slam against every tree branch, drive through overhang, or low 
bridge one might encounter while mobiling around town.  Just look at any 
state vehicle which still uses 30-50Mhz systems for regional mobile 
coverage.  Just about everyone I've seen (if you can find them today) 
has a bent antenna at the top.

It's a fair balance to be certain and much the same as AM (as well as 
LORAN)has faced over the years with it's incredibly short RX length to 
freq. antenna ratio. Many early stations wanted super powers to overcome 
the inefficient receive antennas.  This specific instance is the same.

While you can certainly gain a fair amount of groundwave coverage by 
going to HF IFB, your RX will need to be equally effective.  Otherwise, 
what's the point when a high-band VHF IFB will do much the same within 
50 miles, but with smaller and far more efficient antennas.

MM

On 11/28/2010 12:23 AM, Broadcast List USER wrote:
> On Nov 27, 2010, at 11:40 PM, Tom Spencer wrote:
>
>> You know, this scenario is quite possibly able to be addressed by a
>> high-powered HF "Marti" on 26.95 MHz or so.  100 w into even a whip;
>> should get a hundred miles or so out of it.
> Tom Spencer
> Cool idea.
>
> The equipment is NOT hard to find, even at surplus.
>
> A LOT of 300 Watt base stations are now available since many low band
> paging companies have gone under.
>
> I have never thought of using those transmitters for RPU, but for IFB,
> very cool, and not something that doesn't go where needed.
>
> --chip
>