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<body class='hmmessage'><div dir='ltr'>1 - Matching is relatively simple.<div>2 - Power-handling capacity is not - an ATU must be capable of reliably dealing with 1kW in order to to give Ofcom's maximum permitted EMRP of 70W.</div><div>3 - Ensuring an efficient radiation pattern with a low-budget non-resonant length antenna is virtually impossible - it's a matter of an expensive and lengthy trial-and-error exercise.</div><div>Conclusion?<br>Generation of AM MW is simple and relatively cheap.</div><div>Getting it to the Customer is not - it's an entirely different ball game<br><br><div><div style="color:rgb(34, 34, 34);font-family:arial, sans-serif;font-size:12.8000001907349px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;widows:1;word-spacing:0px;background-color:rgb(255, 255, 255);"><font size="3"><b>Ian Hickling</b><br></font></div><font style="color:rgb(34, 34, 34);font-family:arial,sans-serif;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;widows:1;word-spacing:0px;background-color:rgb(255, 255, 255);font-size:12pt;" size="3"><font style="color:rgb(34, 34, 34);background-color:rgb(255, 255, 255);">Partner</font></font><br><br><a href="http://www.transplanuk.com/" target="_blank" style="color:rgb(17, 85, 204);"><img alt="" src="https://ci4.googleusercontent.com/proxy/2SkDsnIzSZgRbNnNKBSiwxiFhFQWRGV55mTjVL23fulnJpstZmYxeKrrYefY4qxiSgkMrAETld64XINLXCsujE_zI5gAsQyWeCWvHixcrNYtar3Sij4YlVBgN2NSQ-n2DsgZvrnpWZlfwCQ=s0-d-e1-ft#http://www.transplanuk.com/wp-content/uploads/2014/07/transplan_UK_weblogo_190x60.png"></a><div style="color:rgb(34, 34, 34);font-family:arial, sans-serif;font-size:12.8000001907349px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;widows:1;word-spacing:0px;"><i><font size="3">Office: 01635 578435 (7am-11pm UK time)</font></i></div><div style="color:rgb(34, 34, 34);font-family:arial, sans-serif;font-size:12.8000001907349px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;widows:1;word-spacing:0px;"><i><font size="3">Carphone: 07530 980115 (only responds when driving)</font></i></div><div style="color:rgb(34, 34, 34);font-family:arial, sans-serif;font-size:12.8000001907349px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;widows:1;word-spacing:0px;"><i><font size="3">6 Horn Street, Compton, NEWBURY, RG20 6QS</font></i></div></div><br><br><div><hr id="stopSpelling">Date: Tue, 15 Sep 2015 08:16:55 +0100<br>From: ravensound@pilgrimsound.co.uk<br>To: cma-l@mailman.commedia.org.uk<br>Subject: Re: [cma-l] AMCR<br><br>
<div class="ecxmoz-cite-prefix">Hello Marc et al,<br>
<br>
I mentioned DRM on AM because it would be easily implemented in a
software box. I think the Talk 107 test used two programme
channels on one FM carrier. In fact the main issue with medium
wave is getting a stable earth system without ploughing a field!
Antennas can be short (most RSLs use them) but they aren't very
efficient due to being very small impedance compared to the
ground. As has been pointed out this isn't a problem if you can
site the antenna in (or on) water. I wondered if given that SDR
requires an rf box maybe a clever designer could come up with a
low impedance amp that could include matching directly connected
to the vertical antenna sitting on a ground plane.<br>
<br>
Regards, Tony<br>
<br>
<br>
On 14/09/15 22:37, Marc Steele wrote:<br>
</div>
<blockquote cite="mid:CACHRDZDhVFQmamcWJSaYkijVtVP4v2EMQ_3ZXRHRPLirgmZzzA@mail.gmail.com">
<div dir="ltr">Hello,
<div><br>
</div>
<div>It's seems entirely feasible that you could build a basic
AM transmitter with SDR technology. Even taking on DRM should
be feasible.</div>
<div><br>
</div>
<div>However, at the frequencies used, you still have the
antenna problem (they need to be larger to match the longer
wavelength) and tuning units to worry about. Well, that and
all the other practical issues Ian mentioned earlier.</div>
<div><br>
</div>
<div>Wasn't there some DRM experiments done a few years back on
the old Talk 107 frequency in Edinburgh? IIRC, coverage was on
a par with analogue FM but the quality wasn't great (it was a
trade-off between the two).</div>
<div><br>
</div>
<div>Regards,</div>
<div><br>
</div>
<div>Marc.</div>
</div>
<div class="ecxgmail_extra"><br>
<div class="ecxgmail_quote">On 14 September 2015 at 19:53, Tony
Bailey <span dir="ltr"><<a href="mailto:ravensound@pilgrimsound.co.uk" target="_blank">ravensound@pilgrimsound.co.uk</a>></span>
wrote:<br>
<blockquote class="ecxgmail_quote">
<div>
<div>Reading this thread may explain why none of the last
London tranche AM licensees (new not existing) got on
the air. There are a number of LRSLs around the country
on AM although of course they only have to radiate 1
Watt. Maybe it's a job for the SDR black box brigade to
take on now that they've finished playing with DAB? DRM
anyone?<br>
<br>
Regards, Tony Bailey<br>
<br>
<br>
<br>
On 14/09/15 15:11, Ian Hickling wrote:<br>
</div>
<blockquote>
<div dir="ltr">Hi Shankar
<div>The point I am making is that in awarding an AM
Community Radio Licence, Ofcom should as a matter if
conscience and indeed good business practice make
sure that the Licensee is fully aware of the
additional costs and hazards over and above those
known and anticipated for the much simpler and
better-publicised FM platform.<br>
These are, I suggest:</div>
<div>
<ul>
<li><span>Few installation companies</span></li>
<li><span>Few experts with suitable knowledge and
experience</span></li>
<li><span>Poor listener acceptability</span></li>
<li><span>Poor licensing record - only 5 out of a
total of 274 UK awards</span></li>
<li><span>Low receiver availability</span></li>
<li><span>Lower audio quality</span></li>
<li><span>Subject to overseas interference outside
daylight hours</span></li>
<li><span>Unpredictable coverage</span></li>
<li><span>Very large and expensive antenna</span></li>
<li><span>Requirement for specific site size and
features</span></li>
<li><span>Low availability of UK-produced
transmitters</span></li>
<li><span>Low availability of suitable Aerial
Tuning Units.</span></li>
<li><span>Higher price for transmitters and
ancilliaries</span></li>
<li><span>Uncertainty as to CE-marking of imported
equipment</span></li>
</ul>
<div>Do I need to go on?<br>
Please - somebody correct me if you disagree?</div>
</div>
<div><br>
<div>
<div><b>Ian Hickling</b><br>
</div>
Partner<br>
<br>
<a href="http://www.transplanuk.com/" target="_blank"><img alt=""></a>
<div><i>Office: 01635 578435 (7am-11pm UK time)</i></div>
<div><i>Carphone: 07530 980115 (only responds when
driving)</i></div>
<div><i>6 Horn Street, Compton, NEWBURY, RG20 6QS</i></div>
</div>
<br>
<br>
<div>
<hr><br>
</div>
</div>
</div>
</blockquote>
</div>
</blockquote>
</div>
</div>
</blockquote>
<br>
<pre class="ecxmoz-signature">--
Local Reports at <a class="ecxmoz-txt-link-freetext" href="http://www.ravensound.pilgrimsound.co.uk" target="_blank">http://www.ravensound.pilgrimsound.co.uk</a></pre>
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