Hi Michael-
Last time you & I talked (about 3 months ago) you said you were running
amateur grade gear on your IRLP node at the KOIN-TV tower. Apparently you
recently changed to commercial grade gear, which is a good thing! Also, the
last time you & I talked you REFUSED the suggestion of using cavity filters on
your transmittes because it would prevent you from being frequency agile.
Apparently you decided to change this also?
Those are good moves, Michael. Those actions will go a long way to resolving
the interference problems that have been associated with your IRLP node.
Perhaps, that is all that was needed!
But I really think you should re-check your deviation reports. The repeaters
in this area are not running 6 KHz deviation. Good amateur practice for
practically all voice repeaters is about 4.5 KHz deviation or no more than 5
Khz MAX. Your suggestion of 6 KHz deviation is roughly 20-25% over. On the
other hand, that is far better than the 9 KHz deviation for your system (as
checked by "Dalcomm") as you stated in your previous e-mail to me a few months
ago. I have attached that e-mail immediately below.
------ Original Message ------
>Received: 03 September 2004
>From: "mbloom0947" <[EMAIL PROTECTED]>
>Dear John, Thank you for your response. Actually, we did use a radio
>communications company called Dalcomm Communications, who are very
>experienced in this sort of thing and quite well equipped. I checked >back
with them and learned that the PEAK deviation (not the average) was >9 KHz. Of
course the average deviation would depend upon an integration >of the signal
over time and would be dependent upon the nature of the >source audio. I do
appreciate your offer to do the measurements and >acknowledge that you have
made this kind offer in the past. The reason >I chose to use Dalcomm was that
I wanted the measurements to be made by >an independent company with no
preconceived notions whose only interest >is to provide accurate result.
Sincerely Michael Bloom W7RAT
------ Original Message ------
Received: Tue, 21 Dec 2004 04:55:31 PM CST
From: "mbloom0947" <[EMAIL PROTECTED]>
> Since I am the "guy running the IRLP node" you refer to, I thought I
> might take a moment to reply.
>
> The equipment now consists solely of Motorola GM300's, not amateur
> grade equipment. For the last six months or more both the 2m and
> 440 transmitters have had large cavity filters in place. I believe
> you may still be thinking of the original experimental equipment used
> for proof of concept. The 2m cavity is a Sinclair 10" diameter
> unit. As for the deviation I have measured it with a Motorola Model
> 2600 service monitor at 6 KHz, about the same as other repeaters in
> this area. The node can be heard 100 miles away in some directions
> by mobiles and those same mobiles running 75 watts, about the same as
> the node transmitter output, can be heard as well. As for the
> frequency, I'm running a SIMPLEX node on a SIMPLEX frequency.
>
> I just thought I'd bring you up to date and suggest that you check
> your facts next time.
>
> Sincerely,
> Michael Bloom W7RAT
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